1
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Ma Y, Jie H, Zhao L, He P, Lv X, Xu Y, Zhang Y, Xing H, Jie Y. BnXTH1 regulates cadmium tolerance by modulating vacuolar compartmentalization and the cadmium binding capacity of cell walls in ramie (Boehmeria nivea). J Hazard Mater 2024; 470:134172. [PMID: 38569340 DOI: 10.1016/j.jhazmat.2024.134172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 04/05/2024]
Abstract
Xyloglucan endotransglucosylase/hydrolases (XTH) are cell wall-modifying enzymes important in plant response to abiotic stress. However, the role of XTH in cadmium (Cd) tolerance in ramie remains largely unknown. Here, we identified and cloned BnXTH1, a member of the XTH family, in response to Cd stress in ramie. The BnXTH1 promoter (BnXTH1p) demonstrated that MeJA induces the response of BnXTH1p to Cd stress. Moreover, overexpressing BnXTH1 in Boehmeria nivea increased Cd tolerance by significantly increasing the Cd content in the cell wall and decreasing Cd inside ramie cells. Cadmium stress induced BnXTH1-expression and consequently increased xyloglucan endotransglucosylase (XET) activity, leading to high xyloglucan contents and increased hemicellulose contents in ramie. The elevated hemicellulose content increased Cd chelation onto the cell walls and reduced the level of intracellular Cd. Interestingly, overexpressing BnXTH1 significantly increased the content of Cd in vacuoles of ramie and vacuolar compartmentalization genes. Altogether, these results evidence that Cd stress induced MeJA accumulation in ramie, thus, activating BnXTH1 expression and increasing the content of xyloglucan to enhance the hemicellulose binding capacity and increase Cd chelation onto cell walls. BnXTH1 also enhances the vacuolar Cd compartmentalization and reduces the level of Cd entering the organelles and soluble solution.
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Affiliation(s)
- Yushen Ma
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China; Hunan Academy of Forestry, Changsha 410004, Hunan, China
| | - Hongdong Jie
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Long Zhao
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Pengliang He
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Xueying Lv
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Yan Xu
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Ying Zhang
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Hucheng Xing
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China; Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Changsha 410128, China
| | - Yucheng Jie
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China; Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Changsha 410128, China.
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2
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Orr A, Wickner W. Sec18 binds the tethering/SM complex HOPS to engage the Qc-SNARE for membrane fusion. Mol Biol Cell 2024; 35:ar71. [PMID: 38536444 DOI: 10.1091/mbc.e24-02-0060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2024] Open
Abstract
Membrane fusion is regulated by Rab GTPases, their tethering effectors such as HOPS, SNARE proteins on each fusion partner, SM proteins to catalyze SNARE assembly, Sec17 (SNAP), and Sec18 (NSF). Though concentrated HOPS can support fusion without Sec18, we now report that fusion falls off sharply at lower HOPS levels, where direct Sec18 binding to HOPS restores fusion. This Sec18-dependent fusion needs adenine nucleotide but neither ATP hydrolysis nor Sec17. Sec18 enhances HOPS recognition of the Qc-SNARE. With high levels of HOPS, Qc has a Km for fusion of a few nM. Either lower HOPS levels, or substitution of a synthetic tether for HOPS, strikingly increases the Km for Qc to several hundred nM. With dilute HOPS, Sec18 returns the Km for Qc to low nM. In contrast, HOPS concentration and Sec18 have no effect on Qb-SNARE recognition. Just as Qc is required for fusion but not for the initial assembly of SNAREs in trans, impaired Qc recognition by limiting HOPS without Sec18 still allows substantial trans-SNARE assembly. Thus, in addition to the known Sec18 functions of disassembling SNARE complexes, oligomerizing Sec17 for membrane association, and allowing Sec17 to drive fusion without complete SNARE zippering, we report a fourth Sec18 function, the Sec17-independent binding of Sec18 to HOPS to enhance functional Qc-SNARE engagement.
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Affiliation(s)
- Amy Orr
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755-3844
| | - William Wickner
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755-3844
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3
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Mellouk N, Lensen A, Lopez-Montero N, Gil M, Valenzuela C, Klinkert K, Moneron G, Swistak L, DiGregorio D, Echard A, Enninga J. Post-translational targeting of Rab35 by the effector IcsB of Shigella determines intracellular bacterial niche formation. Cell Rep 2024; 43:114034. [PMID: 38568808 DOI: 10.1016/j.celrep.2024.114034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 11/12/2023] [Accepted: 03/18/2024] [Indexed: 04/05/2024] Open
Abstract
Escape from the bacterial-containing vacuole (BCV) is a key step of Shigella host cell invasion. Rab GTPases subverted to in situ-formed macropinosomes in the vicinity of the BCV have been shown to promote its rupture. The involvement of the BCV itself has remained unclear. We demonstrate that Rab35 is non-canonically entrapped at the BCV. Stimulated emission depletion imaging localizes Rab35 directly on the BCV membranes before vacuolar rupture. The bacterial effector IcsB, a lysine Nε-fatty acylase, is a key regulator of Rab35-BCV recruitment, and we show post-translational acylation of Rab35 by IcsB in its polybasic region. While Rab35 and IcsB are dispensable for the first step of BCV breakage, they are needed for the unwrapping of damaged BCV remnants from Shigella. This provides a framework for understanding Shigella invasion implicating re-localization of a Rab GTPase via its bacteria-dependent post-translational modification to support the mechanical unpeeling of the BCV.
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Affiliation(s)
- Nora Mellouk
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France.
| | - Arthur Lensen
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France
| | - Noelia Lopez-Montero
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France
| | - Magdalena Gil
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France
| | - Camila Valenzuela
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France
| | - Kerstin Klinkert
- Institut Pasteur, Université de Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 75015 Paris, France
| | - Gael Moneron
- Institut Pasteur, CNRS UMR3571, Synapse and Circuit Dynamics Unit, 75015 Paris, France
| | - Léa Swistak
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France
| | - David DiGregorio
- Institut Pasteur, CNRS UMR3571, Synapse and Circuit Dynamics Unit, 75015 Paris, France
| | - Arnaud Echard
- Institut Pasteur, Université de Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 75015 Paris, France
| | - Jost Enninga
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France.
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4
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Lehman SS, Williamson CD, Tucholski T, Ellis NA, Bouchard S, Jarnik M, Allen M, Nita-Lazar A, Machner MP. The Legionella pneumophila effector DenR hijacks the host NRas proto-oncoprotein to downregulate MAPK signaling. Cell Rep 2024; 43:114033. [PMID: 38568811 DOI: 10.1016/j.celrep.2024.114033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 01/17/2024] [Accepted: 03/18/2024] [Indexed: 04/05/2024] Open
Abstract
Small GTPases of the Ras subfamily are best known for their role as proto-oncoproteins, while their function during microbial infection has remained elusive. Here, we show that Legionella pneumophila hijacks the small GTPase NRas to the Legionella-containing vacuole (LCV) surface. A CRISPR interference screen identifies a single L. pneumophila effector, DenR (Lpg1909), required for this process. Recruitment is specific for NRas, while its homologs KRas and HRas are excluded from LCVs. The C-terminal hypervariable tail of NRas is sufficient for recruitment, and interference with either NRas farnesylation or S-acylation sites abrogates recruitment. Intriguingly, we detect markers of active NRas signaling on the LCV, suggesting it acts as a signaling platform. Subsequent phosphoproteomics analyses show that DenR rewires the host NRas signaling landscape, including dampening of the canonical mitogen-activated protein kinase pathway. These results provide evidence for L. pneumophila targeting NRas and suggest a link between NRas GTPase signaling and microbial infection.
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Affiliation(s)
- Stephanie S Lehman
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chad D Williamson
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Trisha Tucholski
- Functional Cellular Networks Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nicole A Ellis
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sabrina Bouchard
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michal Jarnik
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Morgan Allen
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Aleksandra Nita-Lazar
- Functional Cellular Networks Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Matthias P Machner
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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5
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Kenney LJ. Peeling the onion: additional layers of regulation in the acid stress response. J Bacteriol 2024; 206:e0006924. [PMID: 38488356 PMCID: PMC11025319 DOI: 10.1128/jb.00069-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2024] Open
Abstract
Bacteria are capable of withstanding large changes in osmolality and cytoplasmic pH, unlike eukaryotes that tightly regulate their pH and cellular composition. Previous studies on the bacterial acid stress response described a rapid, brief acidification, followed by immediate recovery. More recent experiments with better pH probes have imaged single living cells, and we now appreciate that following acid stress, bacteria maintain an acidic cytoplasm for as long as the stress remains. This acidification enables pathogens to sense a host environment and turn on their virulence programs, for example, enabling survival and replication within acidic vacuoles. Single-cell analysis identified an intracellular pH threshold of ~6.5. Acid stress reduces the internal pH below this threshold, triggering the assembly of a type III secretion system in Salmonella and the secretion of virulence factors in the host. These pathways are significant because preventing intracellular acidification of Salmonella renders it avirulent, suggesting that acid stress pathways represent a potential therapeutic target. Although we refer to the acid stress response as singular, it is actually a complex response that involves numerous two-component signaling systems, several amino acid decarboxylation systems, as well as cellular buffering systems and electron transport chain components, among others. In a recent paper in the Journal of Bacteriology, M. G. Gorelik, H. Yakhnin, A. Pannuri, A. C. Walker, C. Pourciau, D. Czyz, T. Romeo, and P. Babitzke (J Bacteriol 206:e00354-23, 2024, https://doi.org/10.1128/jb.00354-23) describe a new connection linking the carbon storage regulator CsrA to the acid stress response, highlighting new additional layers of complexity.
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Affiliation(s)
- Linda J. Kenney
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch Galveston, Galveston, Texas, USA
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6
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Zack SR, Venkatesan M, Nikolaienko R, Cook B, Melki R, Zima AV, Campbell EM. Altered vacuole membrane protein 1 (VMP1) expression is associated with increased NLRP3 inflammasome activation and mitochondrial dysfunction. Inflamm Res 2024; 73:563-580. [PMID: 38411635 DOI: 10.1007/s00011-024-01856-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 12/26/2023] [Accepted: 01/26/2024] [Indexed: 02/28/2024] Open
Abstract
BACKGROUND Altered expression of vacuole membrane protein 1 (VMP1) has recently been observed in the context of multiple sclerosis and Parkinson's disease (PD). However, how changes in VMP1 expression may impact pathogenesis has not been explored. OBJECTIVE This study aimed to characterize how altered VMP1 expression affects NLRP3 inflammasome activation and mitochondrial function. METHODS VMP1 expression was depleted in a monocytic cell line using CRISPR-Cas9. The effect of VMP1 on NLRP3 inflammasome activation was examined by stimulating cells with LPS and ATP or α-synuclein fibrils. Inflammasome activation was determined by caspase-1 activation using both a FLICA assay and a biosensor as well as by the release of proinflammatory molecules measured by ELISA. RNA-sequencing was utilized to define global gene expression changes resulting from VMP1 deletion. SERCA activity and mitochondrial function were investigated using various fluorescence microscopy-based approaches including a novel method that assesses the function of individual mitochondria in a cell. RESULTS Here, we report that genetic deletion of VMP1 from a monocytic cell line resulted in increased NLRP3 inflammasome activation and release of proinflammatory molecules. Examination of the VMP1-dependent changes in these cells revealed that VMP1 deficiency led to decreased SERCA activity and increased intracellular [Ca2+]. We also observed calcium overload in mitochondria in VMP1 depleted cells, which was associated with mitochondrial dysfunction and release of mitochondrial DNA into the cytoplasm and the extracellular environment. CONCLUSIONS Collectively, these studies reveal VMP1 as a negative regulator of inflammatory responses, and we postulate that decreased expression of VMP1 can aggravate the inflammatory sequelae associated with neurodegenerative diseases like PD.
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Affiliation(s)
- Stephanie R Zack
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Meghana Venkatesan
- Department of Integrative Cell Biology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Roman Nikolaienko
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Ben Cook
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Ronald Melki
- Institut Francois Jacob (MIRCen), CEA, CNRS, 92260, Fontenay-Aux-Roses, France
| | - Aleksey V Zima
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Edward M Campbell
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, 60153, USA.
- Department of Integrative Cell Biology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, 60153, USA.
- Department of Neuroscience, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, 60153, USA.
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7
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Zhao XY, Lempke SL, Urbán Arroyo JC, Brown IG, Yin B, Magaj MM, Holness NK, Smiley J, Redemann S, Ewald SE. iNOS is necessary for GBP-mediated T. gondii clearance in murine macrophages via vacuole nitration and intravacuolar network collapse. Nat Commun 2024; 15:2698. [PMID: 38538595 PMCID: PMC10973475 DOI: 10.1038/s41467-024-46790-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 03/04/2024] [Indexed: 04/02/2024] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite of rodents and humans. Interferon-inducible guanylate binding proteins (GBPs) are mediators of T. gondii clearance, however, this mechanism is incomplete. Here, using automated spatially targeted optical micro proteomics we demonstrate that inducible nitric oxide synthetase (iNOS) is highly enriched at GBP2+ parasitophorous vacuoles (PV) in murine macrophages. iNOS expression in macrophages is necessary to limit T. gondii load in vivo and in vitro. Although iNOS activity is dispensable for GBP2 recruitment and PV membrane ruffling; parasites can replicate, egress and shed GBP2 when iNOS is inhibited. T. gondii clearance by iNOS requires nitric oxide, leading to nitration of the PV and collapse of the intravacuolar network of membranes in a chromosome 3 GBP-dependent manner. We conclude that reactive nitrogen species generated by iNOS cooperate with GBPs to target distinct structures in the PV that are necessary for optimal parasite clearance in macrophages.
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Affiliation(s)
- Xiao-Yu Zhao
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Samantha L Lempke
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jan C Urbán Arroyo
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Isabel G Brown
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Bocheng Yin
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Magdalena M Magaj
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Nadia K Holness
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jamison Smiley
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Stefanie Redemann
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Sarah E Ewald
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA.
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8
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Schroeder EA, Toro-Moreno M, Raphemot R, Sylvester K, Colón IC, Derbyshire ER. Toxoplasma and Plasmodium associate with host Arfs during infection. mSphere 2024; 9:e0077023. [PMID: 38349168 PMCID: PMC10964417 DOI: 10.1128/msphere.00770-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 01/17/2024] [Indexed: 03/27/2024] Open
Abstract
The apicomplexans Toxoplasma gondii and Plasmodium are intracellular parasites that reside within a host-derived compartment termed the parasitophorous vacuole (PV). During infection, the parasites must acquire critical host resources and transport them across their PV for development. However, the mechanism by which host resources are trafficked to and across the PV remains uncertain. Here, we investigated host ADP ribosylation factors (Arfs), a class of proteins involved in vesicular trafficking that may be exploited by T. gondii and Plasmodium berghei for nutrient acquisition. Using overexpressed Arf proteins coupled with immunofluorescence microscopy, we found that all Arfs were internalized into the T. gondii PV, with most vacuoles containing at least one punctum of Arf protein by the end of the lytic cycle. We further characterized Arf1, the most abundant Arf inside the T. gondii PV, and observed that active recycling between its GDP/GTP-bound state influenced Arf1 internalization independent of host guanine nucleotide exchange factors (GEFs). In addition, Arf1 colocalized with vesicle coat complexes and exogenous sphingolipids, suggesting a role in nutrient acquisition. While Arf1 and Arf4 were not observed inside the PV during P. berghei infection, our gene depletion studies showed that liver stage development and survival depended on the expression of Arf4 and the host GEF, GBF1. Collectively, these observations indicate that apicomplexans use distinct mechanisms to subvert the host vesicular trafficking network and efficiently replicate. The findings also pave the way for future studies to identify parasite proteins critical to host vesicle recruitment and the components of vesicle cargo. IMPORTANCE The parasites Toxoplasma gondii and Plasmodium live complex intracellular lifestyles where they must acquire essential host nutrients while avoiding recognition. Although previous work has sought to identify the specific nutrients scavenged by apicomplexans, the mechanisms by which host materials are transported to and across the parasite vacuole membrane are largely unknown. Here, we examined members of the host vesicular trafficking network to identify specific pathways subverted by T. gondii and Plasmodium berghei. Our results indicate that T. gondii selectively internalizes host Arfs, a class of proteins involved in intracellular trafficking. For P. berghei, host Arfs were restricted by the parasite's vacuole membrane, but proteins involved in vesicular trafficking were identified as essential for liver stage development. A greater exploration into how and why apicomplexans subvert host vesicular trafficking could help identify targets for host-directed therapeutics.
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Affiliation(s)
- Erin A. Schroeder
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Maria Toro-Moreno
- Department of Chemistry, Duke University, Durham, North Carolina, USA
| | - Rene Raphemot
- Department of Chemistry, Duke University, Durham, North Carolina, USA
| | - Kayla Sylvester
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Isabel C. Colón
- Department of Chemistry, Duke University, Durham, North Carolina, USA
| | - Emily R. Derbyshire
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Chemistry, Duke University, Durham, North Carolina, USA
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9
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Bitew MA, Gaete PS, Swale C, Maru P, Contreras JE, Saeij JPJ. Two Toxoplasma gondii putative pore-forming proteins, GRA47 and GRA72, influence small molecule permeability of the parasitophorous vacuole. mBio 2024; 15:e0308123. [PMID: 38380952 PMCID: PMC10936148 DOI: 10.1128/mbio.03081-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 02/01/2024] [Indexed: 02/22/2024] Open
Abstract
Toxoplasma gondii, a medically important intracellular parasite, uses GRA proteins secreted from dense granule organelles to mediate nutrient flux across the parasitophorous vacuole membrane (PVM). GRA17 and GRA23 are known pore-forming proteins on the PVM involved in this process, but the roles of additional proteins have remained largely uncharacterized. We recently identified GRA72 as synthetically lethal with GRA17. Deleting GRA72 produced similar phenotypes to Δgra17 parasites, and computational predictions suggested it forms a pore. To understand how GRA72 functions, we performed immunoprecipitation experiments and identified GRA47 as an interactor of GRA72. Deletion of GRA47 resulted in an aberrant "bubble vacuole" morphology with reduced small molecule permeability, mirroring the phenotype observed in GRA17 and GRA72 knockouts. Structural predictions indicated that GRA47 and GRA72 form heptameric and hexameric pores, respectively, with conserved histidine residues lining the pore. Mutational analysis highlighted the critical role of these histidines for protein functionality. Validation through electrophysiology confirmed alterations in membrane conductance, corroborating their pore-forming capabilities. Furthermore, Δgra47 parasites and parasites expressing GRA47 with a histidine mutation had reduced in vitro proliferation and attenuated virulence in mice. Our findings show the important roles of GRA47 and GRA72 in regulating PVM permeability, thereby expanding the repertoire of potential therapeutic targets against Toxoplasma infections. IMPORTANCE Toxoplasma gondii is a parasite that poses significant health risks to those with impaired immunity. It replicates inside host cells shielded by the PVM, which controls nutrient and waste exchange with the host. GRA72, previously identified as essential in the absence of the GRA17 nutrient channel, is implicated in forming an alternative nutrient channel. Here we found that GRA47 associates with GRA72 and is also important for the PVM's permeability to small molecules. Removal of GRA47 leads to distorted vacuoles and impairs small molecule transport across the PVM, resembling the effects of GRA17 and GRA72 deletions. Structural models suggest GRA47 and GRA72 form distinct pore structures, with a pore-lining histidine critical to their function. Toxoplasma strains lacking GRA47 or those with a histidine mutation have impaired growth and reduced virulence in mice, highlighting these proteins as potential targets for new treatments against toxoplasmosis.
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Affiliation(s)
- Mebratu A. Bitew
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Pablo S. Gaete
- Department of Physiology and Membrane Biology, University of California, Davis, California, USA
| | - Christopher Swale
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences (IAB), INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Parag Maru
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Jorge E. Contreras
- Department of Physiology and Membrane Biology, University of California, Davis, California, USA
| | - Jeroen P. J. Saeij
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA
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10
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Sanchez L, Lensen A, Connor MG, Hamon M, Enninga J, Valenzuela C. Shigella generates distinct IAM subpopulations during epithelial cell invasion to promote efficient intracellular niche formation. Eur J Cell Biol 2024; 103:151381. [PMID: 38183814 DOI: 10.1016/j.ejcb.2023.151381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 12/20/2023] [Accepted: 12/24/2023] [Indexed: 01/08/2024] Open
Abstract
The facultative intracellular pathogen Shigella flexneri invades non-phagocytic epithelial gut cells. Through a syringe-like apparatus called type 3 secretion system, it injects effector proteins into the host cell triggering actin rearrangements leading to its uptake within a tight vacuole, termed the bacterial-containing vacuole (BCV). Simultaneously, Shigella induces the formation of large vesicles around the entry site, which we refer to as infection-associated macropinosomes (IAMs). After entry, Shigella ruptures the BCV and escapes into the host cytosol by disassembling the BCV remnants. Previously, IAM formation has been shown to be required for efficient BCV escape, but the molecular events associated with BCV disassembly have remained unclear. To identify host components required for BCV disassembly, we performed a microscopy-based screen to monitor the recruitment of BAR domain-containing proteins, which are a family of host proteins involved in membrane shaping and sensing (e.g. endocytosis and recycling) during Shigella epithelial cell invasion. We identified endosomal recycling BAR protein Sorting Nexin-8 (SNX8) localized to IAMs in a PI(3)P-dependent manner before BCV disassembly. At least two distinct IAM subpopulations around the BCV were found, either being recycled back to cellular compartments such as the plasma membrane or transitioning to become RAB11A positive "contact-IAMs" involved in promoting BCV rupture. The IAM subpopulation duality was marked by the exclusive recruitment of either SNX8 or RAB11A. Hindering PI(3)P production at the IAMs led to an inhibition of SNX8 recruitment at these compartments and delayed both, the step of BCV rupture time and successful BCV disassembly. Finally, siRNA depletion of SNX8 accelerated BCV rupture and unpeeling of BCV remnants, indicating that SNX8 is involved in controlling the timing of the cytosolic release. Overall, our work sheds light on how Shigella establishes its intracellular niche through the subversion of a specific set of IAMs.
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Affiliation(s)
- Lisa Sanchez
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France
| | - Arthur Lensen
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France
| | - Michael G Connor
- Institut Pasteur, Université Paris Cité, Chromatin and Infection Unit, 75015 Paris, France
| | - Mélanie Hamon
- Institut Pasteur, Université Paris Cité, Chromatin and Infection Unit, 75015 Paris, France
| | - Jost Enninga
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France.
| | - Camila Valenzuela
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France.
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11
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Schulze-Luehrmann J, Liebler-Tenorio E, Felipe-López A, Lührmann A. Cell death induction facilitates egress of Coxiella burnetii from infected host cells at late stages of infection. Mol Microbiol 2024; 121:513-528. [PMID: 38115201 DOI: 10.1111/mmi.15210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/21/2023]
Abstract
Intracellular bacteria have evolved mechanisms to invade host cells, establish an intracellular niche that allows survival and replication, produce progeny, and exit the host cell after completion of the replication cycle to infect new target cells. Bacteria exit their host cell by (i) initiation of apoptosis, (ii) lytic cell death, and (iii) exocytosis. While bacterial egress is essential for bacterial spreading and, thus, pathogenesis, we currently lack information about egress mechanisms for the obligate intracellular pathogen C. burnetii, the causative agent of the zoonosis Q fever. Here, we demonstrate that C. burnetii inhibits host cell apoptosis early during infection, but induces and/or increases apoptosis at later stages of infection. Only at later stages of infection did we observe C. burnetii egress, which depends on previously established large bacteria-filled vacuoles and a functional intrinsic apoptotic cascade. The released bacteria are not enclosed by a host cell membrane and can infect and replicate in new target cells. In summary, our data argue that C. burnetii egress in a non-synchronous way at late stages of infection. Apoptosis-induction is important for C. burnetii egress, but other pathways most likely contribute.
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Affiliation(s)
- Jan Schulze-Luehrmann
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | | | - Alfonso Felipe-López
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Anja Lührmann
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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12
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Neuber J, Lang C, Aurass P, Flieger A. Tools and mechanisms of vacuolar escape leading to host egress in Legionella pneumophila infection: Emphasis on bacterial phospholipases. Mol Microbiol 2024; 121:368-384. [PMID: 37891705 DOI: 10.1111/mmi.15183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 09/29/2023] [Accepted: 10/06/2023] [Indexed: 10/29/2023]
Abstract
The phenomenon of host cell escape exhibited by intracellular pathogens is a remarkably versatile occurrence, capable of unfolding through lytic or non-lytic pathways. Among these pathogens, the bacterium Legionella pneumophila stands out, having adopted a diverse spectrum of strategies to disengage from their host cells. A pivotal juncture that predates most of these host cell escape modalities is the initial escape from the intracellular compartment. This critical step is increasingly supported by evidence suggesting the involvement of several secreted pathogen effectors, including lytic proteins. In this intricate landscape, L. pneumophila emerges as a focal point for research, particularly concerning secreted phospholipases. While nestled within its replicative vacuole, the bacterium deftly employs both its type II (Lsp) and type IVB (Dot/Icm) secretion systems to convey phospholipases into either the phagosomal lumen or the host cell cytoplasm. Its repertoire encompasses numerous phospholipases A (PLA), including three enzymes-PlaA, PlaC, and PlaD-bearing the GDSL motif. Additionally, there are 11 patatin-like phospholipases A as well as PlaB. Furthermore, the bacterium harbors three extracellular phospholipases C (PLCs) and one phospholipase D. Within this comprehensive review, we undertake an exploration of the pivotal role played by phospholipases in the broader context of phagosomal and host cell egress. Moreover, we embark on a detailed journey to unravel the established and potential functions of the secreted phospholipases of L. pneumophila in orchestrating this indispensable process.
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Affiliation(s)
- Jonathan Neuber
- Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany
| | - Christina Lang
- Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany
| | - Philipp Aurass
- Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany
| | - Antje Flieger
- Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany
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13
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Chatterjee A, Sepuri NBV. Methionine sulfoxide reductase 2 regulates Cvt autophagic pathway by altering the stability of Atg19 and Ape1 in Saccharomyces cerevisiae. J Biol Chem 2024; 300:105662. [PMID: 38246354 PMCID: PMC10875273 DOI: 10.1016/j.jbc.2024.105662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/31/2023] [Accepted: 01/08/2024] [Indexed: 01/23/2024] Open
Abstract
The reversible oxidation of methionine plays a crucial role in redox regulation of proteins. Methionine oxidation in proteins causes major structural modifications that can destabilize and abrogate their function. The highly conserved methionine sulfoxide reductases protect proteins from oxidative damage by reducing their oxidized methionines, thus restoring their stability and function. Deletion or mutation in conserved methionine sulfoxide reductases leads to aging and several human neurological disorders and also reduces yeast growth on nonfermentable carbon sources. Despite their importance in human health, limited information about their physiological substrates in humans and yeast is available. For the first time, we show that Mxr2 interacts in vivo with two core proteins of the cytoplasm to vacuole targeting (Cvt) autophagy pathway, Atg19, and Ape1 in Saccharomyces cerevisiae. Deletion of MXR2 induces instability and early turnover of immature Ape1 and Atg19 proteins and reduces the leucine aminopeptidase activity of Ape1 without affecting the maturation process of Ape1. Additonally, Mxr2 interacts with the immature Ape1, dependent on Met17 present within the propeptide of Ape1 as a single substitution mutation of Met17 to Leu abolishes this interaction. Importantly, Ape1 M17L mutant protein resists oxidative stress-induced degradation in WT and mxr2Δ cells. By identifying Atg19 and Ape1 as cytosolic substrates of Mxr2, our study maps the hitherto unexplored connection between Mxr2 and the Cvt autophagy pathway and sheds light on Mxr2-dependent oxidative regulation of the Cvt pathway.
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Affiliation(s)
- Arpan Chatterjee
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
| | - Naresh Babu V Sepuri
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India.
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14
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Steinbach A, Bhadkamkar V, Jimenez-Morales D, Stevenson E, Jang GM, Krogan NJ, Swaney DL, Mukherjee S. Cross-family small GTPase ubiquitination by the intracellular pathogen Legionella pneumophila. Mol Biol Cell 2024; 35:ar27. [PMID: 38117589 PMCID: PMC10916871 DOI: 10.1091/mbc.e23-06-0260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 12/04/2023] [Accepted: 12/13/2023] [Indexed: 12/22/2023] Open
Abstract
The intracellular bacterial pathogen Legionella pneumophila (L.p.) manipulates eukaryotic host ubiquitination machinery to form its replicative vacuole. While nearly 10% of L.p.'s ∼330 secreted effector proteins are ubiquitin ligases or deubiquitinases, a comprehensive measure of temporally resolved changes in the endogenous host ubiquitinome during infection has not been undertaken. To elucidate how L.p. hijacks host cell ubiquitin signaling, we generated a proteome-wide analysis of changes in protein ubiquitination during infection. We discover that L.p. infection increases ubiquitination of host regulators of subcellular trafficking and membrane dynamics, most notably ∼40% of mammalian Ras superfamily small GTPases. We determine that these small GTPases undergo nondegradative ubiquitination at the Legionella-containing vacuole (LCV) membrane. Finally, we find that the bacterial effectors SidC/SdcA play a central role in cross-family small GTPase ubiquitination, and that these effectors function upstream of SidE family ligases in the polyubiquitination and retention of GTPases in the LCV membrane. This work highlights the extensive reconfiguration of host ubiquitin signaling by bacterial effectors during infection and establishes simultaneous ubiquitination of small GTPases across the Ras superfamily as a novel consequence of L.p. infection. Our findings position L.p. as a tool to better understand how small GTPases can be regulated by ubiquitination in uninfected contexts.
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Affiliation(s)
- Adriana Steinbach
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143
- George Williams Hooper Foundation, University of California, San Francisco, CA 94143
| | - Varun Bhadkamkar
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143
- George Williams Hooper Foundation, University of California, San Francisco, CA 94143
| | - David Jimenez-Morales
- Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA 94158
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University, CA 94309
| | - Erica Stevenson
- Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA 94158
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
- Quantitative Biosciences Institute, University of California, San Francisco, CA 94158
| | - Gwendolyn M. Jang
- Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA 94158
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
- Quantitative Biosciences Institute, University of California, San Francisco, CA 94158
| | - Nevan J. Krogan
- Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA 94158
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
- Quantitative Biosciences Institute, University of California, San Francisco, CA 94158
| | - Danielle L. Swaney
- Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA 94158
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
- Quantitative Biosciences Institute, University of California, San Francisco, CA 94158
| | - Shaeri Mukherjee
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143
- George Williams Hooper Foundation, University of California, San Francisco, CA 94143
- Chan Zuckerberg Biohub, San Francisco, CA 94158
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15
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Hiller M, Diwo M, Wamp S, Gutsmann T, Lang C, Blankenfeldt W, Flieger A. Structure-function relationships underpin disulfide loop cleavage-dependent activation of Legionella pneumophila lysophospholipase A PlaA. Mol Microbiol 2024; 121:497-512. [PMID: 38130174 DOI: 10.1111/mmi.15201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 11/03/2023] [Indexed: 12/23/2023]
Abstract
Legionella pneumophila, the causative agent of a life-threatening pneumonia, intracellularly replicates in a specialized compartment in lung macrophages, the Legionella-containing vacuole (LCV). Secreted proteins of the pathogen govern important steps in the intracellular life cycle including bacterial egress. Among these is the type II secreted PlaA which, together with PlaC and PlaD, belongs to the GDSL phospholipase family found in L. pneumophila. PlaA shows lysophospholipase A (LPLA) activity which increases after secretion and subsequent processing by the zinc metalloproteinase ProA within a disulfide loop. Activity of PlaA contributes to the destabilization of the LCV in the absence of the type IVB-secreted effector SdhA. We here present the 3D structure of PlaA which shows a typical α/β-hydrolase fold and reveals that the uncleaved disulfide loop forms a lid structure covering the catalytic triad S30/D278/H282. This leads to reduction of substrate access before activation; however, the catalytic site gets more accessible when the disulfide loop is processed. After structural modeling, a similar activation process is suggested for the GDSL hydrolase PlaC, but not for PlaD. Furthermore, the size of the PlaA substrate-binding site indicated preference toward phospholipids comprising ~16 carbon fatty acid residues which was verified by lipid hydrolysis, suggesting a molecular ruler mechanism. Indeed, mutational analysis changed the substrate profile with respect to fatty acid chain length. In conclusion, our analysis revealed the structural basis for the regulated activation and substrate preference of PlaA.
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Affiliation(s)
- Miriam Hiller
- Division of Enteropathogenic Bacteria and Legionella (FG11), Robert Koch Institute, Wernigerode, Germany
| | - Maurice Diwo
- Structure and Function of Proteins, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Sabrina Wamp
- Division of Enteropathogenic Bacteria and Legionella (FG11), Robert Koch Institute, Wernigerode, Germany
| | - Thomas Gutsmann
- Research Center Borstel, Leibniz Lung Center, Division of Biophysics, Borstel, Germany
- CSSB-Centre for Structural Systems Biology, Hamburg, Germany
| | - Christina Lang
- Division of Enteropathogenic Bacteria and Legionella (FG11), Robert Koch Institute, Wernigerode, Germany
| | - Wulf Blankenfeldt
- Structure and Function of Proteins, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Antje Flieger
- Division of Enteropathogenic Bacteria and Legionella (FG11), Robert Koch Institute, Wernigerode, Germany
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16
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Qu M, Liu X, Wang X, Li Z, Zhou L, Li H. Palmitoylation of vacuole membrane protein 1 promotes small extracellular vesicle secretion via interaction with ALIX and influences intercellular communication. Cell Commun Signal 2024; 22:150. [PMID: 38403678 PMCID: PMC10895845 DOI: 10.1186/s12964-024-01529-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 02/13/2024] [Indexed: 02/27/2024] Open
Abstract
BACKGROUND Small extracellular vesicles (EVs), exemplified by exosomes, mediate intercellular communication by transporting proteins, mRNAs, and miRNAs. Post-translational modifications are involved in controlling small EV secretion process. However, whether palmitoylation regulates small EV secretion, remains largely unexplored. METHODS Vacuole Membrane Protein 1 (VMP1) was testified to be S-palmitoylated by Palmitoylation assays. VMP1 mutant plasmids were constructed to screen out the exact palmitoylation sites. Small EVs were isolated, identified and compared between wild-type VMP1 or mutant VMP1 transfected cells. Electron microscope and immunofluorescence were used to detect multivesicular body (MVB) number and morphology change when VMP1 was mutated. Immunoprecipitation and Mass spectrum were adopted to identify the protein that interacted with palmitoylated VMP1, while knock down experiment was used to explore the function of targeted protein ALIX. Taking human Sertoli cells (SCs) and human spermatogonial stem cell like cells (SSCLCs) as a model of intercellular communication, SSCLC maintenance was detected by flow cytometry and qPCR at 12 days of differentiation. In vivo, mouse model was established by intraperitoneal injection with palmitoylation inhibitor, 2-bromopalmitate (2BP) for 3 months. RESULTS VMP1 was identified to be palmitoylated at cysteine 263,278 by ZDHHC3. Specifically, palmitoylation of VMP1 regulated its subcellular location and enhanced the amount of small EV secretion. Mutation of VMP1 palmitoylation sites interfered with the morphology and biogenesis of MVBs through suppressing intraluminal vesicle formation. Furthermore, inhibition of VMP1 palmitoylation impeded small EV secretion by affecting the interaction of VMP1 with ALIX, an accessory protein of the ESCRT machinery. Taking SCs and SSCLCs as a model of intercellular communication, we discovered VMP1 palmitoylation in SCs was vital to the growth status of SSCLCs in a co-culture system. Inhibition of VMP1 palmitoylation caused low self-maintenance, increased apoptosis, and decreased proliferation rate of SSCLCs. In vivo, intraperitoneal injection of 2BP inhibited VMP1 palmitoylation and exosomal marker expression in mouse testes, which were closely associated with the level of spermatogenic cell apoptosis and proliferation. CONCLUSIONS Our study revealed a novel mechanism for small EV secretion regulated by VMP1 palmitoylation in Sertoli cells, and demonstrated its pivotal role in intercellular communication and SSC niche.
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Affiliation(s)
- Mengyuan Qu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.
- The Reproduction Medical Center, The Third Affiliated Hospital of Shenzhen University (Luohu Hospital), 47 Youyi Road, Shenzhen, 518000, Guangdong, China.
| | - Xinyu Liu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China
| | - Xiaotong Wang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China
- The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zili Li
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China
| | - Liquan Zhou
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.
| | - Honggang Li
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.
- Wuhan Huake Reproductive Medicine Hospital, Wuhan, China.
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17
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Kotani T, Yasuda Y, Nakatogawa H. Molecular Mechanism of Autophagy, Cytoplasmic Zoning by Lipid Membranes. J Biochem 2024; 175:155-165. [PMID: 37983716 DOI: 10.1093/jb/mvad099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/02/2023] [Accepted: 11/06/2023] [Indexed: 11/22/2023] Open
Abstract
Autophagy is a highly conserved intracellular degradation mechanism. The most distinctive feature of autophagy is the formation of double-membrane structures called autophagosomes, which compartmentalize portions of the cytoplasm. The outer membrane of the autophagosome fuses with the vacuolar/lysosomal membrane, leading to the degradation of the contents of the autophagosome. Approximately 30 years have passed since the identification of autophagy-related (ATG) genes and Atg proteins essential for autophagosome formation, and the primary functions of these Atg proteins have been elucidated. These achievements have significantly advanced our understanding of the mechanism of autophagosome formation. This article summarizes our current knowledge on how the autophagosome precursor is generated, and how the membrane expands and seals to complete the autophagosome.
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Affiliation(s)
- Tetsuya Kotani
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, S2-14 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan
| | - Yuri Yasuda
- School of Life Science and Technology, Tokyo Institute of Technology, S2-14 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan
| | - Hitoshi Nakatogawa
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, S2-14 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, S2-14 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan
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18
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Chang YY, Valenzuela C, Lensen A, Lopez-Montero N, Sidik S, Salogiannis J, Enninga J, Rohde J. Microtubules provide force to promote membrane uncoating in vacuolar escape for a cyto-invasive bacterial pathogen. Nat Commun 2024; 15:1065. [PMID: 38316786 PMCID: PMC10844605 DOI: 10.1038/s41467-024-45182-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 01/15/2024] [Indexed: 02/07/2024] Open
Abstract
Intracellular bacterial pathogens gain entry to mammalian cells inside a vacuole derived from the host membrane. Some of them escape the bacteria-containing vacuole (BCV) and colonize the cytosol. Bacteria replicating within BCVs coopt the microtubule network to position it within infected cells, whereas the role of microtubules for cyto-invasive pathogens remains obscure. Here, we show that the microtubule motor cytoplasmic dynein-1 and specific activating adaptors are hijacked by the enterobacterium Shigella flexneri. These host proteins were found on infection-associated macropinosomes (IAMs) formed during Shigella internalization. We identified Rab8 and Rab13 as mediators of dynein recruitment and discovered that the Shigella effector protein IpaH7.8 promotes Rab13 retention on moving BCV membrane remnants, thereby facilitating membrane uncoating of the Shigella-containing vacuole. Moreover, the efficient unpeeling of BCV remnants contributes to a successful intercellular spread. Taken together, our work demonstrates how a bacterial pathogen subverts the intracellular transport machinery to secure a cytosolic niche.
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Affiliation(s)
- Yuen-Yan Chang
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Camila Valenzuela
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France
| | - Arthur Lensen
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France
| | - Noelia Lopez-Montero
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France
| | - Saima Sidik
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada
| | - John Salogiannis
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, USA
| | - Jost Enninga
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France.
| | - John Rohde
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada.
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19
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Peterson A, Baskett C, Ratcliff WC, Burnetti A. Transforming yeast into a facultative photoheterotroph via expression of vacuolar rhodopsin. Curr Biol 2024; 34:648-654.e3. [PMID: 38218181 DOI: 10.1016/j.cub.2023.12.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 11/03/2023] [Accepted: 12/13/2023] [Indexed: 01/15/2024]
Abstract
Phototrophic metabolism, the capture of light for energy, was a pivotal biological innovation that greatly increased the total energy available to the biosphere. Chlorophyll-based photosynthesis is the most familiar phototrophic metabolism, but retinal-based microbial rhodopsins transduce nearly as much light energy as chlorophyll does,1 via a simpler mechanism, and are found in far more taxonomic groups. Although this system has apparently spread widely via horizontal gene transfer,2,3,4 little is known about how rhodopsin genes (with phylogenetic origins within prokaryotes5,6) are horizontally acquired by eukaryotic cells with complex internal membrane architectures or the conditions under which they provide a fitness advantage. To address this knowledge gap, we sought to determine whether Saccharomyces cerevisiae, a heterotrophic yeast with no known evolutionary history of phototrophy, can function as a facultative photoheterotroph after acquiring a single rhodopsin gene. We inserted a rhodopsin gene from Ustilago maydis,7 which encodes a proton pump localized to the vacuole, an organelle normally acidified via a V-type rotary ATPase, allowing the rhodopsin to supplement heterotrophic metabolism. Probes of the physiology of modified cells show that they can deacidify the cytoplasm using light energy, demonstrating the ability of rhodopsins to ameliorate the effects of starvation and quiescence. Further, we show that yeast-bearing rhodopsins gain a selective advantage when illuminated, proliferating more rapidly than their non-phototrophic ancestor or rhodopsin-bearing yeast cultured in the dark. These results underscore the ease with which rhodopsins may be horizontally transferred even in eukaryotes, providing novel biological function without first requiring evolutionary optimization.
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Affiliation(s)
- Autumn Peterson
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30309, USA; Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA 30309, USA
| | - Carina Baskett
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30309, USA; Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA 30309, USA
| | - William C Ratcliff
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30309, USA; Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA 30309, USA.
| | - Anthony Burnetti
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30309, USA; Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA 30309, USA.
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20
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Malik S, Walley JW. Unveiling a new regulator: Vacuolar V-ATPase mediates brassinosteroid signaling in Arabidopsis. Mol Plant 2024; 17:227-229. [PMID: 38155571 DOI: 10.1016/j.molp.2023.12.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 12/24/2023] [Accepted: 12/26/2023] [Indexed: 12/30/2023]
Affiliation(s)
- Shikha Malik
- Department of Plant Pathology, Entomology, and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Justin W Walley
- Department of Plant Pathology, Entomology, and Microbiology, Iowa State University, Ames, IA 50011, USA.
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21
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Santin A, Russo MT, de Los Ríos LM, Chiurazzi M, d'Alcalà MR, Lacombe B, Ferrante MI, Rogato A. The tonoplast localized protein PtNPF1 participates in the regulation of nitrogen response in diatoms. New Phytol 2024; 241:1592-1604. [PMID: 38084038 DOI: 10.1111/nph.19461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 11/21/2023] [Indexed: 01/26/2024]
Abstract
Diatoms are a highly successful group of phytoplankton, well adapted also to oligotrophic environments and capable of handling nutrient fluctuations in the ocean, particularly nitrate. The presence of a large vacuole is an important trait contributing to their adaptive features. It confers diatoms the ability to accumulate and store nutrients, such as nitrate, when they are abundant outside and then to reallocate them into the cytosol to meet deficiencies, in a process called luxury uptake. The molecular mechanisms that regulate these nitrate fluxes are still not known in diatoms. In this work, we provide new insights into the function of Phaeodactylum tricornutum NPF1, a putative low-affinity nitrate transporter. To accomplish this, we generated overexpressing strains and CRISPR/Cas9 loss-of-function mutants. Microscopy observations confirmed predictions that PtNPF1 is localized on the vacuole membrane. Furthermore, functional characterizations performed on knock-out mutants revealed a transient growth delay phenotype linked to altered nitrate uptake. Together, these results allowed us to hypothesize that PtNPF1 is presumably involved in modulating intracellular nitrogen fluxes, managing intracellular nutrient availability. This ability might allow diatoms to fine-tune the assimilation, storage and reallocation of nitrate, conferring them a strong advantage in oligotrophic environments.
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Affiliation(s)
- Anna Santin
- Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, 80121, Italy
| | | | - Laura Morales de Los Ríos
- Institute for Plant Science of Montpellier (IPSiM), University of Montpellier, CNRS, INRAE, Montpellier SupAgro, Place Pierre Viala 2, Montpellier, 34060, France
| | - Maurizio Chiurazzi
- Institute of Biosciences and BioResources, CNR, Via P. Castellino 111, Naples, 80131, Italy
| | | | - Benoît Lacombe
- Institute for Plant Science of Montpellier (IPSiM), University of Montpellier, CNRS, INRAE, Montpellier SupAgro, Place Pierre Viala 2, Montpellier, 34060, France
| | - Maria Immacolata Ferrante
- Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, 80121, Italy
- National Institute of Oceanography and Applied Geophysics, Trieste, 34010, Italy
| | - Alessandra Rogato
- Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, 80121, Italy
- Institute of Biosciences and BioResources, CNR, Via P. Castellino 111, Naples, 80131, Italy
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22
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Ghosh S, Bandyopadhyay S, Smith DM, Adak S, Semenkovich CF, Nagy L, Wolfgang MJ, O’Connor TJ. Legionella pneumophila usurps host cell lipids for vacuole expansion and bacterial growth. PLoS Pathog 2024; 20:e1011996. [PMID: 38386622 PMCID: PMC10883544 DOI: 10.1371/journal.ppat.1011996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 01/22/2024] [Indexed: 02/24/2024] Open
Abstract
Vacuolar pathogens reside in membrane-bound compartments within host cells. Maintaining the integrity of this compartment is paramount to bacterial survival and replication as it protects against certain host surveillance mechanisms that function to eradicate invading pathogens. Preserving this compartment during bacterial replication requires expansion of the vacuole membrane to accommodate the increasing number of bacteria, and yet, how this is accomplished remains largely unknown. Here, we show that the vacuolar pathogen Legionella pneumophila exploits multiple sources of host cell fatty acids, including inducing host cell fatty acid scavenging pathways, in order to promote expansion of the replication vacuole and bacteria growth. Conversely, when exogenous lipids are limited, the decrease in host lipid availability restricts expansion of the replication vacuole membrane, resulting in a higher density of bacteria within the vacuole. Modifying the architecture of the vacuole prioritizes bacterial growth by allowing the greatest number of bacteria to remain protected by the vacuole membrane despite limited resources for its expansion. However, this trade-off is not without risk, as it can lead to vacuole destabilization, which is detrimental to the pathogen. However, when host lipid resources become extremely scarce, for example by inhibiting host lipid scavenging, de novo biosynthetic pathways, and/or diverting host fatty acids to storage compartments, bacterial replication becomes severely impaired, indicating that host cell fatty acid availability also directly regulates L. pneumophila growth. Collectively, these data demonstrate dual roles for host cell fatty acids in replication vacuole expansion and bacterial proliferation, revealing the central functions for these molecules and their metabolic pathways in L. pneumophila pathogenesis.
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Affiliation(s)
- Soma Ghosh
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Saumya Bandyopadhyay
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Danielle M. Smith
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sangeeta Adak
- Division of Endocrinology, Metabolism and Lipid Research, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Clay F. Semenkovich
- Division of Endocrinology, Metabolism and Lipid Research, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Laszlo Nagy
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Medicine, Institute for Fundamental Biomedical Research, Johns Hopkins All Children’s Hospital, St. Petersburg, Florida, United States of America
| | - Michael J. Wolfgang
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Tamara J. O’Connor
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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23
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Riaz M, Sultana R, Ahmad J, Mehmood A, Sattar S, Hammad Tanveer M, Zulkiffal M, Sarwar M. Autophagy related genes mediated mitophagy in yeast, mammals and higher plants. Cell Mol Biol (Noisy-le-grand) 2024; 70:1-11. [PMID: 38372120 DOI: 10.14715/cmb/2024.70.1.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Indexed: 02/20/2024]
Abstract
Autophagy is classified into macro-autophagy and micro-autophagy. Two major types of autophagy in the complex eukaryotic organism are microautophagy and macroautophagy. During microautophagy, cytoplasmic components that need to be degraded are taken up by lysosomes in animals and by vacuole in yeast and plants via the invagination of tonoplast. While macroautophagy is initiated after the formation of a cup-shaped membrane structure, a phagophore develops at cargo that grows in size and is sealed by double-membrane vesicles to form autophagosome; a generalized mechanism for degradation of the organelle. Autophagic removal of damaged mitochondria is a conserved cellular process to maintain a healthy mitochondrion called Mitophagy. In plants and animals, mitophagy has crucial roles in stress responses, senescence, development, and programmed cell death. Mitophagy appears in mammals, fungi, and plants but many genes that controlled mitophagy are absent from plants. Numerous studies have been conducted by using ATG mutants for the identification of functional roles of Autophagy Related Genes (ATG) required during the autophagy process at various steps like; auto phagosome formation, ATG protein recruitment, etc. The role of more than 25 ATG genes in mitophagy has been discussed in this review paper. The main parameters, reviewed and summarized in this review paper, are the name of species, common name, function, domain, deletion, induction, and localization of these autophagy-related genes in the cell. This review will facilitate the students, researchers, and academics for their further research insights.
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Affiliation(s)
- Muhammad Riaz
- Wheat Research Institute, Ayyub Agriculture Research Institute, Faisalabad, 38040, Punjab, Pakistan.
| | - Razia Sultana
- Wheat Research Institute, Ayyub Agriculture Research Institute, Faisalabad, 38040, Punjab, Pakistan.
| | - Javed Ahmad
- Wheat Research Institute, Ayyub Agriculture Research Institute, Faisalabad, 38040, Punjab, Pakistan.
| | - Azhar Mehmood
- Wheat Research Institute, Ayyub Agriculture Research Institute, Faisalabad, 38040, Punjab, Pakistan.
| | - Saira Sattar
- Plant Breeding and Genetics, University of Agriculture, Faisalabad, 38040, Punjab, Pakistan.
| | - Muhammad Hammad Tanveer
- Wheat Research Institute, Ayyub Agriculture Research Institute, Faisalabad, 38040, Punjab, Pakistan.
| | - Muhammad Zulkiffal
- Wheat Research Institute, Ayyub Agriculture Research Institute, Faisalabad, 38040, Punjab, Pakistan.
| | - Muhammad Sarwar
- Wheat Research Institute, Ayyub Agriculture Research Institute, Faisalabad, 38040, Punjab, Pakistan.
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24
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Piro F, Masci S, Kannan G, Focaia R, Schultz TL, Thaprawat P, Carruthers VB, Di Cristina M. A Toxoplasma gondii putative amino acid transporter localizes to the plant-like vacuolar compartment and controls parasite extracellular survival and stage differentiation. mSphere 2024; 9:e0059723. [PMID: 38051073 PMCID: PMC10871165 DOI: 10.1128/msphere.00597-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 12/07/2023] Open
Abstract
Toxoplasma gondii is a protozoan parasite that infects a broad spectrum of hosts and can colonize many organs and cell types. The ability to reside within a wide range of different niches requires substantial adaptability to diverse microenvironments. Very little is known about how this parasite senses various milieus and adapts its metabolism to survive, replicate during the acute stage, and then differentiate to the chronic stage. T. gondii possesses a lysosome-like organelle known as the plant-like vacuolar compartment (PLVAC), which serves various functions, including digestion, ion storage and homeostasis, endocytosis, and autophagy. Lysosomes are critical for maintaining cellular health and function by degrading waste materials and recycling components. To supply the cell with the essential building blocks and energy sources required for the maintenance of its functions and structures, the digested solutes generated within the lysosome are transported into the cytosol by proteins embedded in the lysosomal membrane. Currently, a limited number of PLVAC transporters have been characterized, with TgCRT being the sole potential transporter of amino acids and small peptides identified thus far. To bridge this knowledge gap, we used lysosomal amino acid transporters from other organisms as queries to search the T. gondii proteome. This led to the identification of four potential amino acid transporters, which we have designated as TgAAT1-4. Assessing their expression and sub-cellular localization, we found that one of them, TgAAT1, localized to the PLVAC and is necessary for normal parasite extracellular survival and bradyzoite differentiation. Moreover, we present preliminary data showing the possible involvement of TgAAT1 in the PLVAC transport of arginine.IMPORTANCEToxoplasma gondii is a highly successful parasite infecting a broad range of warm-blooded organisms, including about one-third of all humans. Although Toxoplasma infections rarely result in symptomatic disease in individuals with a healthy immune system, the incredibly high number of persons infected, along with the risk of severe infection in immunocompromised patients and the potential link of chronic infection to mental disorders, makes this infection a significant public health concern. As a result, there is a pressing need for new treatment approaches that are both effective and well tolerated. The limitations in understanding how Toxoplasma gondii manages its metabolism to adapt to changing environments and triggers its transformation into bradyzoites have hindered the discovery of vulnerabilities in its metabolic pathways or nutrient acquisition mechanisms to identify new therapeutic targets. In this work, we have shown that the lysosome-like organelle plant-like vacuolar compartment (PLVAC), acting through the putative arginine transporter TgAAT1, plays a pivotal role in regulating the parasite's extracellular survival and differentiation into bradyzoites.
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Affiliation(s)
- Federica Piro
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Silvia Masci
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Geetha Kannan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Riccardo Focaia
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Tracey L. Schultz
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Pariyamon Thaprawat
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Vern B. Carruthers
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Manlio Di Cristina
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
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25
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Fréville A, Ressurreição M, van Ooij C. Identification of a non-exported Plasmepsin V substrate that functions in the parasitophorous vacuole of malaria parasites. mBio 2024; 15:e0122323. [PMID: 38078758 PMCID: PMC10790765 DOI: 10.1128/mbio.01223-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 10/26/2023] [Indexed: 01/17/2024] Open
Abstract
IMPORTANCE In the manuscript, the authors investigate the role of the protease Plasmepsin V in the parasite-host interaction. Whereas processing by Plasmepsin V was previously thought to target a protein for export into the host cell, the authors now show that there are proteins cleaved by this protease that are not exported but instead function at the host-parasite interface. This changes the view of this protease, which turns out to have a much broader role than anticipated. The result shows that the protease may have a function much more similar to that of related organisms. The authors also investigate the requirements for protein export by analyzing exported and non-exported proteins and find commonalities between the proteins of each set that further our understanding of the requirements for protein export.
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Affiliation(s)
- Aline Fréville
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Margarida Ressurreição
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Christiaan van Ooij
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
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26
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Rinkenberger N, Rosenberg A, Radke JB, Bhushan J, Tomita T, Weiss LM, Sibley LD. Susceptibility of Toxoplasma gondii to autophagy in human cells relies on multiple interacting parasite loci. mBio 2024; 15:e0259523. [PMID: 38095418 PMCID: PMC10790690 DOI: 10.1128/mbio.02595-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/06/2023] [Indexed: 01/04/2024] Open
Abstract
IMPORTANCE Autophagy is a process used by cells to recycle organelles and macromolecules and to eliminate intracellular pathogens. Previous studies have shown that some stains of Toxoplasma gondii are resistant to autophagy-dependent growth restriction, while others are highly susceptible. Although it is known that autophagy-mediated control requires activation by interferon gamma, the basis for why parasite strains differ in their susceptibility is unknown. Our findings indicate that susceptibility involves at least five unlinked parasite genes on different chromosomes, including several secretory proteins targeted to the parasite-containing vacuole and exposed to the host cell cytosol. Our findings reveal that susceptibility to autophagy-mediated growth restriction relies on differential recognition of parasite proteins exposed at the host-pathogen interface, thus identifying a new mechanism for cell-autonomous control of intracellular pathogens.
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Affiliation(s)
- Nicholas Rinkenberger
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Alex Rosenberg
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Joshua B. Radke
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Jaya Bhushan
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Tadakimi Tomita
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Louis M. Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri, USA
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27
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Pitman EL, Counihan NA, Modak JK, Chowdury M, Gilson PR, Webb CT, de Koning-Ward TF. Dissecting EXP2 sequence requirements for protein export in malaria parasites. Front Cell Infect Microbiol 2024; 13:1332146. [PMID: 38282616 PMCID: PMC10811066 DOI: 10.3389/fcimb.2023.1332146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 12/19/2023] [Indexed: 01/30/2024] Open
Abstract
Apicomplexan parasites that reside within a parasitophorous vacuole harbor a conserved pore-forming protein that enables small-molecule transfer across the parasitophorous vacuole membrane (PVM). In Plasmodium parasites that cause malaria, this nutrient pore is formed by EXP2 which can complement the function of GRA17, an orthologous protein in Toxoplasma gondii. EXP2, however, has an additional function in Plasmodium parasites, serving also as the pore-forming component of the protein export machinery PTEX. To examine how EXP2 can play this additional role, transgenes that encoded truncations of EXP2, GRA17, hybrid GRA17-EXP2, or EXP2 under the transcriptional control of different promoters were expressed in EXP2 knockdown parasites to determine which could complement EXP2 function. This revealed that EXP2 is a unique pore-forming protein, and its protein export role in P. falciparum cannot be complemented by T. gondii GRA17. This was despite the addition of the EXP2 assembly strand and part of the linker helix to GRA17, which are regions necessary for the interaction of EXP2 with the other core PTEX components. This indicates that the body region of EXP2 plays a critical role in PTEX assembly and/or that the absence of other T. gondii GRA proteins in P. falciparum leads to its reduced efficiency of insertion into the PVM and complementation potential. Altering the timing and abundance of EXP2 expression did not affect protein export but affected parasite viability, indicating that the unique transcriptional profile of EXP2 when compared to other PTEX components enables it to serve an additional role in nutrient exchange.
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Affiliation(s)
- Ethan L. Pitman
- School of Medicine, Deakin University, Geelong, VIC, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia
| | - Natalie A. Counihan
- School of Medicine, Deakin University, Geelong, VIC, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia
| | - Joyanta K. Modak
- School of Medicine, Deakin University, Geelong, VIC, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia
| | - Mrittika Chowdury
- School of Medicine, Deakin University, Geelong, VIC, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia
| | - Paul R. Gilson
- Burnet Institute, Melbourne, VIC, Australia
- Department of Microbiology and Immunology, University of Melbourne, Parkville, VIC, Australia
| | - Chaille T. Webb
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia
- Centre to Impact AMR, Monash University, Clayton, VIC, Australia
| | - Tania F. de Koning-Ward
- School of Medicine, Deakin University, Geelong, VIC, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia
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28
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Seizova S, Ferrel A, Boothroyd J, Tonkin CJ. Toxoplasma protein export and effector function. Nat Microbiol 2024; 9:17-28. [PMID: 38172621 DOI: 10.1038/s41564-023-01563-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 11/16/2023] [Indexed: 01/05/2024]
Abstract
Toxoplasma gondii is a single-celled eukaryotic parasite with a considerable host range that must invade the cells of warm-blooded hosts to survive and replicate. The challenges and opportunities that such a strategy represent have been met by the evolution of effectors that are delivered into host cells, counter host defences and co-opt host cell functions for their own purposes. These effectors are delivered in two waves using distinct machinery for each. In this Review, we focus on understanding the architecture of these protein-export systems and how their protein cargo is recognized and selected. We discuss the recent findings on the role that host manipulation has in latent Toxoplasma infections. We also discuss how these recent findings compare to protein export in the related Plasmodium spp. (the causative agent of malaria) and how this can inform our understanding of host manipulation in the larger Apicomplexa phylum and its evolution.
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Affiliation(s)
- Simona Seizova
- School of Life Sciences, The University of Dundee, Dundee, UK
| | - Abel Ferrel
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA, USA
| | - John Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA, USA.
| | - Christopher J Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.
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29
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Kim H, Budin I. Intracellular sphingolipid sorting drives membrane phase separation in the yeast vacuole. J Biol Chem 2024; 300:105496. [PMID: 38013088 PMCID: PMC10776997 DOI: 10.1016/j.jbc.2023.105496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 11/08/2023] [Accepted: 11/19/2023] [Indexed: 11/29/2023] Open
Abstract
The yeast vacuole membrane can phase separate into ordered and disordered domains, a phenomenon that is required for micro-lipophagy under nutrient limitation. Despite its importance as a biophysical model and physiological significance, it is not yet resolved if specific lipidome changes drive vacuole phase separation. Here we report that the metabolism of sphingolipids (SLs) and their sorting into the vacuole membrane can control this process. We first developed a vacuole isolation method to identify lipidome changes during the onset of phase separation in early stationary stage cells. We found that early stationary stage vacuoles are defined by an increased abundance of putative raft components, including 40% higher ergosterol content and a nearly 3-fold enrichment in complex SLs (CSLs). These changes were not found in the corresponding whole cell lipidomes, indicating that lipid sorting is associated with domain formation. Several facets of SL composition-headgroup stoichiometry, longer chain lengths, and increased hydroxylations-were also markers of phase-separated vacuole lipidomes. To test SL function in vacuole phase separation, we carried out a systematic genetic dissection of their biosynthetic pathway. The abundance of CSLs controlled the extent of domain formation and associated micro-lipophagy processes, while their headgroup composition altered domain morphology. These results suggest that lipid trafficking can drive membrane phase separation in vivo and identify SLs as key mediators of this process in yeast.
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Affiliation(s)
- Hyesoo Kim
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Itay Budin
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA.
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30
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Powell CJ, Jenkins ML, Hill TB, Blank ML, Cabo LF, Thompson LR, Burke JE, Boyle JP, Boulanger MJ. Toxoplasma gondii mitochondrial association factor 1b interactome reveals novel binding partners including Ral GTPase accelerating protein α1. J Biol Chem 2024; 300:105582. [PMID: 38141762 PMCID: PMC10821591 DOI: 10.1016/j.jbc.2023.105582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 11/22/2023] [Accepted: 12/05/2023] [Indexed: 12/25/2023] Open
Abstract
The intracellular parasite, Toxoplasma gondii, has developed sophisticated molecular strategies to subvert host processes and promote growth and survival. During infection, T. gondii replicates in a parasitophorous vacuole (PV) and modulates host functions through a network of secreted proteins. Of these, Mitochondrial Association Factor 1b (MAF1b) recruits host mitochondria to the PV, a process that confers an in vivo growth advantage, though the precise mechanisms remain enigmatic. To address this knowledge gap, we mapped the MAF1b interactome in human fibroblasts using a commercial Yeast-2-hybrid (Y2H) screen, which revealed several previously unidentified binding partners including the GAP domain of Ral GTPase Accelerating Protein α1 (RalGAPα1(GAP)). Recombinantly produced MAF1b and RalGAPα1(GAP) formed as a stable binary complex as shown by size exclusion chromatography with a Kd of 334 nM as measured by isothermal titration calorimetry (ITC). Notably, no binding was detected between RalGAPα1(GAP) and the structurally conserved MAF1b homolog, MAF1a, which does not recruit host mitochondria. Next, we used hydrogen deuterium exchange mass spectrometry (HDX-MS) to map the RalGAPα1(GAP)-MAF1b interface, which led to identification of the "GAP-binding loop" on MAF1b that was confirmed by mutagenesis and ITC to be necessary for complex formation. A high-confidence Alphafold model predicts the GAP-binding loop to lie at the RalGAPα1(GAP)-MAF1b interface further supporting the HDX-MS data. Mechanistic implications of a RalGAPα1(GAP)-MAF1b complex are discussed in the context of T. gondii infection and indicates that MAF1b may have evolved multiple independent functions to increase T. gondii fitness.
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Affiliation(s)
- Cameron J Powell
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Tara B Hill
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Matthew L Blank
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Leah F Cabo
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Lexie R Thompson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada; Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jon P Boyle
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Martin J Boulanger
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada.
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31
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Zhang H, Ling Q. NBR1-mediated selective chloroplast autophagy is important to plant stress tolerance. Autophagy 2024; 20:205-206. [PMID: 37635361 PMCID: PMC10761070 DOI: 10.1080/15548627.2023.2251324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/14/2023] [Accepted: 08/18/2023] [Indexed: 08/29/2023] Open
Abstract
Macroautophagy/autophagy is a conserved process in eukaryotes responsible for degrading unwanted or damaged macromolecules and organelles through the lysosome or vacuole for recycling and reutilization. Our previous studies revealed the degradation of chloroplast proteins through a pathway dependent on the ubiquitin proteasome system, known as CHLORAD. Recently, we demonstrated a role for selective autophagy in regulating chloroplast protein import and enhancing stress tolerance in plants. Specifically, we found that K63-ubiquitination of TOC components at the chloroplast outer envelope membrane is recognized by the selective autophagy adaptor NBR1, leading to the degradation of TOC proteins under UV-B irradiation and heat stresses in Arabidopsis. This process was shown to control chloroplast protein import and influence photosynthetic activity. Based on our results, we have, for the first time, demonstrated that selective autophagy plays a vital role in chloroplast protein degradation, specifically in response to certain abiotic stresses.
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Affiliation(s)
- Hui Zhang
- National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Qihua Ling
- National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
- CAS-JIC Center of Excellence for Plant and Microbial Sciences (CEPAMS), Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
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32
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Kraft C, Reggiori F. Phagophore closure, autophagosome maturation and autophagosome fusion during macroautophagy in the yeast Saccharomyces cerevisiae. FEBS Lett 2024; 598:73-83. [PMID: 37585559 DOI: 10.1002/1873-3468.14720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/07/2023] [Accepted: 08/07/2023] [Indexed: 08/18/2023]
Abstract
Macroautophagy, hereafter referred to as autophagy, is a complex process in which multiple membrane-remodeling events lead to the formation of a cisterna known as the phagophore, which then expands and closes into a double-membrane vesicle termed the autophagosome. During the past decade, enormous progress has been made in understanding the molecular function of the autophagy-related proteins and their role in generating these phagophores. In this Review, we discuss the current understanding of three membrane remodeling steps in autophagy that remain to be largely characterized; namely, the closure of phagophores, the maturation of the resulting autophagosomes into fusion-competent vesicles, and their fusion with vacuoles/lysosomes. Our review will mainly focus on the yeast Saccharomyces cerevisiae, which has been the leading model system for the study of molecular events in autophagy and has led to the discovery of the major mechanistic concepts, which have been found to be mostly conserved in higher eukaryotes.
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Affiliation(s)
- Claudine Kraft
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Germany
| | - Fulvio Reggiori
- Department of Biomedicine, Aarhus University, Denmark
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Denmark
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33
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Noda NN. Structural view on autophagosome formation. FEBS Lett 2024; 598:84-106. [PMID: 37758522 DOI: 10.1002/1873-3468.14742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 09/02/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023]
Abstract
Autophagy is a conserved intracellular degradation system in eukaryotes, involving the sequestration of degradation targets into autophagosomes, which are subsequently delivered to lysosomes (or vacuoles in yeasts and plants) for degradation. In budding yeast, starvation-induced autophagosome formation relies on approximately 20 core Atg proteins, grouped into six functional categories: the Atg1/ULK complex, the phosphatidylinositol-3 kinase complex, the Atg9 transmembrane protein, the Atg2-Atg18/WIPI complex, the Atg8 lipidation system, and the Atg12-Atg5 conjugation system. Additionally, selective autophagy requires cargo receptors and other factors, including a fission factor, for specific sequestration. This review covers the 30-year history of structural studies on core Atg proteins and factors involved in selective autophagy, examining X-ray crystallography, NMR, and cryo-EM techniques. The molecular mechanisms of autophagy are explored based on protein structures, and future directions in the structural biology of autophagy are discussed, considering the advancements in the era of AlphaFold.
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Affiliation(s)
- Nobuo N Noda
- Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
- Institute of Microbial Chemistry (BIKAKEN), Tokyo, Japan
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34
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Okuma H, Saijo-Hamano Y, Yamada H, Sherif AA, Hashizaki E, Sakai N, Kato T, Imasaki T, Kikkawa S, Nitta E, Sasai M, Abe T, Sugihara F, Maniwa Y, Kosako H, Takei K, Standley DM, Yamamoto M, Nitta R. Structural basis of Irgb6 inactivation by Toxoplasma gondii through the phosphorylation of switch I. Genes Cells 2024; 29:17-38. [PMID: 37984375 DOI: 10.1111/gtc.13080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/12/2023] [Accepted: 10/29/2023] [Indexed: 11/22/2023]
Abstract
Irgb6 is a priming immune-related GTPase (IRG) that counteracts Toxoplasma gondii. It is known to be recruited to the low virulent type II T. gondii parasitophorous vacuole (PV), initiating cell-autonomous immunity. However, the molecular mechanism by which immunity-related GTPases become inactivated after the parasite infection remains obscure. Here, we found that Thr95 of Irgb6 is prominently phosphorylated in response to low virulent type II T. gondii infection. We observed that a phosphomimetic T95D mutation in Irgb6 impaired its localization to the PV and exhibited reduced GTPase activity in vitro. Structural analysis unveiled an atypical conformation of nucleotide-free Irgb6-T95D, resulting from a conformational change in the G-domain that allosterically modified the PV membrane-binding interface. In silico docking corroborated the disruption of the physiological membrane binding site. These findings provide novel insights into a T. gondii-induced allosteric inactivation mechanism of Irgb6.
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Affiliation(s)
- Hiromichi Okuma
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yumiko Saijo-Hamano
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroshi Yamada
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Aalaa Alrahman Sherif
- Department of Genome Informatics, Research Institute for Microbial Diseases, Osaka, Japan
- Laboratory of Systems Immunology, WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Emi Hashizaki
- Laboratory of Immunoparasitology, Osaka University, Osaka, Japan
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka, Japan
| | | | - Takaaki Kato
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tsuyoshi Imasaki
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Satoshi Kikkawa
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Eriko Nitta
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Miwa Sasai
- Laboratory of Immunoparasitology, Osaka University, Osaka, Japan
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka, Japan
| | - Tadashi Abe
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Fuminori Sugihara
- Core Instrumentation Facility, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Yoshimasa Maniwa
- Division of Thoracic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hidetaka Kosako
- Division of Cell Signaling, Fujii Memorial Institute of Medical Sciences, Tokushima University, Tokushima, Japan
| | - Kohji Takei
- Department of Neuroscience, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Daron M Standley
- Department of Genome Informatics, Research Institute for Microbial Diseases, Osaka, Japan
- Laboratory of Systems Immunology, WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Masahiro Yamamoto
- Laboratory of Immunoparasitology, Osaka University, Osaka, Japan
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka, Japan
| | - Ryo Nitta
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
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35
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Clough B, Fisch D, Mize TH, Encheva V, Snijders A, Frickel EM. p97/VCP targets Toxoplasma gondii vacuoles for parasite restriction in interferon-stimulated human cells. mSphere 2023; 8:e0051123. [PMID: 37975677 PMCID: PMC10732073 DOI: 10.1128/msphere.00511-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 10/09/2023] [Indexed: 11/19/2023] Open
Abstract
IMPORTANCE Toxoplasma gondii (Tg) is a ubiquitous parasitic pathogen, infecting about one-third of the global population. Tg is controlled in immunocompetent people by mechanisms that are not fully understood. Tg infection drives the production of the inflammatory cytokine interferon gamma (IFNγ), which upregulates intracellular anti-pathogen defense pathways. In this study, we describe host proteins p97/VCP, UBXD1, and ANKRD13A that control Tg at the parasitophorous vacuole (PV) in IFNγ-stimulated endothelial cells. p97/VCP is an ATPase that interacts with a network of cofactors and is active in a wide range of ubiquitin-dependent cellular processes. We demonstrate that PV ubiquitination is a pre-requisite for recruitment of these host defense proteins, and their deposition directs Tg PVs to acidification in endothelial cells. We show that p97/VCP universally targets PVs in human cells and restricts Tg in different human cell types. Overall, these findings reveal new players of intracellular host defense of a vacuolated pathogen.
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Affiliation(s)
- Barbara Clough
- Institute for Microbiology and Infection, School of Biosciences, The University of Birmingham, Birmingham, United Kingdom
- Host-Toxoplasma Interaction Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Daniel Fisch
- Institute for Microbiology and Infection, School of Biosciences, The University of Birmingham, Birmingham, United Kingdom
- Host-Toxoplasma Interaction Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Todd H. Mize
- Advanced Mass Spectrometry Facility, School of Biosciences, The University of Birmingham, Birmingham, United Kingdom
| | - Vesela Encheva
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Ambrosius Snijders
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Eva-Maria Frickel
- Institute for Microbiology and Infection, School of Biosciences, The University of Birmingham, Birmingham, United Kingdom
- Host-Toxoplasma Interaction Laboratory, The Francis Crick Institute, London, United Kingdom
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36
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Yang W, Feng Y, Yan J, Kang C, Yao T, Sun H, Cheng Z. Phosphate (Pi) Transporter PIT1 Induces Pi Starvation in Salmonella-Containing Vacuole in HeLa Cells. Int J Mol Sci 2023; 24:17216. [PMID: 38139044 PMCID: PMC10743064 DOI: 10.3390/ijms242417216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium), an important foodborne pathogen, causes diarrheal illness and gastrointestinal diseases. S. Typhimurium survives and replicates in phagocytic and non-phagocytic cells for acute or chronic infections. In these cells, S. Typhimurium resides within Salmonella-containing vacuoles (SCVs), in which the phosphate (Pi) concentration is low. S. Typhimurium senses low Pi and expresses virulence factors to modify host cells. However, the mechanism by which host cells reduce the Pi concentration in SCVs is not clear. In this study, we show that through the TLR4-MyD88-NF-κB signaling pathway, S. Typhimurium upregulates PIT1, which in turn transports Pi from SCVs into the cytosol and results in Pi starvation in SCVs. Immunofluorescence and western blotting analysis reveal that after the internalization of S. Typhimurium, PIT1 is located on SCV membranes. Silencing or overexpressing PIT1 inhibits or promotes Pi starvation, Salmonella pathogenicity island-2 (SPI-2) gene expression, and replication in SCVs. The S. Typhimurium ΔmsbB mutant or silenced TLR4-MyD88-NF-κB pathway suppresses the expression of the SPI-2 genes and promotes the fusion of SCVs with lysosomes. Our results illustrate that S. Typhimurium exploits the host innate immune responses as signals to promote intracellular replication, and they provide new insights for the development of broad-spectrum therapeutics to combat bacterial infections.
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Affiliation(s)
- Wen Yang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin 300457, China
| | - Yingxing Feng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Jun Yan
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin 300457, China
| | - Chenbo Kang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin 300457, China
| | - Ting Yao
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin 300457, China
| | - Hongmin Sun
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- TEDA Institute of Biological Sciences and Biotechnology, Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, Tianjin 300457, China
| | - Zhihui Cheng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China; (W.Y.); (Y.F.); (J.Y.); (C.K.); (T.Y.); (H.S.)
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
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37
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Yang L, Jiang L. The seven rice vacuolar sorting receptors localize to prevacuolar compartments. J Plant Physiol 2023; 291:154137. [PMID: 37984048 DOI: 10.1016/j.jplph.2023.154137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/24/2023] [Accepted: 11/06/2023] [Indexed: 11/22/2023]
Abstract
Vacuolar sorting is critically important in plants as it regulates the mobilization of proteins and plays a major role in important agricultural traits like yield and seed protein content. Vacuolar sorting receptors (VSRs) are integral membrane proteins that mediate protein trafficking from the Golgi apparatus to the vacuole via the intermediate membrane-bound prevacuolar compartment (PVC)/multivesicular body (MVB). VSR proteins, such as an 80 kD (BP-80) from pea, also serve as markers for PVC/MVB. Dissecting VSR-mediated protein trafficking pathways may provide ways to enhance agronomic traits and crop yield. Green fluorescence protein (GFP) fusions with the seven Arabidopsis (Arabidopsis thaliana) VSRs were previously shown to localize to PVCs in transgenic tobacco BY-2 cells. The Rice (Oryza sativa) genome contains seven VSRs (OsVSR1-7), but little is known about their subcellular localizations. Here we studied the subcellular localization of OsVSR1-7 b y using a reporter approach, in which GFP-OsVSR1-7 fusions containing the transmembrane domain (TMD) and cytoplasmic tail (CT) of individual OsVSR were expressed in the protoplasts of rice, transgenic tobacco BY-2 cells and transgenic rice plants. Immunofluorescent labelling studies and confocal laser scanning microscope observation demonstrated that the seven OsVSRs are localized to PVCs and form ring-like structures upon wortmannin treatment. Therefore, we have verified the subcellular localization of OsVSR1-7 in this study. The OsVSRs tagged with GFP can serve as PVCs/MVBs markers in rice for the future studies.
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Affiliation(s)
- Lei Yang
- The Engineering Research Institute of Agriculture and Forestry, Ludong University, Yantai, 264025, China; School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China.
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38
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Aihara K, Nakazawa Y, Takeda S, Hatsusaka N, Onouchi T, Hiramatsu N, Nagata M, Nagai N, Funakoshi-Tago M, Yamamoto N, Sasaki H. Aquaporins contribute to vacuoles formation in Nile grass type II diabetic rats. Med Mol Morphol 2023; 56:274-287. [PMID: 37493821 DOI: 10.1007/s00795-023-00365-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 07/09/2023] [Indexed: 07/27/2023]
Abstract
Regulation of ion and water microcirculation within the lens is tightly controlled through aquaporin channels and connexin junctions. However, cataracts can occur when the lens becomes cloudy. Various factors can induce cataracts, including diabetes which is a well-known cause. The most common phenotype of diabetic cataracts is a cortical and/or posterior subcapsular opacity. In addition to the three main types and two subtypes of cataracts, a vacuole formation is frequently observed; however, their origin remains unclear. In this study, we focused on the aquaporins and connexins involved in diabetes-induced cataracts and vacuoles in Nile grass type II diabetes. The results showed that the expression of aquaporin 0 and aquaporin 5 increased, and that of connexin 43 decreased in diabetic rat lenses. Additionally, aquaporin 0 and 5 were strongly localized in peripheral of vacuoles, suggesting that aquaporins are involved in vacuoles formation. Transillumination photography revealed large vacuoles at the tip of the Y-suture in the anterior capsule of the diabetic lens, and several small vacuoles were observed in the posterior capsule. Within the vacuoles, cytoplasmic degradation and aggregation of fibrous material were observed. Our findings suggest that aquaporins are potential candidate proteins for preventing vacuole formation.
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Affiliation(s)
- Kana Aihara
- Faculty of Pharmacy, Keio University, 1-5-30, Shibako-en, Minato-ku, Tokyo, 105-8512, Japan
| | - Yosuke Nakazawa
- Faculty of Pharmacy, Keio University, 1-5-30, Shibako-en, Minato-ku, Tokyo, 105-8512, Japan.
| | - Shun Takeda
- Department of Ophthalmology, Kanazawa Medical University, 1-1 Daigaku Uchinada-machi, Kahoku-gun, Kahoku, Ishikawa, 920-0293, Japan
| | - Natsuko Hatsusaka
- Department of Ophthalmology, Kanazawa Medical University, 1-1 Daigaku Uchinada-machi, Kahoku-gun, Kahoku, Ishikawa, 920-0293, Japan
| | - Takanori Onouchi
- Research Promotion Headquarters, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
| | - Noriko Hiramatsu
- Research Promotion Headquarters, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
| | - Mayumi Nagata
- Department of Ophthalmology, Dokkyo Medical University, Shimotsugagun, Tochigi, 321-0293, Japan
| | - Noriaki Nagai
- Faculty of Pharmacy, Kindai University, Higashi-Osaka, Osaka, 577-8502, Japan
| | - Megumi Funakoshi-Tago
- Faculty of Pharmacy, Keio University, 1-5-30, Shibako-en, Minato-ku, Tokyo, 105-8512, Japan
| | - Naoki Yamamoto
- Research Promotion Headquarters, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
| | - Hiroshi Sasaki
- Department of Ophthalmology, Kanazawa Medical University, 1-1 Daigaku Uchinada-machi, Kahoku-gun, Kahoku, Ishikawa, 920-0293, Japan.
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Timm S, Eisenhut M. Four plus one: vacuoles serve in photorespiration. Trends Plant Sci 2023; 28:1340-1343. [PMID: 37635005 DOI: 10.1016/j.tplants.2023.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/07/2023] [Accepted: 08/08/2023] [Indexed: 08/29/2023]
Abstract
Photorespiration is inevitable for oxygenic photosynthesis. It has fascinated researchers over decades because of its multicompartmental organization. Recently, Lin and Tsay identified a vacuole glycerate transporter contributing to photorespiratory metabolism under short-term nitrogen depletion. This key finding adds a fifth interacting subcellular compartment and extends the photorespiratory metabolic repair module.
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Affiliation(s)
- Stefan Timm
- University of Rostock, Plant Physiology Department, Albert-Einstein-Straße 3, 18059 Rostock, Germany.
| | - Marion Eisenhut
- Bielefeld University, Faculty of Biology, Computational Biology, CeBiTec, Universitätsstraße 27, D-33615 Bielefeld, Germany.
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40
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Yang Y, Mei L, Chen J, Chen X, Wang Z, Liu L, Yang A. Legionella pneumophila-mediated host posttranslational modifications. J Mol Cell Biol 2023; 15:mjad032. [PMID: 37156500 PMCID: PMC10720952 DOI: 10.1093/jmcb/mjad032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 01/17/2023] [Accepted: 05/06/2023] [Indexed: 05/10/2023] Open
Abstract
Legionella pneumophila is a Gram-negative bacterium ubiquitously present in freshwater environments and causes a serious type of pneumonia called Legionnaires' disease. During infections, L. pneumophila releases over 300 effector proteins into host cells through an Icm/Dot type IV secretion system to manipulate the host defense system for survival within the host. Notably, certain effector proteins mediate posttranslational modifications (PTMs), serving as useful approaches exploited by L. pneumophila to modify host proteins. Some effectors catalyze the addition of host protein PTMs, while others mediate the removal of PTMs from host proteins. In this review, we summarize L. pneumophila effector-mediated PTMs of host proteins, including phosphorylation, ubiquitination, glycosylation, AMPylation, phosphocholination, methylation, and ADP-ribosylation, as well as dephosphorylation, deubiquitination, deAMPylation, deADP-ribosylation, dephosphocholination, and delipidation. We describe their molecular mechanisms and biological functions in the regulation of bacterial growth and Legionella-containing vacuole biosynthesis and in the disruption of host immune and defense machinery.
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Affiliation(s)
- Yi Yang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Ligang Mei
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Jing Chen
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Xiaorong Chen
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Zhuolin Wang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Lu Liu
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Aimin Yang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
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41
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Cheng CY, Romero DP, Zoltner M, Yao MC, Turkewitz AP. Structure and dynamics of the contractile vacuole complex in Tetrahymena thermophila. J Cell Sci 2023; 136:jcs261511. [PMID: 37902010 PMCID: PMC10729820 DOI: 10.1242/jcs.261511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/23/2023] [Indexed: 10/31/2023] Open
Abstract
The contractile vacuole complex (CVC) is a dynamic and morphologically complex membrane organelle, comprising a large vesicle (bladder) linked with a tubular reticulum (spongiome). CVCs provide key osmoregulatory roles across diverse eukaryotic lineages, but probing the mechanisms underlying their structure and function is hampered by the limited tools available for in vivo analysis. In the experimentally tractable ciliate Tetrahymena thermophila, we describe four proteins that, as endogenously tagged constructs, localize specifically to distinct CVC zones. The DOPEY homolog Dop1p and the CORVET subunit Vps8Dp localize both to the bladder and spongiome but with different local distributions that are sensitive to osmotic perturbation, whereas the lipid scramblase Scr7p colocalizes with Vps8Dp. The H+-ATPase subunit Vma4 is spongiome specific. The live imaging permitted by these probes revealed dynamics at multiple scales including rapid exchange of CVC-localized and soluble protein pools versus lateral diffusion in the spongiome, spongiome extension and branching, and CVC formation during mitosis. Although the association with DOP1 and VPS8D implicate the CVC in endosomal trafficking, both the bladder and spongiome might be isolated from bulk endocytic input.
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Affiliation(s)
- Chao-Yin Cheng
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Daniel P. Romero
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Martin Zoltner
- Biotechnology Biomedicine Centre of the Academy of Sciences, České Budějovice, 370 05, Czech Republic
| | - Meng-Chao Yao
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | - Aaron P. Turkewitz
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
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42
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Anand A, Mazur AC, Rosell-Arevalo P, Franzkoch R, Breitsprecher L, Listian SA, Hüttel SV, Müller D, Schäfer DG, Vormittag S, Hilbi H, Maniak M, Gutierrez MG, Barisch C. ER-dependent membrane repair of mycobacteria-induced vacuole damage. mBio 2023; 14:e0094323. [PMID: 37676004 PMCID: PMC10653851 DOI: 10.1128/mbio.00943-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/13/2023] [Indexed: 09/08/2023] Open
Abstract
IMPORTANCE Tuberculosis still remains a global burden and is one of the top infectious diseases from a single pathogen. Mycobacterium tuberculosis, the causative agent, has perfected many ways to replicate and persist within its host. While mycobacteria induce vacuole damage to evade the toxic environment and eventually escape into the cytosol, the host recruits repair machineries to restore the MCV membrane. However, how lipids are delivered for membrane repair is poorly understood. Using advanced fluorescence imaging and volumetric correlative approaches, we demonstrate that this involves the recruitment of the endoplasmic reticulum (ER)-Golgi lipid transfer protein OSBP8 in the Dictyostelium discoideum/Mycobacterium marinum system. Strikingly, depletion of OSBP8 affects lysosomal function accelerating mycobacterial growth. This indicates that an ER-dependent repair pathway constitutes a host defense mechanism against intracellular pathogens such as M. tuberculosis.
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Affiliation(s)
- Aby Anand
- Division of Molecular Infection Biology, Department of Biology & Center of Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany
| | - Anna-Carina Mazur
- Division of Molecular Infection Biology, Department of Biology & Center of Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany
| | - Patricia Rosell-Arevalo
- Host–Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Rico Franzkoch
- Integrated Bioimaging Facility, Center of Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany
| | - Leonhard Breitsprecher
- Integrated Bioimaging Facility, Center of Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany
| | - Stevanus A. Listian
- Division of Molecular Infection Biology, Department of Biology & Center of Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany
| | - Sylvana V. Hüttel
- Division of Molecular Infection Biology, Department of Biology & Center of Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany
| | - Danica Müller
- Division of Molecular Infection Biology, Department of Biology & Center of Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany
| | - Deise G. Schäfer
- Division of Molecular Infection Biology, Department of Biology & Center of Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany
| | - Simone Vormittag
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Markus Maniak
- Department of Cell Biology, University of Kassel, Kassel, Germany
| | - Maximiliano G. Gutierrez
- Host–Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Caroline Barisch
- Division of Molecular Infection Biology, Department of Biology & Center of Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Division of Host-Microbe Interactome, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
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43
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Bass AR, Egan MS, Alexander-Floyd J, Lopes Fischer N, Doerner J, Shin S. Human GBP1 facilitates the rupture of the Legionella-containing vacuole and inflammasome activation. mBio 2023; 14:e0170723. [PMID: 37737612 PMCID: PMC10653807 DOI: 10.1128/mbio.01707-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 07/27/2023] [Indexed: 09/23/2023] Open
Abstract
IMPORTANCE Inflammasomes are essential for host defense against intracellular bacterial pathogens like Legionella, as they activate caspases, which promote cytokine release and cell death to control infection. In mice, interferon (IFN) signaling promotes inflammasome responses against bacteria by inducing a family of IFN-inducible GTPases known as guanylate-binding proteins (GBPs). Within murine macrophages, IFN promotes the rupture of the Legionella-containing vacuole (LCV), while GBPs are dispensable for this process. Instead, GBPs facilitate the lysis of cytosol-exposed Legionella. In contrast, the functions of IFN and GBPs in human inflammasome responses to Legionella are poorly understood. We show that IFN-γ enhances inflammasome responses to Legionella in human macrophages. Human GBP1 is required for these IFN-γ-driven inflammasome responses. Furthermore, GBP1 co-localizes with Legionella and/or LCVs in a type IV secretion system (T4SS)-dependent manner and promotes damage to the LCV, which leads to increased exposure of the bacteria to the host cell cytosol. Thus, our findings reveal species- and pathogen-specific differences in how GBPs function to promote inflammasome responses.
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Affiliation(s)
- Antonia R. Bass
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Marisa S. Egan
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jasmine Alexander-Floyd
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Natasha Lopes Fischer
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jessica Doerner
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sunny Shin
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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44
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Terawaki S, Vasilev F, Moriwaki T, Otomo T. HOPS, CORVET and newly-identified Hybrid tethering complexes contribute differentially towards multiple modes of endocytosis. Sci Rep 2023; 13:18734. [PMID: 37907479 PMCID: PMC10618185 DOI: 10.1038/s41598-023-45418-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 10/19/2023] [Indexed: 11/02/2023] Open
Abstract
Vesicular transport driven by membrane trafficking systems conserved in eukaryotes is critical to cellular functionality and homeostasis. It is known that homotypic fusion and vacuole protein sorting (HOPS) and class C core endosomal vacuole tethering (CORVET) interact with Rab-GTPases and SNARE proteins to regulate vesicle transport, fusion, and maturation in autophagy and endocytosis pathways. In this study, we identified two novel "Hybrid" tethering complexes in mammalian cells in which one of the subunits of HOPS or CORVET is replaced with the subunit from the other. Substrates taken up by receptor-mediated endocytosis or pinocytosis were transported by distinctive pathways, and the newly identified hybrid complexes contributed to pinocytosis in the presence of HOPS, whereas receptor-mediated endocytosis was exclusively dependent on HOPS. Our study provides new insights into the molecular mechanisms of the endocytic pathway and the function of the vacuolar protein sorting-associated (VPS) protein family.
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Affiliation(s)
- Seigo Terawaki
- Department of Molecular and Genetic Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192, Japan
| | - Filipp Vasilev
- Department of Molecular and Genetic Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192, Japan
| | - Takahito Moriwaki
- Department of Molecular and Genetic Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192, Japan
| | - Takanobu Otomo
- Department of Molecular and Genetic Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama, 701-0192, Japan.
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45
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Shi Y, Liu D, He Y, Tang J, Chen H, Gong P, Luo JS, Zhang Z. CHLORIDE CHANNEL-b mediates vacuolar nitrate efflux to improve low nitrogen adaptation in Arabidopsis. Plant Physiol 2023; 193:1987-2002. [PMID: 37527482 DOI: 10.1093/plphys/kiad438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 06/15/2023] [Accepted: 07/02/2023] [Indexed: 08/03/2023]
Abstract
The vacuole is an important organelle for nitrate storage, and the reuse of vacuolar nitrate under nitrate starvation helps plants adapt to low-nitrate environments. CHLORIDE CHANNEL-b (CLC-b) in the vacuolar membrane is a nitrate transporter; however, its regulation and effects on nitrate efflux have not been established. Here, we evaluated CLC-b expression and its effects on physiological parameters under low nitrate conditions. CLC-b expression increased significantly in the roots of wild-type Arabidopsis (Arabidopsis thaliana) Col-0 under nitrate starvation. Under low nitrate, clcb mutants showed reductions in chlorophyll content and xylem sap nitrate concentration, shoot/root nitrate ratios, shoot/root total N ratios, and biomass. CLC-b-overexpression yielded opposite phenotypes and increased nitrogen use efficiency. CLC-b mutants showed elevated chlorate tolerance and an increased proportion of vacuolar nitrate relative to the total protoplast nitrate content as compared to the wild type. Yeast 1-hybrid, EMSA, and chromatin immunoprecipitation (ChIP) experiments showed that HRS1 HOMOLOG2 (HHO2), the expression of which is downregulated under low nitrate, binds directly to the promoter of CLC-b. clcb/hho2 double mutants and HHO2-overexpressing clcb plants had similar phenotypes under low nitrate to those of clcb single mutants. Thus, CLC-b mediates vacuolar nitrate efflux and is negatively regulated by HHO2, providing a theoretical basis for improving plant adaptability to low nitrate.
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Affiliation(s)
- Yujiao Shi
- College of Resources, Hunan Agricultural University, Changsha 410128, China
| | - Dong Liu
- College of Resources, Hunan Agricultural University, Changsha 410128, China
| | - Yiqi He
- College of Resources, Hunan Agricultural University, Changsha 410128, China
| | - Jing Tang
- College of Resources, Hunan Agricultural University, Changsha 410128, China
| | - Haifei Chen
- College of Resources, Hunan Agricultural University, Changsha 410128, China
- Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Provincial Key Laboratory of Nutrition in Common University, National Engineering Laboratory on Soil and Fertilizer Resources Efficient Utilization, Changsha 410128, China
| | - Pan Gong
- College of Resources, Hunan Agricultural University, Changsha 410128, China
- Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Provincial Key Laboratory of Nutrition in Common University, National Engineering Laboratory on Soil and Fertilizer Resources Efficient Utilization, Changsha 410128, China
| | - Jin-Song Luo
- College of Resources, Hunan Agricultural University, Changsha 410128, China
- Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Provincial Key Laboratory of Nutrition in Common University, National Engineering Laboratory on Soil and Fertilizer Resources Efficient Utilization, Changsha 410128, China
| | - Zhenhua Zhang
- College of Resources, Hunan Agricultural University, Changsha 410128, China
- Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Provincial Key Laboratory of Nutrition in Common University, National Engineering Laboratory on Soil and Fertilizer Resources Efficient Utilization, Changsha 410128, China
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46
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Zhang S, Tong M, Zheng D, Huang H, Li L, Ungermann C, Pan Y, Luo H, Lei M, Tang Z, Fu W, Chen S, Liu X, Zhong Q. C9orf72-catalyzed GTP loading of Rab39A enables HOPS-mediated membrane tethering and fusion in mammalian autophagy. Nat Commun 2023; 14:6360. [PMID: 37821429 PMCID: PMC10567733 DOI: 10.1038/s41467-023-42003-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 09/25/2023] [Indexed: 10/13/2023] Open
Abstract
The multi-subunit homotypic fusion and vacuole protein sorting (HOPS) membrane-tethering complex is required for autophagosome-lysosome fusion in mammals, yet reconstituting the mammalian HOPS complex remains a challenge. Here we propose a "hook-up" model for mammalian HOPS complex assembly, which requires two HOPS sub-complexes docking on membranes via membrane-associated Rabs. We identify Rab39A as a key small GTPase that recruits HOPS onto autophagic vesicles. Proper pairing with Rab2 and Rab39A enables HOPS complex assembly between proteoliposomes for its tethering function, facilitating efficient membrane fusion. GTP loading of Rab39A is important for the recruitment of HOPS to autophagic membranes. Activation of Rab39A is catalyzed by C9orf72, a guanine exchange factor associated with amyotrophic lateral sclerosis and familial frontotemporal dementia. Constitutive activation of Rab39A can rescue autophagy defects caused by C9orf72 depletion. These results therefore reveal a crucial role for the C9orf72-Rab39A-HOPS axis in autophagosome-lysosome fusion.
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Affiliation(s)
- Shen Zhang
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Mindan Tong
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Denghao Zheng
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huiying Huang
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Linsen Li
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Christian Ungermann
- Osnabrück University, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
| | - Yi Pan
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hanyan Luo
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ming Lei
- State Key Laboratory of Oncogenes and Related Genes, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
- Shanghai Institute of Precision Medicine, 200125, Shanghai, China
| | - Zaiming Tang
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wan Fu
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - She Chen
- National Institute of Biological Sciences, 102206, Beijing, China
| | - Xiaoxia Liu
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Qing Zhong
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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47
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Okreglak V, Ling R, Ingaramo M, Thayer NH, Millett-Sikking A, Gottschling DE. Cell cycle-linked vacuolar pH dynamics regulate amino acid homeostasis and cell growth. Nat Metab 2023; 5:1803-1819. [PMID: 37640943 PMCID: PMC10590757 DOI: 10.1038/s42255-023-00872-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/21/2023] [Indexed: 08/31/2023]
Abstract
Amino acid homeostasis is critical for many cellular processes. It is well established that amino acids are compartmentalized using pH gradients generated between organelles and the cytoplasm; however, the dynamics of this partitioning has not been explored. Here we develop a highly sensitive pH reporter and find that the major amino acid storage compartment in Saccharomyces cerevisiae, the lysosome-like vacuole, alkalinizes before cell division and re-acidifies as cells divide. The vacuolar pH dynamics require the uptake of extracellular amino acids and activity of TORC1, the v-ATPase and the cycling of the vacuolar specific lipid phosphatidylinositol 3,5-bisphosphate, which is regulated by the cyclin-dependent kinase Pho85 (CDK5 in mammals). Vacuolar pH regulation enables amino acid sequestration and mobilization from the organelle, which is important for mitochondrial function, ribosome homeostasis and cell size control. Collectively, our data provide a new paradigm for the use of dynamic pH-dependent amino acid compartmentalization during cell growth/division.
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Affiliation(s)
- Voytek Okreglak
- Calico Life Sciences, LLC, South San Francisco, CA, USA.
- Altos Labs, Redwood City, CA, USA.
| | - Rachel Ling
- Calico Life Sciences, LLC, South San Francisco, CA, USA
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48
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Aoki M, Izumi R, Suzuki N. [Efficacy of Aceneuramic Acid for Distal Myopathy with Rimmed Vacuoles]. Brain Nerve 2023; 75:1149-1154. [PMID: 37849366 DOI: 10.11477/mf.1416202492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
Distal myopathy with rimmed vacuoles (DMRV), also known as GNE myopathy, is a rare disease affecting the distal muscles, such as the tibialis anterior muscle. The GNE gene, which codes for a key enzyme in the sialic acid biosynthesis pathway, is mutated in a homozygous or compound heterozygous manner, and the lack of sialic acid in skeletal muscle is the critical underlying mechanism in DMRV pathogenesis. DMRV mouse models were established, and supplementation with sialic acid improved the phenotypes of the models. A phase 1 clinical trial using aceneuramic acid was conducted at Tohoku University Hospital, Japan, followed by trials using a slow-release product. A phase II/III study, subsequent extended trial, and confirmatory trial were also conducted. Regulatory approval is currently under review.
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Affiliation(s)
- Masashi Aoki
- Department of Neurology, Tohoku University School of Medicine
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49
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Zeng Y, Liang Z, Liu Z, Li B, Cui Y, Gao C, Shen J, Wang X, Zhao Q, Zhuang X, Erdmann PS, Wong KB, Jiang L. Recent advances in plant endomembrane research and new microscopical techniques. New Phytol 2023; 240:41-60. [PMID: 37507353 DOI: 10.1111/nph.19134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 06/19/2023] [Indexed: 07/30/2023]
Abstract
The endomembrane system consists of various membrane-bound organelles including the endoplasmic reticulum (ER), Golgi apparatus, trans-Golgi network (TGN), endosomes, and the lysosome/vacuole. Membrane trafficking between distinct compartments is mainly achieved by vesicular transport. As the endomembrane compartments and the machineries regulating the membrane trafficking are largely conserved across all eukaryotes, our current knowledge on organelle biogenesis and endomembrane trafficking in plants has mainly been shaped by corresponding studies in mammals and yeast. However, unique perspectives have emerged from plant cell biology research through the characterization of plant-specific regulators as well as the development and application of the state-of-the-art microscopical techniques. In this review, we summarize our current knowledge on the plant endomembrane system, with a focus on several distinct pathways: ER-to-Golgi transport, protein sorting at the TGN, endosomal sorting on multivesicular bodies, vacuolar trafficking/vacuole biogenesis, and the autophagy pathway. We also give an update on advanced imaging techniques for the plant cell biology research.
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Affiliation(s)
- Yonglun Zeng
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Zizhen Liang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Zhiqi Liu
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Baiying Li
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Yong Cui
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361102, China
| | - Caiji Gao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Jinbo Shen
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China
| | - Xiangfeng Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Qiong Zhao
- School of Life Sciences, East China Normal University, Shanghai, 200062, China
| | - Xiaohong Zhuang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Philipp S Erdmann
- Human Technopole, Viale Rita Levi-Montalcini, 1, Milan, I-20157, Italy
| | - Kam-Bo Wong
- Centre for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong (CUHK), Shatin, Hong Kong, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- The CUHK Shenzhen Research Institute, Shenzhen, 518057, China
- Institute of Plant Molecular Biology and Agricultural Biotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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50
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Zhang X, Wang L, Pan T, Wu X, Shen J, Jiang L, Tajima H, Blumwald E, Qiu QS. Plastid KEA-type cation/H + antiporters are required for vacuolar protein trafficking in Arabidopsis. J Integr Plant Biol 2023; 65:2157-2174. [PMID: 37252889 DOI: 10.1111/jipb.13537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 05/28/2023] [Indexed: 06/01/2023]
Abstract
Arabidopsis plastid antiporters KEA1 and KEA2 are critical for plastid development, photosynthetic efficiency, and plant development. Here, we show that KEA1 and KEA2 are involved in vacuolar protein trafficking. Genetic analyses found that the kea1 kea2 mutants had short siliques, small seeds, and short seedlings. Molecular and biochemical assays showed that seed storage proteins were missorted out of the cell and the precursor proteins were accumulated in kea1 kea2. Protein storage vacuoles (PSVs) were smaller in kea1 kea2. Further analyses showed that endosomal trafficking in kea1 kea2 was compromised. Vacuolar sorting receptor 1 (VSR1) subcellular localizations, VSR-cargo interactions, and p24 distribution on the endoplasmic reticulum (ER) and Golgi apparatus were affected in kea1 kea2. Moreover, plastid stromule growth was reduced and plastid association with the endomembrane compartments was disrupted in kea1 kea2. Stromule growth was regulated by the cellular pH and K+ homeostasis maintained by KEA1 and KEA2. The organellar pH along the trafficking pathway was altered in kea1 kea2. Overall, KEA1 and KEA2 regulate vacuolar trafficking by controlling the function of plastid stromules via adjusting pH and K+ homeostasis.
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Affiliation(s)
- Xiao Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, 810000, China
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, 730000, China
| | - Lu Wang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, 810000, China
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, 730000, China
| | - Ting Pan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
| | - Xuexia Wu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
| | - Jinbo Shen
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Hiromi Tajima
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Eduardo Blumwald
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, 810000, China
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, 730000, China
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