1
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Wang B, Pareek G, Kundu M. ULK/Atg1: phasing in and out of autophagy. Trends Biochem Sci 2024; 49:494-505. [PMID: 38565496 PMCID: PMC11162330 DOI: 10.1016/j.tibs.2024.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/28/2024] [Accepted: 03/08/2024] [Indexed: 04/04/2024]
Abstract
Autophagy - a highly regulated intracellular degradation process - is pivotal in maintaining cellular homeostasis. Liquid-liquid phase separation (LLPS) is a fundamental mechanism regulating the formation and function of membrane-less compartments. Recent research has unveiled connections between LLPS and autophagy, suggesting that phase separation events may orchestrate the spatiotemporal organization of autophagic machinery and cargo sequestration. The Unc-51-like kinase (ULK)/autophagy-related 1 (Atg1) family of proteins is best known for its regulatory role in initiating autophagy, but there is growing evidence that the functional spectrum of ULK/Atg1 extends beyond autophagy regulation. In this review, we explore the spatial and temporal regulation of the ULK/Atg1 family of kinases, focusing on their recruitment to LLPS-driven compartments, and highlighting their multifaceted functions beyond their traditional role.
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Affiliation(s)
- Bo Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, China; Shenzhen Research Institute of Xiamen University, Shenzhen, 518057, China
| | - Gautam Pareek
- Department of Cell and Molecular Biology, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Mondira Kundu
- Department of Cell and Molecular Biology, St Jude Children's Research Hospital, Memphis, TN 38105, USA.
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2
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Tedesco G, Santarosa M, Maestro R. Beyond self‑eating: Emerging autophagy‑independent functions for the autophagy molecules in cancer (Review). Int J Oncol 2024; 64:57. [PMID: 38606507 PMCID: PMC11087037 DOI: 10.3892/ijo.2024.5645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 03/21/2024] [Indexed: 04/13/2024] Open
Abstract
Autophagy is a conserved catabolic process that controls organelle quality, removes misfolded or abnormally aggregated proteins and is part of the defense mechanisms against intracellular pathogens. Autophagy contributes to the suppression of tumor initiation by promoting genome stability, cellular integrity, redox balance and proteostasis. On the other hand, once a tumor is established, autophagy can support cancer cell survival and promote epithelial‑to‑mesenchymal transition. A growing number of molecules involved in autophagy have been identified. In addition to their key canonical activity, several of these molecules, such as ATG5, ATG12 and Beclin‑1, also exert autophagy‑independent functions in a variety of biological processes. The present review aimed to summarize autophagy‑independent functions of molecules of the autophagy machinery and how the activity of these molecules can influence signaling pathways that are deregulated in cancer progression.
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Affiliation(s)
- Giulia Tedesco
- Unit of Oncogenetics and Functional Oncogenomics, CRO Aviano, National Cancer Institute, IRCCS, I-33081 Aviano, Italy
| | - Manuela Santarosa
- Unit of Oncogenetics and Functional Oncogenomics, CRO Aviano, National Cancer Institute, IRCCS, I-33081 Aviano, Italy
| | - Roberta Maestro
- Unit of Oncogenetics and Functional Oncogenomics, CRO Aviano, National Cancer Institute, IRCCS, I-33081 Aviano, Italy
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3
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Leclerc NR, Dunne TM, Shrestha S, Johnson CP, Kelley JB. TOR signaling regulates GPCR levels on the plasma membrane and suppresses the Saccharomyces cerevisiae mating pathway. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.09.593412. [PMID: 38798445 PMCID: PMC11118302 DOI: 10.1101/2024.05.09.593412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Saccharomyces cerevisiae respond to mating pheromone through the GPCRs Ste2 and Ste3, which promote growth of a mating projection in response to ligand binding. This commitment to mating is nutritionally and energetically taxing, and so we hypothesized that the cell may suppress mating signaling during starvation. We set out to investigate negative regulators of the mating pathway in nutritionally depleted environments. Here, we report that nutrient deprivation led to loss of Ste2 from the plasma membrane. Recapitulating this effect with nitrogen starvation led us to hypothesize that it was due to TORC1 signaling. Rapamycin inhibition of TORC1 impacted membrane levels of all yeast GPCRs. Inhibition of TORC1 also dampened mating pathway output. Deletion analysis revealed that TORC1 repression leads to α-arrestin-directed CME through TORC2-Ypk1 signaling. We then set out to determine whether major downstream effectors of the TOR complexes also downregulate pathway output during mating. We found that autophagy contributes to pathway downregulation through analysis of strains lacking ATG8 . We also show that Ypk1 significantly reduced pathway output. Thus, both autophagy machinery and TORC2-Ypk1 signaling serve as attenuators of pheromone signaling during mating. Altogether, we demonstrate that the stress-responsive TOR complexes coordinate GPCR endocytosis and reduce the magnitude of pheromone signaling, in ligand-independent and ligand-dependent contexts. One Sentence Summary TOR signaling regulates the localization of all Saccharomyces cerevisiae GPCRs during starvation and suppress the mating pathway in the presence and absence of ligand.
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Singh SP, Verma RK, Goel R, Kumar V, Singh RR, Sawant SV. Arabidopsis BECLIN1-induced autophagy mediates reprogramming in tapetal programmed cell death by altering the gross cellular homeostasis. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 208:108471. [PMID: 38503186 DOI: 10.1016/j.plaphy.2024.108471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 02/14/2024] [Accepted: 02/23/2024] [Indexed: 03/21/2024]
Abstract
In flowering plants, the tapetum degeneration in post-meiotic anther occurs through developmental programmed cell death (dPCD), which is one of the most critical and sensitive steps for the proper development of male gametophytes and fertility. Yet the pathways of dPCD, its regulation, and its interaction with autophagy remain elusive. Here, we report that high-level expression of Arabidopsis autophagy-related gene BECLIN1 (BECN1 or AtATG6) in the tobacco tapetum prior to their dPCD resulted in developmental defects. BECN1 induces severe autophagy and multiple cytoplasm-to-vacuole pathways, which alters tapetal cell reactive oxygen species (ROS)-homeostasis that represses the tapetal dPCD. The transcriptome analysis reveals that BECN1- expression caused major changes in the pathway, resulting in altered cellular homeostasis in the tapetal cell. Moreover, BECN1-mediated autophagy reprograms the execution of tapetal PCD by altering the expression of the key developmental PCD marker genes: SCPL48, CEP1, DMP4, BFN1, MC9, EXI1, and Bcl-2 member BAG5, and BAG6. This study demonstrates that BECN1-mediated autophagy is inhibitory to the dPCD of the tapetum, but the severity of autophagy leads to autophagic death in the later stages. The delayed and altered mode of tapetal degeneration resulted in male sterility.
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Affiliation(s)
- Surendra Pratap Singh
- Plant Molecular Biology Laboratory, CSIR National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India; Department of Botany, University of Lucknow, Lucknow, 226007, India.
| | - Rishi Kumar Verma
- Plant Molecular Biology Laboratory, CSIR National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
| | - Ridhi Goel
- Plant Molecular Biology Laboratory, CSIR National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
| | - Verandra Kumar
- Plant Molecular Biology Laboratory, CSIR National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India.
| | | | - Samir V Sawant
- Plant Molecular Biology Laboratory, CSIR National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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5
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Tsong H, Holzbaur ELF, Stavoe AKH. Aging Differentially Affects Axonal Autophagosome Formation and Maturation. Autophagy 2023; 19:3079-3095. [PMID: 37464898 PMCID: PMC10621248 DOI: 10.1080/15548627.2023.2236485] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 06/21/2023] [Accepted: 07/03/2023] [Indexed: 07/20/2023] Open
Abstract
Misregulation of neuronal macroautophagy/autophagy has been implicated in age-related neurodegenerative diseases. We compared autophagosome formation and maturation in primary murine neurons during development and through aging to elucidate how aging affects neuronal autophagy. We observed an age-related decrease in the rate of autophagosome formation leading to a significant decrease in the density of autophagosomes along the axon. Next, we identified a surprising increase in the maturation of autophagic vesicles in neurons from aged mice. While we did not detect notable changes in endolysosomal content in the distal axon during early aging, we did observe a significant loss of acidified vesicles in the distal axon during late aging. Interestingly, we found that autophagic vesicles were transported more efficiently in neurons from adult mice than in neurons from young mice. This efficient transport of autophagic vesicles in both the distal and proximal axon is maintained in neurons during early aging, but is lost during late aging. Our data indicate that early aging does not negatively impact autophagic vesicle transport nor the later stages of autophagy. However, alterations in autophagic vesicle transport efficiency during late aging reveal that aging differentially impacts distinct aspects of neuronal autophagy.Abbreviations: ACAP3: ArfGAP with coiled-coil, ankyrin repeat and PH domains 3; ARF6: ADP-ribosylation factor 6; ATG: autophagy related; AVs: autophagic vesicles; DCTN1/p150Glued: dynactin 1; DRG: dorsal root ganglia; GAP: GTPase activating protein; GEF: guanine nucleotide exchange factor; LAMP2: lysosomal-associated protein 2; LysoT: LysoTracker; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MAPK8IP1/JIP1: mitogen-activated protein kinase 8 interacting protein 1; MAPK8IP3/JIP3: mitogen-activated protein kinase 8 interacting protein 3; mCh: mCherry; PE: phosphatidylethanolamine.
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Affiliation(s)
- Heather Tsong
- Department of Neurobiology & Anatomy, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Erika LF Holzbaur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrea KH Stavoe
- Department of Neurobiology & Anatomy, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
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Miklaszewska M, Zienkiewicz K, Klugier-Borowska E, Rygielski M, Feussner I, Zienkiewicz A. CALEOSIN 1 interaction with AUTOPHAGY-RELATED PROTEIN 8 facilitates lipid droplet microautophagy in seedlings. PLANT PHYSIOLOGY 2023; 193:2361-2380. [PMID: 37619984 PMCID: PMC10663143 DOI: 10.1093/plphys/kiad471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/16/2023] [Accepted: 08/05/2023] [Indexed: 08/26/2023]
Abstract
Lipid droplets (LDs) of seed tissues are storage organelles for triacylglycerols (TAGs) that provide the energy and carbon for seedling establishment. In the major route of LD degradation (lipolysis), TAGs are mobilized by lipases. However, LDs may also be degraded via lipophagy, a type of selective autophagy, which mediates LD delivery to vacuoles or lysosomes. The exact mechanisms of LD degradation and the mobilization of their content in plants remain unresolved. Here, we provide evidence that LDs are degraded via a process morphologically resembling microlipophagy in Arabidopsis (Arabidopsis thaliana) seedlings. We observed the entry and presence of LDs in the central vacuole as well as their breakdown. Moreover, we show co-localization of AUTOPHAGY-RELATED PROTEIN 8b (ATG8b) and LDs during seed germination and localization of lipidated ATG8 (ATG8-PE) to the LD fraction. We further demonstrate that structural LD proteins from the caleosin family, CALEOSIN 1 (CLO1), CALEOSIN 2 (CLO2), and CALEOSIN 3 (CLO3), interact with ATG8 proteins and possess putative ATG8-interacting motifs (AIMs). Deletion of the AIM localized directly before the proline knot disrupts the interaction of CLO1 with ATG8b, suggesting a possible role of this region in the interaction between these proteins. Collectively, we provide insights into LD degradation by microlipophagy in germinating seeds with a particular focus on the role of structural LD proteins in this process.
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Affiliation(s)
- Magdalena Miklaszewska
- Department of Plant Physiology and Biotechnology, University of Gdańsk, Wita Stwosza 59, Gdańsk 80-308, Poland
- Department for Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Justus-von-Liebig-Weg 11, Goettingen 37077, Germany
| | - Krzysztof Zienkiewicz
- Department for Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Justus-von-Liebig-Weg 11, Goettingen 37077, Germany
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland
| | - Ewa Klugier-Borowska
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland
| | - Marcin Rygielski
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland
| | - Ivo Feussner
- Department for Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Justus-von-Liebig-Weg 11, Goettingen 37077, Germany
- Service Unit for Metabolomics and Lipidomics, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig-Weg 11, Goettingen 37077, Germany
- Department of Plant Biochemistry, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig-Weg 11, Goettingen 37077, Germany
| | - Agnieszka Zienkiewicz
- Department for Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Justus-von-Liebig-Weg 11, Goettingen 37077, Germany
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland
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Wu S, Edskes HK, Wickner RB. Human proteins curing yeast prions. Proc Natl Acad Sci U S A 2023; 120:e2314781120. [PMID: 37903258 PMCID: PMC10636303 DOI: 10.1073/pnas.2314781120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 09/25/2023] [Indexed: 11/01/2023] Open
Abstract
Recognition that common human amyloidoses are prion diseases makes the use of the Saccharomyces cerevisiae prion model systems to screen for possible anti-prion components of increasing importance. [PSI+] and [URE3] are amyloid-based prions of Sup35p and Ure2p, respectively. Yeast has at least six anti-prion systems that together cure nearly all [PSI+] and [URE3] prions arising in their absence. We made a GAL-promoted bank of 14,913 human open reading frames in a yeast shuttle plasmid and isolated 20 genes whose expression cures [PSI+] or [URE3]. PRPF19 is an E3 ubiquitin ligase that cures [URE3] if its U-box is intact. DNAJA1 is a J protein that cures [PSI+] unless its interaction with Hsp70s is defective. Human Bag5 efficiently cures [URE3] and [PSI+]. Bag family proteins share a 110 to 130 residue "BAG domain"; Bag 1, 2, 3, 4, and 6 each have one BAG domain while Bag5 has five BAG domains. Two BAG domains are necessary for curing [PSI+], but one can suffice to cure [URE3]. Although most Bag proteins affect autophagy in mammalian cells, mutations blocking autophagy in yeast do not affect Bag5 curing of [PSI+] or [URE3]. Curing by Bag proteins depends on their interaction with Hsp70s, impairing their role, with Hsp104 and Sis1, in the amyloid filament cleavage necessary for prion propagation. Since Bag5 curing is reduced by overproduction of Sis1, we propose that Bag5 cures prions by blocking Sis1 access to Hsp70s in its role with Hsp104 in filament cleavage.
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Affiliation(s)
- Songsong Wu
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD20892-0830
| | - Herman K. Edskes
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD20892-0830
| | - Reed B. Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD20892-0830
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8
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Abeliovich H. Mitophagy in yeast: known unknowns and unknown unknowns. Biochem J 2023; 480:1639-1657. [PMID: 37850532 PMCID: PMC10586778 DOI: 10.1042/bcj20230279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 09/06/2023] [Accepted: 09/22/2023] [Indexed: 10/19/2023]
Abstract
Mitophagy, the autophagic breakdown of mitochondria, is observed in eukaryotic cells under various different physiological circumstances. These can be broadly categorized into two types: mitophagy related to quality control events and mitophagy induced during developmental transitions. Quality control mitophagy involves the lysosomal or vacuolar degradation of malfunctioning or superfluous mitochondria within lysosomes or vacuoles, and this is thought to serve as a vital maintenance function in respiring eukaryotic cells. It plays a crucial role in maintaining physiological balance, and its disruption has been associated with the progression of late-onset diseases. Developmentally induced mitophagy has been reported in the differentiation of metazoan tissues which undergo metabolic shifts upon developmental transitions, such as in the differentiation of red blood cells and muscle cells. Although the mechanistic studies of mitophagy in mammalian cells were initiated after the initial mechanistic findings in Saccharomyces cerevisiae, our current understanding of the physiological role of mitophagy in yeast remains more limited, despite the presence of better-defined assays and tools. In this review, I present my perspective on our present knowledge of mitophagy in yeast, focusing on physiological and mechanistic aspects. I aim to focus on areas where our understanding is still incomplete, such as the role of mitochondrial dynamics and the phenomenon of protein-level selectivity.
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Affiliation(s)
- Hagai Abeliovich
- Institute of Biochemistry, Food Science and Nutrition, Hebrew University of Jerusalem, 1 Hankin St, Rehovot 7610001, Israel
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9
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Sęk W, Kot AM, Rapoport A, Kieliszek M. Physiological and genetic regulation of anhydrobiosis in yeast cells. Arch Microbiol 2023; 205:348. [PMID: 37782422 PMCID: PMC10545650 DOI: 10.1007/s00203-023-03683-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 08/28/2023] [Accepted: 09/10/2023] [Indexed: 10/03/2023]
Abstract
Anhydrobiosis is a state of living organisms during which their metabolism is reversibly delayed or suspended due to a high degree of dehydration. Yeast cells, which are widely used in the food industry, may be induced into this state. The degree of viability of yeast cells undergoing the drying process also depends on rehydration. In an attempt to explain the essence of the state of anhydrobiosis and clarify the mechanisms responsible for its course, scientists have described various cellular compounds and structures that are responsible for it. The structures discussed in this work include the cell wall and plasma membrane, vacuoles, mitochondria, and lysosomes, among others, while the most important compounds include trehalose, glycogen, glutathione, and lipid droplets. Various proteins (Stf2p; Sip18p; Hsp12p and Hsp70p) and genes (STF2; Nsip18; TRX2; TPS1 and TPS2) are also responsible for the process of anhydrobiosis. Each factor has a specific function and is irreplaceable, detailed information is presented in this overview.
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Affiliation(s)
- Wioletta Sęk
- Department of Food Biotechnology and Microbiology, Institute of Food Sciences, Warsaw University of Life Sciences, Nowoursynowska 159C, 02-776, Warsaw, Poland
| | - Anna M Kot
- Department of Food Biotechnology and Microbiology, Institute of Food Sciences, Warsaw University of Life Sciences, Nowoursynowska 159C, 02-776, Warsaw, Poland.
| | - Alexander Rapoport
- Laboratory of Cell Biology, Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas Str., 1, Riga, 1004, Latvia
| | - Marek Kieliszek
- Department of Food Biotechnology and Microbiology, Institute of Food Sciences, Warsaw University of Life Sciences, Nowoursynowska 159C, 02-776, Warsaw, Poland.
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10
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Libberecht K, Vangansewinkel T, Van Den Bosch L, Lambrichts I, Wolfs E. Proteostasis plays an important role in demyelinating Charcot Marie Tooth disease. Biochem Pharmacol 2023; 216:115760. [PMID: 37604292 DOI: 10.1016/j.bcp.2023.115760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 08/23/2023]
Abstract
Type 1 Charcot-Marie-Tooth disease (CMT1) is the most common demyelinating peripheral neuropathy. Patients suffer from progressive muscle weakness and sensory problems. The underlying disease mechanisms of CMT1 are still unclear and no therapy is currently available, hence patients completely rely on supportive care. Balancing protein levels is a complex multistep process fundamental to maintain cells in their healthy state and a disrupted proteostasis is a hallmark of several neurodegenerative diseases. When protein misfolding occurs, protein quality control systems are activated such as chaperones, the lysosomal-autophagy system and proteasomal degradation to ensure proper degradation. However, in pathological circumstances, these mechanisms are overloaded and thereby become inefficient to clear the load of misfolded proteins. Recent evidence strongly indicates that a disbalance in proteostasis plays an important role in several forms of CMT1. In this review, we present an overview of the protein quality control systems, their role in CMT1, and potential treatment strategies to restore proteostasis.
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Affiliation(s)
- Karen Libberecht
- UHasselt, Biomedical Research Institute (BIOMED), Lab for Functional Imaging & Research on Stem Cells (FIERCELab), Diepenbeek, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.
| | - Tim Vangansewinkel
- UHasselt, Biomedical Research Institute (BIOMED), Lab for Functional Imaging & Research on Stem Cells (FIERCELab), Diepenbeek, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium; UHasselt, Biomedical Research Institute (BIOMED), Lab for Histology and Regeneration (HISTOREGEN Lab), Diepenbeek, Belgium
| | - Ludo Van Den Bosch
- KU Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Ivo Lambrichts
- UHasselt, Biomedical Research Institute (BIOMED), Lab for Histology and Regeneration (HISTOREGEN Lab), Diepenbeek, Belgium
| | - Esther Wolfs
- UHasselt, Biomedical Research Institute (BIOMED), Lab for Functional Imaging & Research on Stem Cells (FIERCELab), Diepenbeek, Belgium.
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Vijjamarri AK, Gupta N, Onu C, Niu X, Zhang F, Kumar R, Lin Z, Greenberg M, Hinnebusch AG. mRNA decapping activators Pat1 and Dhh1 regulate transcript abundance and translation to tune cellular responses to nutrient availability. Nucleic Acids Res 2023; 51:9314-9336. [PMID: 37439347 PMCID: PMC10516646 DOI: 10.1093/nar/gkad584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 06/17/2023] [Accepted: 07/10/2023] [Indexed: 07/14/2023] Open
Abstract
We have examined the roles of yeast mRNA decapping-activators Pat1 and Dhh1 in repressing the translation and abundance of specific mRNAs in nutrient-replete cells using ribosome profiling, RNA-Seq, CAGE analysis of capped mRNAs, RNA Polymerase II ChIP-Seq, and TMT-mass spectrometry of mutants lacking one or both factors. Although the Environmental Stress Response (ESR) is activated in dhh1Δ and pat1Δ mutants, hundreds of non-ESR transcripts are elevated in a manner indicating cumulative repression by Pat1 and Dhh1 in wild-type cells. These mRNAs show both reduced decapping and diminished transcription in the mutants, indicating that impaired mRNA turnover drives transcript derepression in cells lacking Dhh1 or Pat1. mRNA degradation stimulated by Dhh1/Pat1 is not dictated by poor translation nor enrichment for suboptimal codons. Pat1 and Dhh1 also collaborate to reduce translation and protein production from many mRNAs. Transcripts showing concerted translational repression by Pat1/Dhh1 include mRNAs involved in cell adhesion or utilization of the poor nitrogen source allantoin. Pat1/Dhh1 also repress numerous transcripts involved in respiration, catabolism of non-preferred carbon or nitrogen sources, or autophagy; and we obtained evidence for elevated respiration and autophagy in the mutants. Thus, Pat1 and Dhh1 function as post-transcriptional repressors of multiple pathways normally activated only during nutrient limitation.
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Affiliation(s)
- Anil Kumar Vijjamarri
- 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
| | - Neha Gupta
- 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
| | - Chisom Onu
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - Xiao Niu
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA
| | - Fan Zhang
- 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
| | - Rakesh Kumar
- 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
| | - Zhenguo Lin
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA
| | - Miriam L Greenberg
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - Alan G Hinnebusch
- 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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12
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Lee Y, Kim B, Jang HS, Huh WK. Atg1-dependent phosphorylation of Vps34 is required for dynamic regulation of the phagophore assembly site and autophagy in Saccharomyces cerevisiae. Autophagy 2023; 19:2428-2442. [PMID: 36803233 PMCID: PMC10392759 DOI: 10.1080/15548627.2023.2182478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 02/13/2023] [Accepted: 02/15/2023] [Indexed: 02/22/2023] Open
Abstract
Macroautophagy/autophagy is a key catabolic pathway in which double-membrane autophagosomes sequester various substrates destined for degradation, enabling cells to maintain homeostasis and survive under stressful conditions. Several autophagy-related (Atg) proteins are recruited to the phagophore assembly site (PAS) and cooperatively function to generate autophagosomes. Vps34 is a class III phosphatidylinositol 3-kinase, and Atg14-containing Vps34 complex I plays essential roles in autophagosome formation. However, the regulatory mechanisms of yeast Vps34 complex I are still poorly understood. Here, we demonstrate that Atg1-dependent phosphorylation of Vps34 is required for robust autophagy activity in Saccharomyces cerevisiae. Following nitrogen starvation, Vps34 in complex I is selectively phosphorylated on multiple serine/threonine residues in its helical domain. This phosphorylation is important for full autophagy activation and cell survival. The absence of Atg1 or its kinase activity leads to complete loss of Vps34 phosphorylation in vivo, and Atg1 directly phosphorylates Vps34 in vitro, regardless of its complex association type. We also demonstrate that the localization of Vps34 complex I to the PAS provides a molecular basis for the complex I-specific phosphorylation of Vps34. This phosphorylation is required for the normal dynamics of Atg18 and Atg8 at the PAS. Together, our results reveal a novel regulatory mechanism of yeast Vps34 complex I and provide new insights into the Atg1-dependent dynamic regulation of the PAS.Abbreviations: ATG: autophagy-related; BARA: the repeated, autophagy-specific Co-IP: co-immunoprecipitation; GFP: green fluorescent protein; IP-MS: immunoprecipitation followed by tandem mass spectrometry; NTD: the N-terminal domain; PAS: phagophore assembly site; PtdIns3P: phosphatidylinositol-3-phosphate; PtdIns3K: phosphatidylinositol 3-kinase; SUR: structurally uncharacterized region; Vps34[KD]: Vps34D731N.
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Affiliation(s)
- Yongook Lee
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Bongkeun Kim
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hae-Soo Jang
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Won-Ki Huh
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
- Institute of Microbiology, Seoul National University, Seoul, Republic of Korea
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13
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Attfield PV. Crucial aspects of metabolism and cell biology relating to industrial production and processing of Saccharomyces biomass. Crit Rev Biotechnol 2023; 43:920-937. [PMID: 35731243 DOI: 10.1080/07388551.2022.2072268] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/27/2022] [Accepted: 04/21/2022] [Indexed: 12/16/2022]
Abstract
The multitude of applications to which Saccharomyces spp. are put makes these yeasts the most prolific of industrial microorganisms. This review considers biological aspects pertaining to the manufacture of industrial yeast biomass. It is proposed that the production of yeast biomass can be considered in two distinct but interdependent phases. Firstly, there is a cell replication phase that involves reproduction of cells by their transitions through multiple budding and metabolic cycles. Secondly, there needs to be a cell conditioning phase that enables the accrued biomass to withstand the physicochemical challenges associated with downstream processing and storage. The production of yeast biomass is not simply a case of providing sugar, nutrients, and other growth conditions to enable multiple budding cycles to occur. In the latter stages of culturing, it is important that all cells are induced to complete their current budding cycle and subsequently enter into a quiescent state engendering robustness. Both the cell replication and conditioning phases need to be optimized and considered in concert to ensure good biomass production economics, and optimum performance of industrial yeasts in food and fermentation applications. Key features of metabolism and cell biology affecting replication and conditioning of industrial Saccharomyces are presented. Alternatives for growth substrates are discussed, along with the challenges and prospects associated with defining the genetic bases of industrially important phenotypes, and the generation of new yeast strains."I must be cruel only to be kind: Thus bad begins, and worse remains behind." William Shakespeare: Hamlet, Act 3, Scene 4.
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14
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Santana-Sosa S, Matos-Perdomo E, Ayra-Plasencia J, Machín F. A Yeast Mitotic Tale for the Nucleus and the Vacuoles to Embrace. Int J Mol Sci 2023; 24:9829. [PMID: 37372977 DOI: 10.3390/ijms24129829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/02/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
The morphology of the nucleus is roughly spherical in most eukaryotic cells. However, this organelle shape needs to change as the cell travels through narrow intercellular spaces during cell migration and during cell division in organisms that undergo closed mitosis, i.e., without dismantling the nuclear envelope, such as yeast. In addition, the nuclear morphology is often modified under stress and in pathological conditions, being a hallmark of cancer and senescent cells. Thus, understanding nuclear morphological dynamics is of uttermost importance, as pathways and proteins involved in nuclear shaping can be targeted in anticancer, antiaging, and antifungal therapies. Here, we review how and why the nuclear shape changes during mitotic blocks in yeast, introducing novel data that associate these changes with both the nucleolus and the vacuole. Altogether, these findings suggest a close relationship between the nucleolar domain of the nucleus and the autophagic organelle, which we also discuss here. Encouragingly, recent evidence in tumor cell lines has linked aberrant nuclear morphology to defects in lysosomal function.
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Affiliation(s)
- Silvia Santana-Sosa
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Emiliano Matos-Perdomo
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Jessel Ayra-Plasencia
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Félix Machín
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
- Faculty of Health Sciences, Fernando Pessoa Canarias University, 35450 Santa María de Guía, Spain
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15
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Strížová A, Šmátralová P, Chovančíková P, Machala Z, Polčic P. Defects in Mitochondrial Functions Affect the Survival of Yeast Cells Treated with Non-Thermal Plasma. Int J Mol Sci 2023; 24:ijms24119391. [PMID: 37298346 DOI: 10.3390/ijms24119391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/14/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Exposure of living cells to non-thermal plasma produced in various electrical discharges affects cell physiology and often results in cell death. Even though plasma-based techniques have started finding practical applications in biotechnology and medicine, the molecular mechanisms of interaction of cells with plasma remain poorly understood. In this study, the involvement of selected cellular components or pathways in plasma-induced cell killing was studied employing yeast deletion mutants. The changes in yeast sensitivity to plasma-activated water were observed in mutants with the defect in mitochondrial functions, including transport across the outer mitochondrial membrane (∆por1), cardiolipin biosynthesis (∆crd1, ∆pgs1), respiration (ρ0) and assumed signaling to the nucleus (∆mdl1, ∆yme1). Together these results indicate that mitochondria play an important role in plasma-activated water cell killing, both as the target of the damage and the participant in the damage signaling, which may lead to the induction of cell protection. On the other hand, our results show that neither mitochondria-ER contact sites, UPR, autophagy, nor proteasome play a major role in the protection of yeast cells from plasma-induced damage.
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Affiliation(s)
- Anna Strížová
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina CH1, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Paulína Šmátralová
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina CH1, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Petra Chovančíková
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina CH1, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Zdenko Machala
- Division of Environmental Physics, Faculty of Mathematics, Physics, and Informatics, Comenius University in Bratislava, Mlynská dolina F2, 84248 Bratislava, Slovakia
| | - Peter Polčic
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina CH1, Ilkovičova 6, 84215 Bratislava, Slovakia
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16
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Cisilotto B, Scariot FJ, Schwarz LV, Mattos Rocha RK, Longaray Delamare AP, Echeverrigaray S. Differences in yeast behaviour during ageing of sparkling wines made with Charmat and Traditional methods. Food Microbiol 2023; 110:104171. [DOI: 10.1016/j.fm.2022.104171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 10/17/2022] [Accepted: 10/20/2022] [Indexed: 11/16/2022]
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17
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Jiao W, Ding W, Rollins JA, Liu J, Zhang Y, Zhang X, Pan H. Cross-Talk and Multiple Control of Target of Rapamycin (TOR) in Sclerotinia sclerotiorum. Microbiol Spectr 2023; 11:e0001323. [PMID: 36943069 PMCID: PMC10100786 DOI: 10.1128/spectrum.00013-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/23/2023] [Indexed: 03/23/2023] Open
Abstract
Sclerotinia sclerotiorum is a necrotrophic phytopathogenic fungus that cross-talks with its hosts for control of cell-death pathways for colonization. Target of rapamycin (TOR) is a central regulator that controls cell growth, intracellular metabolism, and stress responses in a variety of eukaryotes, but little is known about TOR signaling in S. sclerotiorum. In this study, we identified a conserved TOR signaling pathway and characterized SsTOR as a critical component of this pathway. Hyphal growth of S. sclerotiorum was retarded by silencing SsTOR, moreover, sclerotia and compound appressoria formation were severely disrupted. Notably, pathogenicity assays of strains shows that the virulence of the SsTOR-silenced strains were dramatically decreased. SsTOR was determined to participate in cell wall integrity (CWI) by regulating the phosphorylation level of SsSmk3, a core MAP kinase in the CWI pathway. Importantly, the inactivation of SsTOR induced autophagy in S. sclerotiorum potentially through SsAtg1 and SsAtg13. Taken together, our results suggest that SsTOR is a global regulator controlling cell growth, stress responses, cell wall integrity, autophagy, and virulence of S. sclerotiorum. IMPORTANCE TOR is a conserved protein kinase that regulates cell growth and metabolism in response to growth factors and nutrient abundance. Here, we used gene silencing to characterize SsTOR, which is a critical component of TOR signaling pathway. SsTOR-silenced strains have limited mycelium growth, and the virulence of the SsTOR-silenced strains was decreased. Phosphorylation analysis indicated that SsTOR influenced CWI by regulating the phosphorylation level of SsSmk3. Autophagy is essential to preserve cellular homeostasis in response to cellular and environmental stresses. Inactivation of SsTOR induced autophagy in S. sclerotiorum potentially through SsAtg1 and SsAtg13. These findings further indicated that SsTOR is a global regulator of the growth, development, and pathogenicity of S. sclerotiorum in multiple ways.
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Affiliation(s)
- Wenli Jiao
- College of Plant Sciences, Jilin University, Changchun, China
| | - Weichen Ding
- College of Plant Sciences, Jilin University, Changchun, China
| | - Jeffrey A. Rollins
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Jinliang Liu
- College of Plant Sciences, Jilin University, Changchun, China
| | - Yanhua Zhang
- College of Plant Sciences, Jilin University, Changchun, China
| | - Xianghui Zhang
- College of Plant Sciences, Jilin University, Changchun, China
| | - Hongyu Pan
- College of Plant Sciences, Jilin University, Changchun, China
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18
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Li X, Mei Q, Yu Q, Wang M, He F, Xiao D, Liu H, Ge F, Yu X, Li S. The TORC1 activates Rpd3L complex to deacetylate Ino80 and H2A.Z and repress autophagy. SCIENCE ADVANCES 2023; 9:eade8312. [PMID: 36888706 PMCID: PMC9995077 DOI: 10.1126/sciadv.ade8312] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
Autophagy is a critical process to maintain homeostasis, differentiation, and development. How autophagy is tightly regulated by nutritional changes is poorly understood. Here, we identify chromatin remodeling protein Ino80 and histone variant H2A.Z as the deacetylation targets for histone deacetylase Rpd3L complex and uncover how they regulate autophagy in response to nutrient availability. Mechanistically, Rpd3L deacetylates Ino80 K929, which protects Ino80 from being degraded by autophagy. The stabilized Ino80 promotes H2A.Z eviction from autophagy-related genes, leading to their transcriptional repression. Meanwhile, Rpd3L deacetylates H2A.Z, which further blocks its deposition into chromatin to repress the transcription of autophagy-related genes. Rpd3-mediated deacetylation of Ino80 K929 and H2A.Z is enhanced by the target of rapamycin complex 1 (TORC1). Inactivation of TORC1 by nitrogen starvation or rapamycin inhibits Rpd3L, leading to induction of autophagy. Our work provides a mechanism for chromatin remodelers and histone variants in modulating autophagy in response to nutrient availability.
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Affiliation(s)
- Xin Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Qianyun Mei
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Qi Yu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Min Wang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Fei He
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Duncheng Xiao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Huan Liu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Feng Ge
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Xilan Yu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Shanshan Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
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19
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Shen ZF, Li L, Zhu XM, Liu XH, Klionsky DJ, Lin FC. Current opinions on mitophagy in fungi. Autophagy 2023; 19:747-757. [PMID: 35793406 PMCID: PMC9980689 DOI: 10.1080/15548627.2022.2098452] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 11/02/2022] Open
Abstract
Mitophagy, as one of the most important cellular processes to ensure quality control of mitochondria, aims at transporting damaged, aging, dysfunctional or excess mitochondria to vacuoles (plants and fungi) or lysosomes (mammals) for degradation and recycling. The normal functioning of mitophagy is critical for cellular homeostasis from yeasts to humans. Although the role of mitophagy has been well studied in mammalian cells and in certain model organisms, especially the budding yeast Saccharomyces cerevisiae, our understanding of its significance in other fungi, particularly in pathogenic filamentous fungi, is still at the preliminary stage. Recent studies have shown that mitophagy plays a vital role in spore production, vegetative growth and virulence of pathogenic fungi, which are very different from its roles in mammal and yeast. In this review, we summarize the functions of mitophagy for mitochondrial quality and quantity control, fungal growth and pathogenesis that have been reported in the field of molecular biology over the past two decades. These findings may help researchers and readers to better understand the multiple functions of mitophagy and provide new perspectives for the study of mitophagy in fungal pathogenesis.Abbreviations: AIM/LIR: Atg8-family interacting motif/LC3-interacting region; BAR: Bin-Amphiphysin-Rvs; BNIP3: BCL2 interacting protein 3; CK2: casein kinase 2; Cvt: cytoplasm-to-vacuole targeting; ER: endoplasmic reticulum; IMM: inner mitochondrial membrane; mETC: mitochondrial electron transport chain; OMM: outer mitochondrial membrane; OPTN: optineurin; PAS: phagophore assembly site; PD: Parkinson disease; PE: phosphatidylethanolamine; PHB2: prohibitin 2; PX: Phox homology; ROS, reactive oxygen species; TM: transmembrane.
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Affiliation(s)
- Zi-Fang Shen
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, China
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lin Li
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, China
| | - Xue-Ming Zhu
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, China
| | - Xiao-Hong Liu
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Daniel J. Klionsky
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Fu-Cheng Lin
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, China
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, China
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20
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Ding JL, Zhang H, Feng MG, Ying SH. Divergent Physiological Functions of Four Atg22-like Proteins in Conidial Germination, Development, and Virulence of the Entomopathogenic Fungus Beauveria bassiana. J Fungi (Basel) 2023; 9:jof9020262. [PMID: 36836376 PMCID: PMC9959203 DOI: 10.3390/jof9020262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/18/2023] Open
Abstract
In yeast, Atg22 functions as a vacuolar efflux transporter to release the nutrients from the vacuole to the cytosol after the degradation of autophagic bodies. There are more than one Atg22 domain-containing proteins in filamentous fungi, but their physiological roles are largely unknown. In this study, four Atg22-like proteins (BbAtg22A through D) were functionally characterized in the filamentous entomopathogenic fungus Beauveria bassiana. These Atg22-like proteins exhibit different sub-cellular distributions. BbAtg22A localizes in lipid droplets. BbAtg22B and BbAtg22C are completely distributed in the vacuole, and BbAtg22D has an additional association with the cytomembrane. The ablation of Atg22-like proteins did not block autophagy. Four Atg22-like proteins systematically contribute to the fungal response to starvation and virulence in B. bassiana. With the exception of ∆Bbatg22C, the other three proteins contribute to dimorphic transmission. Additionally, BbAtg22A and BbAtg22D are required for cytomembrane integrity. Meanwhile, four Atg22-like proteins contribute to conidiation. Therefore, Atg22-like proteins link distinct sub-cellular structures for the development and virulence in B. bassiana. Our findings provide a novel insight into the non-autophagic roles of autophagy-related genes in filamentous fungi.
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21
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Fatty Acyl Coenzyme A Synthetase Fat1p Regulates Vacuolar Structure and Stationary-Phase Lipophagy in Saccharomyces cerevisiae. Microbiol Spectr 2023; 11:e0462522. [PMID: 36598223 PMCID: PMC9927365 DOI: 10.1128/spectrum.04625-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
During yeast stationary phase, a single spherical vacuole (lysosome) is created by the fusion of several small ones. Moreover, the vacuolar membrane is reconstructed into two distinct microdomains. Little is known, however, about how cells maintain vacuolar shape or regulate their microdomains. Here, we show that Fat1p, a fatty acyl coenzyme A (acyl-CoA) synthetase and fatty acid transporter, and not the synthetases Faa1p and Faa4p, is essential for vacuolar shape preservation, the development of vacuolar microdomains, and cell survival in stationary phase of the yeast Saccharomyces cerevisiae. Furthermore, Fat1p negatively regulates general autophagy in both log- and stationary-phase cells. In contrast, Fat1p promotes lipophagy, as the absence of FAT1 limits the entry of lipid droplets into the vacuole and reduces the degradation of liquid droplet (LD) surface proteins. Notably, supplementing with unsaturated fatty acids or overexpressing the desaturase Ole1p can reverse all aberrant phenotypes caused by FAT1 deficiency. We propose that Fat1p regulates stationary phase vacuolar morphology, microdomain differentiation, general autophagy, and lipophagy by controlling the degree of fatty acid saturation in membrane lipids. IMPORTANCE The ability to sense environmental changes and adjust the levels of cellular metabolism is critical for cell viability. Autophagy is a recycling process that makes the most of already-existing energy resources, and the vacuole/lysosome is the ultimate autophagic processing site in cells. Lipophagy is an autophagic process to select degrading lipid droplets. In yeast cells in stationary phase, vacuoles fuse and remodel their membranes to create a single spherical vacuole with two distinct membrane microdomains, which are required for yeast lipophagy. In this study, we discovered that Fat1p was capable of rapidly responding to changes in nutritional status and preserving cell survival by regulating membrane lipid saturation to maintain proper vacuolar morphology and the level of lipophagy in the yeast S. cerevisiae. Our findings shed light on how cells maintain vacuolar structure and promote the differentiation of vacuole surface microdomains for stationary-phase lipophagy.
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22
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Alao JP, Legon L, Dabrowska A, Tricolici AM, Kumar J, Rallis C. Interplays of AMPK and TOR in Autophagy Regulation in Yeast. Cells 2023; 12:cells12040519. [PMID: 36831186 PMCID: PMC9953913 DOI: 10.3390/cells12040519] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/08/2023] Open
Abstract
Cells survey their environment and need to balance growth and anabolism with stress programmes and catabolism towards maximum cellular bioenergetics economy and survival. Nutrient-responsive pathways, such as the mechanistic target of rapamycin (mTOR) interact and cross-talk, continuously, with stress-responsive hubs such as the AMP-activated protein kinase (AMPK) to regulate fundamental cellular processes such as transcription, protein translation, lipid and carbohydrate homeostasis. Especially in nutrient stresses or deprivations, cells tune their metabolism accordingly and, crucially, recycle materials through autophagy mechanisms. It has now become apparent that autophagy is pivotal in lifespan, health and cell survival as it is a gatekeeper of clearing damaged macromolecules and organelles and serving as quality assurance mechanism within cells. Autophagy is hard-wired with energy and nutrient levels as well as with damage-response, and yeasts have been instrumental in elucidating such connectivities. In this review, we briefly outline cross-talks and feedback loops that link growth and stress, mainly, in the fission yeast Schizosaccharomyces pombe, a favourite model in cell and molecular biology.
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23
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Inactive Proteasomes Routed to Autophagic Turnover Are Confined within the Soluble Fraction of the Cell. Biomolecules 2022; 13:biom13010077. [PMID: 36671462 PMCID: PMC9855985 DOI: 10.3390/biom13010077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 12/22/2022] [Accepted: 12/27/2022] [Indexed: 01/01/2023] Open
Abstract
Previous studies demonstrated that dysfunctional yeast proteasomes accumulate in the insoluble protein deposit (IPOD), described as the final deposition site for amyloidogenic insoluble proteins and that this compartment also mediates proteasome ubiquitination, a prerequisite for their targeted autophagy (proteaphagy). Here, we examined the solubility state of proteasomes subjected to autophagy as a result of their inactivation, or under nutrient starvation. In both cases, only soluble proteasomes could serve as a substrate to autophagy, suggesting a modified model whereby substrates for proteaphagy are dysfunctional proteasomes in their near-native soluble state, and not as previously believed, those sequestered at the IPOD. Furthermore, the insoluble fraction accumulating in the IPOD represents an alternative pathway, enabling the removal of inactive proteasomes that escaped proteaphagy when the system became saturated. Altogether, we suggest that the relocalization of proteasomes to soluble aggregates represents a general stage of proteasome recycling through autophagy.
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24
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Vázquez-Bolado A, López-San Segundo R, García-Blanco N, Rozalén AE, González-Álvarez D, Suárez MB, Pérez-Hidalgo L, Moreno S. The Greatwall-Endosulfine Switch Accelerates Autophagic Flux during the Cell Divisions Leading to G1 Arrest and Entry into Quiescence in Fission Yeast. Int J Mol Sci 2022; 24:ijms24010148. [PMID: 36613592 PMCID: PMC9820488 DOI: 10.3390/ijms24010148] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/16/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Entry into quiescence in the fission yeast Schizosaccharomyces pombe is induced by nitrogen starvation. In the absence of nitrogen, proliferating fission yeast cells divide twice without cell growth and undergo cell cycle arrest in G1 before becoming G0 quiescent cells. Under these conditions, autophagy is induced to produce enough nitrogen for the two successive cell divisions that take place before the G1 arrest. In parallel to the induction of autophagy, the Greatwall-Endosulfine switch is activated upon nitrogen starvation to down-regulate protein phosphatase PP2A/B55 activity, which is essential for cell cycle arrest in G1 and implementation of the quiescent program. Here we show that, although inactivation of PP2A/B55 by the Greatwall-Endosulfine switch is not required to promote autophagy initiation, it increases autophagic flux at least in part by upregulating the expression of a number of autophagy-related genes.
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Affiliation(s)
- Alicia Vázquez-Bolado
- Instituto de Biología Funcional y Genómica (IBFG), CSIC, Salamanca University, Zacarías González 2, 37007 Salamanca, Spain
| | - Rafael López-San Segundo
- Instituto de Biología Funcional y Genómica (IBFG), CSIC, Salamanca University, Zacarías González 2, 37007 Salamanca, Spain
| | - Natalia García-Blanco
- Instituto de Biología Funcional y Genómica (IBFG), CSIC, Salamanca University, Zacarías González 2, 37007 Salamanca, Spain
| | - Ana Elisa Rozalén
- Instituto de Biología Funcional y Genómica (IBFG), CSIC, Salamanca University, Zacarías González 2, 37007 Salamanca, Spain
| | - Daniel González-Álvarez
- Instituto de Biología Funcional y Genómica (IBFG), CSIC, Salamanca University, Zacarías González 2, 37007 Salamanca, Spain
| | - M. Belén Suárez
- Instituto de Biología Funcional y Genómica (IBFG), CSIC, Salamanca University, Zacarías González 2, 37007 Salamanca, Spain
- Department of Microbiology and Genetics, Salamanca University, 37007 Salamanca, Spain
| | - Livia Pérez-Hidalgo
- Instituto de Biología Funcional y Genómica (IBFG), CSIC, Salamanca University, Zacarías González 2, 37007 Salamanca, Spain
| | - Sergio Moreno
- Instituto de Biología Funcional y Genómica (IBFG), CSIC, Salamanca University, Zacarías González 2, 37007 Salamanca, Spain
- Correspondence:
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Hofer SJ, Simon AK, Bergmann M, Eisenberg T, Kroemer G, Madeo F. Mechanisms of spermidine-induced autophagy and geroprotection. NATURE AGING 2022; 2:1112-1129. [PMID: 37118547 DOI: 10.1038/s43587-022-00322-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 10/28/2022] [Indexed: 04/30/2023]
Abstract
Aging involves the systemic deterioration of all known cell types in most eukaryotes. Several recently discovered compounds that extend the healthspan and lifespan of model organisms decelerate pathways that govern the aging process. Among these geroprotectors, spermidine, a natural polyamine ubiquitously found in organisms from all kingdoms, prolongs the lifespan of fungi, nematodes, insects and rodents. In mice, it also postpones the manifestation of various age-associated disorders such as cardiovascular disease and neurodegeneration. The specific features of spermidine, including its presence in common food items, make it an interesting candidate for translational aging research. Here, we review novel insights into the geroprotective mode of action of spermidine at the molecular level, as we discuss strategies for elucidating its clinical potential.
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Affiliation(s)
- Sebastian J Hofer
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université de Paris Cité, Sorbonne Université, Inserm U1138, Institut Universitaire de France, Paris, France
- Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France
| | - Anna Katharina Simon
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
- Max Delbrück Center, Berlin, Germany
| | - Martina Bergmann
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Tobias Eisenberg
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
| | - Guido Kroemer
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université de Paris Cité, Sorbonne Université, Inserm U1138, Institut Universitaire de France, Paris, France.
- Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France.
- Institut du Cancer Paris CARPEM, Department of Biology, Hôpital Européen Georges Pompidou, AP-HP, Paris, France.
| | - Frank Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria.
- Field of Excellence BioHealth, University of Graz, Graz, Austria.
- BioTechMed Graz, Graz, Austria.
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Distinct roles for different autophagy-associated genes in the virulence of the fungal wheat pathogen Zymoseptoria tritici. Fungal Genet Biol 2022; 163:103748. [PMID: 36309095 DOI: 10.1016/j.fgb.2022.103748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 09/16/2022] [Accepted: 10/13/2022] [Indexed: 01/06/2023]
Abstract
The fungal wheat pathogen Zymoseptoria tritici causes major crop losses as the causal agent of the disease Septoria tritici blotch. The infection cycle of Z. tritici displays two distinct phases, beginning with an extended symptomless phase of 1-2 weeks, before the fungus induces host cell death and tissue collapse in the leaf. Recent evidence suggests that the fungus uses little host-derived nutrition during asymptomatic colonisation, raising questions as to the sources of energy required for this initial growth phase. Autophagy is crucial for the pathogenicity of other fungal plant pathogens through its roles in supporting cellular differentiation and growth under starvation. Here we characterised the contributions of the autophagy genes ZtATG1 and ZtATG8 to the development and virulence of Z. tritici. Deletion of ZtATG1 led to inhibition of autophagy but had no impact on starvation-induced hyphal differentiation or virulence, suggesting that autophagy is not required for Z. tritici pathogenicity. Contrastingly, ZtATG8 deletion delayed the transition to necrotrophic growth, despite having no influence on filamentous growth under starvation, pointing to an autophagy-independent role of ZtATG8 during Z. tritici infection. To our knowledge, this study represents the first to find autophagy not to contribute to the virulence of a fungal plant pathogen, and reveals novel roles for different autophagy-associated proteins in Z. tritici.
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The Plant Homeodomain Protein Clp1 Regulates Fungal Development, Virulence, and Autophagy Homeostasis in Magnaporthe oryzae. Microbiol Spectr 2022; 10:e0102122. [PMID: 36036638 PMCID: PMC9602895 DOI: 10.1128/spectrum.01021-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Rice blast disease caused by Magnaporthe oryzae is a serious threat to global grain yield and food security. Cti6 is a nuclear protein containing a plant homeodomain (PHD) that is involved in transcriptional regulation in Saccharomyces cerevisiae. The biological function of its homologous protein in M. oryzae has been elusive. Here, we report Clp1 with a PHD domain in M. oryzae, a homologous protein of the yeast Cti6. Clp1 was mainly located in the nucleus and partly in the vesicles. Clp1 colocalized and interacted with the autophagy-related proteins Atg5, Atg7, Atg16, Atg24, and Atg28 at preautophagosomal structures (PAS) and autophagosomes, and the loss of Clp1 increased the fungal background autophagy level. Δclp1 displayed reduced hyphal growth and hyperbranching, abnormal fungal morphology (including colony, spore, and appressorium), hindered appressorial glycogen metabolism and turgor production, weakened plant infection, and decreased virulence. The PHD is indispensable for the function of Clp1. Therefore, this study revealed that Clp1 regulates development and pathogenicity by maintaining autophagy homeostasis and affecting gene transcription in M. oryzae. IMPORTANCE The fungal pathogen Magnaporthe oryzae causes serious diseases of grasses such as rice and wheat. Autophagy plays an indispensable role in the pathogenic process of M. oryzae. Here, we report a Cti6-like protein, Clp1, that is involved in fungal development and infection of plants through controlling autophagy homeostasis in the cytoplasm and gene transcription in the nucleus in M. oryzae. This study will help us to understand an elaborated molecular mechanism of autophagy, gene transcription, and virulence in the rice blast fungus.
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Tir N, Heistinger L, Grünwald-Gruber C, Jakob LA, Dickgiesser S, Rasche N, Mattanovich D. From strain engineering to process development: monoclonal antibody production with an unnatural amino acid in Pichia pastoris. Microb Cell Fact 2022; 21:157. [PMID: 35953849 PMCID: PMC9367057 DOI: 10.1186/s12934-022-01882-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/26/2022] [Indexed: 11/25/2022] Open
Abstract
Background Expansion of the genetic code is a frequently employed approach for the modification of recombinant protein properties. It involves reassignment of a codon to another, e.g., unnatural, amino acid and requires the action of a pair of orthogonal tRNA and aminoacyl tRNA synthetase modified to recognize only the desired amino acid. This approach was applied for the production of trastuzumab IgG carrying p-azido-l-phenylalanine (pAzF) in the industrial yeast Pichia pastoris. Combining the knowledge of protein folding and secretion with bioreactor cultivations, the aim of the work was to make the production of monoclonal antibodies with an expanded genetic code cost-effective on a laboratory scale. Results Co-translational transport of proteins into the endoplasmic reticulum through secretion signal prepeptide change and overexpression of lumenal chaperones Kar2p and Lhs1p improved the production of trastuzumab IgG and its Fab fragment with incorporated pAzF. In the case of Fab, a knockout of vacuolar targeting for protein degradation further increased protein yield. Fed-batch bioreactor cultivations of engineered P. pastoris strains increased IgG and IgGpAzF productivity by around 50- and 20-fold compared to screenings, yielding up to 238 mg L−1 and 15 mg L−1 of fully assembled tetrameric protein, respectively. Successful site-specific incorporation of pAzF was confirmed by mass spectrometry. Conclusions Pichia pastoris was successfully employed for cost-effective laboratory-scale production of a monoclonal antibody with an unnatural amino acid. Applying the results of this work in glycoengineered strains, and taking further steps in process development opens great possibilities for utilizing P. pastoris in the development of antibodies for subsequent conjugations with, e.g., bioactive payloads. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01882-6.
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Affiliation(s)
- Nora Tir
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria.,Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria
| | - Lina Heistinger
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria.,Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria.,Department of Biology, Institute of Biochemistry, ETH Zürich, 8093, Zurich, Switzerland
| | - Clemens Grünwald-Gruber
- University of Natural Resources and Life Sciences, Vienna Core Facility Mass Spectrometry, Muthgasse 18, 1190, Vienna, Austria
| | - Leo A Jakob
- Department of Biotechnology, Institute of Bioprocess Science and Engineering, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria
| | - Stephan Dickgiesser
- ADCs & Targeted NBE Therapeutics, Merck Healthcare KGaA, Frankfurter Str. 250, 64293, Darmstadt, Germany
| | - Nicolas Rasche
- ADCs & Targeted NBE Therapeutics, Merck Healthcare KGaA, Frankfurter Str. 250, 64293, Darmstadt, Germany
| | - Diethard Mattanovich
- Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria.
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Yu G, Klionsky DJ. Life and Death Decisions—The Many Faces of Autophagy in Cell Survival and Cell Death. Biomolecules 2022; 12:biom12070866. [PMID: 35883421 PMCID: PMC9313301 DOI: 10.3390/biom12070866] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/16/2022] [Accepted: 06/17/2022] [Indexed: 02/01/2023] Open
Abstract
Autophagy is a process conserved from yeast to humans. Since the discovery of autophagy, its physiological role in cell survival and cell death has been intensively investigated. The inherent ability of the autophagy machinery to sequester, deliver, and degrade cytoplasmic components enables autophagy to participate in cell survival and cell death in multiple ways. The primary role of autophagy is to send cytoplasmic components to the vacuole or lysosomes for degradation. By fine-tuning autophagy, the cell regulates the removal and recycling of cytoplasmic components in response to various stress or signals. Recent research has shown the implications of the autophagy machinery in other pathways independent of lysosomal degradation, expanding the pro-survival role of autophagy. Autophagy also facilitates certain forms of regulated cell death. In addition, there is complex crosstalk between autophagy and regulated cell death pathways, with a number of genes shared between them, further suggesting a deeper connection between autophagy and cell death. Finally, the mitochondrion presents an example where the cell utilizes autophagy to strike a balance between cell survival and cell death. In this review, we consider the current knowledge on the physiological role of autophagy as well as its regulation and discuss the multiple functions of autophagy in cell survival and cell death.
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Affiliation(s)
- Ge Yu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA;
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Daniel J. Klionsky
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA;
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2216, USA
- Correspondence:
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Characterization of Protein-Membrane Interactions in Yeast Autophagy. Cells 2022; 11:cells11121876. [PMID: 35741004 PMCID: PMC9221364 DOI: 10.3390/cells11121876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/03/2022] [Accepted: 06/07/2022] [Indexed: 02/06/2023] Open
Abstract
Cells rely on autophagy to degrade cytosolic material and maintain homeostasis. During autophagy, content to be degraded is encapsulated in double membrane vesicles, termed autophagosomes, which fuse with the yeast vacuole for degradation. This conserved cellular process requires the dynamic rearrangement of membranes. As such, the process of autophagy requires many soluble proteins that bind to membranes to restructure, tether, or facilitate lipid transfer between membranes. Here, we review the methods that have been used to investigate membrane binding by the core autophagy machinery and additional accessory proteins involved in autophagy in yeast. We also review the key experiments demonstrating how each autophagy protein was shown to interact with membranes.
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31
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Xu C, Fan J. Links between autophagy and lipid droplet dynamics. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2848-2858. [PMID: 35560198 DOI: 10.1093/jxb/erac003] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/06/2022] [Indexed: 06/15/2023]
Abstract
Autophagy is a catabolic process in which cytoplasmic components are delivered to vacuoles or lysosomes for degradation and nutrient recycling. Autophagy-mediated degradation of membrane lipids provides a source of fatty acids for the synthesis of energy-rich, storage lipid esters such as triacylglycerol (TAG). In eukaryotes, storage lipids are packaged into dynamic subcellular organelles, lipid droplets. In times of energy scarcity, lipid droplets can be degraded via autophagy in a process termed lipophagy to release fatty acids for energy production via fatty acid β-oxidation. On the other hand, emerging evidence suggests that lipid droplets are required for the efficient execution of autophagic processes. Here, we review recent advances in our understanding of metabolic interactions between autophagy and TAG storage, and discuss mechanisms of lipophagy. Free fatty acids are cytotoxic due to their detergent-like properties and their incorporation into lipid intermediates that are toxic at high levels. Thus, we also discuss how cells manage lipotoxic stresses during autophagy-mediated mobilization of fatty acids from lipid droplets and organellar membranes for energy generation.
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Affiliation(s)
- Changcheng Xu
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Jilian Fan
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
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32
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Shiraishi K, Sakai Y. Autophagy as a Survival Strategy for Eukaryotic Microbes Living in the Phyllosphere. FRONTIERS IN PLANT SCIENCE 2022; 13:867486. [PMID: 35401602 PMCID: PMC8992653 DOI: 10.3389/fpls.2022.867486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Abstract
Autophagy is an intracellular degradation process that is highly conserved among eukaryotes at the molecular level. The process was originally revealed in the budding yeast, but the physiological role of autophagy in yeast cells had remained unknown as autophagy-deficient yeast mutants did now show a clear growth phenotype in laboratory conditions. In this review, we introduce the role of autophagy in the methylotrophic yeast Candida boidinii grown on the leaf surface of Arabidopsis thaliana. Autophagy is shown to be required for proliferation in the phyllosphere, and selective autophagic pathways such as pexophagy and cytoplasm-to-vacuole targeting (Cvt) pathway are strictly regulated during both the daily cycle and the host plant life cycle. This review describes our current understanding of the role of autophagy as a survival strategy for phyllosphere fungi. Critical functions of autophagy for pathogen invasions are also discussed.
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33
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Fission Yeast Autophagy Machinery. Cells 2022; 11:cells11071086. [PMID: 35406650 PMCID: PMC8997447 DOI: 10.3390/cells11071086] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/19/2022] [Accepted: 03/22/2022] [Indexed: 01/27/2023] Open
Abstract
Autophagy is a conserved process that delivers cytoplasmic components to the vacuole/lysosome. It plays important roles in maintaining cellular homeostasis and conferring stress resistance. In the fission yeast Schizosaccharomyces pombe, autophagy is important for cell survival under nutrient depletion and ER stress conditions. Experimental analyses of fission yeast autophagy machinery in the last 10 years have unveiled both similarities and differences in autophagosome biogenesis mechanisms between fission yeast and other model eukaryotes for autophagy research, in particular, the budding yeast Saccharomyces cerevisiae. More recently, selective autophagy pathways that deliver hydrolytic enzymes, the ER, and mitochondria to the vacuole have been discovered in fission yeast, yielding novel insights into how cargo selectivity can be achieved in autophagy. Here, we review the progress made in understanding the autophagy machinery in fission yeast.
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Marshall RS, Vierstra RD. A trio of ubiquitin ligases sequentially drives ubiquitylation and autophagic degradation of dysfunctional yeast proteasomes. Cell Rep 2022; 38:110535. [PMID: 35294869 DOI: 10.1016/j.celrep.2022.110535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 12/08/2021] [Accepted: 02/25/2022] [Indexed: 12/22/2022] Open
Abstract
As central effectors of ubiquitin (Ub)-mediated proteolysis, proteasomes are regulated at multiple levels, including degradation of unwanted or dysfunctional particles via autophagy (termed proteaphagy). In yeast, inactive proteasomes are exported from the nucleus, sequestered into cytoplasmic aggresomes via the Hsp42 chaperone, extensively ubiquitylated, and then tethered to the expanding phagophore by the autophagy receptor Cue5. Here, we demonstrate the need for ubiquitylation driven by the trio of Ub ligases (E3s), San1, Rsp5, and Hul5, which together with their corresponding E2s work sequentially to promote nuclear export and Cue5 recognition. Whereas San1 functions prior to nuclear export, Rsp5 and Hul5 likely decorate aggresome-localized proteasomes in concert. Ultimately, topologically complex Ub chain(s) containing both K48 and K63 Ub-Ub linkages are assembled, mainly on the regulatory particle, to generate autophagy-competent substrates. Because San1, Rsp5, Hul5, Hsp42, and Cue5 also participate in general proteostasis, proteaphagy likely engages a fundamental mechanism for eliminating inactive/misfolded proteins.
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Affiliation(s)
- Richard S Marshall
- Department of Biology, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, USA.
| | - Richard D Vierstra
- Department of Biology, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, USA.
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35
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The effect of nutrient deprivation on proteasome activity in 4-week-old mice and 24-week-old mice. J Nutr Biochem 2022; 105:108993. [DOI: 10.1016/j.jnutbio.2022.108993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 10/20/2021] [Accepted: 02/03/2022] [Indexed: 11/21/2022]
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36
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Proteomic and Phosphoryproteomic Investigations Reveal that Autophagy-Related Protein 1, a Protein Kinase for Autophagy Initiation, Synchronously Deploys Phosphoregulation on the Ubiquitin-Like Conjugation System in the Mycopathogen Beauveria bassiana. mSystems 2022; 7:e0146321. [PMID: 35133188 PMCID: PMC8823290 DOI: 10.1128/msystems.01463-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Autophagy is a conserved intracellular degradation mechanism in eukaryotes and is initiated by the protein kinase autophagy-related protein 1 (Atg1). However, except for the autophosphorylation activity of Atg1, the target proteins phosphorylated by Atg1 are largely unknown in filamentous fungi. In Beauveria bassiana (a filamentous insect-pathogenic fungus), Atg1 is indispensable for autophagy and is associated with fungal development. Comparative omics-based analyses revealed that B. bassiana Atg1 (BbAtg1) has key influence on the proteome and phosphoproteome during conidiogenesis. In terms of its physiological functions, the BbAtg1-mediated phosphoproteome is primarily associated with metabolism, signal transduction, cell cycle, and autophagy. At the proteomic level, BbAtg1 mainly regulates genes involved in protein synthesis, protein fate, and protein with binding function. Furthermore, integrative analyses of phosphoproteomic and proteomic data led to the identification of several potential targets regulated by BbAtg1 phosphorylation activity. Notably, we demonstrated that BbAtg1 phosphorylated BbAtg3, an essential component of the ubiquitin-like conjugation system in autophagic progress. Our findings indicate that in addition to being a critical component of the autophagy initiation, Atg1 orchestrates autophagosome elongation via its phosphorylation activity. The data from our study will facilitate future studies on the noncanonical targets of Atg1 and help decipher the Atg1-mediated phosphorylation networks. IMPORTANCE Autophagy-related protein 1 (Atg1) is a serine/threonine protein kinase for autophagy initiation. In contrast to the unicellular yeast, the target proteins phosphorylated by Atg1 are largely unknown in filamentous fungi. In this study, the entomopathogenic fungus Beauveria bassiana was used as a representative of filamentous fungi due to its importance in the applied and fundamental research. We revealed that Atg1 mediates the comprehensive proteome and phosphoproteome, which differ from those revealed in yeast. Further investigation revealed that Atg1 directly phosphorylates the E2-like enzyme Atg3 of the ubiquitin-like conjugation system (ULCS), and the phosphorylation of Atg3 is indispensable for ULCS functionality. Interestingly, the phosphorylation site of Atg3 is conserved among a set of insect- and plant-pathogenic fungi but not in human-pathogenic fungi. This study reveals new regulatory mechanisms of autophagy and provides new insights into the evolutionary diversity of the Atg1 kinase signaling pathways among different pathogenic fungi.
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37
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de Moura Ferreira MA, da Silveira FA, da Silveira WB. Ethanol stress responses in Kluyveromyces marxianus: current knowledge and perspectives. Appl Microbiol Biotechnol 2022; 106:1341-1353. [DOI: 10.1007/s00253-022-11799-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 11/02/2022]
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38
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Heidary Moghaddam R, Samimi Z, Asgary S, Mohammadi P, Hozeifi S, Hoseinzadeh-Chahkandak F, Xu S, Farzaei MH. Natural AMPK Activators in Cardiovascular Disease Prevention. Front Pharmacol 2022; 12:738420. [PMID: 35046800 PMCID: PMC8762275 DOI: 10.3389/fphar.2021.738420] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/03/2021] [Indexed: 12/11/2022] Open
Abstract
Cardiovascular diseases (CVD), as a life-threatening global disease, is receiving worldwide attention. Seeking novel therapeutic strategies and agents is of utmost importance to curb CVD. AMP-activated protein kinase (AMPK) activators derived from natural products are promising agents for cardiovascular drug development owning to regulatory effects on physiological processes and diverse cardiometabolic disorders. In the past decade, different therapeutic agents from natural products and herbal medicines have been explored as good templates of AMPK activators. Hereby, we overviewed the role of AMPK signaling in the cardiovascular system, as well as evidence implicating AMPK activators as potential therapeutic tools. In the present review, efforts have been made to compile and update relevant information from both preclinical and clinical studies, which investigated the role of natural products as AMPK activators in cardiovascular therapeutics.
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Affiliation(s)
- Reza Heidary Moghaddam
- Clinical Research Development Center, Imam Ali and Taleghani Hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Zeinab Samimi
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Sedigheh Asgary
- Isfahan Cardiovascular Research Center, Cardiovascular Research Institute,.Isfahan University of Medical Sciences, Isfahan, Iran
| | - Pantea Mohammadi
- Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Soroush Hozeifi
- School of Medicine, Birjand University of Medical Sciences, Birjand, Iran
| | | | - Suowen Xu
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Mohammad Hosein Farzaei
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran.,Medical Technology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
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40
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Ebrahimi M, Habernig L, Broeskamp F, Aufschnaiter A, Diessl J, Atienza I, Matz S, Ruiz FA, Büttner S. Phosphate Restriction Promotes Longevity via Activation of Autophagy and the Multivesicular Body Pathway. Cells 2021; 10:3161. [PMID: 34831384 PMCID: PMC8620443 DOI: 10.3390/cells10113161] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 11/05/2021] [Accepted: 11/08/2021] [Indexed: 01/05/2023] Open
Abstract
Nutrient limitation results in an activation of autophagy in organisms ranging from yeast, nematodes and flies to mammals. Several evolutionary conserved nutrient-sensing kinases are critical for efficient adaptation of yeast cells to glucose, nitrogen or phosphate depletion, subsequent cell-cycle exit and the regulation of autophagy. Here, we demonstrate that phosphate restriction results in a prominent extension of yeast lifespan that requires the coordinated activity of autophagy and the multivesicular body pathway, enabling efficient turnover of cytoplasmic and plasma membrane cargo. While the multivesicular body pathway was essential during the early days of aging, autophagy contributed to long-term survival at later days. The cyclin-dependent kinase Pho85 was critical for phosphate restriction-induced autophagy and full lifespan extension. In contrast, when cell-cycle exit was triggered by exhaustion of glucose instead of phosphate, Pho85 and its cyclin, Pho80, functioned as negative regulators of autophagy and lifespan. The storage of phosphate in form of polyphosphate was completely dispensable to in sustaining viability under phosphate restriction. Collectively, our results identify the multifunctional, nutrient-sensing kinase Pho85 as critical modulator of longevity that differentially coordinates the autophagic response to distinct kinds of starvation.
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Affiliation(s)
- Mahsa Ebrahimi
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; (M.E.); (L.H.); (F.B.); (J.D.); (S.M.)
| | - Lukas Habernig
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; (M.E.); (L.H.); (F.B.); (J.D.); (S.M.)
| | - Filomena Broeskamp
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; (M.E.); (L.H.); (F.B.); (J.D.); (S.M.)
| | - Andreas Aufschnaiter
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden;
| | - Jutta Diessl
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; (M.E.); (L.H.); (F.B.); (J.D.); (S.M.)
| | - Isabel Atienza
- Instituto de Investigación e Innovación Biomédica de Cádiz (INIBICA), University of Cadiz, 11001 Cadiz, Spain; (I.A.); (F.A.R.)
| | - Steffen Matz
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; (M.E.); (L.H.); (F.B.); (J.D.); (S.M.)
| | - Felix A. Ruiz
- Instituto de Investigación e Innovación Biomédica de Cádiz (INIBICA), University of Cadiz, 11001 Cadiz, Spain; (I.A.); (F.A.R.)
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; (M.E.); (L.H.); (F.B.); (J.D.); (S.M.)
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
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Proteasome Inhibition Is an Effective Treatment Strategy for Microsporidia Infection in Honey Bees. Biomolecules 2021; 11:biom11111600. [PMID: 34827599 PMCID: PMC8615682 DOI: 10.3390/biom11111600] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 12/26/2022] Open
Abstract
The microsporidia Nosema ceranae is an obligate intracellular parasite that causes honey bee mortality and contributes to colony collapse. Fumagillin is presently the only pharmacological control for N. ceranae infections in honey bees. Resistance is already emerging, and alternative controls are critically needed. Nosema spp. exhibit increased sensitivity to heat shock, a common proteotoxic stress. Thus, we hypothesized that targeting the Nosema proteasome, the major protease removing misfolded proteins, might be effective against N. ceranae infections in honey bees. Nosema genome analysis and molecular modeling revealed an unexpectedly compact proteasome apparently lacking multiple canonical subunits, but with highly conserved proteolytic active sites expected to be receptive to FDA-approved proteasome inhibitors. Indeed, N. ceranae were strikingly sensitive to pharmacological disruption of proteasome function at doses that were well tolerated by honey bees. Thus, proteasome inhibition is a novel candidate treatment strategy for microsporidia infection in honey bees.
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Vtc5 Is Localized to the Vacuole Membrane by the Conserved AP-3 Complex to Regulate Polyphosphate Synthesis in Budding Yeast. mBio 2021; 12:e0099421. [PMID: 34544285 PMCID: PMC8510523 DOI: 10.1128/mbio.00994-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Polyphosphates (polyP) are energy-rich polymers of inorganic phosphates assembled into chains ranging from 3 residues to thousands of residues in length. They are thought to exist in all cells on earth and play roles in an eclectic mix of functions ranging from phosphate homeostasis to cell signaling, infection control, and blood clotting. In the budding yeast Saccharomyces cerevisiae, polyP chains are synthesized by the vacuole-bound vacuolar transporter chaperone (VTC) complex, which synthesizes polyP while simultaneously translocating it into the vacuole lumen, where it is stored at high concentrations. VTC’s activity is promoted by an accessory subunit called Vtc5. In this work, we found that the conserved AP-3 complex is required for proper Vtc5 localization to the vacuole membrane. In human cells, previous work has demonstrated that mutation of AP-3 subunits gives rise to Hermansky-Pudlak syndrome, a rare disease with molecular phenotypes that include decreased polyP accumulation in platelet dense granules. In yeast AP-3 mutants, we found that Vtc5 is rerouted to the vacuole lumen by the endosomal sorting complex required for transport (ESCRT), where it is degraded by the vacuolar protease Pep4. Cells lacking functional AP-3 have decreased levels of polyP, demonstrating that membrane localization of Vtc5 is required for its VTC stimulatory activity in vivo. Our work provides insight into the molecular trafficking of a critical regulator of polyP metabolism in yeast. We speculate that AP-3 may also be responsible for the delivery of polyP regulatory proteins to platelet dense granules in higher eukaryotes.
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Siva Sankar D, Dengjel J. Protein complexes and neighborhoods driving autophagy. Autophagy 2021; 17:2689-2705. [PMID: 33183148 PMCID: PMC8526019 DOI: 10.1080/15548627.2020.1847461] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 10/16/2020] [Accepted: 11/02/2020] [Indexed: 01/02/2023] Open
Abstract
Autophagy summarizes evolutionarily conserved, intracellular degradation processes targeting cytoplasmic material for lysosomal degradation. These encompass constitutive processes as well as stress responses, which are often found dysregulated in diseases. Autophagy pathways help in the clearance of damaged organelles, protein aggregates and macromolecules, mediating their recycling and maintaining cellular homeostasis. Protein-protein interaction networks contribute to autophagosome biogenesis, substrate loading, vesicular trafficking and fusion, protein translocations across membranes and degradation in lysosomes. Hypothesis-free proteomic approaches tremendously helped in the functional characterization of protein-protein interactions to uncover molecular mechanisms regulating autophagy. In this review, we elaborate on the importance of understanding protein-protein-interactions of varying affinities and on the strengths of mass spectrometry-based proteomic approaches to study these, generating new mechanistic insights into autophagy regulation. We discuss in detail affinity purification approaches and recent developments in proximity labeling coupled to mass spectrometry, which uncovered molecular principles of autophagy mechanisms.Abbreviations: AMPK: AMP-activated protein kinase; AP-MS: affinity purification-mass spectrometry; APEX2: ascorbate peroxidase-2; ATG: autophagy related; BioID: proximity-dependent biotin identification; ER: endoplasmic reticulum; GFP: green fluorescent protein; iTRAQ: isobaric tag for relative and absolute quantification; MS: mass spectrometry; PCA: protein-fragment complementation assay; PL-MS: proximity labeling-mass spectrometry; PtdIns3P: phosphatidylinositol-3-phosphate; PTM: posttranslational modification; PUP-IT: pupylation-based interaction tagging; RFP: red fluorescent protein; SILAC: stable isotope labeling by amino acids in cell culture; TAP: tandem affinity purification; TMT: tandem mass tag.
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Affiliation(s)
| | - Jörn Dengjel
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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Kruasuwan W, Puseenam A, Phithakrotchanakoon C, Tanapongpipat S, Roongsawang N. Modulation of heterologous protein secretion in the thermotolerant methylotrophic yeast Ogataea thermomethanolica TBRC 656 by CRISPR-Cas9 system. PLoS One 2021; 16:e0258005. [PMID: 34582499 PMCID: PMC8478189 DOI: 10.1371/journal.pone.0258005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 09/16/2021] [Indexed: 11/18/2022] Open
Abstract
The thermotolerant methylotrophic yeast Ogataea thermomethanolica TBRC 656 is a potential host strain for industrial protein production. Heterologous proteins are often retained intracellularly in yeast resulting in endoplasmic reticulum (ER) stress and poor secretion, and despite efforts to engineer protein secretory pathways, heterologous protein production is often lower than expected. We hypothesized that activation of genes involved in the secretory pathway could mitigate ER stress. In this study, we created mutants defective in protein secretory-related functions using clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) tools. Secretion of the model protein xylanase was significantly decreased in loss of function mutants for oxidative stress (sod1Δ) and vacuolar and protein sorting (vps1Δ and ypt7Δ) genes. However, xylanase secretion was unaffected in an autophagy related atg12Δ mutant. Then, we developed a system for sequence-specific activation of target gene expression (CRISPRa) in O. thermomethanolica and used it to activate SOD1, VPS1 and YPT7 genes. Production of both non-glycosylated xylanase and glycosylated phytase was enhanced in the gene activated mutants, demonstrating that CRISPR-Cas9 systems can be used as tools for understanding O. thermomethanolica genes involved in protein secretion, which could be applied for increasing heterologous protein secretion in this yeast.
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Affiliation(s)
- Worarat Kruasuwan
- Microbial Cell Factory Research Team, Microbial Biotechnology and Biochemicals Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Aekkachai Puseenam
- Microbial Cell Factory Research Team, Microbial Biotechnology and Biochemicals Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Chitwadee Phithakrotchanakoon
- Microbial Systems and Computational Biology Research Team, Thailand Bioresource Research Center, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Sutipa Tanapongpipat
- Microbial Cell Factory Research Team, Microbial Biotechnology and Biochemicals Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Niran Roongsawang
- Microbial Cell Factory Research Team, Microbial Biotechnology and Biochemicals Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
- * E-mail:
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Abstract
The evolutionary theory of aging has set the foundations for a comprehensive understanding of aging. The biology of aging has listed and described the "hallmarks of aging," i.e., cellular and molecular mechanisms involved in human aging. The present paper is the first to infer the order of appearance of the hallmarks of bilaterian and thereby human aging throughout evolution from their presence in progressively narrower clades. Its first result is that all organisms, even non-senescent, have to deal with at least one mechanism of aging - the progressive accumulation of misfolded or unstable proteins. Due to their cumulation, these mechanisms are called "layers of aging." A difference should be made between the first four layers of unicellular aging, present in some unicellular organisms and in all multicellular opisthokonts, that stem and strike "from the inside" of individual cells and span from increasingly abnormal protein folding to deregulated nutrient sensing, and the last four layers of metacellular aging, progressively appearing in metazoans, that strike the cells of a multicellular organism "from the outside," i.e., because of other cells, and span from transcriptional alterations to the disruption of intercellular communication. The evolution of metazoans and eumetazoans probably solved the problem of aging along with the problem of unicellular aging. However, metacellular aging originates in the mechanisms by which the effects of unicellular aging are kept under control - e.g., the exhaustion of stem cells that contribute to replace damaged somatic cells. In bilaterians, additional functions have taken a toll on generally useless potentially limited lifespan to increase the fitness of organisms at the price of a progressively less efficient containment of the damage of unicellular aging. In the end, this picture suggests that geroscience should be more efficient in targeting conditions of metacellular aging rather than unicellular aging itself.
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Affiliation(s)
- Maël Lemoine
- CNRS, ImmunoConcEpT, UMR 5164, Univ. Bordeaux, Bordeaux, France
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Rahman MA, Kumar R, Sanchez E, Nazarko TY. Lipid Droplets and Their Autophagic Turnover via the Raft-Like Vacuolar Microdomains. Int J Mol Sci 2021; 22:8144. [PMID: 34360917 PMCID: PMC8348048 DOI: 10.3390/ijms22158144] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/26/2021] [Accepted: 07/26/2021] [Indexed: 01/01/2023] Open
Abstract
Although once perceived as inert structures that merely serve for lipid storage, lipid droplets (LDs) have proven to be the dynamic organelles that hold many cellular functions. The LDs' basic structure of a hydrophobic core consisting of neutral lipids and enclosed in a phospholipid monolayer allows for quick lipid accessibility for intracellular energy and membrane production. Whereas formed at the peripheral and perinuclear endoplasmic reticulum, LDs are degraded either in the cytosol by lipolysis or in the vacuoles/lysosomes by autophagy. Autophagy is a regulated breakdown of dysfunctional, damaged, or surplus cellular components. The selective autophagy of LDs is called lipophagy. Here, we review LDs and their degradation by lipophagy in yeast, which proceeds via the micrometer-scale raft-like lipid domains in the vacuolar membrane. These vacuolar microdomains form during nutrient deprivation and facilitate internalization of LDs via the vacuolar membrane invagination and scission. The resultant intra-vacuolar autophagic bodies with LDs inside are broken down by vacuolar lipases and proteases. This type of lipophagy is called microlipophagy as it resembles microautophagy, the type of autophagy when substrates are sequestered right at the surface of a lytic compartment. Yeast microlipophagy via the raft-like vacuolar microdomains is a great model system to study the role of lipid domains in microautophagic pathways.
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Affiliation(s)
- Muhammad Arifur Rahman
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA; (M.A.R.); (E.S.)
| | - Ravinder Kumar
- Department of Obstetrics, Gynecology and Reproductive Science, University of California, San Francisco, CA 94143, USA;
| | - Enrique Sanchez
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA; (M.A.R.); (E.S.)
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Taras Y. Nazarko
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA; (M.A.R.); (E.S.)
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Wang Q, Lu L, Zeng M, Wang D, Zhang TZ, Xie Y, Gao SB, Fu S, Zhou XP, Wu JX. Rice black-streaked dwarf virus P10 promotes phosphorylation of GAPDH (glyceraldehyde-3-phosphate dehydrogenase) to induce autophagy in Laodelphax striatellus. Autophagy 2021; 18:745-764. [PMID: 34313529 DOI: 10.1080/15548627.2021.1954773] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Macroautophagy/autophagy is an important innate and adaptive immune response that can clear microbial pathogens through guiding their degradation. Virus infection in animals and plants is also known to induce autophagy. However, how virus infection induces autophagy is largely unknown. Here, we provide evidence that the early phase of rice black-streaked dwarf virus (RBSDV) infection in Laodelphax striatellus can also induce autophagy, leading to suppression of RBSDV invasion and accumulation. We have determined that the main capsid protein of RBSDV (P10) is the inducer of autophagy. RBSDV P10 can specifically interact with GAPDH (glyceraldehyde-3-phosphate dehydrogenase), both in vitro and in vivo. Silencing of GAPDH in L. striatellus could significantly reduce the activity of autophagy induced by RBSDV infection. Furthermore, our results also showed that both RBSDV infection and RBSDV P10 alone can promote phosphorylation of AMP-activated protein kinase (AMPK), resulting in GAPDH phosphorylation and relocation of GAPDH from the cytoplasm into the nucleus in midgut cells of L. striatellus or Sf9 insect cells. Once inside the nucleus, phosphorylated GAPDH can activate autophagy to suppress virus infection. Together, these data illuminate the mechanism by which RBSDV induces autophagy in L. striatellus, and indicate that the autophagy pathway in an insect vector participates in the anti-RBSDV innate immune response.
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Affiliation(s)
- Qi Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Lina Lu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Ming Zeng
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Dan Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Tian-Ze Zhang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Yi Xie
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Shi-Bo Gao
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Shuai Fu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Xue-Ping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China.,State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, P.R. China
| | - Jian-Xiang Wu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
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Msn2/4 transcription factors positively regulate expression of Atg39 ER-phagy receptor. Sci Rep 2021; 11:11919. [PMID: 34099851 PMCID: PMC8184937 DOI: 10.1038/s41598-021-91480-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 05/27/2021] [Indexed: 12/18/2022] Open
Abstract
Selective autophagy requires the autophagy receptor specifically localizing to the target for degradation. In the budding yeast, Atg39 and Atg40 function as an autophagy receptor for the endoplasmic reticulum (ER)-selective autophagy, referred to as ER-phagy. The expression level of the ATG39 gene is increased in response to ER stress and nitrogen starvation. Under unstressed conditions, ATG39 transcription is repressed by Mig1/2 repressors. ER stress activates Snf1 AMP-activated protein kinase (AMPK), which negatively regulates Mig1/2 and consequently derepresses ATG39 transcription. However, ATG39 expression is still induced by ER stress and nitrogen starvation in the absence of Snf1, suggesting that additional molecules are involved in regulation of ATG39 expression. Here, we identify Msn2/4 transcription factors as an activator of ATG39 transcription. Not only ATG39 promoter activity but also ER-phagy are downregulated by loss of Msn2/4 and disruption of Msn2/4-binding consensus sequences located in the ATG39 promoter. We also find that the cAMP-dependent protein kinase pathway is involved in Msn2/4-mediated transcriptional regulation of ATG39. Our results suggest that yeast ER-phagy is appropriately controlled through modulation of the expression level of the ER-phagy receptor involving multiple signaling pathways and transcription factors.
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He CW, Cui XF, Ma SJ, Xu Q, Ran YP, Chen WZ, Mu JX, Li H, Zhu J, Gong Q, Xie Z. Membrane recruitment of Atg8 by Hfl1 facilitates turnover of vacuolar membrane proteins in yeast cells approaching stationary phase. BMC Biol 2021; 19:117. [PMID: 34088313 PMCID: PMC8176713 DOI: 10.1186/s12915-021-01048-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 05/07/2021] [Indexed: 12/03/2022] Open
Abstract
Background The vacuole/lysosome is the final destination of autophagic pathways, but can also itself be degraded in whole or in part by selective macroautophagic or microautophagic processes. Diverse molecular mechanisms are involved in these processes, the characterization of which has lagged behind those of ATG-dependent macroautophagy and ESCRT-dependent endosomal multivesicular body pathways. Results Here we show that as yeast cells gradually exhaust available nutrients and approach stationary phase, multiple vacuolar integral membrane proteins with unrelated functions are degraded in the vacuolar lumen. This degradation depends on the ESCRT machinery, but does not strictly require ubiquitination of cargos or trafficking of cargos out of the vacuole. It is also temporally and mechanistically distinct from NPC-dependent microlipophagy. The turnover is facilitated by Atg8, an exception among autophagy proteins, and an Atg8-interacting vacuolar membrane protein, Hfl1. Lack of Atg8 or Hfl1 led to the accumulation of enlarged lumenal membrane structures in the vacuole. We further show that a key function of Hfl1 is the membrane recruitment of Atg8. In the presence of Hfl1, lipidation of Atg8 is not required for efficient cargo turnover. The need for Hfl1 can be partially bypassed by blocking Atg8 delipidation. Conclusions Our data reveal a vacuolar membrane protein degradation process with a unique dependence on vacuole-associated Atg8 downstream of ESCRTs, and we identify a specific role of Hfl1, a protein conserved from yeast to plants and animals, in membrane targeting of Atg8. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01048-7.
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Affiliation(s)
- Cheng-Wen He
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xue-Fei Cui
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Shao-Jie Ma
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,Present address: Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Qin Xu
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yan-Peng Ran
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Wei-Zhi Chen
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jun-Xi Mu
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Hui Li
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jing Zhu
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Qingqiu Gong
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zhiping Xie
- State Key Laboratory of Microbial Metabolism and Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
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