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Guo C, Sachithanandham J, Zhong W, Craney M, Villano J, Pekosz A, Gould SJ. Antigen-display exosomes provide adjuvant-free protection against SARS-CoV-2 disease at nanogram levels of spike protein. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.04.574272. [PMID: 38328234 PMCID: PMC10849639 DOI: 10.1101/2024.01.04.574272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
As the only bionormal nanovesicle, exosomes have high potential as a nanovesicle for delivering vaccines and therapeutics. We show here that the loading of type-1 membrane proteins into the exosome membrane is induced by exosome membrane anchor domains, EMADs, that maximize protein delivery to the plasma membrane, minimize protein sorting to other compartments, and direct proteins into exosome membranes. Using SARS-CoV-2 spike as an example and EMAD13 as our most effective exosome membrane anchor, we show that cells expressing a spike-EMAD13 fusion protein produced exosomes that carry dense arrays of spike trimers on 50% of all exosomes. Moreover, we find that immunization with spike-EMAD13 exosomes induced strong neutralizing antibody responses and protected hamsters against SARS-CoV-2 disease at doses of just 0.5-5 ng of spike protein, without adjuvant, demonstrating that antigen-display exosomes are particularly immunogenic, with important implications for both structural and expression-dependent vaccines.
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Affiliation(s)
- Chenxu Guo
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Jaiprasath Sachithanandham
- Department of Microbiology and Immunology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205
| | - William Zhong
- Department of Microbiology and Immunology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205
| | - Morgan Craney
- Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Jason Villano
- Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Andrew Pekosz
- Department of Microbiology and Immunology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205
| | - Stephen J Gould
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
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Tyagi S, Sarveswaran N, Higerd-Rusli GP, Liu S, Dib-Hajj FB, Waxman SG, Dib-Hajj SD. Conserved but not critical: Trafficking and function of NaV1.7 are independent of highly conserved polybasic motifs. Front Mol Neurosci 2023; 16:1161028. [PMID: 37008789 PMCID: PMC10060856 DOI: 10.3389/fnmol.2023.1161028] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 03/02/2023] [Indexed: 03/18/2023] Open
Abstract
Non-addictive treatment of chronic pain represents a major unmet clinical need. Peripheral voltage-gated sodium (NaV) channels are an attractive target for pain therapy because they initiate and propagate action potentials in primary afferents that detect and transduce noxious stimuli. NaV1.7 sets the gain on peripheral pain-signaling neurons and is the best validated peripheral ion channel involved in human pain, and previous work has shown that it is transported in vesicles in sensory axons which also carry Rab6a, a small GTPase known to be involved in vesicular packaging and axonal transport. Understanding the mechanism of the association between Rab6a and NaV1.7 could inform therapeutic modalities to decrease trafficking of NaV1.7 to the distal axonal membrane. Polybasic motifs (PBM) have been shown to regulate Rab-protein interactions in a variety of contexts. In this study, we explored whether two PBMs in the cytoplasmic loop that joins domains I and II of human NaV1.7 were responsible for association with Rab6a and regulate axonal trafficking of the channel. Using site-directed mutagenesis we generated NaV1.7 constructs with alanine substitutions in the two PBMs. Voltage-clamp recordings showed that the constructs retain wild-type like gating properties. Optical Pulse-chase Axonal Long-distance (OPAL) imaging in live sensory axons shows that mutations of these PBMs do not affect co-trafficking of Rab6a and NaV1.7, or the accumulation of the channel at the distal axonal surface. Thus, these polybasic motifs are not required for interaction of NaV1.7 with the Rab6a GTPase, or for trafficking of the channel to the plasma membrane.
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Affiliation(s)
- Sidharth Tyagi
- Medical Scientist Training Program, Yale School of Medicine, New Haven, CT, United States
- Center for Neuroscience and Regeneration Research, West Haven, CT, United States
- Department of Neurology, Yale School of Medicine, New Haven, CT, United States
- Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT, United States
| | - Nivedita Sarveswaran
- Center for Neuroscience and Regeneration Research, West Haven, CT, United States
- Department of Neurology, Yale School of Medicine, New Haven, CT, United States
- Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT, United States
| | - Grant P. Higerd-Rusli
- Medical Scientist Training Program, Yale School of Medicine, New Haven, CT, United States
- Center for Neuroscience and Regeneration Research, West Haven, CT, United States
- Department of Neurology, Yale School of Medicine, New Haven, CT, United States
- Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT, United States
| | - Shujun Liu
- Center for Neuroscience and Regeneration Research, West Haven, CT, United States
- Department of Neurology, Yale School of Medicine, New Haven, CT, United States
- Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT, United States
| | - Fadia B. Dib-Hajj
- Center for Neuroscience and Regeneration Research, West Haven, CT, United States
- Department of Neurology, Yale School of Medicine, New Haven, CT, United States
- Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT, United States
| | - Stephen G. Waxman
- Center for Neuroscience and Regeneration Research, West Haven, CT, United States
- Department of Neurology, Yale School of Medicine, New Haven, CT, United States
- Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT, United States
- *Correspondence: Stephen G. Waxman,
| | - Sulayman D. Dib-Hajj
- Center for Neuroscience and Regeneration Research, West Haven, CT, United States
- Department of Neurology, Yale School of Medicine, New Haven, CT, United States
- Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT, United States
- Sulayman D. Dib-Hajj,
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Sultana P, Novotny J. Rab11 and Its Role in Neurodegenerative Diseases. ASN Neuro 2022; 14:17590914221142360. [PMID: 36464817 PMCID: PMC9726856 DOI: 10.1177/17590914221142360] [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: 12/08/2022] Open
Abstract
Vesicles mediate the trafficking of membranes/proteins in the endocytic and secretory pathways. These pathways are regulated by small GTPases of the Rab family. Rab proteins belong to the Ras superfamily of GTPases, which are significantly involved in various intracellular trafficking and signaling processes in the nervous system. Rab11 is known to play a key role especially in recycling many proteins, including receptors important for signal transduction and preservation of functional activities of nerve cells. Rab11 activity is controlled by GEFs (guanine exchange factors) and GAPs (GTPase activating proteins), which regulate its function through modulating GTP/GDP exchange and the intrinsic GTPase activity, respectively. Rab11 is involved in the transport of several growth factor molecules important for the development and repair of neurons. Overexpression of Rab11 has been shown to significantly enhance vesicle trafficking. On the other hand, a reduced expression of Rab11 was observed in several neurodegenerative diseases. Current evidence appears to support the notion that Rab11 and its cognate proteins may be potential targets for therapeutic intervention. In this review, we briefly discuss the function of Rab11 and its related interaction partners in intracellular pathways that may be involved in neurodegenerative processes.
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Affiliation(s)
| | - Jiri Novotny
- Jiri Novotny, Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic.
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Early Endosomal Vps34-Derived Phosphatidylinositol-3-Phosphate Is Indispensable for the Biogenesis of the Endosomal Recycling Compartment. Cells 2022; 11:cells11060962. [PMID: 35326413 PMCID: PMC8946653 DOI: 10.3390/cells11060962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/17/2022] [Accepted: 03/09/2022] [Indexed: 12/29/2022] Open
Abstract
Phosphatidylinositol-3-phosphate (PI3P), a major identity tag of early endosomes (EEs), provides a platform for the recruitment of numerous cellular proteins containing an FYVE or PX domain that is required for PI3P-dependent maturation of EEs. Most of the PI3P in EEs is generated by the activity of Vps34, a catalytic component of class III phosphatidylinositol-3-phosphate kinase (PI3Ks) complex. In this study, we analyzed the role of Vps34-derived PI3P in the EE recycling circuit of unperturbed cells using VPS34-IN1 (IN1), a highly specific inhibitor of Vps34. IN1-mediated PI3P depletion resulted in the rapid dissociation of recombinant FYVE- and PX-containing PI3P-binding modules and endogenous PI3P-binding proteins, including EEA1 and EE sorting nexins. IN1 treatment triggered the rapid restructuring of EEs into a PI3P-independent functional configuration, and after IN1 washout, EEs were rapidly restored to a PI3P-dependent functional configuration. Analysis of the PI3P-independent configuration showed that the Vps34-derived PI3P is not essential for the pre-EE-associated functions and the fast recycling loop of the EE recycling circuit but contributes to EE maturation toward the degradation circuit, as previously shown in Vps34 knockout and knockdown studies. However, our study shows that Vps34-derived PI3P is also essential for the establishment of the Rab11a-dependent pathway, including recycling cargo sorting in this pathway and membrane flux from EEs to the pericentriolar endosomal recycling compartment (ERC). Rab11a endosomes of PI3P-depleted cells expanded and vacuolized outside the pericentriolar area without the acquisition of internalized transferrin (Tf). These endosomes had high levels of FIP5 and low levels of FIP3, suggesting that their maturation was arrested before the acquisition of FIP3. Consequently, Tf-loaded-, Rab11a/FIP5-, and Rab8a-positive endosomes disappeared from the pericentriolar area, implying that PI3P-associated functions are essential for ERC biogenesis. ERC loss was rapidly reversed after IN1 washout, which coincided with the restoration of FIP3 recruitment to Rab11a-positive endosomes and their dynein-dependent migration to the cell center. Thus, our study shows that Vps34-derived PI3P is indispensable in the recycling circuit to maintain the slow recycling pathway and biogenesis of the ERC.
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Li X, Cordat E, Schmitt MJ, Becker B. Boosting endoplasmic reticulum folding capacity reduces unfolded protein response activation and intracellular accumulation of human kidney anion exchanger 1 in Saccharomyces cerevisiae. Yeast 2021; 38:521-534. [PMID: 34033682 DOI: 10.1002/yea.3652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/20/2021] [Accepted: 05/21/2021] [Indexed: 11/09/2022] Open
Abstract
Human kidney anion exchanger 1 (kAE1) facilitates simultaneous efflux of bicarbonate and absorption of chloride at the basolateral membrane of α-intercalated cells. In these cells, kAE1 contributes to systemic acid-base balance along with the proton pump v-H+ -ATPase and the cytosolic carbonic anhydrase II. Recent electron microscopy analyses in yeast demonstrate that heterologous expression of several kAE1 variants causes a massive accumulation of the anion transporter in intracellular membrane structures. Here, we examined the origin of these kAE1 aggregations in more detail. Using various biochemical techniques and advanced light and electron microscopy, we showed that accumulation of kAE1 mainly occurs in endoplasmic reticulum (ER) membranes which eventually leads to strong unfolded protein response (UPR) activation and severe growth defect in kAE1 expressing yeast cells. Furthermore, our data indicate that UPR activation is dose dependent and uncoupled from the bicarbonate transport activity. By using truncated kAE1 variants, we identified the C-terminal region of kAE1 as crucial factor for the increased ER stress level. Finally, a redistribution of ER-localized kAE1 to the cell periphery was achieved by boosting the ER folding capacity. Our findings not only demonstrate a promising strategy for preventing intracellular kAE1 accumulation and improving kAE1 plasma membrane targeting but also highlight the versatility of yeast as model to investigate kAE1-related research questions including the analysis of structural features, protein degradation and trafficking. Furthermore, our approach might be a promising strategy for future analyses to further optimize the cell surface targeting of other disease-related PM proteins, not only in yeast but also in mammalian cells.
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Affiliation(s)
- Xiaobing Li
- Molecular and Cell Biology, Department of Biosciences and Centre of Human and Molecular Biology (ZHMB), Saarland University, Saarbrücken, Germany
| | - Emmanuelle Cordat
- Department of Physiology and Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Manfred J Schmitt
- Molecular and Cell Biology, Department of Biosciences and Centre of Human and Molecular Biology (ZHMB), Saarland University, Saarbrücken, Germany
| | - Björn Becker
- Molecular and Cell Biology, Department of Biosciences and Centre of Human and Molecular Biology (ZHMB), Saarland University, Saarbrücken, Germany
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6
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Lujan P, Campelo F. Should I stay or should I go? Golgi membrane spatial organization for protein sorting and retention. Arch Biochem Biophys 2021; 707:108921. [PMID: 34038703 DOI: 10.1016/j.abb.2021.108921] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/12/2021] [Accepted: 05/03/2021] [Indexed: 12/23/2022]
Abstract
The Golgi complex is the membrane-bound organelle that lies at the center of the secretory pathway. Its main functions are to maintain cellular lipid homeostasis, to orchestrate protein processing and maturation, and to mediate protein sorting and export. These functions are not independent of one another, and they all require that the membranes of the Golgi complex have a well-defined biochemical composition. Importantly, a finely-regulated spatiotemporal organization of the Golgi membrane components is essential for the correct performance of the organelle. In here, we review our current mechanistic and molecular understanding of how Golgi membranes are spatially organized in the lateral and axial directions to fulfill their functions. In particular, we highlight the current evidence and proposed models of intra-Golgi transport, as well as the known mechanisms for the retention of Golgi residents and for the sorting and export of transmembrane cargo proteins. Despite the controversies, conflicting evidence, clashes between models, and technical limitations, the field has moved forward and we have gained extensive knowledge in this fascinating topic. However, there are still many important questions that remain to be completely answered. We hope that this review will help boost future investigations on these issues.
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Affiliation(s)
- Pablo Lujan
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain.
| | - Felix Campelo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain.
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Rab11-mediated post-Golgi transport of the sialyltransferase ST3GAL4 suggests a new mechanism for regulating glycosylation. J Biol Chem 2021; 296:100354. [PMID: 33524390 PMCID: PMC7949161 DOI: 10.1016/j.jbc.2021.100354] [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: 09/18/2020] [Revised: 01/20/2021] [Accepted: 01/27/2021] [Indexed: 02/06/2023] Open
Abstract
Glycosylation, the most common posttranslational modification of proteins, is a stepwise process that relies on tight regulation of subcellular glycosyltransferase location to control the addition of each monosaccharide. Glycosyltransferases primarily reside and function in the endoplasmic reticulum (ER) and the Golgi apparatus; whether and how they traffic beyond the Golgi, how this trafficking is controlled, and how it impacts glycosylation remain unclear. Our previous work identified a connection between N-glycosylation and Rab11, a key player in the post-Golgi transport that connects recycling endosomes and other compartments. To learn more about the specific role of Rab11, we knocked down Rab11 in HeLa cells. Our findings indicate that Rab11 knockdown results in a dramatic enhancement in the sialylation of N-glycans. Structural analyses of glycans using lectins and LC-MS revealed that α2,3-sialylation is selectively enhanced, suggesting that an α2,3-sialyltransferase that catalyzes the sialyation of glycoproteins is activated or upregulated as the result of Rab11 knockdown. ST3GAL4 is the major α2,3-sialyltransferase that acts on N-glycans; we demonstrated that the localization of ST3GAL4, but not the levels of its mRNA, protein, or donor substrate, was altered by Rab11 depletion. In knockdown cells, ST3GAL4 is densely distributed in the trans-Golgi network, compared with the wider distribution in the Golgi and in other peripheral puncta in control cells, whereas the α2,6-sialyltransferase ST6GAL1 is predominantly localized to the Golgi regardless of Rab11 knockdown. This indicates that Rab11 may negatively regulate α2,3-sialylation by transporting ST3GAL4 to post-Golgi compartments (PGCs), which is a novel mechanism of glycosyltransferase regulation.
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8
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Deng S, Liu J, Wu X, Lu W. Golgi Apparatus: A Potential Therapeutic Target for Autophagy-Associated Neurological Diseases. Front Cell Dev Biol 2020; 8:564975. [PMID: 33015059 PMCID: PMC7509445 DOI: 10.3389/fcell.2020.564975] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 08/17/2020] [Indexed: 12/13/2022] Open
Abstract
Autophagy has dual effects in human diseases: appropriate autophagy may protect cells from stress, while excessive autophagy may cause cell death. Additionally, close interactions exist between autophagy and the Golgi. This review outlines recent advances regarding the role of the Golgi apparatus in autophagy. The signaling processes of autophagy are dependent on the normal function of the Golgi. Specifically, (i) autophagy-related protein 9 is mainly located in the Golgi and forms new autophagosomes in response to stressors; (ii) Golgi fragmentation is induced by Golgi-related proteins and accompanied with autophagy induction; and (iii) the endoplasmic reticulum-Golgi intermediate compartment and the reticular trans-Golgi network play essential roles in autophagosome formation to provide a template for lipidation of microtubule-associated protein 1A/1B-light chain 3 and induce further ubiquitination. Golgi-related proteins regulate formation of autophagosomes, and disrupted formation of autophagy can influence Golgi function. Notably, aberrant autophagy has been demonstrated to be implicated in neurological diseases. Thus, targeted therapies aimed at protecting the Golgi or regulating Golgi proteins might prevent or ameliorate autophagy-related neurological diseases. Further studies are needed to investigate the potential application of Golgi therapy in autophagy-based neurological diseases.
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Affiliation(s)
- Shuwen Deng
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jia Liu
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Xiaomei Wu
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Wei Lu
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
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9
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Yang Y, Gaspard G, McMullen N, Duncan R. Polycistronic Genome Segment Evolution and Gain and Loss of FAST Protein Function during Fusogenic Orthoreovirus Speciation. Viruses 2020; 12:v12070702. [PMID: 32610593 PMCID: PMC7412057 DOI: 10.3390/v12070702] [Citation(s) in RCA: 9] [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: 03/29/2020] [Revised: 06/03/2020] [Accepted: 06/25/2020] [Indexed: 12/29/2022] Open
Abstract
The Reoviridae family is the only non-enveloped virus family with members that use syncytium formation to promote cell–cell virus transmission. Syncytiogenesis is mediated by a fusion-associated small transmembrane (FAST) protein, a novel family of viral membrane fusion proteins. Previous evidence suggested the fusogenic reoviruses arose from an ancestral non-fusogenic virus, with the preponderance of fusogenic species suggesting positive evolutionary pressure to acquire and maintain the fusion phenotype. New phylogenetic analyses that included the atypical waterfowl subgroup of avian reoviruses and recently identified new orthoreovirus species indicate a more complex relationship between reovirus speciation and fusogenic capacity, with numerous predicted internal indels and 5’-terminal extensions driving the evolution of the orthoreovirus’ polycistronic genome segments and their encoded FAST and fiber proteins. These inferred recombination events generated bi- and tricistronic genome segments with diverse gene constellations, they occurred pre- and post-orthoreovirus speciation, and they directly contributed to the evolution of the four extant orthoreovirus FAST proteins by driving both the gain and loss of fusion capability. We further show that two distinct post-speciation genetic events led to the loss of fusion in the waterfowl isolates of avian reovirus, a recombination event that replaced the p10 FAST protein with a heterologous, non-fusogenic protein and point substitutions in a conserved motif that destroyed the p10 assembly into multimeric fusion platforms.
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Affiliation(s)
- Yiming Yang
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada; (Y.Y.); (G.G.); (N.M.)
| | - Gerard Gaspard
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada; (Y.Y.); (G.G.); (N.M.)
| | - Nichole McMullen
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada; (Y.Y.); (G.G.); (N.M.)
| | - Roy Duncan
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada; (Y.Y.); (G.G.); (N.M.)
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
- Correspondence:
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Tan JZA, Fourriere L, Wang J, Perez F, Boncompain G, Gleeson PA. Distinct anterograde trafficking pathways of BACE1 and amyloid precursor protein from the TGN and the regulation of amyloid-β production. Mol Biol Cell 2020; 31:27-44. [PMID: 31746668 PMCID: PMC6938271 DOI: 10.1091/mbc.e19-09-0487] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 11/01/2019] [Accepted: 11/15/2019] [Indexed: 01/08/2023] Open
Abstract
Processing of amyloid precursor protein (APP) by the β-secretase BACE1 is the initial step of the amyloidogenic pathway to generate amyloid-β (Aβ). Although newly synthesized BACE1 and APP are transported along the secretory pathway, it is not known whether BACE1 and APP share the same post-Golgi trafficking pathways or are partitioned into different transport routes. Here we demonstrate that BACE1 exits the Golgi in HeLa cells and primary neurons by a pathway distinct from the trafficking pathway for APP. By using the Retention Using Selective Hooks system, we show that BACE1 is transported from the trans-Golgi network to the plasma membrane in an AP-1- and Arf1/4-dependent manner. Subsequently, BACE1 is endocytosed to early and recycling endosomes. Perturbation of BACE1 post-Golgi trafficking results in an increase in BACE1 cleavage of APP and increased production of both Aβ40 and Aβ42. These findings reveal that Golgi exit of BACE1 and APP in primary neurons is tightly regulated, resulting in their segregation along different transport routes, which limits APP processing.
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Affiliation(s)
- Jing Zhi A. Tan
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - Lou Fourriere
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - Jingqi Wang
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - Franck Perez
- Dynamics of Intracellular Organization Laboratory, Institut Curie, PSL Research University, Sorbonne Université, Centre National de la Recherche Scientifique, UMR 144, 75248 Paris, France
| | - Gaelle Boncompain
- Dynamics of Intracellular Organization Laboratory, Institut Curie, PSL Research University, Sorbonne Université, Centre National de la Recherche Scientifique, UMR 144, 75248 Paris, France
| | - Paul A. Gleeson
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
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Makowski SL, Kuna RS, Field SJ. Induction of membrane curvature by proteins involved in Golgi trafficking. Adv Biol Regul 2019; 75:100661. [PMID: 31668661 PMCID: PMC7056495 DOI: 10.1016/j.jbior.2019.100661] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 09/25/2019] [Accepted: 09/30/2019] [Indexed: 12/22/2022]
Abstract
The Golgi apparatus serves a key role in processing and sorting lipids and proteins for delivery to their final cellular destinations. Vesicle exit from the Golgi initiates with directional deformation of the lipid bilayer to produce a bulge. Several mechanisms have been described by which lipids and proteins can induce directional membrane curvature to promote vesicle budding. Here we review some of the mechanisms implicated in inducing membrane curvature at the Golgi to promote vesicular trafficking to various cellular destinations.
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Affiliation(s)
- Stefanie L Makowski
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Ramya S Kuna
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Seth J Field
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA, 92093, USA.
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12
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Rotavirus Species B Encodes a Functional Fusion-Associated Small Transmembrane Protein. J Virol 2019; 93:JVI.00813-19. [PMID: 31375572 DOI: 10.1128/jvi.00813-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 07/19/2019] [Indexed: 02/07/2023] Open
Abstract
Rotavirus is an important cause of diarrheal disease in young mammals. Rotavirus species A (RVA) causes most human rotavirus diarrheal disease and primarily affects infants and young children. Rotavirus species B (RVB) has been associated with sporadic outbreaks of human adult diarrheal disease. RVA and RVB are predicted to encode mostly homologous proteins but differ significantly in the proteins encoded by the NSP1 gene. In the case of RVB, the NSP1 gene encodes two putative protein products of unknown function, NSP1-1 and NSP1-2. We demonstrate that human RVB NSP1-1 mediates syncytium formation in cultured human cells. Based on sequence alignment, NSP1-1 proteins from species B, G, and I contain features consistent with fusion-associated small transmembrane (FAST) proteins, which have previously been identified in other genera of the Reoviridae family. Like some other FAST proteins, RVB NSP1-1 is predicted to have an N-terminal myristoyl modification. Addition of an N-terminal FLAG peptide disrupts NSP1-1-mediated fusion. NSP1-1 from a human RVB mediates fusion of human cells but not hamster cells and, thus, may serve as a species tropism determinant. NSP1-1 also can enhance RVA replication in human cells, both in single-cycle infection studies and during a multicycle time course in the presence of fetal bovine serum, which inhibits rotavirus spread. These findings suggest potential yet untested roles for NSP1-1 in RVB species tropism, immune evasion, and pathogenesis.IMPORTANCE While species A rotavirus is commonly associated with diarrheal disease in young children, species B rotavirus has caused sporadic outbreaks of adult diarrheal disease. A major genetic difference between species A and B rotaviruses is the NSP1 gene, which encodes two proteins for species B rotavirus. We demonstrate that the smaller of these proteins, NSP1-1, can mediate fusion of cultured human cells. Comparison with viral proteins of similar function provides insight into NSP1-1 domain organization and fusion mechanism. These comparisons suggest that there is a fatty acid modification at the amino terminus of the protein, and our results show that an intact amino terminus is required for NSP1-1-mediated fusion. NSP1-1 from a human virus mediates fusion of human cells, but not hamster cells, and enhances species A rotavirus replication in culture. These findings suggest potential, but currently untested, roles for NSP1-1 in RVB host species tropism, immune evasion, and pathogenesis.
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Abstract
With no limiting membrane surrounding virions, nonenveloped viruses have no need for membrane fusion to gain access to intracellular replication compartments. Consequently, nonenveloped viruses do not encode membrane fusion proteins. The only exception to this dogma is the fusogenic reoviruses that encode fusion-associated small transmembrane (FAST) proteins that induce syncytium formation. FAST proteins are the smallest viral membrane fusion proteins and, unlike their enveloped virus counterparts, are nonstructural proteins that evolved specifically to induce cell-to-cell, not virus-cell, membrane fusion. This distinct evolutionary imperative is reflected in structural and functional features that distinguish this singular family of viral fusogens from all other protein fusogens. These rudimentary fusogens comprise specific combinations of different membrane effector motifs assembled into small, modular membrane fusogens. FAST proteins offer a minimalist model to better understand the ubiquitous process of protein-mediated membrane fusion and to reveal novel mechanisms of nonenveloped virus dissemination that contribute to virulence.
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Affiliation(s)
- Roy Duncan
- Department of Microbiology & Immunology, Department of Biochemistry & Molecular Biology, and Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2;
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14
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Clathrin Adaptor Complex-interacting Protein Irc6 Functions through the Conserved C-Terminal Domain. Sci Rep 2019; 9:4436. [PMID: 30872642 PMCID: PMC6418106 DOI: 10.1038/s41598-019-40852-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 02/25/2019] [Indexed: 01/19/2023] Open
Abstract
Clathrin coats drive transport vesicle formation from the plasma membrane and in pathways between the trans-Golgi network (TGN) and endosomes. Clathrin adaptors play central roles orchestrating assembly of clathrin coats. The yeast clathrin adaptor-interacting protein Irc6 is an orthologue of human p34, which is mutated in the inherited skin disorder punctate palmoplantar keratoderma type I. Irc6 and p34 bind to clathrin adaptor complexes AP-1 and AP-2 and are members of a conserved family characterized by a two-domain architecture. Irc6 is required for AP-1-dependent transport between the TGN and endosomes in yeast. Here we present evidence that the C-terminal two amino acids of Irc6 are required for AP-1 binding and transport function. Additionally, like the C-terminal domain, the N-terminal domain when overexpressed partially restores AP-1-mediated transport in cells lacking full-length Irc6. These findings support a functional role for Irc6 binding to AP-1. Negative genetic interactions with irc6∆ are enriched for genes related to membrane traffic and nuclear processes, consistent with diverse cellular roles for Irc6.
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15
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Abstract
The Golgi apparatus is a central sorting station in the cell. It receives newly synthesized molecules from the endoplasmic reticulum and directs them to different subcellular destinations, such as the plasma membrane or the endocytic pathway. Importantly, in the last few years, it has emerged that the maintenance of Golgi structure is connected to the proper regulation of membrane trafficking. Rab proteins are small GTPases that are considered to be the master regulators of the intracellular membrane trafficking. Several of the over 60 human Rabs are involved in the regulation of transport pathways at the Golgi as well as in the maintenance of its architecture. This chapter will summarize the different roles of Rab GTPases at the Golgi, both as regulators of membrane transport, scaffold, and tethering proteins and in preserving the structure and function of this organelle.
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16
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Deng Y, Pakdel M, Blank B, Sundberg EL, Burd CG, von Blume J. Activity of the SPCA1 Calcium Pump Couples Sphingomyelin Synthesis to Sorting of Secretory Proteins in the Trans-Golgi Network. Dev Cell 2018; 47:464-478.e8. [PMID: 30393074 PMCID: PMC6261503 DOI: 10.1016/j.devcel.2018.10.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 08/29/2018] [Accepted: 10/05/2018] [Indexed: 12/24/2022]
Abstract
How the principal functions of the Golgi apparatus-protein processing, lipid synthesis, and sorting of macromolecules-are integrated to constitute cargo-specific trafficking pathways originating from the trans-Golgi network (TGN) is unknown. Here, we show that the activity of the Golgi localized SPCA1 calcium pump couples sorting and export of secreted proteins to synthesis of new lipid in the TGN membrane. A secreted Ca2+-binding protein, Cab45, constitutes the core component of a Ca2+-dependent, oligomerization-driven sorting mechanism whereby secreted proteins bound to Cab45 are packaged into a TGN-derived vesicular carrier whose membrane is enriched in sphingomyelin, a lipid implicated in TGN-to-cell surface transport. SPCA1 activity is controlled by the sphingomyelin content of the TGN membrane, such that local sphingomyelin synthesis promotes Ca2+ flux into the lumen of the TGN, which drives secretory protein sorting and export, thereby establishing a protein- and lipid-specific secretion pathway.
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Affiliation(s)
- Yongqiang Deng
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Mehrshad Pakdel
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Birgit Blank
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Emma L Sundberg
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Christopher G Burd
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.
| | - Julia von Blume
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
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17
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Secretory Vesicle Polar Sorting, Endosome Recycling and Cytoskeleton Organization Require the AP-1 Complex in Aspergillus nidulans. Genetics 2018; 209:1121-1138. [PMID: 29925567 DOI: 10.1534/genetics.118.301240] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 06/19/2018] [Indexed: 11/18/2022] Open
Abstract
The AP-1 complex is essential for membrane protein traffic via its role in the pinching-off and sorting of secretory vesicles (SVs) from the trans-Golgi and/or endosomes. While its essentiality is undisputed in metazoa, its role in simpler eukaryotes seems less clear. Here, we dissect the role of AP-1 in the filamentous fungus Aspergillus nidulans and show that it is absolutely essential for growth due to its role in clathrin-dependent maintenance of polar traffic of specific membrane cargoes toward the apex of growing hyphae. We provide evidence that AP-1 is involved in both anterograde sorting of RabERab11-labeled SVs and RabA/BRab5-dependent endosome recycling. Additionally, AP-1 is shown to be critical for microtubule and septin organization, further rationalizing its essentiality in cells that face the challenge of cytoskeleton-dependent polarized cargo traffic. This work also opens a novel issue on how nonpolar cargoes, such as transporters, are sorted to the eukaryotic plasma membrane.
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18
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Ma T, Li B, Wang R, Lau PK, Huang Y, Jiang L, Schekman R, Guo Y. A mechanism for differential sorting of the planar cell polarity proteins Frizzled6 and Vangl2 at the trans-Golgi network. J Biol Chem 2018; 293:8410-8427. [PMID: 29666182 DOI: 10.1074/jbc.ra118.001906] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/12/2018] [Indexed: 01/14/2023] Open
Abstract
In planar cell polarity (PCP), the epithelial cells are polarized along the plane of the cell surface perpendicular to the classical apical-basal axis, a process mediated by several conserved signaling receptors. Two PCP-signaling proteins, VANGL planar cell polarity protein 2 (Vangl2) and Frizzled6 (Fzd6), are located asymmetrically on opposite boundaries of the cell. Examining sorting of these two proteins at the trans-Golgi network (TGN), we demonstrated previously that the GTP-binding protein ADP-ribosylation factor-related protein 1 (Arfrp1) and the clathrin-associated adaptor protein complex 1 (AP-1) are required for Vangl2 transport from the TGN. In contrast, TGN export of Frizzled6 does not depend on Arfrp1 or AP-1. Here, to further investigate the TGN sorting process in mammalian cells, we reconstituted release of Vangl2 and Frizzled6 from the TGN into vesicles in vitro Immunoblotting of released vesicles indicated that Vangl2 and Frizzled6 exit the TGN in separate compartments. Knockdown analysis revealed that a clathrin adaptor, epsinR, regulates TGN export of Frizzled6 but not of Vangl2. Protein interaction analysis suggested that epsinR forms a stable complex with clathrin and that this complex interacts with a conserved polybasic motif in the Frizzled6 cytosolic domain to package Frizzled6 into transport vesicles. Moreover, we found that Frizzled6-epsinR binding dissociates epsinR from AP-1, which may separate these two cargo adaptors from each other to perform distinct cargo-sorting functions. Our results suggest that Vangl2 and Frizzled6 are packaged into separate vesicles that are regulated by different clathrin adaptors at the TGN, which may contribute to their asymmetric localizations.
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Affiliation(s)
- Tianji Ma
- From the Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Baiying Li
- the Centre for Cell and Developmental Biology, State Key Laboratory of Agrobiotechnology, School of Life Sciences, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Ryan Wang
- the Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, and
| | - Pik Ki Lau
- From the Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yan Huang
- From the Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Liwen Jiang
- the Centre for Cell and Developmental Biology, State Key Laboratory of Agrobiotechnology, School of Life Sciences, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Randy Schekman
- the Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, and
| | - Yusong Guo
- From the Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China,
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