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Frisby D, Murakonda AB, Ashraf B, Dhawan K, Almeida-Souza L, Naslavsky N, Caplan S. Endosomal actin branching, fission and receptor recycling require FCHSD2 recruitment by MICAL-L1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.27.601011. [PMID: 38979241 PMCID: PMC11230409 DOI: 10.1101/2024.06.27.601011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Endosome fission is required for the release of carrier vesicles and the recycling of receptors to the plasma membrane. Early events in endosome budding and fission rely on actin branching to constrict the endosomal membrane, ultimately leading to nucleotide hydrolysis and enzymatic fission. However, our current understanding of this process is limited, particularly regarding the coordination between the early and late steps of endosomal fission. Here we have identified a novel interaction between the endosomal scaffolding protein, MICAL-L1, and the human homolog of the Drosophila Nervous Wreck (Nwk) protein, FCH and double SH3 domains protein 2 (FCHSD2). We demonstrate that MICAL-L1 recruits FCHSD2 to the endosomal membrane, where it is required for ARP2/3-mediated generation of branched actin, endosome fission and receptor recycling to the plasma membrane. Since MICAL-L1 first recruits FCHSD2 to the endosomal membrane, and is subsequently responsible for recruitment of the ATPase and fission protein EHD1 to endosomes, our findings support a model in which MICAL-L1 orchestrates endosomal fission by connecting between the early actin-driven and subsequent nucleotide hydrolysis steps of the process.
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2
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Gopaldass N, Mayer A. PROPPINs and membrane fission in the endo-lysosomal system. Biochem Soc Trans 2024; 52:1233-1241. [PMID: 38747700 DOI: 10.1042/bst20230897] [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: 02/27/2024] [Revised: 04/21/2024] [Accepted: 04/22/2024] [Indexed: 06/27/2024]
Abstract
PROPPINs constitute a conserved protein family with multiple members being expressed in many eukaryotes. PROPPINs have mainly been investigated for their role in autophagy, where they co-operate with several core factors for autophagosome formation. Recently, novel functions of these proteins on endo-lysosomal compartments have emerged. PROPPINs support the division of these organelles and the formation of tubulo-vesicular cargo carriers that mediate protein exit from them, such as those generated by the Retromer coat. In both cases, PROPPINs provide membrane fission activity. Integrating information from yeast and human cells this review summarizes the most important molecular features that allow these proteins to facilitate membrane fission and thus provide a critical element to endo-lysosomal protein traffic.
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Affiliation(s)
- Navin Gopaldass
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland
| | - Andreas Mayer
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland
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3
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Gopaldass N, Chen KE, Collins B, Mayer A. Assembly and fission of tubular carriers mediating protein sorting in endosomes. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00746-8. [PMID: 38886588 DOI: 10.1038/s41580-024-00746-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2024] [Indexed: 06/20/2024]
Abstract
Endosomes are central protein-sorting stations at the crossroads of numerous membrane trafficking pathways in all eukaryotes. They have a key role in protein homeostasis and cellular signalling and are involved in the pathogenesis of numerous diseases. Endosome-associated protein assemblies or coats collect transmembrane cargo proteins and concentrate them into retrieval domains. These domains can extend into tubular carriers, which then pinch off from the endosomal membrane and deliver the cargoes to appropriate subcellular compartments. Here we discuss novel insights into the structure of a number of tubular membrane coats that mediate the recruitment of cargoes into these carriers, focusing on sorting nexin-based coats such as Retromer, Commander and ESCPE-1. We summarize current and emerging views of how selective tubular endosomal carriers form and detach from endosomes by fission, highlighting structural aspects, conceptual challenges and open questions.
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Affiliation(s)
- Navin Gopaldass
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland.
| | - Kai-En Chen
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland, Australia
| | - Brett Collins
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland, Australia
| | - Andreas Mayer
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland.
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4
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Shortill SP, Frier MS, Davey M, Conibear E. N-terminal signals in the SNX-BAR paralogs Vps5 and Vin1 guide endosomal coat complex formation. Mol Biol Cell 2024; 35:ar76. [PMID: 38598303 PMCID: PMC11238075 DOI: 10.1091/mbc.e24-01-0043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/03/2024] [Accepted: 04/05/2024] [Indexed: 04/12/2024] Open
Abstract
Endosomal coats incorporate membrane-binding subunits such as sorting nexin (SNX) proteins. The Saccharomyces cerevisiae SNX-BAR paralogs Vin1 and Vps5 are respective subunits of the endosomal VINE and retromer complexes whose dimerizing BAR domains are required for complex assembly and membrane association. However, a degree of promiscuity is predicted for yeast BAR-BAR pairings, and recent work has implicated the unstructured N-terminal domains of Vin1 and Vps5 in coat formation. Here, we map N-terminal signals in both SNX-BAR paralogs that contribute to the assembly and function of two distinct endosomal coats in vivo. Whereas Vin1 leverages a polybasic region and adjacent hydrophobic motif to bind Vrl1 and form VINE, the N-terminus of Vps5 interacts with the retromer subunit Vps29 at two sites, including a conserved hydrophobic pocket in Vps29 that engages other accessory proteins in humans. We also examined the sole isoform of Vps5 from the milk yeast Kluyveromyces lactis and found that ancestral yeasts may have used a nested N-terminal signal to form both VINE and retromer. Our results suggest that the specific assembly of Vps5-family SNX-BAR coats depends on inputs from unique N-terminal sequence features in addition to BAR domain coupling, expanding our understanding of endosomal coat biology.
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Affiliation(s)
- Shawn P. Shortill
- Department of Medical Genetics, University of British Columbia, Vancouver, BC VH6 3N1, Canada
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Mia S. Frier
- Department of Medical Genetics, University of British Columbia, Vancouver, BC VH6 3N1, Canada
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Michael Davey
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Elizabeth Conibear
- Department of Medical Genetics, University of British Columbia, Vancouver, BC VH6 3N1, Canada
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
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5
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Xia S, Li D, Deng X, Liu Z, Zhu H, Liu Y, Li D. Integration of protein sequence and protein-protein interaction data by hypergraph learning to identify novel protein complexes. Brief Bioinform 2024; 25:bbae274. [PMID: 38851299 PMCID: PMC11162299 DOI: 10.1093/bib/bbae274] [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: 02/22/2024] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/10/2024] Open
Abstract
Protein-protein interactions (PPIs) are the basis of many important biological processes, with protein complexes being the key forms implementing these interactions. Understanding protein complexes and their functions is critical for elucidating mechanisms of life processes, disease diagnosis and treatment and drug development. However, experimental methods for identifying protein complexes have many limitations. Therefore, it is necessary to use computational methods to predict protein complexes. Protein sequences can indicate the structure and biological functions of proteins, while also determining their binding abilities with other proteins, influencing the formation of protein complexes. Integrating these characteristics to predict protein complexes is very promising, but currently there is no effective framework that can utilize both protein sequence and PPI network topology for complex prediction. To address this challenge, we have developed HyperGraphComplex, a method based on hypergraph variational autoencoder that can capture expressive features from protein sequences without feature engineering, while also considering topological properties in PPI networks, to predict protein complexes. Experiment results demonstrated that HyperGraphComplex achieves satisfactory predictive performance when compared with state-of-art methods. Further bioinformatics analysis shows that the predicted protein complexes have similar attributes to known ones. Moreover, case studies corroborated the remarkable predictive capability of our model in identifying protein complexes, including 3 that were not only experimentally validated by recent studies but also exhibited high-confidence structural predictions from AlphaFold-Multimer. We believe that the HyperGraphComplex algorithm and our provided proteome-wide high-confidence protein complex prediction dataset will help elucidate how proteins regulate cellular processes in the form of complexes, and facilitate disease diagnosis and treatment and drug development. Source codes are available at https://github.com/LiDlab/HyperGraphComplex.
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Affiliation(s)
- Simin Xia
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Shushan District, Hefei 230032, China
- State Key Laboratory of Medical Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 38 Life Science Park, Changping District, Beijing 102206, China
| | - Dianke Li
- State Key Laboratory of Medical Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 38 Life Science Park, Changping District, Beijing 102206, China
- State Key Laboratory of Farm Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China
| | - Xinru Deng
- State Key Laboratory of Medical Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 38 Life Science Park, Changping District, Beijing 102206, China
| | - Zhongyang Liu
- State Key Laboratory of Medical Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 38 Life Science Park, Changping District, Beijing 102206, China
| | - Huaqing Zhu
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Shushan District, Hefei 230032, China
| | - Yuan Liu
- State Key Laboratory of Medical Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 38 Life Science Park, Changping District, Beijing 102206, China
| | - Dong Li
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Shushan District, Hefei 230032, China
- State Key Laboratory of Medical Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, 38 Life Science Park, Changping District, Beijing 102206, China
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6
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Wible DJ, Parikh Z, Cho EJ, Chen MD, Jeter CR, Mukhopadhyay S, Dalby KN, Varadarajan S, Bratton SB. Unexpected inhibition of the lipid kinase PIKfyve reveals an epistatic role for p38 MAPKs in endolysosomal fission and volume control. Cell Death Dis 2024; 15:80. [PMID: 38253602 PMCID: PMC10803372 DOI: 10.1038/s41419-024-06423-0] [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: 05/09/2023] [Revised: 12/19/2023] [Accepted: 01/02/2024] [Indexed: 01/24/2024]
Abstract
p38 mitogen-activated protein kinases (MAPKs) participate in autophagic signaling; and previous reports suggest that pyridinyl imidazole p38 MAPK inhibitors, including SB203580 and SB202190, induce cell death in some cancer cell-types through unrestrained autophagy. Subsequent studies, however, have suggested that the associated cytoplasmic vacuolation resulted from off-target inhibition of an unidentified enzyme. Herein, we report that SB203580-induced vacuolation is rapid, reversible, and relies on the class III phosphatidylinositol 3-kinase (PIK3C3) complex and the production of phosphatidylinositol 3-phosphate [PI(3)P] but not on autophagy per se. Rather, vacuolation resulted from the accumulation of Rab7 on late endosome and lysosome (LEL) membranes, combined with an osmotic imbalance that triggered severe swelling in these organelles. Inhibition of PIKfyve, the lipid kinase that converts PI(3)P to PI(3,5)P2 on LEL membranes, produced a similar phenotype in cells; therefore, we performed in vitro kinase assays and discovered that both SB203580 and SB202190 directly inhibited recombinant PIKfyve. Cancer cells treated with either drug likewise displayed significant reductions in the endogenous levels of PI(3,5)P2. Despite these results, SB203580-induced vacuolation was not entirely due to off-target inhibition of PIKfyve, as a drug-resistant p38α mutant suppressed vacuolation; and combined genetic deletion of both p38α and p38β dramatically sensitized cells to established PIKfyve inhibitors, including YM201636 and apilimod. The rate of vacuole dissolution (i.e., LEL fission), following the removal of apilimod, was also significantly reduced in cells treated with BIRB-796, a structurally unrelated p38 MAPK inhibitor. Thus, our studies indicate that pyridinyl imidazole p38 MAPK inhibitors induce cytoplasmic vacuolation through the combined inhibition of both PIKfyve and p38 MAPKs, and more generally, that p38 MAPKs act epistatically to PIKfyve, most likely to promote LEL fission.
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Affiliation(s)
- Daric J Wible
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Zalak Parikh
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Eun Jeong Cho
- Targeted Therapeutic Drug Discovery and Development Program, Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Miao-Der Chen
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Collene R Jeter
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Somshuvra Mukhopadhyay
- Division of Pharmacology & Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Kevin N Dalby
- Targeted Therapeutic Drug Discovery and Development Program, Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Shankar Varadarajan
- Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3BX, UK
| | - Shawn B Bratton
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA.
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7
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Mann D, Fromm SA, Martinez-Sanchez A, Gopaldass N, Choy R, Mayer A, Sachse C. Atg18 oligomer organization in assembled tubes and on lipid membrane scaffolds. Nat Commun 2023; 14:8086. [PMID: 38057304 DOI: 10.1038/s41467-023-43460-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 11/09/2023] [Indexed: 12/08/2023] Open
Abstract
Autophagy-related protein 18 (Atg18) participates in the elongation of early autophagosomal structures in concert with Atg2 and Atg9 complexes. How Atg18 contributes to the structural coordination of Atg2 and Atg9 at the isolation membrane remains to be understood. Here, we determined the cryo-EM structures of Atg18 organized in helical tubes, Atg18 oligomers in solution as well as on lipid membrane scaffolds. The helical assembly is composed of Atg18 tetramers forming a lozenge cylindrical lattice with remarkable structural similarity to the COPII outer coat. When reconstituted with lipid membranes, using subtomogram averaging we determined tilted Atg18 dimer structures bridging two juxtaposed lipid membranes spaced apart by 80 Å. Moreover, lipid reconstitution experiments further delineate the contributions of Atg18's FRRG motif and the amphipathic helical extension in membrane interaction. The observed structural plasticity of Atg18's oligomeric organization and membrane binding properties provide a molecular framework for the positioning of downstream components of the autophagy machinery.
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Affiliation(s)
- Daniel Mann
- Ernst-Ruska Centre 3/Structural Biology, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany
- Institute for Biological Information Processing 6/Structural Cellular Biology, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany
| | - Simon A Fromm
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- EMBL Imaging Centre, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Antonio Martinez-Sanchez
- Department of Information and Communications Engineering, Faculty of Computers Sciences, University of Murcia, Murcia, Spain
| | - Navin Gopaldass
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Ramona Choy
- Ernst-Ruska Centre 3/Structural Biology, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany
- Institute for Biological Information Processing 6/Structural Cellular Biology, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany
| | - Andreas Mayer
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Carsten Sachse
- Ernst-Ruska Centre 3/Structural Biology, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany.
- Institute for Biological Information Processing 6/Structural Cellular Biology, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany.
- Department of Biology, Heinrich Heine University, Universitätsstr. 1, Düsseldorf, Germany.
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8
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Shimizu T, Tamura N, Nishimura T, Saito C, Yamamoto H, Mizushima N. Comprehensive analysis of autophagic functions of WIPI family proteins and their implications for the pathogenesis of β-propeller associated neurodegeneration. Hum Mol Genet 2023; 32:2623-2637. [PMID: 37364041 PMCID: PMC10407718 DOI: 10.1093/hmg/ddad096] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/15/2023] [Accepted: 06/13/2023] [Indexed: 06/28/2023] Open
Abstract
β-propellers that bind polyphosphoinositides (PROPPINs) are an autophagy-related protein family conserved throughout eukaryotes. The PROPPIN family includes Atg18, Atg21 and Hsv2 in yeast and WD-repeat protein interacting with phosphoinositides (WIPI)1-4 in mammals. Mutations in the WIPI genes are associated with human neuronal diseases, including β-propeller associated neurodegeneration (BPAN) caused by mutations in WDR45 (encoding WIPI4). In contrast to yeast PROPPINs, the functions of mammalian WIPI1-WIPI4 have not been systematically investigated. Although the involvement of WIPI2 in autophagy has been clearly shown, the functions of WIPI1, WIPI3 and WIPI4 in autophagy remain poorly understood. In this study, we comprehensively analyzed the roles of WIPI proteins by using WIPI-knockout (single, double and quadruple knockout) HEK293T cells and recently developed HaloTag-based reporters, which enable us to monitor autophagic flux sensitively and quantitatively. We found that WIPI2 was nearly essential for autophagy. Autophagic flux was unaffected or only slightly reduced by single deletion of WIPI3 (encoded by WDR45B) or WIPI4 but was profoundly reduced by double deletion of WIPI3 and WIPI4. Furthermore, we revealed variable effects of BPAN-related missense mutations on the autophagic activity of WIPI4. BPAN is characterized by neurodevelopmental and neurodegenerative abnormalities, and we found a possible association between the magnitude of the defect of the autophagic activity of WIPI4 mutants and the severity of neurodevelopmental symptoms. However, some of the BPAN-related missense mutations, which produce neurodegenerative signs, showed almost normal autophagic activity, suggesting that non-autophagic functions of WIPI4 may be related to neurodegeneration in BPAN.
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Affiliation(s)
- Takahiro Shimizu
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
| | - Norito Tamura
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
| | - Taki Nishimura
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- PRESTO, Japan Science and Technology Agency, Tokyo 102-0076, Japan
| | - Chieko Saito
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
| | - Hayashi Yamamoto
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- Department of Molecular Oncology, Nippon Medical School, Institute for Advanced Medical Sciences, Tokyo 113-8602, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- International Research Center for Neurointelligence (WPI-IRCN), UTIAS, The University of Tokyo, Tokyo 113-8655, Japan
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9
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Marquardt L, Thumm M. Autophagic and non-autophagic functions of the Saccharomyces cerevisiae PROPPINs Atg18, Atg21 and Hsv2. Biol Chem 2023; 404:813-819. [PMID: 37139661 DOI: 10.1515/hsz-2023-0126] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 04/17/2023] [Indexed: 05/05/2023]
Abstract
Atg18, Atg21 and Hsv2 are homologous β-propeller proteins binding to PI3P and PI(3,5)P2. Atg18 is thought to organize lipid transferring protein complexes at contact sites of the growing autophagosome (phagophore) with both the ER and the vacuole. Atg21 is restricted to the vacuole phagophore contact, where it organizes part of the Atg8-lipidation machinery. The role of Hsv2 is less understood, it partly affects micronucleophagy. Atg18 is further involved in regulation of PI(3,5)P2 synthesis. Recently, a novel Atg18-retromer complex and its role in vacuole homeostasis and membrane fission was uncovered.
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Affiliation(s)
- Lisa Marquardt
- Institute of Cellular Biochemistry, University Medicine, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Michael Thumm
- Institute of Cellular Biochemistry, University Medicine, Humboldtallee 23, D-37073 Göttingen, Germany
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10
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Simonetti B, Daly JL, Cullen PJ. Out of the ESCPE room: Emerging roles of endosomal SNX-BARs in receptor transport and host-pathogen interaction. Traffic 2023; 24:234-250. [PMID: 37089068 PMCID: PMC10768393 DOI: 10.1111/tra.12885] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/22/2023] [Accepted: 03/28/2023] [Indexed: 04/25/2023]
Abstract
Several functions of the human cell, such as sensing nutrients, cell movement and interaction with the surrounding environment, depend on a myriad of transmembrane proteins and their associated proteins and lipids (collectively termed "cargoes"). To successfully perform their tasks, cargo must be sorted and delivered to the right place, at the right time, and in the right amount. To achieve this, eukaryotic cells have evolved a highly organized sorting platform, the endosomal network. Here, a variety of specialized multiprotein complexes sort cargo into itineraries leading to either their degradation or their recycling to various organelles for further rounds of reuse. A key sorting complex is the Endosomal SNX-BAR Sorting Complex for Promoting Exit (ESCPE-1) that promotes the recycling of an array of cargos to the plasma membrane and/or the trans-Golgi network. ESCPE-1 recognizes a hydrophobic-based sorting motif in numerous cargoes and orchestrates their packaging into tubular carriers that pinch off from the endosome and travel to the target organelle. A wide range of pathogens mimic this sorting motif to hijack ESCPE-1 transport to promote their invasion and survival within infected cells. In other instances, ESCPE-1 exerts restrictive functions against pathogens by limiting their replication and infection. In this review, we discuss ESCPE-1 assembly and functions, with a particular focus on recent advances in the understanding of its role in membrane trafficking, cellular homeostasis and host-pathogen interaction.
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Affiliation(s)
- Boris Simonetti
- Charles River Laboratories, Discovery House, Quays Office ParkConference Avenue, PortisheadBristolUK
| | - James L. Daly
- Department of Infectious DiseasesSchool of Immunology and Microbial Sciences, Guy's Hospital, King's College LondonLondonUK
| | - Peter J. Cullen
- School of Biochemistry, Faculty of Life Sciences, Biomedical Sciences BuildingUniversity of BristolBristolUK
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11
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Arlt H, Raman B, Filali-Mouncef Y, Hu Y, Leytens A, Hardenberg R, Guimarães R, Kriegenburg F, Mari M, Smaczynska-de Rooij II, Ayscough KR, Dengjel J, Ungermann C, Reggiori F. The dynamin Vps1 mediates Atg9 transport to the sites of autophagosome formation. J Biol Chem 2023; 299:104712. [PMID: 37060997 DOI: 10.1016/j.jbc.2023.104712] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/14/2023] [Accepted: 04/06/2023] [Indexed: 04/17/2023] Open
Abstract
Autophagy is a key process in eukaryotes to maintain cellular homeostasis by delivering cellular components to lysosomes/vacuoles for degradation and reuse of the resulting metabolites. Membrane rearrangements and trafficking events are mediated by the core machinery of autophagy-related (Atg) proteins, which carry out a variety of functions. How Atg9, a lipid scramblase and the only conserved transmembrane protein within this core Atg machinery, is trafficked during autophagy remained largely unclear. Here, we addressed this question in yeast Saccharomyces cerevisiae and found that retromer complex and dynamin Vps1 mutants alter Atg9 subcellular distribution and severely impair the autophagic flux by affecting two separate autophagy steps. We provide evidence that Vps1 interacts with Atg9 at Atg9 reservoirs. In the absence of Vps1, Atg9 fails to reach the sites of autophagosome formation, and this results in an autophagy defect. The function of Vps1 in autophagy requires its GTPase activity. Moreover, Vps1 point mutants associated with human diseases such as microcytic anemia and Charcot-Marie-Tooth are unable to sustain autophagy and affect Atg9 trafficking. Together, our data provide novel insights on the role of dynamins in Atg9 trafficking and suggest that a defect in this autophagy step could contribute to severe human pathologies.
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Affiliation(s)
- Henning Arlt
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Babu Raman
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Yasmina Filali-Mouncef
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Yan Hu
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000 Aarhus C, Denmark
| | - Alexandre Leytens
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Ralph Hardenberg
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Rodrigo Guimarães
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Franziska Kriegenburg
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Muriel Mari
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000 Aarhus C, Denmark
| | | | - Kathryn R Ayscough
- Department of Biomedical Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Jörn Dengjel
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Christian Ungermann
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000 Aarhus C, Denmark; Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Høegh-Guldbergs Gade 6B, 8000 Aarhus C, Denmark.
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Gopaldass N, De Leo MG, Courtellemont T, Mercier V, Bissig C, Roux A, Mayer A. Retromer oligomerization drives SNX-BAR coat assembly and membrane constriction. EMBO J 2023; 42:e112287. [PMID: 36644906 PMCID: PMC9841331 DOI: 10.15252/embj.2022112287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 11/02/2022] [Accepted: 11/02/2022] [Indexed: 01/17/2023] Open
Abstract
Proteins exit from endosomes through tubular carriers coated by retromer, a complex that impacts cellular signaling, lysosomal biogenesis and numerous diseases. The coat must overcome membrane tension to form tubules. We explored the dynamics and driving force of this process by reconstituting coat formation with yeast retromer and the BAR-domain sorting nexins Vps5 and Vps17 on oriented synthetic lipid tubules. This coat oligomerizes bidirectionally, forming a static tubular structure that does not exchange subunits. High concentrations of sorting nexins alone constrict membrane tubes to an invariant radius of 19 nm. At lower concentrations, oligomers of retromer must bind and interconnect the sorting nexins to drive constriction. Constricting less curved membranes into tubes, which requires more energy, coincides with an increased surface density of retromer on the sorting nexin layer. Retromer-mediated crosslinking of sorting nexins at variable densities may thus tune the energy that the coat can generate to deform the membrane. In line with this, genetic ablation of retromer oligomerization impairs endosomal protein exit in yeast and human cells.
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Affiliation(s)
- Navin Gopaldass
- Department of ImmunobiologyUniversity of LausanneEpalingesSwitzerland
| | | | | | - Vincent Mercier
- Department of BiochemistryUniversity of GenevaGenevaSwitzerland
| | - Christin Bissig
- Department of ImmunobiologyUniversity of LausanneEpalingesSwitzerland
| | - Aurélien Roux
- Department of BiochemistryUniversity of GenevaGenevaSwitzerland
- Swiss National Centre for Competence in Research Program Chemical BiologyGenevaSwitzerland
| | - Andreas Mayer
- Department of ImmunobiologyUniversity of LausanneEpalingesSwitzerland
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Vargas Duarte P, Reggiori F. The Organization and Function of the Phagophore-ER Membrane Contact Sites. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231183898. [PMID: 37465355 PMCID: PMC10350784 DOI: 10.1177/25152564231183898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 06/06/2023] [Accepted: 06/06/2023] [Indexed: 07/20/2023]
Abstract
Macroautophagy is characterized by the de novo formation of double-membrane vesicles termed autophagosomes. The precursor structure of autophagosomes is a membrane cistern called phagophore, which elongates through a massive acquisition of lipids until closure. The phagophore establishes membrane-contact sites (MCSs) with the endoplasmic reticulum (ER), where conserved ATG proteins belonging to the ATG9 lipid scramblase, ATG2 lipid transfer and Atg18/WIPI4 β-propeller families concentrate. Several recent in vivo and in vitro studies have uncovered the relevance of these proteins and MCSs in the lipid supply required for autophagosome formation. Although important conceptual advances have been reached, the functional interrelationship between ATG9, ATG2 and Atg18/WIPI4 proteins at the phagophore-ER MCSs and their role in the phagophore expansion are not completely understood. In this review, we describe the current knowledge about the structure, interactions, localizations, and molecular functions of these proteins, with a particular emphasis on the yeast Saccharomyces cerevisiae and mammalian systems.
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Affiliation(s)
| | - Fulvio Reggiori
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus C, Denmark
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Kümmel D, Herrmann E, Langemeyer L, Ungermann C. Molecular insights into endolysosomal microcompartment formation and maintenance. Biol Chem 2022; 404:441-454. [PMID: 36503831 DOI: 10.1515/hsz-2022-0294] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/22/2022] [Indexed: 12/14/2022]
Abstract
Abstract
The endolysosomal system of eukaryotic cells has a key role in the homeostasis of the plasma membrane, in signaling and nutrient uptake, and is abused by viruses and pathogens for entry. Endocytosis of plasma membrane proteins results in vesicles, which fuse with the early endosome. If destined for lysosomal degradation, these proteins are packaged into intraluminal vesicles, converting an early endosome to a late endosome, which finally fuses with the lysosome. Each of these organelles has a unique membrane surface composition, which can form segmented membrane microcompartments by membrane contact sites or fission proteins. Furthermore, these organelles are in continuous exchange due to fission and fusion events. The underlying machinery, which maintains organelle identity along the pathway, is regulated by signaling processes. Here, we will focus on the Rab5 and Rab7 GTPases of early and late endosomes. As molecular switches, Rabs depend on activating guanine nucleotide exchange factors (GEFs). Over the last years, we characterized the Rab7 GEF, the Mon1-Ccz1 (MC1) complex, and key Rab7 effectors, the HOPS complex and retromer. Structural and functional analyses of these complexes lead to a molecular understanding of their function in the context of organelle biogenesis.
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Affiliation(s)
- Daniel Kümmel
- Institute of Biochemistry, University of Münster , Corrensstraße 36 , D-48149 Münster , Germany
| | - Eric Herrmann
- Institute of Biochemistry, University of Münster , Corrensstraße 36 , D-48149 Münster , Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry section , Osnabrück University , Barbarastraße 13 , D-49076 Osnabrück , Germany
- Center of Cellular Nanoanalytics (CellNanOs) , Osnabrück University , Barbarastraße 11 , D-49076 Osnabrück , Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry section , Osnabrück University , Barbarastraße 13 , D-49076 Osnabrück , Germany
- Center of Cellular Nanoanalytics (CellNanOs) , Osnabrück University , Barbarastraße 11 , D-49076 Osnabrück , Germany
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