1
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Guo Q, Chen KE, Gimenez-Andres M, Jellett AP, Gao Y, Simonetti B, Liu M, Danson CM, Heesom KJ, Cullen PJ, Collins BM. Structural basis for coupling of the WASH subunit FAM21 with the endosomal SNX27-Retromer complex. Proc Natl Acad Sci U S A 2024; 121:e2405041121. [PMID: 39116126 PMCID: PMC11331091 DOI: 10.1073/pnas.2405041121] [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: 03/11/2024] [Accepted: 06/27/2024] [Indexed: 08/10/2024] Open
Abstract
Endosomal membrane trafficking is mediated by specific protein coats and formation of actin-rich membrane domains. The Retromer complex coordinates with sorting nexin (SNX) cargo adaptors including SNX27, and the SNX27-Retromer assembly interacts with the Wiskott-Aldrich syndrome protein and SCAR homolog (WASH) complex which nucleates actin filaments establishing the endosomal recycling domain. Crystal structures, modeling, biochemical, and cellular validation reveal how the FAM21 subunit of WASH interacts with both Retromer and SNX27. FAM21 binds the FERM domain of SNX27 using acidic-Asp-Leu-Phe (aDLF) motifs similar to those found in the SNX1 and SNX2 subunits of the ESCPE-1 complex. Overlapping FAM21 repeats and a specific Pro-Leu containing motif bind three distinct sites on Retromer involving both the VPS35 and VPS29 subunits. Mutation of the major VPS35-binding site does not prevent cargo recycling; however, it partially reduces endosomal WASH association indicating that a network of redundant interactions promote endosomal activity of the WASH complex. These studies establish the molecular basis for how SNX27-Retromer is coupled to the WASH complex via overlapping and multiplexed motif-based interactions required for the dynamic assembly of endosomal membrane recycling domains.
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Affiliation(s)
- Qian Guo
- The University of Queensland, Institute for Molecular Bioscience, St Lucia, QLD4072, Australia
| | - Kai-en Chen
- The University of Queensland, Institute for Molecular Bioscience, St Lucia, QLD4072, Australia
| | - Manuel Gimenez-Andres
- School of Biochemistry, Faculty of Life Sciences, University of Bristol, BristolBS8 1TD, United Kingdom
| | - Adam P. Jellett
- School of Biochemistry, Faculty of Life Sciences, University of Bristol, BristolBS8 1TD, United Kingdom
| | - Ya Gao
- The University of Queensland, Institute for Molecular Bioscience, St Lucia, QLD4072, Australia
| | - Boris Simonetti
- School of Biochemistry, Faculty of Life Sciences, University of Bristol, BristolBS8 1TD, United Kingdom
| | - Meihan Liu
- The University of Queensland, Institute for Molecular Bioscience, St Lucia, QLD4072, Australia
| | - Chris M. Danson
- School of Biochemistry, Faculty of Life Sciences, University of Bristol, BristolBS8 1TD, United Kingdom
| | - Kate J. Heesom
- Bristol Proteomics Facility, School of Biochemistry, Faculty of Life Sciences, University of Bristol, BristolBS8 1TD, United Kingdom
| | - Peter J. Cullen
- School of Biochemistry, Faculty of Life Sciences, University of Bristol, BristolBS8 1TD, United Kingdom
| | - Brett M. Collins
- The University of Queensland, Institute for Molecular Bioscience, St Lucia, QLD4072, Australia
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2
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Chandra M, Kendall AK, Ford MGJ, Jackson LP. VARP binds SNX27 to promote endosomal supercomplex formation on membranes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.11.603126. [PMID: 39026782 PMCID: PMC11257539 DOI: 10.1101/2024.07.11.603126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Multiple essential membrane trafficking pathways converge at endosomes to maintain cellular homeostasis by sorting critical transmembrane cargo proteins to the plasma membrane or the trans-Golgi network (TGN). The Retromer heterotrimer (VPS26/VPS35/VPS29 subunits) binds multiple sorting nexin (SNX) proteins on endosomal membranes, but molecular mechanisms regarding formation and regulation of metazoan SNX/Retromer complexes have been elusive. Here, we combine biochemical and biophysical approaches with AlphaFold2 Multimer modeling to identify a direct interaction between the VARP N-terminus and SNX27 PDZ domain. VARP and SNX27 interact with high nanomolar affinity using the binding pocket established for PDZ binding motif (PDZbm) cargo. Specific point mutations in VARP abrogate the interaction in vitro. We further establish a full biochemical reconstitution system using purified mammalian proteins to directly and systematically test whether multiple endosomal coat complexes are recruited to membranes to generate tubules. We successfully use purified coat components to demonstrate which combinations of Retromer with SNX27, ESCPE-1 (SNX2/SNX6), or both complexes can remodel membranes containing physiological cargo motifs and phospholipid composition. SNX27, alone and with Retromer, induces tubule formation in the presence of PI(3)P and PDZ cargo motifs. ESCPE-1 deforms membranes enriched with Folch I and CI-MPR cargo motifs, but surprisingly does not recruit Retromer. Finally, we find VARP is required to reconstitute a proposed endosomal "supercomplex" containing SNX27, ESCPE-1, and Retromer on PI(3)P-enriched membranes. These data suggest VARP functions as a key regulator in metazoans to promote cargo sorting out of endosomes.
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Affiliation(s)
- Mintu Chandra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Amy K Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Marijn G J Ford
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
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3
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Fuentealba LM, Pizarro H, Marzolo MP. OCRL1 Deficiency Affects the Intracellular Traffic of ApoER2 and Impairs Reelin-Induced Responses. Biomolecules 2024; 14:799. [PMID: 39062513 PMCID: PMC11274606 DOI: 10.3390/biom14070799] [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: 05/29/2024] [Revised: 07/01/2024] [Accepted: 07/02/2024] [Indexed: 07/28/2024] Open
Abstract
Lowe Syndrome (LS) is a rare X-linked disorder characterized by renal dysfunction, cataracts, and several central nervous system (CNS) anomalies. The mechanisms underlying the neurological dysfunction in LS remain unclear, albeit they share some phenotypic characteristics similar to the deficiency or dysfunction of the Reelin signaling, a relevant pathway with roles in CNS development and neuronal functions. In this study, we investigated the role of OCRL1, an inositol polyphosphate 5-phosphatase encoded by the OCRL gene, mutated in LS, focusing on its impact on endosomal trafficking and receptor recycling in human neuronal cells. Specifically, we tested the effects of OCRL1 deficiency in the trafficking and signaling of ApoER2/LRP8, a receptor for the ligand Reelin. We found that loss of OCRL1 impairs ApoER2 intracellular trafficking, leading to reduced receptor expression and decreased levels at the plasma membrane. Additionally, human neurons deficient in OCRL1 showed impairments in ApoER2/Reelin-induced responses. Our findings highlight the critical role of OCRL1 in regulating ApoER2 endosomal recycling and its impact on the ApoER2/Reelin signaling pathway, providing insights into potential mechanisms underlying the neurological manifestations of LS.
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Affiliation(s)
| | | | - María-Paz Marzolo
- Laboratorio de Tráfico Intracelular y Señalización, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 7810128, Chile; (L.M.F.); (H.P.)
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4
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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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5
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Boesch DJ, Singla A, Han Y, Kramer DA, Liu Q, Suzuki K, Juneja P, Zhao X, Long X, Medlyn MJ, Billadeau DD, Chen Z, Chen B, Burstein E. Structural organization of the retriever-CCC endosomal recycling complex. Nat Struct Mol Biol 2024; 31:910-924. [PMID: 38062209 PMCID: PMC11260360 DOI: 10.1038/s41594-023-01184-4] [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: 06/05/2023] [Accepted: 11/17/2023] [Indexed: 12/19/2023]
Abstract
The recycling of membrane proteins from endosomes to the cell surface is vital for cell signaling and survival. Retriever, a trimeric complex of vacuolar protein-sorting-associated protein (VPS)35L, VPS26C and VPS29, together with the CCC complex comprising coiled-coil domain-containing (CCDC)22, CCDC93 and copper metabolism domain-containing (COMMD) proteins, plays a crucial role in this process. The precise mechanisms underlying retriever assembly and its interaction with CCC have remained elusive. Here, we present a high-resolution structure of retriever in humans determined using cryogenic electron microscopy. The structure reveals a unique assembly mechanism, distinguishing it from its remotely related paralog retromer. By combining AlphaFold predictions and biochemical, cellular and proteomic analyses, we further elucidate the structural organization of the entire retriever-CCC complex across evolution and uncover how cancer-associated mutations in humans disrupt complex formation and impair membrane protein homeostasis. These findings provide a fundamental framework for understanding the biological and pathological implications associated with retriever-CCC-mediated endosomal recycling.
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Affiliation(s)
- Daniel J Boesch
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, USA
| | - Amika Singla
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yan Han
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Daniel A Kramer
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, USA
| | - Qi Liu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kohei Suzuki
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Puneet Juneja
- Cryo-EM Facility, Office of Biotechnology, Iowa State University, Ames, IA, USA
| | - Xuefeng Zhao
- Information Technology Services, Iowa State University, Ames, IA, USA
| | - Xin Long
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Michael J Medlyn
- Division of Oncology Research, College of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Daniel D Billadeau
- Division of Oncology Research, College of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Zhe Chen
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Baoyu Chen
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, USA.
| | - Ezra Burstein
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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6
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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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7
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Overduin M, Bhat R. Recognition and remodeling of endosomal zones by sorting nexins. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184305. [PMID: 38408696 DOI: 10.1016/j.bbamem.2024.184305] [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: 12/23/2023] [Revised: 02/05/2024] [Accepted: 02/18/2024] [Indexed: 02/28/2024]
Abstract
The proteolipid code determines how cytosolic proteins find and remodel membrane surfaces. Here, we investigate how this process works with sorting nexins Snx1 and Snx3. Both proteins form sorting machines by recognizing membrane zones enriched in phosphatidylinositol 3-phosphate (PI3P), phosphatidylserine (PS) and cholesterol. This co-localized combination forms a unique "lipid codon" or lipidon that we propose is responsible for endosomal targeting, as revealed by structures and interactions of their PX domain-based readers. We outline a membrane recognition and remodeling mechanism for Snx1 and Snx3 involving this code element alongside transmembrane pH gradients, dipole moment-guided docking and specific protein-protein interactions. This generates an initial membrane-protein assembly (memtein) that then recruits retromer and additional PX proteins to recruit cell surface receptors for sorting to the trans-Golgi network (TGN), lysosome and plasma membranes. Post-translational modification (PTM) networks appear to regulate how the sorting machines form and operate at each level. The commonalities and differences between these sorting nexins show how the proteolipid code orchestrates parallel flows of molecular information from ribosome emergence to organelle genesis, and illuminates a universally applicable model of the membrane.
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Affiliation(s)
- Michael Overduin
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada.
| | - Rakesh Bhat
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
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8
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Singla A, Boesch DJ, Joyce Fung HY, Ngoka C, Enriquez AS, Song R, Kramer DA, Han Y, Juneja P, Billadeau DD, Bai X, Chen Z, Turer EE, Burstein E, Chen B. Structural basis for Retriever-SNX17 assembly and endosomal sorting. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.12.584676. [PMID: 38559023 PMCID: PMC10980035 DOI: 10.1101/2024.03.12.584676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
During endosomal recycling, Sorting Nexin 17 (SNX17) facilitates the transport of numerous membrane cargo proteins by tethering them to the Retriever complex. Despite its importance, the mechanisms underlying this interaction have remained elusive. Here, we report the structure of the Retriever-SNX17 complex determined using cryogenic electron microscopy (cryo-EM). Our structure reveals that the C-terminal tail of SNX17 engages with a highly conserved interface between the VPS35L and VPS26C subunits of Retriever. Through comprehensive biochemical, cellular, and proteomic analyses, we demonstrate that disrupting this interface impairs the Retriever-SNX17 interaction, subsequently affecting the recycling of SNX17-dependent cargos and altering the composition of the plasma membrane proteome. Intriguingly, we find that the SNX17-binding pocket on Retriever can be utilized by other ligands that share a consensus acidic C-terminal tail motif. By showing how SNX17 is linked to Retriever, our findings uncover a fundamental mechanism underlying endosomal trafficking of critical cargo proteins and reveal a mechanism by which Retriever can engage with other regulatory factors.
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Affiliation(s)
- Amika Singla
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Daniel J. Boesch
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Ho Yee Joyce Fung
- Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Chigozie Ngoka
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Avery S. Enriquez
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Ran Song
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Daniel A. Kramer
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Yan Han
- Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Puneet Juneja
- Cryo-EM facility, Office of Biotechnology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Daniel D. Billadeau
- Division of Oncology Research, College of Medicine, Mayo Clinic, Rochester MN, 55905, USA
| | - Xiaochen Bai
- Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Zhe Chen
- Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Emre E. Turer
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Ezra Burstein
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Baoyu Chen
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
- On sabbatical leave at Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
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9
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Zadka Ł, Sochocka M, Hachiya N, Chojdak-Łukasiewicz J, Dzięgiel P, Piasecki E, Leszek J. Endocytosis and Alzheimer's disease. GeroScience 2024; 46:71-85. [PMID: 37646904 PMCID: PMC10828383 DOI: 10.1007/s11357-023-00923-1] [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: 03/11/2023] [Accepted: 08/22/2023] [Indexed: 09/01/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder and is the most common cause of dementia. The pathogenesis of AD still remains unclear, including two main hypotheses: amyloid cascade and tau hyperphosphorylation. The hallmark neuropathological changes of AD are extracellular deposits of amyloid-β (Aβ) plaques and intracellular neurofibrillary tangles (NFTs). Endocytosis plays an important role in a number of cellular processes including communication with the extracellular environment, nutrient uptake, and signaling by the cell surface receptors. Based on the results of genetic and biochemical studies, there is a link between neuronal endosomal function and AD pathology. Taking this into account, we can state that in the results of previous research, endolysosomal abnormality is an important cause of neuronal lesions in the brain. Endocytosis is a central pathway involved in the regulation of the degradation of amyloidogenic components. The results of the studies suggest that a correlation between alteration in the endocytosis process and associated protein expression progresses AD. In this article, we discuss the current knowledge about endosomal abnormalities in AD.
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Affiliation(s)
- Łukasz Zadka
- Division of Ultrastructural Research, Wroclaw Medical University, 50-368, Wroclaw, Poland
| | - Marta Sochocka
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Rudolfa Weigla 12, 53-114, Wroclaw, Poland.
| | - Naomi Hachiya
- Shonan Research Center, Central Glass Co., Ltd, Shonan Health Innovation Park 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa, 251-8555, Japan
| | | | - Piotr Dzięgiel
- Department of Histology and Embryology, Wroclaw Medical University, Chałubińskiego 6a, 50-368, Wroclaw, Poland
| | - Egbert Piasecki
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Rudolfa Weigla 12, 53-114, Wroclaw, Poland
| | - Jerzy Leszek
- Department of Psychiatry, Wroclaw Medical University, Wybrzeże L. Pasteura 10, 50-367, Wroclaw, Poland
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10
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Chen Q, Sun M, Han X, Xu H, Liu Y. Structural determinants specific for retromer protein sorting nexin 5 in regulating subcellular retrograde membrane trafficking. J Biomed Res 2023; 37:492-506. [PMID: 37964759 PMCID: PMC10687533 DOI: 10.7555/jbr.37.20230112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/17/2023] [Accepted: 05/23/2023] [Indexed: 11/16/2023] Open
Abstract
The endosomal trafficking of signaling membrane proteins, such as receptors, transporters and channels, is mediated by the retromer-mediated sorting machinery, composed of a cargo-selective vacuolar protein sorting trimer and a membrane-deforming subunit of sorting nexin proteins. Recent studies have shown that the isoforms, sorting nexin 5 (SNX5) and SNX6, have played distinctive regulatory roles in retrograde membrane trafficking. However, the molecular insight determined functional differences within the proteins remains unclear. We reported that SNX5 and SNX6 had distinct binding affinity to the cargo protein vesicular monoamine transporter 2 (VMAT2). SNX5, but not SNX6, specifically interacted with VMAT2 through the Phox domain, which contains an alpha-helix binding motif. Using chimeric mutagenesis, we identified that several key residues within this domain were unique in SNX5, but not SNX6, and played an auxiliary role in its binding to VMAT2. Importantly, we generated a set of mutant SNX6, in which the corresponding key residues were mutated to those in SNX5. In addition to the gain in binding affinity to VMAT2, their overexpression functionally rescued the altered retrograde trafficking of VMAT2 induced by siRNA-mediated depletion of SNX5. These data strongly suggest that SNX5 and SNX6 have different functions in retrograde membrane trafficking, which is determined by the different structural elements within the Phox domain of two proteins. Our work provides a new information on the role of SNX5 and SNX6 in the molecular regulation of retrograde membrane trafficking and vesicular membrane targeting in monoamine neurotransmission and neurological diseases.
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Affiliation(s)
- Qing Chen
- Jiangsu Key Laboratory of Xenotransplantation, and Department of Medical Genetics, Nanjing Medical University, Nanjing, Jiangsu 211166, China
| | - Meiheng Sun
- Jiangsu Key Laboratory of Xenotransplantation, and Department of Medical Genetics, Nanjing Medical University, Nanjing, Jiangsu 211166, China
| | - Xu Han
- Jiangsu Key Laboratory of Xenotransplantation, and Department of Medical Genetics, Nanjing Medical University, Nanjing, Jiangsu 211166, China
| | - Hongfei Xu
- Jiangsu Key Laboratory of Xenotransplantation, and Department of Medical Genetics, Nanjing Medical University, Nanjing, Jiangsu 211166, China
| | - Yongjian Liu
- Jiangsu Key Laboratory of Xenotransplantation, and Department of Medical Genetics, Nanjing Medical University, Nanjing, Jiangsu 211166, China
- Department of Neuroscience, University of Pittsburgh Kenneth P. Dietrich School of Arts and Sciences, Pittsburgh, PA 15260, USA
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11
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Naslavsky N, Caplan S. Advances and challenges in understanding endosomal sorting and fission. FEBS J 2023; 290:4187-4195. [PMID: 36413090 PMCID: PMC10200825 DOI: 10.1111/febs.16687] [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: 09/20/2022] [Revised: 11/04/2022] [Accepted: 11/21/2022] [Indexed: 11/23/2022]
Abstract
Endosomes play crucial roles in the cell, serving as focal and 'triage' points for internalized lipids and receptors. As such, endosomes are a critical branching point that determines whether receptors are sorted for degradation or recycling. This Viewpoint aims to highlight recent advances in endosome research, including key endosomal functions such as sorting and fission. Moreover, the Viewpoint addresses key technical and conceptual challenges in studying endosomes.
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Affiliation(s)
- Naava Naslavsky
- Department of Biochemistry & Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Steve Caplan
- Department of Biochemistry & Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
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12
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Lopez-Robles C, Scaramuzza S, Astorga-Simon EN, Ishida M, Williamson CD, Baños-Mateos S, Gil-Carton D, Romero-Durana M, Vidaurrazaga A, Fernandez-Recio J, Rojas AL, Bonifacino JS, Castaño-Díez D, Hierro A. Architecture of the ESCPE-1 membrane coat. Nat Struct Mol Biol 2023; 30:958-969. [PMID: 37322239 PMCID: PMC10352136 DOI: 10.1038/s41594-023-01014-7] [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: 10/13/2022] [Accepted: 05/05/2023] [Indexed: 06/17/2023]
Abstract
Recycling of membrane proteins enables the reuse of receptors, ion channels and transporters. A key component of the recycling machinery is the endosomal sorting complex for promoting exit 1 (ESCPE-1), which rescues transmembrane proteins from the endolysosomal pathway for transport to the trans-Golgi network and the plasma membrane. This rescue entails the formation of recycling tubules through ESCPE-1 recruitment, cargo capture, coat assembly and membrane sculpting by mechanisms that remain largely unknown. Herein, we show that ESCPE-1 has a single-layer coat organization and suggest how synergistic interactions between ESCPE-1 protomers, phosphoinositides and cargo molecules result in a global arrangement of amphipathic helices to drive tubule formation. Our results thus define a key process of tubule-based endosomal sorting.
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Affiliation(s)
| | | | | | - Morié Ishida
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Chad D Williamson
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | | | - David Gil-Carton
- CIC bioGUNE, Derio, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
- BREM Basque Resource for Electron Microscopy, Leioa, Spain
| | - Miguel Romero-Durana
- Barcelona Supercomputing Center (BSC), Barcelona, Spain
- Instituto de Ciencias de la Vid y del Vino (ICVV), CSIC-Universidad de La Rioja-Gobierno de La Rioja, Logroño, Spain
| | | | - Juan Fernandez-Recio
- Barcelona Supercomputing Center (BSC), Barcelona, Spain
- Instituto de Ciencias de la Vid y del Vino (ICVV), CSIC-Universidad de La Rioja-Gobierno de La Rioja, Logroño, Spain
| | | | - Juan S Bonifacino
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
| | - Daniel Castaño-Díez
- BioEM Lab, Biozentrum, University of Basel, Basel, Switzerland.
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, Leioa, Spain.
| | - Aitor Hierro
- CIC bioGUNE, Derio, Spain.
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain.
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13
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Boesch DJ, Singla A, Han Y, Kramer DA, Liu Q, Suzuki K, Juneja P, Zhao X, Long X, Medlyn MJ, Billadeau DD, Chen Z, Chen B, Burstein E. Structural Organization of the Retriever-CCC Endosomal Recycling Complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.543888. [PMID: 37333304 PMCID: PMC10274727 DOI: 10.1101/2023.06.06.543888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
The recycling of membrane proteins from endosomes to the cell surface is vital for cell signaling and survival. Retriever, a trimeric complex of VPS35L, VPS26C and VPS29, together with the CCC complex comprising CCDC22, CCDC93, and COMMD proteins, plays a crucial role in this process. The precise mechanisms underlying Retriever assembly and its interaction with CCC have remained elusive. Here, we present the first high-resolution structure of Retriever determined using cryogenic electron microscopy. The structure reveals a unique assembly mechanism, distinguishing it from its remotely related paralog, Retromer. By combining AlphaFold predictions and biochemical, cellular, and proteomic analyses, we further elucidate the structural organization of the entire Retriever-CCC complex and uncover how cancer-associated mutations disrupt complex formation and impair membrane protein homeostasis. These findings provide a fundamental framework for understanding the biological and pathological implications associated with Retriever-CCC-mediated endosomal recycling.
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Affiliation(s)
- Daniel J. Boesch
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Amika Singla
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Yan Han
- Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Daniel A. Kramer
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Qi Liu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Kohei Suzuki
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Puneet Juneja
- Cryo-EM facility, Office of Biotechnology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Xuefeng Zhao
- Research IT, College of Liberal Arts and Sciences, Iowa State University, 2415 Osborn Dr, Ames, IA 50011, USA
| | - Xin Long
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Michael J. Medlyn
- Division of Oncology Research, College of Medicine, Mayo Clinic, Rochester MN, 55905, USA
| | - Daniel D. Billadeau
- Division of Oncology Research, College of Medicine, Mayo Clinic, Rochester MN, 55905, USA
| | - Zhe Chen
- Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Baoyu Chen
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Ezra Burstein
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
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14
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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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15
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Xie B, Guillem C, Date SS, Cohen CI, Jung C, Kendall AK, Best JT, Graham TR, Jackson LP. An interaction between β'-COP and the ArfGAP, Glo3, maintains post-Golgi cargo recycling. J Cell Biol 2023; 222:e202008061. [PMID: 36811888 PMCID: PMC9960064 DOI: 10.1083/jcb.202008061] [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: 08/24/2020] [Revised: 07/14/2022] [Accepted: 01/24/2023] [Indexed: 02/24/2023] Open
Abstract
The essential COPI coat mediates retrieval of transmembrane proteins at the Golgi and endosomes following recruitment by the small GTPase, Arf1. ArfGAP proteins regulate COPI coats, but molecular details for COPI recognition by ArfGAPs remain elusive. Biochemical and biophysical data reveal how β'-COP propeller domains directly engage the yeast ArfGAP, Glo3, with a low micromolar binding affinity. Calorimetry data demonstrate that both β'-COP propeller domains are required to bind Glo3. An acidic patch on β'-COP (D437/D450) interacts with Glo3 lysine residues located within the BoCCS (binding of coatomer, cargo, and SNAREs) region. Targeted point mutations in either Glo3 BoCCS or β'-COP abrogate the interaction in vitro, and loss of the β'-COP/Glo3 interaction drives Ste2 missorting to the vacuole and aberrant Golgi morphology in budding yeast. These data suggest that cells require the β'-COP/Glo3 interaction for cargo recycling via endosomes and the TGN, where β'-COP serves as a molecular platform to coordinate binding to multiple proteins, including Glo3, Arf1, and the COPI F-subcomplex.
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Affiliation(s)
- Boyang Xie
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Clara Guillem
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Swapneeta S. Date
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Cameron I. Cohen
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Christian Jung
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Amy K. Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Jordan T. Best
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Todd R. Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Lauren P. Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
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16
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Zouhar J, Cao W, Shen J, Rojo E. Retrograde transport in plants: Circular economy in the endomembrane system. Eur J Cell Biol 2023; 102:151309. [PMID: 36933283 DOI: 10.1016/j.ejcb.2023.151309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/09/2023] [Accepted: 03/11/2023] [Indexed: 03/14/2023] Open
Abstract
The study of endomembrane trafficking is crucial for understanding how cells and whole organisms function. Moreover, there is a special interest in investigating endomembrane trafficking in plants, given its role in transport and accumulation of seed storage proteins and in secretion of cell wall material, arguably the two most essential commodities obtained from crops. The mechanisms of anterograde transport in the biosynthetic and endocytic pathways of plants have been thoroughly discussed in recent reviews, but, comparatively, retrograde trafficking pathways have received less attention. Retrograde trafficking is essential to recover membranes, retrieve proteins that have escaped from their intended localization, maintain homeostasis in maturing compartments, and recycle trafficking machinery for its reuse in anterograde transport reactions. Here, we review the current understanding on retrograde trafficking pathways in the endomembrane system of plants, discussing their integration with anterograde transport routes, describing conserved and plant-specific retrieval mechanisms at play, highlighting contentious issues and identifying open questions for future research.
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Affiliation(s)
- Jan Zouhar
- Central European Institute of Technology, Mendel University in Brno, CZ-61300 Brno, Czech Republic.
| | - Wenhan Cao
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, 311300 Hangzhou, China
| | - Jinbo Shen
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, 311300 Hangzhou, China.
| | - Enrique Rojo
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Cantoblanco, E-28049 Madrid, Spain.
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17
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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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18
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Zambo B, Morlet B, Negroni L, Trave G, Gogl G. Native holdup (nHU) to measure binding affinities from cell extracts. SCIENCE ADVANCES 2022; 8:eade3828. [PMID: 36542723 PMCID: PMC9770967 DOI: 10.1126/sciadv.ade3828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Characterizing macromolecular interactions is essential for understanding cellular processes, yet most methods currently used to detect protein interactions from cells are qualitative. Here, we introduce the native holdup (nHU) approach to estimate equilibrium binding constants of protein interactions directly from cell extracts. Compared to other pull-down-based assays, nHU requires less sample preparation and can be coupled to any analytical methods as readouts, such as Western blotting or mass spectrometry. We use nHU to explore interactions of SNX27, a cargo adaptor of the retromer complex and find good agreement between in vitro affinities and those measured directly from cell extracts using nHU. We discuss the strengths and limitations of nHU and provide simple protocols that can be implemented in most laboratories.
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Affiliation(s)
- Boglarka Zambo
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258/CNRS UMR 7104/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, Illkirch F-67404, France
| | - Bastien Morlet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258/CNRS UMR 7104/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, Illkirch F-67404, France
| | - Luc Negroni
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258/CNRS UMR 7104/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, Illkirch F-67404, France
| | - Gilles Trave
- Équipe Labellisée Ligue 2015, Département de Biologie Structurale Intégrative, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258/CNRS UMR 7104/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, Illkirch F-67404, France
- Corresponding author. (G.T.); (G.G.)
| | - Gergo Gogl
- Équipe Labellisée Ligue 2015, Département de Biologie Structurale Intégrative, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258/CNRS UMR 7104/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, Illkirch F-67404, France
- Corresponding author. (G.T.); (G.G.)
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19
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Wang J, Billadeau DD, Jia D. Two siblings, distinct characteristics. Structure 2022; 30:1559-1560. [DOI: 10.1016/j.str.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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20
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Multifaceted Roles of Retromer in EGFR Trafficking and Signaling Activation. Cells 2022; 11:cells11213358. [DOI: 10.3390/cells11213358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 10/21/2022] [Accepted: 10/21/2022] [Indexed: 11/16/2022] Open
Abstract
Mammalian retromer complex contributes to multiple early endosome-associated trafficking pathways whose origins are dependent on which sorting nexin (SNX) they are complexed with. In an attempt to dissect out the contribution of individual retromer–SNX complexes, we examined the trafficking of EGFR in detail within a series of KO cell line models. We demonstrated that the depletion of retromer subunit Vps35 leads to decreased EGFR protein levels in resting cells with enhanced association of EGFR with lysosomal compartments. Compared to control cells, the addition of EGF to Vps35 KO cells resulted in a reduced rate of EGFR degradation; AKT activation and cell prolferation rates were elevated, while ERK activation remained relatively unchanged. These observations are consistent with a prolonged temporal association of EGFR within early endosomes due to the inefficiency of early endosome-associated protein trafficking pathways or organelle maturation due to retromer absence. We did not fully delineate the discrete contributions from retromer-associated SNXs to the phenotypes observed from retromer Vps35 depletion. While each of the knock-outs of SNX1/2, SNX3, or SNX27 promotes the enhanced association of EGFR with early endosomal compartments, only the decreased EGF-mediated EGFR degradation was observed in SNX1/2 dKO cells, while the enhanced AKT activation was only increased in SNX3 KO or SNX27 KO cells. Despite this, each of the knock-outs showed increased EGF-stimulated cell proliferation rates.
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21
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Shortill SP, Frier MS, Wongsangaroonsri P, Davey M, Conibear E. The VINE complex is an endosomal VPS9-domain GEF and SNX-BAR coat. eLife 2022; 11:77035. [PMID: 35938928 PMCID: PMC9507130 DOI: 10.7554/elife.77035] [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: 01/13/2022] [Accepted: 08/05/2022] [Indexed: 11/18/2022] Open
Abstract
Membrane trafficking pathways perform important roles in establishing and maintaining the endosomal network. Retrograde protein sorting from the endosome is promoted by conserved SNX-BAR-containing coat complexes including retromer which enrich cargo at tubular microdomains and generate transport carriers. In metazoans, retromer cooperates with VARP, a conserved VPS9-domain GEF, to direct an endosomal recycling pathway. The function of the yeast VARP homolog Vrl1 has been overlooked due to an inactivating mutation found in commonly studied strains. Here, we demonstrate that Vrl1 has features of a SNX-BAR coat protein and forms an obligate complex with Vin1, the paralog of the retromer SNX-BAR protein Vps5. Unique features in the Vin1 N-terminus allow Vrl1 to distinguish it from Vps5, thereby forming a complex that we have named VINE. The VINE complex occupies endosomal tubules and redistributes a conserved mannose 6-phosphate receptor-like protein from endosomes. We also find that membrane recruitment by Vin1 is essential for Vrl1 GEF activity, suggesting that VINE is a multifunctional coat complex that regulates trafficking and signaling events at the endosome. All healthy cells have a highly organized interior: different compartments with specialized roles are in different places, and in order to do their jobs properly, proteins need to be in the right place. Endosomes are membrane-bound compartments that act as transport hubs where proteins are sorted into small vesicles and delivered to other parts of the cell. Two groups of proteins regulate this transport: the first group, known as VPS9 GEFs, switches on the enzymes that recruit the second group of proteins, called the sorting nexins. This second group is responsible for forming the transport vesicles via which proteins are distributed all over the cell. Defects in protein sorting can lead to various diseases, including neurodegenerative conditions such as Parkinson’s disease and juvenile amyotrophic lateral sclerosis. Scientists often use budding yeast cells to study protein sorting, because these cells are similar to human cells, but easier to grow in large numbers and examine in the laboratory. Previous work showed that a yeast protein called Vrl1 is equivalent to a VPS9 GEF from humans called VARP. However, Vrl1 only exists in wild forms of budding yeast, and not in laboratory strains of the organism. Therefore, researchers had not studied Vrl1 in detail, and its roles remained unclear. To learn more about Vrl1, Shortill et al. started by re-introducing the protein into laboratory strains of budding yeast and observing what happened to protein sorting in these cells. Like VARP, Vrl1 was found in the endosomes of budding yeast. However, biochemical experiments revealed that, while human VARP binds to a protein called retromer, Vrl1 does not bind to the equivalent protein in yeast. Instead, Vrl1 itself has features of both the VPS9 GEFs and the sorting nexins. Shortill et al. also found that Vrl1 interacted with a different protein in the sorting nexin family called Vin1. In the absence of Vrl1, Vin1 was found floating around the cell, but once Vrl1 was re-introduced into the budding yeast, Vin1 relocated to the endosomes. Vrl1 uses its VPS9 GEF part to move itself to the endosome membrane, and Vin1 controls this movement, highlighting the interdependence between the two proteins. Once they are at the endosome together, Vrl1 and Vin1 help redistribute proteins to other parts of the cell. This study suggests that, like VARP, Vrl1 cooperates with sorting nexins to transport proteins. Since many previous experiments about protein sorting were carried out in yeast cells lacking Vrl1, it is possible that this process was overlooked despite its potential importance. These new findings could also help other researchers investigating how endosomes and protein sorting work, or do not work, in the context of neurodegenerative diseases.
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Affiliation(s)
- Shawn P Shortill
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada
| | - Mia S Frier
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada
| | | | - Michael Davey
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada
| | - Elizabeth Conibear
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada
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22
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Shortill SP, Frier MS, Conibear E. You can go your own way: SNX-BAR coat complexes direct traffic at late endosomes. Curr Opin Cell Biol 2022; 76:102087. [DOI: 10.1016/j.ceb.2022.102087] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/23/2022] [Accepted: 04/01/2022] [Indexed: 12/20/2022]
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23
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Abstract
Complex mechanisms govern the sorting of membrane (cargo) proteins at endosomes to ensure that protein localization to the post-Golgi endomembrane system is accurately maintained. Endosomal retrieval complexes mediate sorting by recognizing specific motifs and signals in the cytoplasmic domains of cargo proteins transiting through endosomes. In this review, the recent progress in understanding the molecular mechanisms of how the retromer complex, in conjunction with sorting nexin (SNX) proteins, operates in cargo recognition and sorting is discussed. New data revealing the importance of different SNX proteins and detailing how post-translational modifications can modulate cargo sorting to respond to changes in the environment are highlighted along with the key role that endosomal protein sorting plays in SARS-CoV-2 infection.
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Affiliation(s)
- Xin Yong
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041, China
| | - Lejiao Mao
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041, China
| | - Matthew N J Seaman
- Cambridge Institute for Medical Research, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, CB2 0XY, UK
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041, China
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