1
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Rioux DJ, Prosser DC. A CIE change in our understanding of endocytic mechanisms. Front Cell Dev Biol 2023; 11:1334798. [PMID: 38192364 PMCID: PMC10773762 DOI: 10.3389/fcell.2023.1334798] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 12/04/2023] [Indexed: 01/10/2024] Open
Abstract
The past six decades have seen major advances in our understanding of endocytosis, ranging from descriptive studies based on electron microscopy to biochemical and genetic characterization of factors required for vesicle formation. Most studies focus on clathrin as the major coat protein; indeed, clathrin-mediated endocytosis (CME) is the primary pathway for internalization. Clathrin-independent (CIE) pathways also exist, although mechanistic understanding of these pathways remains comparatively elusive. Here, we discuss how early studies of CME shaped our understanding of endocytosis and describe recent advances in CIE, including pathways in model organisms that are poised to provide key insights into endocytic regulation.
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Affiliation(s)
- Daniel J. Rioux
- Life Sciences, Virginia Commonwealth University, Richmond, VA, United States
- Department of Biology, Virginia Commonwealth University, Richmond, VA, United States
| | - Derek C. Prosser
- Department of Biology, Virginia Commonwealth University, Richmond, VA, United States
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2
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Woodard TK, Rioux DJ, Prosser DC. Actin- and microtubule-based motors contribute to clathrin-independent endocytosis in yeast. Mol Biol Cell 2023; 34:ar117. [PMID: 37647159 PMCID: PMC10846617 DOI: 10.1091/mbc.e23-05-0164] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/14/2023] [Accepted: 08/22/2023] [Indexed: 09/01/2023] Open
Abstract
Most eukaryotic cells utilize clathrin-mediated endocytosis as well as multiple clathrin-independent pathways to internalize proteins and membranes. Although clathrin-mediated endocytosis has been studied extensively and many machinery proteins have been identified, clathrin-independent pathways remain poorly characterized by comparison. We previously identified the first known yeast clathrin-independent endocytic pathway, which relies on the actin-modulating GTPase Rho1, the formin Bni1 and unbranched actin filaments, but does not require the clathrin coat or core clathrin machinery proteins. In this study, we sought to better understand clathrin-independent endocytosis in yeast by exploring the role of myosins as actin-based motors, because actin is required for endocytosis in yeast. We find that Myo2, which transports secretory vesicles, organelles and microtubules along actin cables to sites of polarized growth, participates in clathrin-independent endocytosis. Unexpectedly, the ability of Myo2 to transport microtubule plus ends to the cell cortex appears to be required for its role in clathrin-independent endocytosis. In addition, dynein, dynactin, and proteins involved in cortical microtubule capture are also required. Thus, our results suggest that interplay between actin and microtubules contributes to clathrin-independent internalization in yeast.
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Affiliation(s)
| | - Daniel J. Rioux
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284
- Life Sciences, Virginia Commonwealth University, Richmond, VA 23284
| | - Derek C. Prosser
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284
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3
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Adnan M, Islam W, Waheed A, Hussain Q, Shen L, Wang J, Liu G. SNARE Protein Snc1 Is Essential for Vesicle Trafficking, Membrane Fusion and Protein Secretion in Fungi. Cells 2023; 12:1547. [PMID: 37296667 PMCID: PMC10252874 DOI: 10.3390/cells12111547] [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: 04/08/2023] [Revised: 05/24/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
Fungi are an important group of microorganisms that play crucial roles in a variety of ecological and biotechnological processes. Fungi depend on intracellular protein trafficking, which involves moving proteins from their site of synthesis to the final destination within or outside the cell. The soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) proteins are vital components of vesicle trafficking and membrane fusion, ultimately leading to the release of cargos to the target destination. The v-SNARE (vesicle-associated SNARE) Snc1 is responsible for anterograde and retrograde vesicle trafficking between the plasma membrane (PM) and Golgi. It allows for the fusion of exocytic vesicles to the PM and the subsequent recycling of Golgi-localized proteins back to the Golgi via three distinct and parallel recycling pathways. This recycling process requires several components, including a phospholipid flippase (Drs2-Cdc50), an F-box protein (Rcy1), a sorting nexin (Snx4-Atg20), a retromer submit, and the COPI coat complex. Snc1 interacts with exocytic SNAREs (Sso1/2, Sec9) and the exocytic complex to complete the process of exocytosis. It also interacts with endocytic SNAREs (Tlg1 and Tlg2) during endocytic trafficking. Snc1 has been extensively investigated in fungi and has been found to play crucial roles in various aspects of intracellular protein trafficking. When Snc1 is overexpressed alone or in combination with some key secretory components, it results in enhanced protein production. This article will cover the role of Snc1 in the anterograde and retrograde trafficking of fungi and its interactions with other proteins for efficient cellular transportation.
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Affiliation(s)
- Muhammad Adnan
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (M.A.); (A.W.); (J.W.)
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Waqar Islam
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China;
| | - Abdul Waheed
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (M.A.); (A.W.); (J.W.)
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Quaid Hussain
- Shenzhen Key Laboratory of Marine Bioresource and Eco-Environmental Science, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China;
| | - Ling Shen
- School of Life Science, Jiangsu Normal University, Xuzhou 221116, China;
| | - Juan Wang
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (M.A.); (A.W.); (J.W.)
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Gang Liu
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (M.A.); (A.W.); (J.W.)
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
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4
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Ibanes S, El-Alaoui F, Lai-Kee-Him J, Cazevieille C, Hoh F, Lyonnais S, Bron P, Cipelletti L, Picas L, Piatti S. The Syp1/FCHo2 protein induces septin filament bundling through its intrinsically disordered domain. Cell Rep 2022; 41:111765. [PMID: 36476870 DOI: 10.1016/j.celrep.2022.111765] [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: 03/07/2022] [Revised: 09/30/2022] [Accepted: 11/10/2022] [Indexed: 12/12/2022] Open
Abstract
The septin collar of budding yeast is an ordered array of septin filaments that serves a scaffolding function for the cytokinetic machinery at the bud neck and compartmentalizes the membrane between mother and daughter cell. How septin architecture is aided by septin-binding proteins is largely unknown. Syp1 is an endocytic protein that was implicated in the timely recruitment of septins to the newly forming collar through an unknown mechanism. Using advanced microscopy and in vitro reconstitution assays, we show that Syp1 is able to align laterally and tightly pack septin filaments, thereby forming flat bundles or sheets. This property is shared by the Syp1 mammalian counterpart FCHo2, thus emphasizing conserved protein functions. Interestingly, the septin-bundling activity of Syp1 resides mainly in its intrinsically disordered region. Our data uncover the mechanism through which Syp1 promotes septin collar assembly and offer another example of functional diversity of unstructured protein domains.
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Affiliation(s)
- Sandy Ibanes
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier, France
| | - Fatima El-Alaoui
- IRIM (Institut de Recherche en Infectiologie de Montpellier), University of Montpellier, CNRS UMR 9004, 1919 Route de Mende, 34293 Montpellier, France
| | - Joséphine Lai-Kee-Him
- CBS (Centre de Biologie Structurale), University of Montpellier, CNRS UMR 5048, INSERM U 1054, 29 Rue de Navacelles, 34090 Montpellier, France
| | - Chantal Cazevieille
- COMET Electron Microscopy Platform, INM (Institute for Neurosciences of Montpellier), University of Montpellier, INSERM U 1298, 80 Rue Augustin Fliche, 34091 Montpellier, France
| | - François Hoh
- CBS (Centre de Biologie Structurale), University of Montpellier, CNRS UMR 5048, INSERM U 1054, 29 Rue de Navacelles, 34090 Montpellier, France
| | - Sébastien Lyonnais
- CEMIPAI (Centre d'Etudes des Maladies Infectieuses et Pharmacologie Anti-Infectieuse), University of Montpellier, UAR 3725 CNRS, Montpellier, France
| | - Patrick Bron
- CBS (Centre de Biologie Structurale), University of Montpellier, CNRS UMR 5048, INSERM U 1054, 29 Rue de Navacelles, 34090 Montpellier, France
| | - Luca Cipelletti
- L2C (Laboratoire Charles Coulomb), University of Montpellier, CNRS, Place E. Bataillon, 34095 Montpellier, France; IUF (Institut Universitaire de France), Paris, France
| | - Laura Picas
- IRIM (Institut de Recherche en Infectiologie de Montpellier), University of Montpellier, CNRS UMR 9004, 1919 Route de Mende, 34293 Montpellier, France
| | - Simonetta Piatti
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier, France.
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Tolsma TO, Febvre HP, Olson DM, Di Pietro SM. Cargo-mediated recruitment of the endocytic adaptor protein Sla1 in S. cerevisiae. J Cell Sci 2020; 133:jcs247684. [PMID: 32907853 PMCID: PMC7578355 DOI: 10.1242/jcs.247684] [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: 04/17/2020] [Accepted: 08/27/2020] [Indexed: 11/20/2022] Open
Abstract
Endocytosis of plasma membrane proteins is mediated by their interaction with adaptor proteins. Conversely, emerging evidence suggests that adaptor protein recruitment to the plasma membrane may depend on binding to endocytic cargo. To test this idea, we analyzed the yeast adaptor protein Sla1, which binds membrane proteins harboring the endocytic signal NPFxD via the Sla1 SHD1 domain. Consistently, SHD1 domain point mutations that disrupted NPFxD binding caused a proportional reduction in Sla1-GFP recruitment to endocytic sites. Furthermore, simultaneous SHD1 domain point mutation and deletion of the C-terminal LxxQxTG repeat (SR) region linking Sla1 to coat proteins Pan1 and End3 resulted in total loss of Sla1-GFP recruitment to the plasma membrane. These data suggest that multiple interactions are needed for recruitment of Sla1 to the membrane. Interestingly, a Sla1 fragment containing just the third SH3 domain, which binds ubiquitin, and the SHD1 domain displayed broad surface localization, suggesting plasma membrane recruitment is mediated by interaction with both NPFxD-containing and ubiquitylated plasma membrane proteins. Our results also imply that a Sla1 NPF motif adjacent to the SR region might regulate the Sla1-cargo interaction, mechanistically linking Sla1 cargo binding to endocytic site recruitment.
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Affiliation(s)
- Thomas O Tolsma
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA
| | - Hallie P Febvre
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA
| | - Deanna M Olson
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA
| | - Santiago M Di Pietro
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA
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6
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Farkašovský M. Septin architecture and function in budding yeast. Biol Chem 2020; 401:903-919. [PMID: 31913844 DOI: 10.1515/hsz-2019-0401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 12/28/2019] [Indexed: 01/22/2023]
Abstract
The septins constitute a conserved family of guanosine phosphate-binding and filament-forming proteins widespread across eukaryotic species. Septins appear to have two principal functions. One is to form a cortical diffusion barrier, like the septin collar at the bud neck of Saccharomyces cerevisiae, which prevents movement of membrane-associated proteins between the mother and daughter cells. The second is to serve as a polymeric scaffold for recruiting the proteins required for critical cellular processes to particular subcellular areas. In the last decade, structural information about the different levels of septin organization has appeared, but crucial structural determinants and factors responsible for septin assembly remain largely unknown. This review highlights recent findings on the architecture and function of septins and their remodeling with an emphasis on mitotically dividing budding yeasts.
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Affiliation(s)
- Marian Farkašovský
- Department of Biochemistry and Protein Structure, Institute of Molecular Biology SAS, Dubravska cesta 21, 84551 Bratislava, Slovak Republic
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7
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Commer B, Schultzhaus Z, Shaw BD. Localization of NPFxD motif-containing proteins in Aspergillus nidulans. Fungal Genet Biol 2020; 141:103412. [PMID: 32445863 DOI: 10.1016/j.fgb.2020.103412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 05/04/2020] [Accepted: 05/10/2020] [Indexed: 12/28/2022]
Abstract
During growth, filamentous fungi produce polarized cells called hyphae. It is generally presumed that polarization of hyphae is dependent upon secretion through the Spitzenkörper, as well as a mechanism called apical recycling, which maintains a balance between the tightly coupled processes of endocytosis and exocytosis. Endocytosis predominates in an annular domain called the sub-apical endocytic collar, which is located in the region of plasma membrane 1-5 μm distal to the Spitzenkörper. It has previously been proposed that one function of the sub-apical endocytic collar is to maintain the apical localization of polarization proteins. These proteins mark areas of polarization at the apices of hyphae. However, as hyphae grow, these proteins are displaced along the membrane and some must then be removed at the sub-apical endocytic collar in order to maintain the hyphoid shape. While endocytosis is fairly well characterized in yeast, comparatively little is known about the process in filamentous fungi. Here, a bioinformatics approach was utilized to identify 39 Aspergillus nidulans proteins that are predicted to be cargo of endocytosis based on the presence of an NPFxD peptide motif. This motif is a necessary endocytic signal sequence first established in Saccharomyces cerevisiae, where it marks proteins for endocytosis through an interaction with the adapter protein Sla1p. It is hypothesized that some proteins that contain this NPFxD peptide sequence in A. nidulans will be potential targets for endocytosis, and therefore will localize either to the endocytic collar or to more proximal polarized regions of the cell, e.g. the apical dome or the Spitzenkörper. To test this, a subset of the motif-containing proteins in A. nidulans was tagged with GFP and the dynamic localization was evaluated. The documented localization patterns support the hypothesis that the motif marks proteins for localization to the polarized cell apex in growing hyphae.
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Affiliation(s)
- Blake Commer
- Department of Plant Pathology and Microbiology, Texas A&M University, 2132 TAMU, College Station, TX 77843, USA.
| | - Zachary Schultzhaus
- Department of Plant Pathology and Microbiology, Texas A&M University, 2132 TAMU, College Station, TX 77843, USA.
| | - Brian D Shaw
- Department of Plant Pathology and Microbiology, Texas A&M University, 2132 TAMU, College Station, TX 77843, USA.
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8
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Hoban K, Lux SY, Poprawski J, Zhang Y, Shepherdson J, Castiñeira PG, Pesari S, Yao T, Prosser DC, Norris C, Wendland B. ESCRT-dependent protein sorting is required for the viability of yeast clathrin-mediated endocytosis mutants. Traffic 2020; 21:430-450. [PMID: 32255230 DOI: 10.1111/tra.12731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 12/11/2022]
Abstract
Endocytosis regulates many processes, including signaling pathways, nutrient uptake, and protein turnover. During clathrin-mediated endocytosis (CME), adaptors bind to cytoplasmic regions of transmembrane cargo proteins, and many endocytic adaptors are also directly involved in the recruitment of clathrin. This clathrin-associated sorting protein family includes the yeast epsins, Ent1/2, and AP180/PICALM homologs, Yap1801/2. Mutant strains lacking these four adaptors, but expressing an epsin N-terminal homology (ENTH) domain necessary for viability (4Δ+ENTH), exhibit endocytic defects, such as cargo accumulation at the plasma membrane (PM). This CME-deficient strain provides a sensitized background ideal for revealing cellular components that interact with clathrin adaptors. We performed a mutagenic screen to identify alleles that are lethal in 4Δ+ENTH cells using a colony-sectoring reporter assay. After isolating candidate synthetic lethal genes by complementation, we confirmed that mutations in VPS4 led to inviability of a 4Δ+ENTH strain. Vps4 mediates the final step of endosomal sorting complex required for transport (ESCRT)-dependent trafficking, and we found that multiple ESCRTs are also essential in 4Δ+ENTH cells, including Snf7, Snf8 and Vps36. Deletion of VPS4 from an end3Δ strain, another CME mutant, similarly resulted in inviability, and upregulation of a clathrin-independent endocytosis pathway rescued 4Δ+ENTH vps4Δ cells. Loss of Vps4 from an otherwise wild-type background caused multiple cargoes to accumulate at the PM because of an increase in Rcy1-dependent recycling of internalized protein to the cell surface. Additionally, vps4Δ rcy1Δ mutants exhibited deleterious growth phenotypes. Together, our findings reveal previously unappreciated effects of disrupted ESCRT-dependent trafficking on endocytic recycling and the PM.
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Affiliation(s)
- Kyle Hoban
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Samantha Y Lux
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Joanna Poprawski
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Yorke Zhang
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - James Shepherdson
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Pedro G Castiñeira
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Sanjana Pesari
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Tony Yao
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Derek C Prosser
- Department of Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Carolyn Norris
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Beverly Wendland
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
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Łyszkiewicz M, Ziętara N, Frey L, Pannicke U, Stern M, Liu Y, Fan Y, Puchałka J, Hollizeck S, Somekh I, Rohlfs M, Yilmaz T, Ünal E, Karakukcu M, Patiroğlu T, Kellerer C, Karasu E, Sykora KW, Lev A, Simon A, Somech R, Roesler J, Hoenig M, Keppler OT, Schwarz K, Klein C. Human FCHO1 deficiency reveals role for clathrin-mediated endocytosis in development and function of T cells. Nat Commun 2020; 11:1031. [PMID: 32098969 PMCID: PMC7042371 DOI: 10.1038/s41467-020-14809-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 01/23/2020] [Indexed: 01/05/2023] Open
Abstract
Clathrin-mediated endocytosis (CME) is critical for internalisation of molecules across cell membranes. The FCH domain only 1 (FCHO1) protein is key molecule involved in the early stages of CME formation. The consequences of mutations in FCHO1 in humans were unknown. We identify ten unrelated patients with variable T and B cell lymphopenia, who are homozygous for six distinct mutations in FCHO1. We demonstrate that these mutations either lead to mislocalisation of the protein or prevent its interaction with binding partners. Live-cell imaging of cells expressing mutant variants of FCHO1 provide evidence of impaired formation of clathrin coated pits (CCP). Patient T cells are unresponsive to T cell receptor (TCR) triggering. Internalisation of the TCR receptor is severely perturbed in FCHO1-deficient Jurkat T cells but can be rescued by expression of wild-type FCHO1. Thus, we discovered a previously unrecognised critical role of FCHO1 and CME during T-cell development and function in humans.
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Affiliation(s)
- Marcin Łyszkiewicz
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany.
- Institute for Immunology, Biomedical Center Munich, Ludwig-Maximilians-Universität München, Planegg-Martinsried, 82152, Munich, Germany.
| | - Natalia Ziętara
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
- Institute for Immunology, Biomedical Center Munich, Ludwig-Maximilians-Universität München, Planegg-Martinsried, 82152, Munich, Germany
| | - Laura Frey
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Ulrich Pannicke
- Institute for Transfusion Medicine, University of Ulm, Ulm, Germany
| | - Marcel Stern
- Max von Pettenkofer Institute, Virology, National Reference Center for Retroviruses, Faculty of Medicine, LMU München, Munich, Germany
| | - Yanshan Liu
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Yanxin Fan
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Jacek Puchałka
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Sebastian Hollizeck
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Ido Somekh
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Meino Rohlfs
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany
| | - Tuğba Yilmaz
- Department of Pediatrics, Division of Pediatric Hematology & Oncology, Erciyes University, Kayseri, Turkey
| | - Ekrem Ünal
- Department of Pediatrics, Division of Pediatric Hematology & Oncology, Erciyes University, Kayseri, Turkey
| | - Musa Karakukcu
- Department of Pediatrics, Division of Pediatric Hematology & Oncology, Erciyes University, Kayseri, Turkey
| | - Türkan Patiroğlu
- Department of Pediatrics, Division of Pediatric Hematology & Oncology, Erciyes University, Kayseri, Turkey
- Department of Pediatrics, Division of Pediatric Immunology, Erciyes University, Kayseri, Turkey
| | | | - Ebru Karasu
- Institute for Transfusion Medicine, University of Ulm, Ulm, Germany
| | - Karl-Walter Sykora
- Department of Pediatric Hematology/Oncology, Hannover Medical School, Hannover, Germany
| | - Atar Lev
- Pediatric Department A and the Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer and Sackler Faculty of Medicine Tel Aviv University, Tel Aviv, Israel
| | - Amos Simon
- Pediatric Department A and the Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer and Sackler Faculty of Medicine Tel Aviv University, Tel Aviv, Israel
| | - Raz Somech
- Pediatric Department A and the Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer and Sackler Faculty of Medicine Tel Aviv University, Tel Aviv, Israel
| | - Joachim Roesler
- Department of Pediatrics, Carl Gustav Carus Technical University Dresden, Dresden, Germany
| | - Manfred Hoenig
- Department of Pediatrics, University Medical Centre Ulm, Ulm, Germany
| | - Oliver T Keppler
- Max von Pettenkofer Institute, Virology, National Reference Center for Retroviruses, Faculty of Medicine, LMU München, Munich, Germany
- German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Klaus Schwarz
- Institute for Transfusion Medicine, University of Ulm, Ulm, Germany
- Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Service Baden-Wuerttemberg, Hessen, Germany
| | - Christoph Klein
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU, Munich, Germany.
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Identification of Suppressor of Clathrin Deficiency-1 ( SCD1) and Its Connection to Clathrin-Mediated Endocytosis in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2019; 9:867-877. [PMID: 30679249 PMCID: PMC6404604 DOI: 10.1534/g3.118.200782] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Clathrin is a major coat protein involved in vesicle formation during endocytosis and transport in the endosomal/trans Golgi system. Clathrin is required for normal growth of yeast (Saccharomyces cerevisiae) and in some genetic backgrounds deletion of the clathrin heavy chain gene (CHC1) is lethal. Our lab defined a locus referred to as “suppressor of clathrin deficiency” (SCD1). In the presence of the scd1-v allele (“v” – viable), yeast cells lacking clathrin heavy chain survive but grow slowly, are morphologically abnormal and have many membrane trafficking defects. In the presence of scd1-i (“i”- inviable), chc1∆ causes lethality. As a strategy to identify SCD1, we used pooled linkage analysis and whole genome sequencing. Here, we report that PAL2 (YHR097C) is the SCD1 locus. pal2∆ is synthetic lethal with chc1∆; whereas a deletion of its paralog, PAL1, is not synthetic lethal with clathrin deficiency. Like Pal1, Pal2 has two NPF motifs that are potential binding sites for EH domain proteins such as the early endocytic factor Ede1, and Pal2 associates with Ede1. Also, GFP-tagged Pal2p localizes to cortical patches containing other immobile phase endocytic coat factors. Overall, our data show that PAL2 is the SCD1 locus and the Pal2 protein has characteristics of an early factor involved in clathrin-mediated endocytosis.
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11
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Liu D, Li X, Shen D, Novick P. Two subunits of the exocyst, Sec3p and Exo70p, can function exclusively on the plasma membrane. Mol Biol Cell 2018; 29:736-750. [PMID: 29343551 PMCID: PMC6003224 DOI: 10.1091/mbc.e17-08-0518] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 11/18/2022] Open
Abstract
The exocyst is an octameric complex that tethers secretory vesicles to the plasma membrane in preparation for fusion. We anchored each subunit with a transmembrane (TM) domain at its N- or C-terminus. Only N-terminally anchored TM-Sec3p and C-terminally anchored Exo70p-TM proved functional. These findings orient the complex with respect to the membrane and establish that Sec3p and Exo70p can function exclusively on the membrane. The functions of TM-Sec3p and Exo70p-TM were largely unaffected by blocks in endocytic recycling, suggesting that they act on the plasma membrane rather than on secretory vesicles. Cytosolic pools of the other exocyst subunits were unaffected in TM-sec3 cells, while they were partially depleted in exo70-TM cells. Blocking actin-dependent delivery of secretory vesicles in act1-3 cells results in loss of Sec3p from the purified complex. Our results are consistent with a model in which Sec3p and Exo70p can function exclusively on the plasma membrane while the other subunits are brought to them on secretory vesicles.
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Affiliation(s)
- Dongmei Liu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92130
| | - Xia Li
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92130
| | - David Shen
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92130
| | - Peter Novick
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92130
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