1
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Li X, Liu B, Wen Y, Wang J, Guo YR, Shi A, Lin L. Coordination of RAB-8 and RAB-11 during unconventional protein secretion. J Cell Biol 2024; 223:e202306107. [PMID: 38019180 PMCID: PMC10686230 DOI: 10.1083/jcb.202306107] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 10/17/2023] [Accepted: 11/16/2023] [Indexed: 11/30/2023] Open
Abstract
Multiple physiology-pertinent transmembrane proteins reach the cell surface via the Golgi-bypassing unconventional protein secretion (UcPS) pathway. By employing C. elegans-polarized intestine epithelia, we recently have revealed that the small GTPase RAB-8/Rab8 serves as an important player in the process. Nonetheless, its function and the relevant UcPS itinerary remain poorly understood. Here, we show that deregulated RAB-8 activity resulted in impaired apical UcPS, which increased sensitivity to infection and environmental stress. We also identified the SNARE VTI-1/Vti1a/b as a new RAB-8-interacting factor involved in the apical UcPS. Besides, RAB-11/Rab11 was capable of recruiting RABI-8/Rabin8 to reduce the guanine nucleotide exchange activity of SMGL-1/GEF toward RAB-8, indicating the necessity of a finely tuned RAB-8/RAB-11 network. Populations of RAB-8- and RAB-11-positive endosomal structures containing the apical UcPS cargo moved toward the apical side. In the absence of RAB-11 or its effectors, the cargo was retained in RAB-8- and RAB-11-positive endosomes, respectively, suggesting that these endosomes are utilized as intermediate carriers for the UcPS.
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Affiliation(s)
- Xinxin Li
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bowen Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yue Wen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiabin Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yusong R. Guo
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Anbing Shi
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Long Lin
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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2
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Chatterjee S, Ganguly A, Bhattacharyya D. Reprogramming nucleolar size by genetic perturbation of the extranuclear Rab GTPases Ypt6 and Ypt32. FEBS Lett 2024; 598:283-301. [PMID: 37994551 DOI: 10.1002/1873-3468.14776] [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: 09/03/2023] [Revised: 10/05/2023] [Accepted: 10/09/2023] [Indexed: 11/24/2023]
Abstract
Reprogramming organelle size has been proposed as a potential therapeutic approach. However, there have been few reports of nucleolar size reprogramming. We addressed this question in Saccharomyces cerevisiae by studying mutants having opposite effects on the nucleolar size. Mutations in genes involved in nuclear functions (KAR3, CIN8, and PRP45) led to enlarged nuclei/nucleoli, whereas mutations in secretory pathway family genes, namely the Rab-GTPases YPT6 and YPT32, reduced nucleolar size. When combined with mutations leading to enlarged nuclei/nucleoli, the YPT6 or YPT32 mutants can effectively reprogram the nuclear/nucleolar size almost back to normal. Our results further indicate that null mutation of YPT6 causes secretory stress that indirectly influences nuclear localization of Maf1, the negative regulator of RNA Polymerase III, which might reduce the nucleolar size by inhibiting nucleolar transcript enrichment.
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Affiliation(s)
- Shreosi Chatterjee
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, Maharashtra, India
| | - Abira Ganguly
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, Maharashtra, India
| | - Dibyendu Bhattacharyya
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, Maharashtra, India
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
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3
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Heckle LA, Kozminski KG. Osh-dependent and -independent Regulation of PI4P Levels During Polarized Growth of Saccharomyces cerevisiae. Mol Biol Cell 2023; 34:ar104. [PMID: 37556206 PMCID: PMC10559303 DOI: 10.1091/mbc.e23-03-0089] [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: 03/10/2023] [Revised: 07/03/2023] [Accepted: 07/31/2023] [Indexed: 08/11/2023] Open
Abstract
Polarized secretion facilitates polarized cell growth. For a secretory vesicle to dock at the plasma membrane, it must mature with a progressive association or dissociation of molecules that are, respectively, necessary for or inhibitory to vesicle docking, including an exchange of Rab GTPases. In current models, oxysterol-binding protein homologue 4 (Osh4p) establishes a phosphatidylinositol 4-phosphate (PI4P) gradient along the secretory trafficking pathway such that vesicles have higher PI4P levels after budding from the trans-Golgi relative to when vesicles arrive at the plasma membrane. In this study, using the lipid-binding domain P4M and live-cell imaging, we show that secretory vesicle-associated PI4P levels remain constant when vesicles traffic from the trans-Golgi to the plasma membrane. We also show that deletion of OSH4 does not alter vesicle-associated PI4P levels, though loss of any individual member of the OSH family or complete loss of OSH family function alters the intracellular distribution of PI4P. We propose a model in which the Rab GTPases Ypt32p and Sec4p remain associated with a secretory vesicle during trafficking, independent of PI4P levels and Osh4p. Together these data indicate the necessity of experiments revealing the location and timing of events required for vesicle maturation.
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Affiliation(s)
- Lindsay A. Heckle
- Department of Biology, University of Virginia, Charlottesville, VA 22904
| | - Keith G. Kozminski
- Department of Biology, University of Virginia, Charlottesville, VA 22904
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908
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4
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Nagano M, Aoshima K, Shimamura H, Siekhaus DE, Toshima JY, Toshima J. Distinct role of TGN-resident clathrin adaptors for Vps21p activation in the TGN-endosome trafficking pathway. J Cell Sci 2023; 136:jcs261448. [PMID: 37539494 DOI: 10.1242/jcs.261448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 07/27/2023] [Indexed: 08/05/2023] Open
Abstract
Clathrin-mediated vesicle trafficking plays central roles in post-Golgi transport. In yeast (Saccharomyces cerevisiae), the AP-1 complex and GGA adaptors are predicted to generate distinct transport vesicles at the trans-Golgi network (TGN), and the epsin-related proteins Ent3p and Ent5p (collectively Ent3p/5p) act as accessories for these adaptors. Recently, we showed that vesicle transport from the TGN is crucial for yeast Rab5 (Vps21p)-mediated endosome formation, and that Ent3p/5p are crucial for this process, whereas AP-1 and GGA adaptors are dispensable. However, these observations were incompatible with previous studies showing that these adaptors are required for Ent3p/5p recruitment to the TGN, and thus the overall mechanism responsible for regulation of Vps21p activity remains ambiguous. Here, we investigated the functional relationships between clathrin adaptors in post-Golgi-mediated Vps21p activation. We show that AP-1 disruption in the ent3Δ5Δ mutant impaired transport of the Vps21p guanine nucleotide exchange factor Vps9p transport to the Vps21p compartment and severely reduced Vps21p activity. Additionally, GGA adaptors, the phosphatidylinositol-4-kinase Pik1p and Rab11 GTPases Ypt31p and Ypt32p were found to have partially overlapping functions for recruitment of AP-1 and Ent3p/5p to the TGN. These findings suggest a distinct role of clathrin adaptors for Vps21p activation in the TGN-endosome trafficking pathway.
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Affiliation(s)
- Makoto Nagano
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Kaito Aoshima
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Hiroki Shimamura
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | | | - Junko Y Toshima
- School of Health Science, Tokyo University of Technology, 5-23-22 Nishikamada, Ota-ku, Tokyo 144-8535, Japan
| | - Jiro Toshima
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
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5
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Wilmes S, Kümmel D. Insights into the role of the membranes in Rab GTPase regulation. Curr Opin Cell Biol 2023; 83:102177. [PMID: 37327649 DOI: 10.1016/j.ceb.2023.102177] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/15/2023] [Accepted: 05/19/2023] [Indexed: 06/18/2023]
Abstract
Rab GTPases are molecular switches with essential roles in mediating vesicular trafficking and establishing organelle identity. The conversion from the inactive, cytosolic to the membrane-bound, active species and back is tightly controlled by regulatory proteins. Recently, the roles of membrane properties and lipid composition of different target organelles in determining the activity state of Rabs have come to light. The investigation of several Rab guanine nucleotide exchange factors (GEFs) has revealed principles of how the recruitment via lipid interactions and the spatial confinement on the membrane surface contribute to spatiotemporal specificity in the Rab GTPase network. This paints an intricate picture of the control mechanisms in Rab activation and highlights the importance of the membrane lipid code in the organization of the endomembrane system.
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Affiliation(s)
- Stephan Wilmes
- University of Münster, Institute of Biochemistry, Corrensstraße 36, 48149 Münster, Germany
| | - Daniel Kümmel
- University of Münster, Institute of Biochemistry, Corrensstraße 36, 48149 Münster, Germany.
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6
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Li L, Li J, Yuan L. A direct interaction between CENTLEIN and RABIN8 is required for primary cilium formation. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1434-1444. [PMID: 37475549 PMCID: PMC10520482 DOI: 10.3724/abbs.2023064] [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: 12/30/2022] [Accepted: 03/23/2023] [Indexed: 04/05/2023] Open
Abstract
Primary cilia are formed in nearly all growth-arrested cells and are essential for mammalian development and tissue homeostasis. Defects in primary cilia result in a range of disorders in humans, named ciliopathies. The spatiotemporal localization of RABIN8 on the pericentrosome is an early step in ciliogenesis. Here, we show that CENTLEIN depletion causes the persistent accumulation of RABIN8 on the pericentrosome and primary cilium loss in hTERT-immortalized retinal pigment epithelial cells and murine embryonic fibroblasts. CENTLEIN interacts with RABIN8 directly. A stretch of a 31-amino acid sequence located in the 200‒230 region of the RABIN8 GEF domain is responsible for its physical interaction with CENTLEIN, while expression of the full-length but not the internal deletion lacking the RABIN8-binding site of CENTLEIN largely rescues the ciliogenesis defect provoked by CENTLEIN depletion. Expression of activated RAB8A partially reverses cilium loss in CENTLEIN-null RPE1 cells, so the functional importance of the CENTLEIN-RABIN8 interaction is defined.
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Affiliation(s)
- Liansheng Li
- />Savaid Medical SchoolUniversity of Chinese Academy of SciencesBeijing101408China
| | - Junlin Li
- />Savaid Medical SchoolUniversity of Chinese Academy of SciencesBeijing101408China
| | - Li Yuan
- />Savaid Medical SchoolUniversity of Chinese Academy of SciencesBeijing101408China
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7
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Wilson B, Flett C, Gemperle J, Lawless C, Hartshorn M, Hinde E, Harrison T, Chastney M, Taylor S, Allen J, Norman JC, Zacharchenko T, Caswell PT. Proximity labelling identifies pro-migratory endocytic recycling cargo and machinery of the Rab4 and Rab11 families. J Cell Sci 2023; 136:jcs260468. [PMID: 37232246 PMCID: PMC10323252 DOI: 10.1242/jcs.260468] [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: 07/28/2022] [Accepted: 05/18/2023] [Indexed: 05/27/2023] Open
Abstract
Endocytic recycling controls the return of internalised cargoes to the plasma membrane to coordinate their positioning, availability and downstream signalling. The Rab4 and Rab11 small GTPase families regulate distinct recycling routes, broadly classified as fast recycling from early endosomes (Rab4) and slow recycling from perinuclear recycling endosomes (Rab11), and both routes handle a broad range of overlapping cargoes to regulate cell behaviour. We adopted a proximity labelling approach, BioID, to identify and compare the protein complexes recruited by Rab4a, Rab11a and Rab25 (a Rab11 family member implicated in cancer aggressiveness), revealing statistically robust protein-protein interaction networks of both new and well-characterised cargoes and trafficking machinery in migratory cancer cells. Gene ontological analysis of these interconnected networks revealed that these endocytic recycling pathways are intrinsically connected to cell motility and cell adhesion. Using a knock-sideways relocalisation approach, we were further able to confirm novel links between Rab11, Rab25 and the ESCPE-1 and retromer multiprotein sorting complexes, and identify new endocytic recycling machinery associated with Rab4, Rab11 and Rab25 that regulates cancer cell migration in the 3D matrix.
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Affiliation(s)
- Beverley Wilson
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Chloe Flett
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Jakub Gemperle
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Craig Lawless
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Matthew Hartshorn
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Eleanor Hinde
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Tess Harrison
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Megan Chastney
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Sarah Taylor
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Jennifer Allen
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Jim C. Norman
- Cancer Research UK Beatson Institute, Glasgow, G61 1BD, UK
- School of Cancer Sciences, University of Glasgow, Glasgow, G61 1QH, UK
| | - Thomas Zacharchenko
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Patrick T. Caswell
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
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8
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Li X, Liu D, Griffis E, Novick P. Exploring the consequences of redirecting an exocytic Rab onto endocytic vesicles. Mol Biol Cell 2023; 34:ar38. [PMID: 36857153 PMCID: PMC10162416 DOI: 10.1091/mbc.e23-01-0037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 02/22/2023] [Indexed: 03/02/2023] Open
Abstract
Bidirectional vesicular traffic links compartments along the exocytic and endocytic pathways. Rab GTPases have been implicated in specifying the direction of vesicular transport. To explore this possibility, we sought to redirect an exocytic Rab, Sec4, onto endocytic vesicles by fusing the catalytic domain of the Sec4 GEF, Sec2, onto the CUE localization domain of Vps9, a GEF for the endocytic Rab Ypt51. The Sec2GEF-GFP-CUE construct localized to bright puncta predominantly near sites of polarized growth, and this localization was dependent on the ability of the CUE domain to bind to the ubiquitin moieties added to the cytoplasmic tails of proteins destined for endocytic internalization. Sec4 and Sec4 effectors were recruited to these puncta with various efficiencies. Cells expressing Sec2GEF-GFP-CUE grew surprisingly well and secreted protein at near-normal efficiency, implying that Golgi-derived secretory vesicles were delivered to polarized sites of cell growth despite the misdirection of Sec4 and its effectors. A low efficiency mechanism for localization of Sec2 to secretory vesicles that is independent of known cues might be responsible. In total, the results suggest that while Rabs may play a critical role in specifying the direction of vesicular transport, cells are remarkably tolerant of Rab misdirection.
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Affiliation(s)
- Xia Li
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0644
| | - Dongmei Liu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0644
| | - Eric Griffis
- Nikon Imaging Center, University of California, San Diego, La Jolla, CA 92093-0694
| | - Peter Novick
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0644
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9
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Li X, Liu D, Griffis E, Novick P. Exploring the consequences of redirecting an exocytic Rab onto endocytic vesicles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.09.527811. [PMID: 36798320 PMCID: PMC9934678 DOI: 10.1101/2023.02.09.527811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Bidirectional vesicular traffic links compartments along the exocytic and endocytic pathways. Rab GTPases have been implicated in specifying the direction of vesicular transport because anterograde vesicles are marked with a different Rab than retrograde vesicles. To explore this proposal, we sought to redirect an exocytic Rab, Sec4, onto endocytic vesicles by fusing the catalytic domain of the Sec4 GEF, Sec2, onto the CUE localization domain of Vps9, a GEF for the endocytic Rab, Ypt51. The Sec2GEF-GFP-CUE construct was found to localize to bright puncta predominantly near sites of polarized growth and this localization was strongly dependent upon the ability of the CUE domain to bind to the ubiquitin moieties added to the cytoplasmic tails of proteins destined for endocytic internalization. Sec4 and Sec4 effectors were recruited to these puncta with varying efficiency. The puncta appeared to consist of clusters of 80 nm vesicles and although the puncta are largely static, FRAP analysis suggests that traffic into and out of these clusters continues. Cells expressing Sec2GEF-GFP-CUE grew surprisingly well and secreted protein at near normal efficiency, implying that Golgi derived secretory vesicles were delivered to polarized sites of cell growth, where they tethered and fused with the plasma membrane despite the misdirection of Sec4 and its effectors. In total, the results suggest that while Rabs play a critical role in regulating vesicular transport, cells are remarkably tolerant of Rab misdirection.
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Affiliation(s)
- Xia Li
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, United States
| | - Dongmei Liu
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, United States
| | - Eric Griffis
- Nikon Imaging Center, University of California at San Diego, La Jolla, California, United States
| | - Peter Novick
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, United States
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10
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Chen M, Zhang Y, Jiang K, Wang W, Feng H, Zhen R, Moo C, Zhang Z, Shi J, Chen C. Grab regulates transferrin receptor recycling and iron uptake in developing erythroblasts. Blood 2022; 140:1145-1155. [PMID: 35820059 DOI: 10.1182/blood.2021015189] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 06/25/2022] [Indexed: 11/20/2022] Open
Abstract
Developing erythroblasts acquire massive amounts of iron through the transferrin (Tf) cycle, which involves endocytosis, sorting, and recycling of the Tf-Tf receptor (Tfrc) complex. Previous studies on the hemoglobin-deficit (hbd) mouse have shown that the exocyst complex is indispensable for the Tfrc recycling; however, the precise mechanism underlying the efficient exocytosis and recycling of Tfrc in erythroblasts remains unclear. Here, we identify the guanine nucleotide exchange factor Grab as a critical regulator of the Tf cycle and iron metabolism during erythropoiesis. Grab is highly expressed in differentiating erythroblasts. Loss of Grab diminishes the Tfrc recycling and iron uptake, leading to hemoglobinization defects in mouse primary erythroblasts, mammalian erythroleukemia cells, and zebrafish embryos. These defects can be alleviated by supplementing iron together with hinokitiol, a small-molecule natural compound that can mediate iron transport independent of the Tf cycle. Mechanistically, Grab regulates the exocytosis of Tfrc-associated vesicles by activating the GTPase Rab8, which subsequently promotes the recruitment of the exocyst complex and vesicle exocytosis. Our results reveal a critical role for Grab in regulating the Tf cycle and provide new insights into iron homeostasis and erythropoiesis.
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Affiliation(s)
- Mengying Chen
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Yuhan Zhang
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Kailun Jiang
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Weixi Wang
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - He Feng
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Ru Zhen
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Chingyee Moo
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Zhuonan Zhang
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jiahai Shi
- Synthetic Biology Translational Research Programs, Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; and
| | - Caiyong Chen
- Ministry of Education Key Laboratory of Biosystems Homeostasis and Protection, Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
- Cancer Center, Zhejiang University, Hangzhou, China
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11
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Small GTPase FoSec4-Mediated Protein Secretion Is Important for Polarized Growth, Reproduction and Pathogenicity in the Banana Fusarium Wilt Fungus Fusarium odoratissimum. J Fungi (Basel) 2022; 8:jof8080880. [PMID: 36012867 PMCID: PMC9410047 DOI: 10.3390/jof8080880] [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: 06/26/2022] [Revised: 08/15/2022] [Accepted: 08/17/2022] [Indexed: 11/18/2022] Open
Abstract
Apical secretion at hyphal tips is important for the growth and development of filamentous fungi. In this study, we analyzed the role of the Rab GTPases FoSec4 involved in the secretion of the banana wilt fungal pathogen Fusarium odoratissimum. We found that the deletion of FoSEC4 affects the activity of extracellular hydrolases and protein secretion, indicating that FoSec4 plays an important role in the regulation of protein secretion in F. odoratissimum. As a typical Rab GTPase, Sec4 participates in the Rab cycle through the conversion between the active GTP-bound state and the inactive GDP-bound state, which is regulated by guanine nucleate exchange factors (GEFs) and GTPase-activating proteins (GAPs). We further found that FoSec2 can interact with dominant-negative FoSec4 (GDP-bound and nucleotide-free form, FoSec4DN), and that FoGyp5 can interact with dominant active FoSec4 (GTP-bound and constitutively active form, FoSec4CA). We evaluated the biofunctions of FoSec4, FoSec2 and FoGyp5, and found that FoSec4 is involved in the regulation of vegetative growth, reproduction, pathogenicity and the environmental stress response of F. odoratissimum, and that FocSec2 and FoGyp5 perform biofunctions consistent with FoSec4, indicating that FoSec2 and FoGyp5 may work as the GEF and the GAP, respectively, of FoSec4 in F. odoratissimum. We further found that the amino-terminal region and Sec2 domain are essential for the biological functions of FoSec2, while the carboxyl-terminal region and Tre-2/Bub2/Cdc16 (TBC) domain are essential for the biological functions of FoGyp5. In addition, FoSec4 mainly accumulated at the hyphal tips and partially colocalized with Spitzenkörper; however, FoGyp5 accumulated at the periphery of Spitzenkörper, suggesting that FoGyp5 may recognize and inactivate FoSec4 at a specific location in hyphal tips.
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12
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Ito E, Uemura T. RAB GTPases and SNAREs at the trans-Golgi network in plants. JOURNAL OF PLANT RESEARCH 2022; 135:389-403. [PMID: 35488138 PMCID: PMC9188535 DOI: 10.1007/s10265-022-01392-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/20/2022] [Indexed: 05/07/2023]
Abstract
Membrane traffic is a fundamental cellular system to exchange proteins and membrane lipids among single membrane-bound organelles or between an organelle and the plasma membrane in order to keep integrity of the endomembrane system. RAB GTPases and SNARE proteins, the key regulators of membrane traffic, are conserved broadly among eukaryotic species. However, genome-wide analyses showed that organization of RABs and SNAREs that regulate the post-Golgi transport pathways is greatly diversified in plants compared to other model eukaryotes. Furthermore, some organelles acquired unique properties in plant lineages. Like in other eukaryotic systems, the trans-Golgi network of plants coordinates secretion and vacuolar transport; however, uniquely in plants, it also acts as a platform for endocytic transport and recycling. In this review, we focus on RAB GTPases and SNAREs that function at the TGN, and summarize how these regulators perform to control different transport pathways at the plant TGN. We also highlight the current knowledge of RABs and SNAREs' role in regulation of plant development and plant responses to environmental stimuli.
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Affiliation(s)
- Emi Ito
- Graduate School of Humanities and Sciences, Ochanomizu University, Bunkyo-ku, Tokyo, 112-8610, Japan
| | - Tomohiro Uemura
- Graduate School of Humanities and Sciences, Ochanomizu University, Bunkyo-ku, Tokyo, 112-8610, Japan.
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13
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Pang L, Ma Z, Zhang X, Huang Y, Li R, Miao Y, Li R. The small GTPase RABA2a recruits SNARE proteins to regulate the secretory pathway in parallel with the exocyst complex in Arabidopsis. MOLECULAR PLANT 2022; 15:398-418. [PMID: 34798312 DOI: 10.1016/j.molp.2021.11.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 10/24/2021] [Accepted: 11/12/2021] [Indexed: 05/22/2023]
Abstract
Delivery of proteins to the plasma membrane occurs via secretion, which requires tethering, docking, priming, and fusion of vesicles. In yeast and mammalian cells, an evolutionarily conserved RAB GTPase activation cascade functions together with the exocyst and SNARE proteins to coordinate vesicle transport with fusion at the plasma membrane. However, it is unclear whether this is the case in plants. In this study, we show that the small GTPase RABA2a recruits and interacts with the VAMP721/722-SYP121-SNAP33 SNARE ternary complex for membrane fusion. Through immunoprecipitation coupled with mass spectrometry analysis followed by the validatation with a series of biochemical assays, we identified the SNARE proteins VAMP721 and SYP121 as the interactors and downstream effectors of RABA2a. Further expreiments showed that RABA2a interacts with all members of the SNARE complex in its GTP-bound form and modulates the assembly of the VAMP721/722-SYP121-SNAP33 SNARE ternary complex. Intriguingly, we did not observe the interaction of the exocyst subunits with either RABA2a or theSNARE proteins in several different experiments. Neither RABA2a inactivation affects the subcellular localization or assembly of the exocystnor the exocyst subunit mutant exo84b shows the disrupted RABA2a-SNARE association or SNARE assembly, suggesting that the RABA2a-SNARE- and exocyst-mediated secretory pathways are largely independent. Consistently, our live imaging experiments reveal that the two sets of proteins follow non-overlapping trafficking routes, and genetic and cell biologyanalyses indicate that the two pathways select different cargos. Finally, we demonstrate that the plant-specific RABA2a-SNARE pathway is essential for the maintenance of potassium homeostasis in Arabisopsis seedlings. Collectively, our findings imply that higher plants might have generated different endomembrane sorting pathways during evolution and may enable the highly conserved endomembrane proteins to participate in plant-specific trafficking mechanisms for adaptation to the changing environment.
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Affiliation(s)
- Lei Pang
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Xi Zhang
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
| | - Yuanzhi Huang
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Ruili Li
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Ruixi Li
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China.
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14
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Li T, Guo Y. ADP-Ribosylation Factor Family of Small GTP-Binding Proteins: Their Membrane Recruitment, Activation, Crosstalk and Functions. Front Cell Dev Biol 2022; 10:813353. [PMID: 35186926 PMCID: PMC8850633 DOI: 10.3389/fcell.2022.813353] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 01/14/2022] [Indexed: 11/13/2022] Open
Abstract
Members of the ADP-ribosylation factor (ARF) family of guanine-nucleotide binding proteins play critical roles in various cellular processes, especially in regulating the secretory, and endocytic pathways. The fidelity of intracellular vesicular trafficking depends on proper activations and precise subcellular distributions of ARF family proteins regulated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Here we review recent progress in understanding the membrane recruitment, activation, crosstalk, and functions of ARF family proteins.
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Affiliation(s)
- Tiantian Li
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Yusong Guo
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
- Hong Kong University of Science and Technology, Shenzhen Research Institute, Shenzhen, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
- *Correspondence: Yusong Guo,
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15
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Gross SJ, Webb AM, Peterlin AD, Durrant JR, Judson RJ, Raza Q, Kitajewski JK, Kushner EJ. Notch regulates vascular collagen IV basement membrane through modulation of lysyl hydroxylase 3 trafficking. Angiogenesis 2021; 24:789-805. [PMID: 33956260 PMCID: PMC8487879 DOI: 10.1007/s10456-021-09791-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 04/19/2021] [Indexed: 11/26/2022]
Abstract
Collagen type IV (Col IV) is a basement membrane protein associated with early blood vessel morphogenesis and is essential for blood vessel stability. Defects in vascular Col IV deposition are the basis of heritable disorders, such as small vessel disease, marked by cerebral hemorrhage and drastically shorten lifespan. To date, little is known about how endothelial cells regulate the intracellular transport and selective secretion of Col IV in response to angiogenic cues, leaving a void in our understanding of this critical process. Our aim was to identify trafficking pathways that regulate Col IV deposition during angiogenic blood vessel development. We have identified the GTPase Rab10 as a major regulator of Col IV vesicular trafficking during vascular development using both in vitro imaging and biochemistry as well as in vivo models. Knockdown of Rab10 reduced de novo Col IV secretion in vivo and in vitro. Mechanistically, we determined that Rab10 is an indirect mediator of Col IV secretion, partnering with atypical Rab25 to deliver the enzyme lysyl hydroxylase 3 (LH3) to Col IV-containing vesicles staged for secretion. Loss of Rab10 or Rab25 results in depletion of LH3 from Col IV-containing vesicles and rapid lysosomal degradation of Col IV. Furthermore, we demonstrate that Rab10 is Notch responsive, indicating a novel connection between permissive Notch-based vessel maturation programs and vesicle trafficking. Our results illustrate both a new trafficking-based component in the regulated secretion of Col IV and how this vesicle trafficking program interfaces with Notch signaling to fine-tune basement membrane secretion during blood vessel development.
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Affiliation(s)
- Stephen J Gross
- Department of Biological Sciences, University of Denver, Denver, CO, 80210, USA
| | - Amelia M Webb
- Department of Biological Sciences, University of Denver, Denver, CO, 80210, USA
| | - Alek D Peterlin
- Department of Biological Sciences, University of Denver, Denver, CO, 80210, USA
| | | | - Rachel J Judson
- Department of Biological Sciences, University of Denver, Denver, CO, 80210, USA
| | - Qanber Raza
- Department of Physiology and Biophysics, University of Illinois, Chicago, IL, USA
| | - Jan K Kitajewski
- Department of Physiology and Biophysics, University of Illinois, Chicago, IL, USA
| | - Erich J Kushner
- Department of Biological Sciences, University of Denver, Denver, CO, 80210, USA.
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16
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Borchers AC, Langemeyer L, Ungermann C. Who's in control? Principles of Rab GTPase activation in endolysosomal membrane trafficking and beyond. J Cell Biol 2021; 220:212549. [PMID: 34383013 PMCID: PMC8366711 DOI: 10.1083/jcb.202105120] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/08/2021] [Accepted: 07/08/2021] [Indexed: 12/12/2022] Open
Abstract
The eukaryotic endomembrane system consists of multiple interconnected organelles. Rab GTPases are organelle-specific markers that give identity to these membranes by recruiting transport and trafficking proteins. During transport processes or along organelle maturation, one Rab is replaced by another, a process termed Rab cascade, which requires at its center a Rab-specific guanine nucleotide exchange factor (GEF). The endolysosomal system serves here as a prime example for a Rab cascade. Along with endosomal maturation, the endosomal Rab5 recruits and activates the Rab7-specific GEF Mon1-Ccz1, resulting in Rab7 activation on endosomes and subsequent fusion of endosomes with lysosomes. In this review, we focus on the current idea of Mon1-Ccz1 recruitment and activation in the endolysosomal and autophagic pathway. We compare identified principles to other GTPase cascades on endomembranes, highlight the importance of regulation, and evaluate in this context the strength and relevance of recent developments in in vitro analyses to understand the underlying foundation of organelle biogenesis and maturation.
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Affiliation(s)
- Ann-Christin Borchers
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany.,Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
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17
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Emerging Prospects for Combating Fungal Infections by Targeting Phosphatidylinositol Transfer Proteins. Int J Mol Sci 2021; 22:ijms22136754. [PMID: 34201733 PMCID: PMC8269425 DOI: 10.3390/ijms22136754] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/11/2021] [Accepted: 06/11/2021] [Indexed: 12/27/2022] Open
Abstract
The emergence of fungal “superbugs” resistant to the limited cohort of anti-fungal agents available to clinicians is eroding our ability to effectively treat infections by these virulent pathogens. As the threat of fungal infection is escalating worldwide, this dwindling response capacity is fueling concerns of impending global health emergencies. These developments underscore the urgent need for new classes of anti-fungal drugs and, therefore, the identification of new targets. Phosphoinositide signaling does not immediately appear to offer attractive targets due to its evolutionary conservation across the Eukaryota. However, recent evidence argues otherwise. Herein, we discuss the evidence identifying Sec14-like phosphatidylinositol transfer proteins (PITPs) as unexplored portals through which phosphoinositide signaling in virulent fungi can be chemically disrupted with exquisite selectivity. Recent identification of lead compounds that target fungal Sec14 proteins, derived from several distinct chemical scaffolds, reveals exciting inroads into the rational design of next generation Sec14 inhibitors. Development of appropriately refined next generation Sec14-directed inhibitors promises to expand the chemical weaponry available for deployment in the shifting field of engagement between fungal pathogens and their human hosts.
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18
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Highland CM, Fromme JC. Arf1 directly recruits the Pik1-Frq1 PI4K complex to regulate the final stages of Golgi maturation. Mol Biol Cell 2021; 32:1064-1080. [PMID: 33788598 PMCID: PMC8101487 DOI: 10.1091/mbc.e21-02-0069] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/11/2021] [Accepted: 03/12/2021] [Indexed: 12/21/2022] Open
Abstract
Proper Golgi complex function depends on the activity of Arf1, a GTPase whose effectors assemble and transport outgoing vesicles. Phosphatidylinositol 4-phosphate (PI4P) generated at the Golgi by the conserved PI 4-kinase Pik1 (PI4KIIIβ) is also essential for Golgi function, although its precise roles in vesicle formation are less clear. Arf1 has been reported to regulate PI4P production, but whether Pik1 is a direct Arf1 effector is not established. Using a combination of live-cell time-lapse imaging analyses, acute PI4P depletion experiments, and in vitro protein-protein interaction assays on Golgi-mimetic membranes, we present evidence for a model in which Arf1 initiates the final stages of Golgi maturation by tightly controlling PI4P production through direct recruitment of the Pik1-Frq1 PI4-kinase complex. This PI4P serves as a critical signal for AP-1 and secretory vesicle formation, the final events at maturing Golgi compartments. This work therefore establishes the regulatory and temporal context surrounding Golgi PI4P production and its precise roles in Golgi maturation.
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Affiliation(s)
- Carolyn M. Highland
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - J. Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
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19
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Thomas LL, Highland CM, Fromme JC. Arf1 orchestrates Rab GTPase conversion at the trans-Golgi network. Mol Biol Cell 2021; 32:1104-1120. [PMID: 33788577 PMCID: PMC8351538 DOI: 10.1091/mbc.e20-10-0664] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Rab family GTPases are key organizers of membrane trafficking and function as markers of organelle identity. Accordingly, Rab GTPases often occupy specific membrane domains, and mechanisms exist to prevent the inappropriate mixing of distinct Rab domains. The yeast Golgi complex can be divided into two broad Rab domains: Ypt1 (Rab1) and Ypt6 (Rab6) are present at the early/medial Golgi and sharply transition to Ypt31/32 (Rab11) at the late Golgi/trans-Golgi network (TGN). This Rab conversion has been attributed to GTPase-activating protein (GAP) cascades in which Ypt31/32 recruits the Rab-GAPs Gyp1 and Gyp6 to inactivate Ypt1 and Ypt6, respectively. Here we report that Rab transition at the TGN involves additional layers of regulation. We provide new evidence confirming the TRAPPII complex as an important regulator of Ypt6 inactivation and uncover an unexpected role of the Arf1 GTPase in recruiting Gyp1 to drive Ypt1 inactivation at the TGN. Given its established role in directly recruiting TRAPPII to the TGN, Arf1 is therefore a master regulator of Rab conversion on maturing Golgi compartments.
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Affiliation(s)
- Laura L Thomas
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Carolyn M Highland
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - J Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
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20
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Peterson TA, Piper RC. Deconvolution of Multiple Rab Binding Domains Using the Batch Yeast 2-Hybrid Method DEEPN. Methods Mol Biol 2021; 2293:117-141. [PMID: 34453714 PMCID: PMC8524840 DOI: 10.1007/978-1-0716-1346-7_9] [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] [Indexed: 06/13/2023]
Abstract
A hallmark of functionally significant interactions between Rab proteins and their targets is whether that binding depends on the type of nucleotide bound to the Rab GTPase. A system that can directly compare those sets of interactions mediated by a Rab in its GTP-bound conformation versus its GDP bound conformation would provide a direct route to finding biologically relevant partners. Comprehensive large-scale yeast 2-hybrid assays allow a potential method to compare one interactome against another provided that the same set of potentially interacting partners is interrogated between samples. Here we describe the use of such a yeast 2-hybrid system that lends itself toward comparing pairs of Rab mutants, locked in either their GTP or GDP conformation. Importantly, using a complex library of protein fragments as potential binding ("prey") partners, identification of interacting proteins as well as the domain(s) mediating those interactions can be determined using a series of sequence analyses and binary validation experiments.
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Affiliation(s)
- Tabitha A Peterson
- Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Robert C Piper
- Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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21
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Silva PM, Puerner C, Seminara A, Bassilana M, Arkowitz RA. Secretory Vesicle Clustering in Fungal Filamentous Cells Does Not Require Directional Growth. Cell Rep 2020; 28:2231-2245.e5. [PMID: 31433995 DOI: 10.1016/j.celrep.2019.07.062] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 04/22/2019] [Accepted: 07/18/2019] [Indexed: 11/27/2022] Open
Abstract
During symmetry breaking, the highly conserved Rho GTPase Cdc42 becomes stabilized at a defined site via an amplification process. However, little is known about how a new polarity site is established in an already asymmetric cell-a critical process in a changing environment. The human fungal pathogen Candida albicans switches from budding to filamentous growth in response to external cues, a transition controlled by Cdc42. Here, we have used optogenetic manipulation of cell polarity to reset growth in asymmetric filamentous C. albicans cells. We show that increasing the level of active Cdc42 on the plasma membrane results in disruption of the exocyst subunit Sec3 localization and a striking de novo clustering of secretory vesicles. This new cluster of secretory vesicles is highly dynamic, moving by hops and jumps, until a new growth site is established. Our results reveal that secretory vesicle clustering can occur in the absence of directional growth.
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Affiliation(s)
- Patrícia M Silva
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France
| | - Charles Puerner
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France
| | - Agnese Seminara
- Université Côte d'Azur, CNRS, Institute Physics of Nice (INPHYNI), Ave. J. Vallot, Nice, France
| | - Martine Bassilana
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France
| | - Robert A Arkowitz
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France.
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22
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Franke C, Repnik U, Segeletz S, Brouilly N, Kalaidzidis Y, Verbavatz JM, Zerial M. Correlative single-molecule localization microscopy and electron tomography reveals endosome nanoscale domains. Traffic 2020; 20:601-617. [PMID: 31206952 PMCID: PMC6771687 DOI: 10.1111/tra.12671] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/04/2019] [Accepted: 06/09/2019] [Indexed: 12/12/2022]
Abstract
Many cellular organelles, including endosomes, show compartmentalization into distinct functional domains, which, however, cannot be resolved by diffraction‐limited light microscopy. Single molecule localization microscopy (SMLM) offers nanoscale resolution but data interpretation is often inconclusive when the ultrastructural context is missing. Correlative light electron microscopy (CLEM) combining SMLM with electron microscopy (EM) enables correlation of functional subdomains of organelles in relation to their underlying ultrastructure at nanometer resolution. However, the specific demands for EM sample preparation and the requirements for fluorescent single‐molecule photo‐switching are opposed. Here, we developed a novel superCLEM workflow that combines triple‐color SMLM (dSTORM & PALM) and electron tomography using semi‐thin Tokuyasu thawed cryosections. We applied the superCLEM approach to directly visualize nanoscale compartmentalization of endosomes in HeLa cells. Internalized, fluorescently labeled Transferrin and EGF were resolved into morphologically distinct domains within the same endosome. We found that the small GTPase Rab5 is organized in nanodomains on the globular part of early endosomes. The simultaneous visualization of several proteins in functionally distinct endosomal sub‐compartments demonstrates the potential of superCLEM to link the ultrastructure of organelles with their molecular organization at nanoscale resolution.
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Affiliation(s)
- Christian Franke
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Urska Repnik
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Sandra Segeletz
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Nicolas Brouilly
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Instutut de Biologie du Developpement de Marseille-Luminy, Aix-Marseille Universite, Marseille, France
| | - Yannis Kalaidzidis
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Faculty of Bioengineering and Bioinformatics, Moscow State University, Moscow, Russia
| | - Jean-Marc Verbavatz
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Institut Jacques Monod, CNRS, Université Paris-Diderot, Paris, France
| | - Marino Zerial
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany
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23
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Lipp NF, Ikhlef S, Milanini J, Drin G. Lipid Exchangers: Cellular Functions and Mechanistic Links With Phosphoinositide Metabolism. Front Cell Dev Biol 2020; 8:663. [PMID: 32793602 PMCID: PMC7385082 DOI: 10.3389/fcell.2020.00663] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/01/2020] [Indexed: 12/28/2022] Open
Abstract
Lipids are amphiphilic molecules that self-assemble to form biological membranes. Thousands of lipid species coexist in the cell and, once combined, define organelle identity. Due to recent progress in lipidomic analysis, we now know how lipid composition is finely tuned in different subcellular regions. Along with lipid synthesis, remodeling and flip-flop, lipid transfer is one of the active processes that regulates this intracellular lipid distribution. It is mediated by Lipid Transfer Proteins (LTPs) that precisely move certain lipid species across the cytosol and between the organelles. A particular subset of LTPs from three families (Sec14, PITP, OSBP/ORP/Osh) act as lipid exchangers. A striking feature of these exchangers is that they use phosphatidylinositol or phosphoinositides (PIPs) as a lipid ligand and thereby have specific links with PIP metabolism and are thus able to both control the lipid composition of cellular membranes and their signaling capacity. As a result, they play pivotal roles in cellular processes such as vesicular trafficking and signal transduction at the plasma membrane. Recent data have shown that some PIPs are used as energy by lipid exchangers to generate lipid gradients between organelles. Here we describe the importance of lipid counter-exchange in the cell, its structural basis, and presumed links with pathologies.
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Affiliation(s)
- Nicolas-Frédéric Lipp
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, Université Côte d'Azur, Valbonne, France
| | - Souade Ikhlef
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, Université Côte d'Azur, Valbonne, France
| | - Julie Milanini
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, Université Côte d'Azur, Valbonne, France
| | - Guillaume Drin
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, Université Côte d'Azur, Valbonne, France
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24
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Stalder D, Gershlick DC. Direct trafficking pathways from the Golgi apparatus to the plasma membrane. Semin Cell Dev Biol 2020; 107:112-125. [PMID: 32317144 PMCID: PMC7152905 DOI: 10.1016/j.semcdb.2020.04.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 04/03/2020] [Accepted: 04/06/2020] [Indexed: 12/19/2022]
Abstract
In eukaryotic cells, protein sorting is a highly regulated mechanism important for many physiological events. After synthesis in the endoplasmic reticulum and trafficking to the Golgi apparatus, proteins sort to many different cellular destinations including the endolysosomal system and the extracellular space. Secreted proteins need to be delivered directly to the cell surface. Sorting of secreted proteins from the Golgi apparatus has been a topic of interest for over thirty years, yet there is still no clear understanding of the machinery that forms the post-Golgi carriers. Most evidence points to these post-Golgi carriers being tubular pleomorphic structures that bud from the trans-face of the Golgi. In this review, we present the background studies and highlight the key components of this pathway, we then discuss the machinery implicated in the formation of these carriers, their translocation across the cytosol, and their fusion at the plasma membrane.
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Key Words
- ATP, adenosine triphosphate
- BFA, Brefeldin A
- CARTS, CARriers of the TGN to the cell Surface
- CI-MPR, cation-independent mannose-6 phosphate receptor
- Constitutive Secretion
- CtBP3/BARS, C-terminus binding protein 3/BFA adenosine diphosphate–ribosylated substrate
- ER, endoplasmic reticulum
- GPI-anchored proteins, glycosylphosphatidylinositol-anchored proteins
- GlcCer, glucosylceramidetol
- Golgi to plasma membrane sorting
- PAUF, pancreatic adenocarcinoma up-regulated factor
- PKD, Protein Kinase D
- RUSH, retention using selective hooks
- SBP, streptavidin-binding peptide
- SM, sphingomyelin
- SNARE, soluble N-ethylmaleimide sensitive fusion protein attachment protein receptor
- SPCA1, secretory pathway calcium ATPase 1
- Secretion
- TGN, trans-Golgi Network
- TIRF, total internal reflection fluorescence
- VSV, vesicular stomatitis virus
- pleomorphic tubular carriers
- post-Golgi carriers
- ts, temperature sensitive
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Affiliation(s)
- Danièle Stalder
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - David C Gershlick
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom.
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25
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Extensive GTPase crosstalk regulates Golgi trafficking and maturation. Curr Opin Cell Biol 2020; 65:1-7. [PMID: 32143122 DOI: 10.1016/j.ceb.2020.01.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 01/23/2020] [Indexed: 12/12/2022]
Abstract
Virtually all transport events at the Golgi complex are regulated by Arf and Rab family GTPases. Recent work has advanced our knowledge regarding the mechanisms controlling GTPase activity, and it has become clear that GTPases do not act in isolation but rather function in complex networks of crosstalk and feedback. Together with earlier findings, these recent studies indicate that communication between GTPases, their regulatory proteins, effectors, and lipids plays a pivotal role in Golgi transport and cisternal maturation.
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26
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Ishida M, Bonifacino JS. ARFRP1 functions upstream of ARL1 and ARL5 to coordinate recruitment of distinct tethering factors to the trans-Golgi network. J Cell Biol 2019; 218:3681-3696. [PMID: 31575603 PMCID: PMC6829661 DOI: 10.1083/jcb.201905097] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/09/2019] [Accepted: 08/27/2019] [Indexed: 12/22/2022] Open
Abstract
SNARE-mediated fusion of endosome-derived transport carriers with the trans-Golgi network (TGN) depends on the concerted action of two types of tethering factors: long coiled-coil tethers of the golgin family, and the heterotetrameric complex GARP. Whereas the golgins mediate long-distance capture of the carriers, GARP promotes assembly of the SNAREs. It remains to be determined, however, how the functions of these tethering factors are coordinated. Herein we report that the ARF-like (ARL) GTPase ARFRP1 functions upstream of two other ARL GTPases, ARL1 and ARL5, which in turn recruit golgins and GARP, respectively, to the TGN. We also show that this mechanism is essential for the delivery of retrograde cargos to the TGN. Our findings thus demonstrate that ARFRP1 is a master regulator of retrograde-carrier tethering to the TGN. The coordinated recruitment of distinct tethering factors by a bifurcated GTPase cascade may be paradigmatic of other vesicular fusion events within the cell.
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Affiliation(s)
- Morié Ishida
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Juan S Bonifacino
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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27
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Lipatova Z, Segev N. Ypt/Rab GTPases and their TRAPP GEFs at the Golgi. FEBS Lett 2019; 593:2488-2500. [PMID: 31400292 PMCID: PMC6989042 DOI: 10.1002/1873-3468.13574] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/07/2019] [Accepted: 08/08/2019] [Indexed: 11/06/2022]
Abstract
The conserved Ypt/Rab GTPases regulate the different steps of all intracellular trafficking pathways. Ypt/Rabs are activated by their specific nucleotide exchangers termed GEFs, and when GTP bound, they recruit their downstream effectors, which mediate vesicular transport substeps. In the yeast exocytic pathway, Ypt1 and Ypt31/32 regulate traffic through the Golgi and the conserved modular TRAPP complex acts a GEF for both Ypt1 and Ypt31/32. However, the precise localization and function of these Ypts have been under debate, as is the identity of their corresponding GEFs. We have established that Ypt1 and Ypt31 reside on the two sides of the Golgi, early and late, respectively, and regulate Golgi cisternal progression. We and others have shown that whereas a single TRAPP complex, TRAPP II, activates Ypt31, three TRAPP complexes can activate Ypt1: TRAPPs I, III, and IV. We propose that TRAPP I and II activate Ypt1 and Ypt31, respectively, at the Golgi, whereas TRAPP III and IV activate Ypt1 in autophagy. Resolving these issues is important because both Rabs and TRAPPs are implicated in multiple human diseases, ranging from cancer to neurodegenerative diseases.
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Affiliation(s)
- Zhanna Lipatova
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, IL, USA
| | - Nava Segev
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, IL, USA
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28
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Cuenca A, Insinna C, Zhao H, John P, Weiss MA, Lu Q, Walia V, Specht S, Manivannan S, Stauffer J, Peden AA, Westlake CJ. The C7orf43/TRAPPC14 component links the TRAPPII complex to Rabin8 for preciliary vesicle tethering at the mother centriole during ciliogenesis. J Biol Chem 2019; 294:15418-15434. [PMID: 31467083 DOI: 10.1074/jbc.ra119.008615] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 08/25/2019] [Indexed: 01/08/2023] Open
Abstract
The primary cilium is a cellular sensor that detects light, chemicals, and movement and is important for morphogen and growth factor signaling. The small GTPase Rab11-Rab8 cascade is required for ciliogenesis. Rab11 traffics the guanine nucleotide exchange factor (GEF) Rabin8 to the centrosome to activate Rab8, needed for ciliary growth. Rabin8 also requires the transport particle protein complex (TRAPPC) proteins for centrosome recruitment during ciliogenesis. Here, using an MS-based approach for identifying Rabin8-interacting proteins, we identified C7orf43 (also known as microtubule-associated protein 11 (MAP11)) as being required for ciliation both in human cells and zebrafish embryos. We find that C7orf43 directly binds to Rabin8 and that C7orf43 knockdown diminishes Rabin8 preciliary centrosome accumulation. Interestingly, we found that C7orf43 co-sediments with TRAPPII complex subunits and directly interacts with TRAPPC proteins. Our findings establish that C7orf43 is a TRAPPII-specific complex component, referred to here as TRAPPC14. Additionally, we show that TRAPPC14 is dispensable for TRAPPII complex integrity but mediates Rabin8 association with the TRAPPII complex. Finally, we demonstrate that TRAPPC14 interacts with the distal appendage proteins Fas-binding factor 1 (FBF1) and centrosomal protein 83 (CEP83), which we show here are required for GFP-Rabin8 centrosomal accumulation, supporting a role for the TRAPPII complex in tethering preciliary vesicles to the mother centriole during ciliogenesis. In summary, our findings have revealed an uncharacterized TRAPPII-specific component, C7orf43/TRAPPC14, that regulates preciliary trafficking of Rabin8 and ciliogenesis and support previous findings that the TRAPPII complex functions as a membrane tether.
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Affiliation(s)
- Adrian Cuenca
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Christine Insinna
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Huijie Zhao
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Peter John
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Matthew A Weiss
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Quanlong Lu
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Vijay Walia
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Suzanne Specht
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Selvambigai Manivannan
- Department of Biomedical Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Jimmy Stauffer
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Andrew A Peden
- Department of Biomedical Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Christopher J Westlake
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
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29
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Ehrmann A, Nguyen B, Seifert U. Interlinked GTPase cascades provide a motif for both robust switches and oscillators. J R Soc Interface 2019; 16:20190198. [PMID: 31387482 DOI: 10.1098/rsif.2019.0198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
GTPases regulate a wide range of cellular processes, such as intracellular vesicular transport, signal transduction and protein translation. These hydrolase enzymes operate as biochemical switches by toggling between an active guanosine triphosphate (GTP)-bound state and an inactive guanosine diphosphate (GDP)-bound state. We compare two network motifs, a single-species switch and an interlinked cascade that consists of two species coupled through positive and negative feedback loops. We find that interlinked cascades are closer to the ideal all-or-none switch and are more robust against fluctuating signals. While the single-species switch can only achieve bistability, interlinked cascades can be converted into oscillators by tuning the cofactor concentrations, which catalyse the activity of the cascade. These regimes can only be achieved with sufficient chemical driving provided by GTP hydrolysis. In this study, we present a thermodynamically consistent model that can achieve bistability and oscillations with the same feedback motif.
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Affiliation(s)
- Andreas Ehrmann
- II. Institut für Theoretische Physik, Universität Stuttgart, 70550 Stuttgart, Germany
| | - Basile Nguyen
- II. Institut für Theoretische Physik, Universität Stuttgart, 70550 Stuttgart, Germany
| | - Udo Seifert
- II. Institut für Theoretische Physik, Universität Stuttgart, 70550 Stuttgart, Germany
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30
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Sanzà P, Evans RD, Briggs DA, Cantero M, Montoliu L, Patel S, Sviderskaya EV, Itzen A, Figueiredo AC, Seabra MC, Hume AN. Nucleotide exchange factor Rab3GEP requires DENN and non-DENN elements for activation and targeting of Rab27a. J Cell Sci 2019; 132:jcs.212035. [PMID: 30898842 PMCID: PMC6526710 DOI: 10.1242/jcs.212035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 03/11/2019] [Indexed: 02/04/2023] Open
Abstract
Rab GTPases are compartment-specific molecular switches that regulate intracellular vesicular transport in eukaryotes. GDP/GTP exchange factors (GEFs) control Rab activation, and current models propose that localised and regulated GEF activity is important in targeting Rabs to specific membranes. Here, we investigated the mechanism of GEF function using the Rab27a GEF, Rab3GEP (also known as MADD), in melanocytes as a model. We show that Rab3GEP-deficient melanocytes (melan-R3GKO) manifest partial disruption of melanosome dispersion, a read-out of Rab27a activation and targeting. Using rescue of melanosome dispersion in melan-R3GKO cells and effector pull-down approaches we show that the DENN domain of Rab3GEP (conserved among RabGEFs) is necessary, but insufficient, for its cellular function and GEF activity. Finally, using a mitochondrial re-targeting strategy, we show that Rab3GEP can target Rab27a to specific membranes in a GEF-dependent manner. We conclude that Rab3GEP facilitates the activation and targeting of Rab27a to specific membranes, but that it differs from other DENN-containing RabGEFs in requiring DENN and non-DENN elements for both of these activities and by lacking compartment-specific localisation.
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Affiliation(s)
- Paolo Sanzà
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Richard D Evans
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Deborah A Briggs
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Marta Cantero
- Centro Nacional de Biotecnologia (CNB-CSIC), Madrid 28049, Spain.,CIBERER-ISCIII, Madrid 28029, Spain
| | - Lluis Montoliu
- Centro Nacional de Biotecnologia (CNB-CSIC), Madrid 28049, Spain.,CIBERER-ISCIII, Madrid 28029, Spain
| | - Shyamal Patel
- Cell Biology and Genetics Research Centre, Molecular and Clinical Sciences Research Institute, St. George's, University of London, London SW17 0RE, UK
| | - Elena V Sviderskaya
- Cell Biology and Genetics Research Centre, Molecular and Clinical Sciences Research Institute, St. George's, University of London, London SW17 0RE, UK
| | - Aymelt Itzen
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technische Universität München, Garching 85748, Germany
| | - Ana C Figueiredo
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto 4200-135, Portugal.,i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto 4200-135, Portugal
| | - Miguel C Seabra
- CEDOC Faculdade de Ciencias Medicas, Universidade Nova de Lisboa, Lisbon 1169-056, Portugal
| | - Alistair N Hume
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
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31
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Wang Y, Mousley CJ, Lete MG, Bankaitis VA. An equal opportunity collaboration between lipid metabolism and proteins in the control of membrane trafficking in the trans-Golgi and endosomal systems. Curr Opin Cell Biol 2019; 59:58-72. [PMID: 31039522 DOI: 10.1016/j.ceb.2019.03.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 03/25/2019] [Accepted: 03/27/2019] [Indexed: 12/18/2022]
Abstract
Recent years have witnessed the evolution of the cell biology of lipids into an extremely active area of investigation. Deciphering the involvement of lipid metabolism and lipid signaling in membrane trafficking pathways defines a major nexus of contemporary experimental activity on this front. Significant effort in that direction is invested in understanding the trans-Golgi network/endosomal system where unambiguous connections between membrane trafficking and inositol lipid and phosphatidylcholine metabolism were first discovered. However, powered by new advances in contemporary cell biology, the march of science is rapidly expanding that window of inquiry to include ever more diverse arms of the lipid metabolome, and to include other compartments of the secretory pathway as well.
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Affiliation(s)
- Yaxi Wang
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843-2128, USA
| | - Carl J Mousley
- School of Biomedical Sciences, Curtin Health Innovation Research Institute (CHIRI), Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Marta G Lete
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA
| | - Vytas A Bankaitis
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843-2128, USA; Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA.
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32
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Verdín J, Sánchez-León E, Rico-Ramírez AM, Martínez-Núñez L, Fajardo-Somera RA, Riquelme M. Off the wall: The rhyme and reason of Neurospora crassa hyphal morphogenesis. ACTA ACUST UNITED AC 2019; 5:100020. [PMID: 32743136 PMCID: PMC7389182 DOI: 10.1016/j.tcsw.2019.100020] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/07/2019] [Accepted: 02/10/2019] [Indexed: 12/11/2022]
Abstract
Chitin and β-1,3-glucan synthases are transported separately in chitosomes and macrovesicles. Chitin synthases occupy the core of the SPK; β-1,3-glucan synthases the outer layer. CHS-4 arrival to the SPK and septa is CSE-7 dependent. Rabs YPT-1 and YPT-31 localization at the SPK mimics that of chitosomes and macrovesicles. The exocyst acts as a tether between the SPK outer layer vesicles and the apical PM.
The fungal cell wall building processes are the ultimate determinants of hyphal shape. In Neurospora crassa the main cell wall components, β-1,3-glucan and chitin, are synthesized by enzymes conveyed by specialized vesicles to the hyphal tip. These vesicles follow different secretory routes, which are delicately coordinated by cargo-specific Rab GTPases until their accumulation at the Spitzenkörper. From there, the exocyst mediates the docking of secretory vesicles to the plasma membrane, where they ultimately get fused. Although significant progress has been done on the cellular mechanisms that carry cell wall synthesizing enzymes from the endoplasmic reticulum to hyphal tips, a lot of information is still missing. Here, the current knowledge on N. crassa cell wall composition and biosynthesis is presented with an emphasis on the underlying molecular and cellular secretory processes.
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Key Words
- BGT, β-1,3-glucan transferases
- CHS, chitin synthase
- CLSM, confocal laser scanning microscopy
- CWI, cell wall integrity
- CWP, cell wall proteins
- Cell wall
- ER, endoplasmic reticulum
- FRAP, fluorescence recovery after photobleaching
- GEF, guanine nucleotide exchange factor
- GFP, green fluorescent protein
- GH, glycosyl hydrolases
- GPI, glycosylphosphatidylinositol
- GSC, β-1,3-glucan synthase complex
- MMD, myosin-like motor domain
- MS, mass spectrometry
- MT, microtubule
- NEC, network of elongated cisternae
- PM, plasma membrane
- SPK, Spitzenkörper
- Spitzenkörper
- TIRFM, total internal reflection fluorescence microscopy
- TM, transmembrane
- Tip growth
- Vesicles
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Affiliation(s)
- Jorge Verdín
- Industrial Biotechnology, CIATEJ-Jalisco State Scientific Research and Technology Assistance Center, Mexico National Council for Science and Technology, Zapopan, Jalisco, Mexico
| | - Eddy Sánchez-León
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Adriana M Rico-Ramírez
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada, CICESE Ensenada, Baja California, Mexico
| | - Leonora Martínez-Núñez
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Rosa A Fajardo-Somera
- Karlsruhe Institute of Technology (KIT) South Campus, Institute for Applied Biosciences, Department of Microbiology, Karlsruhe, Germany
| | - Meritxell Riquelme
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada, CICESE Ensenada, Baja California, Mexico
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33
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Grabon A, Bankaitis VA, McDermott MI. The interface between phosphatidylinositol transfer protein function and phosphoinositide signaling in higher eukaryotes. J Lipid Res 2018; 60:242-268. [PMID: 30504233 DOI: 10.1194/jlr.r089730] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/12/2018] [Indexed: 12/22/2022] Open
Abstract
Phosphoinositides are key regulators of a large number of diverse cellular processes that include membrane trafficking, plasma membrane receptor signaling, cell proliferation, and transcription. How a small number of chemically distinct phosphoinositide signals are functionally amplified to exert specific control over such a diverse set of biological outcomes remains incompletely understood. To this end, a novel mechanism is now taking shape, and it involves phosphatidylinositol (PtdIns) transfer proteins (PITPs). The concept that PITPs exert instructive regulation of PtdIns 4-OH kinase activities and thereby channel phosphoinositide production to specific biological outcomes, identifies PITPs as central factors in the diversification of phosphoinositide signaling. There are two evolutionarily distinct families of PITPs: the Sec14-like and the StAR-related lipid transfer domain (START)-like families. Of these two families, the START-like PITPs are the least understood. Herein, we review recent insights into the biochemical, cellular, and physiological function of both PITP families with greater emphasis on the START-like PITPs, and we discuss the underlying mechanisms through which these proteins regulate phosphoinositide signaling and how these actions translate to human health and disease.
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Affiliation(s)
- Aby Grabon
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| | - Vytas A Bankaitis
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| | - Mark I McDermott
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
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34
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Zheng H, Li L, Miao P, Wu C, Chen X, Yuan M, Fang T, Norvienyeku J, Li G, Zheng W, Wang Z, Zhou J. FgSec2A, a guanine nucleotide exchange factor of FgRab8, is important for polarized growth, pathogenicity and deoxynivalenol production in Fusarium graminearum. Environ Microbiol 2018; 20:3378-3392. [PMID: 30105886 DOI: 10.1111/1462-2920.14373] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 08/03/2018] [Accepted: 08/04/2018] [Indexed: 12/20/2022]
Abstract
Sec4/Rab8 is one of the well-studied members of the Rab GTPase family, previous studies have shown that Sec4/Rab8 crucially promotes the pathogenesis of phytopathogens, but the upstream regulators of Rab8 are still unknown. Here, we have identified two Sec2 homologues FgSec2A and FgSec2B in devastating fungal pathogen Fusarium graminearum and investigated their functions and interactions with FgRab8 by live-cell imaging, genetic and functional analyses. Yeast two-hybrid assay shows that FgSec2A specifically interacts with FgRab8DN(N123I) and itself. Importantly, FgSec2A is required for growth, conidiation, DON production and virulence of F. graminearum. Live-cell imaging shows that FgSec2A and FgSec2B are both localized to the tip region of hyphae and conidia. Both N-terminal region and Sec2 domain of FgSec2A are essential for its function, but not for localization, whereas the C-terminal region is important for its polarized localization. Furthermore, constitutively active FgRab8CA(Q69L) partially rescues the defects of ΔFgsec2A. Consistently, FgSec2A is required for the polarized localization of FgRab8. Finally, FgSec2A and FgSec2B show partial functions, but FgSec2A does not interact and co-localize with FgSec2B. Taken together, these results indicate that FgSec2A acts as a FgRab8 guanine nucleotide exchange factor and is necessary for polarized growth, DON production and pathogenicity in F. graminearum.
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Affiliation(s)
- Huawei Zheng
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Lingping Li
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Pengfei Miao
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Congxian Wu
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xiaomin Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Mingyue Yuan
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Tian Fang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Justice Norvienyeku
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Guangpu Li
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Wenhui Zheng
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Zonghua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,College of Ocean Science, Minjiang University, Fuzhou, 350108, China
| | - Jie Zhou
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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35
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Del Bel LM, Brill JA. Sac1, a lipid phosphatase at the interface of vesicular and nonvesicular transport. Traffic 2018; 19:301-318. [PMID: 29411923 DOI: 10.1111/tra.12554] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/02/2018] [Accepted: 02/02/2018] [Indexed: 12/14/2022]
Abstract
The lipid phosphatase Sac1 dephosphorylates phosphatidylinositol 4-phosphate (PI4P), thereby holding levels of this crucial membrane signaling molecule in check. Sac1 regulates multiple cellular processes, including cytoskeletal organization, membrane trafficking and cell signaling. Here, we review the structure and regulation of Sac1, its roles in cell signaling and development and its links to health and disease. Remarkably, many of the diverse roles attributed to Sac1 can be explained by the recent discovery of its requirement at membrane contact sites, where its consumption of PI4P is proposed to drive interorganelle transfer of other cellular lipids, thereby promoting normal lipid homeostasis within cells.
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Affiliation(s)
- Lauren M Del Bel
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Julie A Brill
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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36
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Chua CEL, Tang BL. Rab 10-a traffic controller in multiple cellular pathways and locations. J Cell Physiol 2018; 233:6483-6494. [PMID: 29377137 DOI: 10.1002/jcp.26503] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 01/24/2018] [Indexed: 12/29/2022]
Abstract
Rab GTPases are key regulators of eukaryotic membrane traffic, and their functions and activities are limited to particular intracellular transport steps and their membrane localization is by and large restricted. Some Rabs do participate in more than one transport steps, but broadly speaking, there is a clear demarcation between exocytic and endocytic Rabs. One Rab protein, Rab10, however, appears to be anomalous in this regard and has a diverse array of functions and subcellular localizations. Rab10 has been implicated in a myriad of activities ranging from polarized exocytosis and endosomal sorting in polarized cells, insulin-dependent Glut4 transport in adipocytes, axonal growth in neurons, and endo-phagocytic processes in macrophages. It's reported subcellular localizations include the endoplasmic reticulum (ER), Golgi/TGN, the endosomes/phagosomes and the primary cilia. In this review, we summarize and discuss the multitude of known roles of Rab10 in cellular membrane transport and the molecular players and mechanisms associated with these roles.
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Affiliation(s)
- Christelle En Lin Chua
- Singapore Nuclear Research and Safety Initiative, National University of Singapore, Singapore
| | - Bor L Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore
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37
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Suda Y, Tachikawa H, Inoue I, Kurita T, Saito C, Kurokawa K, Nakano A, Irie K. Activation of Rab GTPase Sec4 by its GEF Sec2 is required for prospore membrane formation during sporulation in yeast Saccharomyces cerevisiae. FEMS Yeast Res 2017; 18:4780275. [DOI: 10.1093/femsyr/fox095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 12/24/2017] [Indexed: 12/20/2022] Open
Affiliation(s)
- Yasuyuki Suda
- Faculty of medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
| | - Hiroyuki Tachikawa
- Laboratory of Biochemistry, Graduate School of Agriculture and Life Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Ichiro Inoue
- Laboratory of Biochemistry, Graduate School of Agriculture and Life Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Tomokazu Kurita
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
| | - Chieko Saito
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
| | - Kazuo Kurokawa
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kenji Irie
- Faculty of medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
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Abstract
Polarized exocytosis is generally considered as the multistep vesicular trafficking process in which membrane-bounded carriers are transported from the Golgi or endosomal compartments to specific sites of the plasma membrane. Polarized exocytosis in cells is achieved through the coordinated actions of membrane trafficking machinery and cytoskeleton orchestrated by signaling molecules such as the Rho family of small GTPases. Elucidating the molecular mechanisms of polarized exocytosis is essential to our understanding of a wide range of pathophysiological processes from neuronal development to tumor invasion.
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Affiliation(s)
- Jingwen Zeng
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018
| | - Shanshan Feng
- Key Laboratory for Regenerative Medicine of Ministry of Education and Department of Developmental & Regenerative Biology, Jinan University, Guangzhou 510632, P.R. China
| | - Bin Wu
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018
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Abstract
Fission yeast Ypt2, an orthologue of the mammalian small GTPase Rab8, is responsible for post-Golgi membrane trafficking. During meiosis, Ypt2 localizes at the spindle pole body (SPB), where it regulates de novo biogenesis of the spore plasma membrane. Recruitment of Ypt2 to the SPB is dependent on its meiosis-specific GDP/GTP exchange factor (GEF), the SPB-resident protein Spo13. Here we have examined the SPB recruitment of Ypt2 by Spo13. The GEF activity of Spo13 was required, but not essential for recruitment. Furthermore, Ypt2 recruitment was regulated in a meiosis-specific manner and partially regulated by the nuclear Dbf2-related (NDR) kinase Sid2, indicating the existence of a novel regulatory mechanism for localization of Rab GTPases during meiosis.
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Affiliation(s)
- Kazuki Imada
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka, Japan.,Department of Chemistry and Biochemistry, National Institute of Technology, Suzuka College, Suzuka, Mie, Japan
| | - Taro Nakamura
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka, Japan
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40
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Langemeyer L, Perz A, Kümmel D, Ungermann C. A guanine nucleotide exchange factor (GEF) limits Rab GTPase-driven membrane fusion. J Biol Chem 2017; 293:731-739. [PMID: 29184002 DOI: 10.1074/jbc.m117.812941] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 11/14/2017] [Indexed: 11/06/2022] Open
Abstract
The identity of organelles in the endomembrane system of any eukaryotic cell critically depends on the correctly localized Rab GTPase, which binds effectors and thus promotes membrane remodeling or fusion. However, it is still unresolved which factors are required and therefore define the localization of the correct fusion machinery. Using SNARE-decorated proteoliposomes that cannot fuse on their own, we now demonstrate that full fusion activity can be achieved by just four soluble factors: a soluble SNARE (Vam7), a guanine nucleotide exchange factor (GEF, Mon1-Ccz1), a Rab-GDP dissociation inhibitor (GDI) complex (prenylated Ypt7-GDI), and a Rab effector complex (HOPS). Our findings reveal that the GEF Mon1-Ccz1 is necessary and sufficient for stabilizing prenylated Ypt7 on membranes. HOPS binding to Ypt7-GTP then drives SNARE-mediated fusion, which is fully GTP-dependent. We conclude that an entire fusion cascade can be controlled by a GEF.
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Affiliation(s)
| | | | - Daniel Kümmel
- Structural Biochemistry, Department of Biology/Chemistry, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
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41
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Song L, Chen Y, Du Y, Wang X, Guo X, Dong J, Xiao D. Saccharomyces cerevisiae proteinase A excretion and wine making. World J Microbiol Biotechnol 2017; 33:210. [DOI: 10.1007/s11274-017-2361-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/26/2017] [Indexed: 01/20/2023]
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42
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Smindak RJ, Heckle LA, Chittari SS, Hand MA, Hyatt DM, Mantus GE, Sanfelippo WA, Kozminski KG. Lipid-dependent regulation of exocytosis in S. cerevisiae by OSBP homolog (Osh) 4. J Cell Sci 2017; 130:3891-3906. [PMID: 28993464 DOI: 10.1242/jcs.205435] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 10/04/2017] [Indexed: 11/20/2022] Open
Abstract
Polarized exocytosis is an essential process in many organisms and cell types for correct cell division or functional specialization. Previous studies established that homologs of the oxysterol-binding protein (OSBP) in S. cerevisiae, which comprise the Osh protein family, are necessary for efficient polarized exocytosis by supporting a late post-Golgi step. We define this step as the docking of a specific sub-population of exocytic vesicles with the plasma membrane. In the absence of other Osh proteins, yeast Osh4p can support this process in a manner dependent upon two lipid ligands, PI4P and sterol. Osh6p, which binds PI4P and phosphatidylserine, is also sufficient to support polarized exocytosis, again in a lipid-dependent manner. These data suggest that Osh-mediated exocytosis depends upon lipid binding and exchange without a strict requirement for sterol. We propose a two-step mechanism for Osh protein-mediated regulation of polarized exocytosis by using Osh4p as a model. We describe a specific in vivo role for lipid binding by an OSBP-related protein (ORP) in the process of polarized exocytosis, guiding our understanding of where and how OSBP and ORPs may function in more complex organisms.
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Affiliation(s)
- Richard J Smindak
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Lindsay A Heckle
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Supraja S Chittari
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Marissa A Hand
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Dylan M Hyatt
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Grace E Mantus
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | | | - Keith G Kozminski
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA .,Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
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43
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Mayers JR, Hu T, Wang C, Cárdenas JJ, Tan Y, Pan J, Bednarek SY. SCD1 and SCD2 Form a Complex That Functions with the Exocyst and RabE1 in Exocytosis and Cytokinesis. THE PLANT CELL 2017; 29:2610-2625. [PMID: 28970336 PMCID: PMC5774579 DOI: 10.1105/tpc.17.00409] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 09/12/2017] [Accepted: 09/26/2017] [Indexed: 05/21/2023]
Abstract
Although exocytosis is critical for the proper trafficking of materials to the plasma membrane, relatively little is known about the mechanistic details of post-Golgi trafficking in plants. Here, we demonstrate that the DENN (Differentially Expressed in Normal and Neoplastic cells) domain protein STOMATAL CYTOKINESIS DEFECTIVE1 (SCD1) and SCD2 form a previously unknown protein complex, the SCD complex, that functionally interacts with subunits of the exocyst complex and the RabE1 family of GTPases in Arabidopsis thaliana Consistent with a role in post-Golgi trafficking, scd1 and scd2 mutants display defects in exocytosis and recycling of PIN2-GFP. Perturbation of exocytosis using the small molecule Endosidin2 results in growth inhibition and PIN2-GFP trafficking defects in scd1 and scd2 mutants. In addition to the exocyst, the SCD complex binds in a nucleotide state-specific manner with Sec4p/Rab8-related RabE1 GTPases and overexpression of wild-type RabE1 rescues scd1 temperature-sensitive mutants. Furthermore, SCD1 colocalizes with the exocyst subunit, SEC15B, and RabE1 at the cell plate and in distinct punctae at or near the plasma membrane. Our findings reveal a mechanism for plant exocytosis, through the identification and characterization of a protein interaction network that includes the SCD complex, RabE1, and the exocyst.
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Affiliation(s)
| | - Tianwei Hu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Chao Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jessica J Cárdenas
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Yuqi Tan
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Jianwei Pan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Sebastian Y Bednarek
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
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44
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Pfeffer SR. Rab GTPases: master regulators that establish the secretory and endocytic pathways. Mol Biol Cell 2017; 28:712-715. [PMID: 28292916 PMCID: PMC5349778 DOI: 10.1091/mbc.e16-10-0737] [Citation(s) in RCA: 200] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 01/11/2017] [Accepted: 01/12/2017] [Indexed: 11/22/2022] Open
Abstract
Several of the most important discoveries in the field of membrane traffic have come from studies of Rab GTPases by Marino Zerial and Peter Novick and their colleagues. Zerial was the first to discover that Rab GTPases represent identity markers for different membrane-bound compartments, and each Rab organizes a collection of specific effectors into function-specifying membrane microdomains to carry out receptor trafficking. Novick discovered that the order (and thus polarity) of Rab GTPases along the secretory and endocytic pathways are established by their specific, cognate guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs), which partner with one Rab to regulate the subsequent- and prior-acting Rabs. Such so-called Rab cascades have evolved to establish domains that contain unique Rab proteins and their cognate effectors, which drive all steps of membrane trafficking. These findings deserve much broader recognition by the biomedical research community and are highlighted here, along with open questions that require serious attention for full understanding of the molecular basis of Rab GTPase-regulated membrane trafficking in eukaryotic cells.
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Affiliation(s)
- Suzanne R Pfeffer
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307
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45
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Abstract
Rab proteins are the major regulators of vesicular trafficking in eukaryotic cells. Their activity can be tightly controlled within cells: Regulated by guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs), they switch between an active GTP-bound state and an inactive GDP-bound state, interacting with downstream effector proteins only in the active state. Additionally, they can bind to membranes via C-terminal prenylated cysteine residues and they can be solubilized and shuttled between membranes by chaperone-like molecules called GDP dissociation inhibitors (GDIs). In this review we give an overview of Rab proteins with a focus on the current understanding of their regulation by GEFs, GAPs and GDI.
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Affiliation(s)
- Matthias P Müller
- a Department of Structural Biochemistry , Max Planck Institute of Molecular Physiology , Dortmund , Germany
| | - Roger S Goody
- a Department of Structural Biochemistry , Max Planck Institute of Molecular Physiology , Dortmund , Germany
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46
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Climer LK, Hendrix RD, Lupashin VV. Conserved Oligomeric Golgi and Neuronal Vesicular Trafficking. Handb Exp Pharmacol 2017; 245:227-247. [PMID: 29063274 DOI: 10.1007/164_2017_65] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The conserved oligomeric Golgi (COG) complex is an evolutionary conserved multi-subunit vesicle tethering complex essential for the majority of Golgi apparatus functions: protein and lipid glycosylation and protein sorting. COG is present in neuronal cells, but the repertoire of COG function in different Golgi-like compartments is an enigma. Defects in COG subunits cause alteration of Golgi morphology, protein trafficking, and glycosylation resulting in human congenital disorders of glycosylation (CDG) type II. In this review we summarize and critically analyze recent advances in the function of Golgi and Golgi-like compartments in neuronal cells and functions and dysfunctions of the COG complex and its partner proteins.
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Affiliation(s)
- Leslie K Climer
- College of Medicine, Physiology and Biophysics, UAMS, Little Rock, AR, USA
| | - Rachel D Hendrix
- College of Medicine, Neurobiology and Developmental Sciences, UAMS, Little Rock, AR, USA
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47
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Tang H, Song M, He Y, Wang J, Wang S, Shen Y, Hou J, Bao X. Engineering vesicle trafficking improves the extracellular activity and surface display efficiency of cellulases in Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:53. [PMID: 28261326 PMCID: PMC5327580 DOI: 10.1186/s13068-017-0738-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 02/17/2017] [Indexed: 05/12/2023]
Abstract
BACKGROUND Cellulase expression via extracellular secretion or surface display in Saccharomyces cerevisiae is one of the most frequently used strategies for a consolidated bioprocess (CBP) of cellulosic ethanol production. However, the inefficiency of the yeast secretory pathway often results in low production of heterologous proteins, which largely limits cellulase secretion or display. RESULTS In this study, the components of the vesicle trafficking from the endoplasmic reticulum (ER) to the Golgi and from the Golgi to the plasma membrane, involved in vesicle budding, tethering and fusion, were over-expressed in Clostridium thermocellum endoglucanase (CelA)- and Sacchromycopsis fibuligera β-glucosidase (BGL1)-secreting or -displaying strains. Engineering the targeted components in the ER to Golgi vesicle trafficking, including Sec12p, Sec13p, Erv25p and Bos1p, enhanced the extracellular activity of CelA. However, only Sec13p over-expression increased BGL1 secretion. By contrast, over-expression of the components in the Golgi to plasma membrane vesicle trafficking, including Sso1p, Snc2p, Sec1p, Exo70p, Ypt32p and Sec4p, showed better performance in increasing BGL1 secretion compared to CelA secretion, and the over-expression of these components all increased BGL1 extracellular activity. These results revealed that various cellulases showed different limitations in protein transport, and engineering vesicle trafficking has protein-specific effects. Importantly, we found that engineering the above vesicle trafficking components, particularly from the ER to the Golgi, also improved the display efficiency of CelA and BGL1 when a-agglutinin was used as surface display system. Further analyses illustrated that the display efficiency of a-agglutinin was increased by engineering vesicle trafficking, and the trend was consistent with displayed CelA and BGL1. These results indicated that fusion with a-agglutinin may affect the proteins' properties and alter the rate-limiting step in the vesicle trafficking. CONCLUSIONS We have demonstrated, for the first time, engineering vesicle trafficking from the ER to the Golgi and from the Golgi to the plasma membrane can enhance the protein display efficiency. We also found that different heterologous proteins had specific limitations in vesicle trafficking pathway and that engineering the vesicle trafficking resulted in a protein-specific effect. These results provide a new strategy to improve the extracellular secretion and surface display of cellulases in S. cerevisiae.
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Affiliation(s)
- Hongting Tang
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Meihui Song
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Yao He
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Jiajing Wang
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Shenghuan Wang
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Yu Shen
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Jin Hou
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Xiaoming Bao
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
- Shandong Provincial Key Laboratory of Microbial Engineering, Qi Lu University of Technology, Jinan, 250353 China
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48
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Imada K, Nakamura T. The exocytic Rabs Ypt3 and Ypt2 regulate the early step of biogenesis of the spore plasma membrane in fission yeast. Mol Biol Cell 2016; 27:3317-3328. [PMID: 27630265 PMCID: PMC5170864 DOI: 10.1091/mbc.e16-03-0162] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 09/07/2016] [Indexed: 11/24/2022] Open
Abstract
Two Rabs, Ypt3 and Ypt2, regulating the trafficking of Golgi-derived secretory vesicles have key roles in biogenesis of the spore plasma membrane in fission yeast. During sporulation, the Rabs and secretory vesicles relocalize at the meiotic spindle pole body, where spore plasma membrane formation subsequently initiates. During fission yeast sporulation, a membrane compartment called the forespore membrane (FSM) is newly formed on the spindle pole body (SPB). The FSM expands by membrane vesicle fusion, encapsulates the daughter nucleus resulting from meiosis, and eventually matures into the plasma membrane of the spore. Although many of the genes involved in FSM formation have been identified, its molecular mechanism is not fully understood. Here a genetic screen for sporulation-deficient mutations identified Ypt3, a Rab-family small GTPase known to function in the exocytic pathway. The ypt3-ki8 mutant showed defects in both the initiation of FSM biogenesis and FSM expansion. We also show that a mutation in Ypt2, another Rab protein that may function in the same pathway as Ypt3, compromises the initiation of FSM formation. As meiosis proceeds, both GFP-Ypt3 and GFP-Ypt2 are observed at the SPB and then relocalize to the FSM. Their localizations at the SPB precede FSM formation and depend on the meiotic SPB component Spo13, a putative GDP/GTP exchange factor for Ypt2. Given that Spo13 is essential for initiating FSM formation, these results suggest that two exocytic Rabs, Ypt3 and Ypt2, regulate the initiation of FSM formation on the SPB in concert with Spo13.
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Affiliation(s)
- Kazuki Imada
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Taro Nakamura
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
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49
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Yamaguchi H, Arakawa S, Kanaseki T, Miyatsuka T, Fujitani Y, Watada H, Tsujimoto Y, Shimizu S. Golgi membrane-associated degradation pathway in yeast and mammals. EMBO J 2016; 35:1991-2007. [PMID: 27511903 DOI: 10.15252/embj.201593191] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 07/14/2016] [Indexed: 01/08/2023] Open
Abstract
Autophagy is a cellular process that degrades subcellular constituents, and is conserved from yeast to mammals. Although autophagy is believed to be essential for living cells, cells lacking Atg5 or Atg7 are healthy, suggesting that a non-canonical degradation pathway exists to compensate for the lack of autophagy. In this study, we show that the budding yeast Saccharomyces cerevisiae, which lacks Atg5, undergoes bulk protein degradation using Golgi-mediated structures to compensate for autophagy when treated with amphotericin B1, a polyene antifungal drug. We named this mechanism Golgi membrane-associated degradation (GOMED) pathway. This process is driven by the disruption of PI(4)P-dependent anterograde trafficking from the Golgi, and it also exists in Atg5-deficient mammalian cells. Biologically, when an Atg5-deficient β-cell line and Atg7-deficient β-cells were cultured in glucose-deprived medium, a disruption in the secretion of insulin granules from the Golgi occurred, and GOMED was induced to digest these (pro)insulin granules. In conclusion, GOMED is activated by the disruption of PI(4)P-dependent anterograde trafficking in autophagy-deficient yeast and mammalian cells.
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Affiliation(s)
- Hirofumi Yamaguchi
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Satoko Arakawa
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Toku Kanaseki
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Takeshi Miyatsuka
- Department of Medicine, Metabolism & Endocrinology, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Yoshio Fujitani
- Department of Medicine, Metabolism & Endocrinology, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Hirotaka Watada
- Department of Medicine, Metabolism & Endocrinology, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Yoshihide Tsujimoto
- Department of Molecular and Cellular Biology, Research Institute, Osaka Medical Center for Cancer and Cardiovascular Diseases, Higashinari, Osaka, Japan
| | - Shigeomi Shimizu
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
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50
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Abstract
ASBTRACT Rab GTPases serve as master regulators of membrane traffic, each typically controlling several different aspects of a specific stage of membrane traffic by recruiting diverse effector proteins such as cytoskeletal motors, vesicle tethering proteins and regulators of SNARE complex assembly. Rabs, in turn, are regulated by specific guanine nucleotide exchange factors (GEFs), which catalyze the displacement of GDP and binding of GTP, as well as GTPase activating proteins (GAPs) that stimulate the slow intrinsic rate of GTP hydrolysis. Here I review our studies on the final stages of the yeast secretory pathway that have led us to propose that adjacent Rabs on a pathway are networked to one another through their regulators; specifically we have shown that the Rab, Ypt32, in its GTP-bound form recruits both Sec2, the GEF that activates the downstream Rab, Sec4, as well as Gyp1, the GAP that inactivates the upstream Rab, Ypt1. The postulated effect of these counter-current cascades is a programmed series of abrupt Rab transitions that lead to critical changes in the functional identity of the membrane as it flows along the exocytic pathway. Phosphoinositides also play key roles in the temporal and spatial regulation of membrane traffic. The Golgi pool of phosphatidylinositol 4-phosphate (PI(4)P) works in concert with Ypt32 to initially recruit Sec2, yet a subsequent drop in PI(4)P levels directs a regulatory switch in Sec2 function in which it binds to the Sec4 effector Sec15 generating a positive feedback loop. PI(4)P distribution together with Sec2 phosphorylation by a casein kinase determines when and where each regulatory circuit is used.
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Affiliation(s)
- Peter Novick
- a Department of Cellular and Molecular Medicine , University of California San Diego , La Jolla , CA , USA
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