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Fairlie GMJ, Nguyen KM, Nam SE, Shaw AL, Parson MAH, Shariati HR, Wang X, Jenkins ML, Gong M, Burke JE, Yip CK. Biochemical and structural characterization of Rab3GAP reveals insights into Rab18 nucleotide exchange activity. Nat Commun 2025; 16:479. [PMID: 39779760 PMCID: PMC11711316 DOI: 10.1038/s41467-025-55828-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Accepted: 12/23/2024] [Indexed: 01/30/2025] Open
Abstract
The heterodimeric Rab3GAP complex is a guanine nucleotide exchange factor (GEF) for the Rab18 GTPase that regulates lipid droplet metabolism, ER-to-Golgi trafficking, secretion, and autophagy. Why both subunits of Rab3GAP are required for Rab18 GEF activity and the molecular basis of how Rab3GAP engages and activates its cognate substrate are unknown. Here we show that human Rab3GAP is conformationally flexible and potentially autoinhibited by the C-terminal domain of its Rab3GAP2 subunit. Our high-resolution structure of the catalytic core of Rab3GAP, determined by cryo-EM, shows that the Rab3GAP2 N-terminal domain binds Rab3GAP1 via an extensive interface. AlphaFold3 modelling analysis together with targeted mutagenesis and in vitro activity assay reveal that Rab3GAP likely engages its substrate Rab18 through an interface away from the switch and interswitch regions. Lastly, we find that three Warburg Micro Syndrome-associated missense mutations do not affect the overall architecture of Rab3GAP but instead likely interfere with substrate binding.
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Affiliation(s)
- Gage M J Fairlie
- Life Sciences Institute, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Kha M Nguyen
- Life Sciences Institute, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Sung-Eun Nam
- Life Sciences Institute, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Alexandria L Shaw
- Life Sciences Institute, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Matthew A H Parson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Hannah R Shariati
- Life Sciences Institute, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Xinyin Wang
- Life Sciences Institute, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Michael Gong
- Life Sciences Institute, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - John E Burke
- Life Sciences Institute, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Calvin K Yip
- Life Sciences Institute, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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Almousa H, Lewis SA, Bakhtiari S, Nordlie SH, Pagnozzi A, Magee H, Efthymiou S, Heim JA, Cornejo P, Zaki MS, Anwar N, Maqbool S, Rahman F, Neilson DE, Vemuri A, Jin SC, Yang XR, Heidari A, van Gassen K, Trimouille A, Thauvin-Robinet C, Liu J, Bruel AL, Tomoum H, Shata MO, Hashem MO, Toosi MB, Karimiani EG, Yeşil G, Lingappa L, Baruah D, Ebrahimzadeh F, Van-Gils J, Faivre L, Zamani M, Galehdari H, Sadeghian S, Shariati G, Mohammad R, van der Smagt J, Qari A, Vincent JB, Innes AM, Dursun A, Özgül RK, Akar HT, Bilguvar K, Mignot C, Keren B, Raveli C, Burglen L, Afenjar A, Kaat LD, van Slegtenhorst M, Alkuraya F, Houlden H, Padilla-Lopez S, Maroofian R, Sacher M, Kruer MC. TRAPPC6B biallelic variants cause a neurodevelopmental disorder with TRAPP II and trafficking disruptions. Brain 2024; 147:311-324. [PMID: 37713627 PMCID: PMC10766242 DOI: 10.1093/brain/awad301] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/11/2023] [Accepted: 08/10/2023] [Indexed: 09/17/2023] Open
Abstract
Highly conserved transport protein particle (TRAPP) complexes regulate subcellular trafficking pathways. Accurate protein trafficking has been increasingly recognized to be critically important for normal development, particularly in the nervous system. Variants in most TRAPP complex subunits have been found to lead to neurodevelopmental disorders with diverse but overlapping phenotypes. We expand on limited prior reports on TRAPPC6B with detailed clinical and neuroradiologic assessments, and studies on mechanisms of disease, and new types of variants. We describe 29 additional patients from 18 independent families with biallelic variants in TRAPPC6B. We identified seven homozygous nonsense (n = 12 patients) and eight canonical splice-site variants (n = 17 patients). In addition, we identified one patient with compound heterozygous splice-site/missense variants with a milder phenotype and one patient with homozygous missense variants. Patients displayed non-progressive microcephaly, global developmental delay/intellectual disability, epilepsy and absent expressive language. Movement disorders including stereotypies, spasticity and dystonia were also observed. Brain imaging revealed reductions in cortex, cerebellum and corpus callosum size with frequent white matter hyperintensity. Volumetric measurements indicated globally diminished volume rather than specific regional losses. We identified a reduced rate of trafficking into the Golgi apparatus and Golgi fragmentation in patient-derived fibroblasts that was rescued by wild-type TRAPPC6B. Molecular studies revealed a weakened interaction between mutant TRAPPC6B (c.454C>T, p.Q152*) and its TRAPP binding partner TRAPPC3. Patient-derived fibroblasts from the TRAPPC6B (c.454C>T, p.Q152*) variant displayed reduced levels of TRAPPC6B as well as other TRAPP II complex-specific members (TRAPPC9 and TRAPPC10). Interestingly, the levels of the TRAPPC6B homologue TRAPPC6A were found to be elevated. Moreover, co-immunoprecipitation experiments showed that TRAPPC6A co-precipitates equally with TRAPP II and TRAPP III, while TRAPPC6B co-precipitates significantly more with TRAPP II, suggesting enrichment of the protein in the TRAPP II complex. This implies that variants in TRAPPC6B may preferentially affect TRAPP II functions compared to TRAPP III functions. Finally, we assessed phenotypes in a Drosophila TRAPPC6B-deficiency model. Neuronal TRAPPC6B knockdown impaired locomotion and led to wing posture defects, supporting a role for TRAPPC6B in neuromotor function. Our findings confirm the association of damaging biallelic TRAPPC6B variants with microcephaly, intellectual disability, language impairments, and epilepsy. A subset of patients also exhibited dystonia and/or spasticity with impaired ambulation. These features overlap with disorders arising from pathogenic variants in other TRAPP subunits, particularly components of the TRAPP II complex. These findings suggest that TRAPPC6B is essential for brain development and function, and TRAPP II complex activity may be particularly relevant for mediating this function.
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Affiliation(s)
- Hashem Almousa
- Department of Biology, Concordia University, Montreal, Quebec H4B1R6, Canada
| | - Sara A Lewis
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
| | - Somayeh Bakhtiari
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
| | - Sandra Hinz Nordlie
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
| | - Alex Pagnozzi
- CSIRO Health and Biosecurity, The Australian e-Health Research Centre, Brisbane 4029, Australia
| | - Helen Magee
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
| | - Stephanie Efthymiou
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Jennifer A Heim
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
| | - Patricia Cornejo
- Pediatric Neuroradiology Division, Pediatric Radiology, Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Department of Child Health, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
- Department of Radiology, Mayo Clinic, Scottsdale, AZ 85259, USA
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo 12622, Egypt
- Genetics Department, Armed Forces College of Medicine (AFCM), Cairo 4460015, Egypt
| | - Najwa Anwar
- Department of Developmental-Behavioural Paediatrics, The Children's Hospital and Institute of Child Health, Lahore 54000, Pakistan
| | - Shazia Maqbool
- Department of Developmental-Behavioural Paediatrics, The Children's Hospital and Institute of Child Health, Lahore 54000, Pakistan
| | - Fatima Rahman
- Department of Developmental-Behavioural Paediatrics, The Children's Hospital and Institute of Child Health, Lahore 54000, Pakistan
| | - Derek E Neilson
- Genetics and Metabolism, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
| | - Anusha Vemuri
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Sheng Chih Jin
- Department of Genetics, Washington University, St.Louis, MO 63110, USA
| | - Xiao-Ru Yang
- Department of Medical Genetics and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, S.W. Calgary, AB T2N 4N1, Canada
| | - Abolfazl Heidari
- Reference Laboratory, Qazvin Medical University, Qazvin 34148-33245, Iran
| | - Koen van Gassen
- Division of Laboratories, Pharmacy and Biomedical Genetics, Section of Clinical Genetics, University Medical Center Utrecht (UMCU), 3584 CX Utrecht, Netherlands
| | - Aurélien Trimouille
- Laboratoire de Génétique Moléculaire, Service de Génétique Médicale, CHU Bordeaux—Hôpital Pellegrin, Place Amélie Raba Léon, 33000 Bordeaux, France
| | - Christel Thauvin-Robinet
- Department of Genetics and Reference Center for Development Disorders and Intellectual Disabilities, FHU TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
- Unité Fontctionnelle d’Innovation diagnostiques des maladies rares, FHU TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
- GAD ‘Génétique des Anomalies du Développement’, INSERM-Université de Bourgogne UMR1231, 21078 Dijon, France
| | - James Liu
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
| | - Ange-Line Bruel
- Unité Fontctionnelle d’Innovation diagnostiques des maladies rares, FHU TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
- GAD ‘Génétique des Anomalies du Développement’, INSERM-Université de Bourgogne UMR1231, 21078 Dijon, France
| | - Hoda Tomoum
- Department of Pediatrics, Ain Shams University, Cairo 11516, Egypt
| | | | - Mais O Hashem
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Mehran Beiraghi Toosi
- Pediatric Neurology Department, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad 13944-91388, Iran
- Neuroscience Research Center, Mashhad University of Medical Science, Mashhad 13944-91388, Iran
| | - Ehsan Ghayoor Karimiani
- Molecular and Clinical Sciences Institute, St.George’s, University of London, London SW17 0RE, UK
| | - Gözde Yeşil
- Istanbul Medical Faculty Department of Medical Genetics, Istanbul University, Istanbul 34452, Turkey
| | - Lokesh Lingappa
- Pediatric Neurology, Rainbow Children Hospital, Hyderabad 500034, India
| | - Debangana Baruah
- Pediatric Neurology, Rainbow Children Hospital, Hyderabad 500034, India
| | - Farnoosh Ebrahimzadeh
- Department of Internal Medicine, Mashhad University of Medical Sciences, Mashhad 13944-91388, Iran
| | - Julien Van-Gils
- Division of Laboratories, Pharmacy and Biomedical Genetics, Section of Clinical Genetics, University Medical Center Utrecht (UMCU), 3584 CX Utrecht, Netherlands
| | - Laurence Faivre
- Department of Genetics and Reference Center for Development Disorders and Intellectual Disabilities, FHU TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
| | - Mina Zamani
- Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz 6135783151, Iran
- Narges Medical Genetics and Prenatal Diagnosis Laboratory, Ahvaz 6155889467, Iran
| | - Hamid Galehdari
- Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz 6135783151, Iran
| | - Saeid Sadeghian
- Department of Pediatric Neurology, Golestan Medical, Educational, and Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz 6135733118, Iran
| | - Gholamreza Shariati
- Narges Medical Genetics and Prenatal Diagnosis Laboratory, Ahvaz 6155889467, Iran
- Department of Medical Genetics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz 6135733118, Iran
| | - Rahema Mohammad
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Jasper van der Smagt
- Division of Laboratories, Pharmacy and Biomedical Genetics, Section of Clinical Genetics, University Medical Center Utrecht (UMCU), 3584 CX Utrecht, Netherlands
| | - Alya Qari
- Medical Genomics Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh 11564, Saudi Arabia
| | - John B Vincent
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON M6J 1H4, Canada
| | - A Micheil Innes
- Department of Medical Genetics and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, S.W. Calgary, AB T2N 4N1, Canada
| | - Ali Dursun
- Department of Pediatric Metabolism, Hacettepe University, Faculty of Medicine & Institute of Child Health, Ankara 06800, Turkey
| | - R Köksal Özgül
- Department of Pediatric Metabolism, Hacettepe University, Faculty of Medicine & Institute of Child Health, Ankara 06800, Turkey
| | - Halil Tuna Akar
- Department of Pediatric Metabolism, Hacettepe University, Faculty of Medicine & Institute of Child Health, Ankara 06800, Turkey
| | - Kaya Bilguvar
- Department of Medical Genetics, Acibadem Mehmet Ali Aydinlar University, Istanbul 34752, Turkey
- Department of Neurosurgery and Genetics, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Cyril Mignot
- Département de Génétique, APHP Sorbonne Université, Hôpital Trousseau & Groupe Hospitalier Pitié-Salpêtrière, 75013 Paris, France
- Centre de Référence Déficiences Intellectuelles de Causes Rares, 75012 Paris, France
| | - Boris Keren
- Département de Génétique, APHP Sorbonne Université, Hôpital Trousseau & Groupe Hospitalier Pitié-Salpêtrière, 75013 Paris, France
| | - Claudia Raveli
- APHP Sorbonne Université, Service de Neuropédiatrie, Hôpital Trousseau, 75012 Paris, France
| | - Lydie Burglen
- Département de Génétique, Centre de référence des malformations et maladies congénitales du cervelet, APHP. Sorbonne Université, Hôpital Trousseau, 75012 Paris, France
| | - Alexandra Afenjar
- Département de Génétique, Centre de référence des malformations et maladies congénitales du cervelet, APHP. Sorbonne Université, Hôpital Trousseau, 75012 Paris, France
| | - Laura Donker Kaat
- Department of Clinical Genetics, Erasmus Medical Center, 3000 Rotterdam, The Netherlands
| | | | - Fowzan Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Henry Houlden
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Sergio Padilla-Lopez
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
| | - Reza Maroofian
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Michael Sacher
- Department of Biology, Concordia University, Montreal, Quebec H4B1R6, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A0C7, Canada
| | - Michael C Kruer
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
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5
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Guan L, Wen X, Zhang Z, Wang L, Zhang X, Yang M, Wang S, Qin Q. Grouper Rab1 inhibits nodovirus infection by affecting virus entry and host immune response. FISH & SHELLFISH IMMUNOLOGY 2023; 143:109136. [PMID: 37839541 DOI: 10.1016/j.fsi.2023.109136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/29/2023] [Accepted: 10/02/2023] [Indexed: 10/17/2023]
Abstract
Rab1, a GTPase, is present in all eukaryotes, and is mainly involved in vesicle trafficking between the endoplasmic reticulum and Golgi, thereby regulating many cellular activities and pathogenic infections. However, little is known of how Rab1 functions in fish during virus infection. Groupers (Epinephelus spp.) are high in economic value and widely cultivated in China and Southeast Asia, although they often suffer from diseases. Red-spotted grouper nervous necrosis virus (RGNNV), a highly pathogenic RNA virus, is a major pathogen in cultured groupers, and causes huge economic losses. A series of host cellular proteins involved in RGNNV infection was identified. However, the impact of Rab1 on RGNNV infection has not yet been reported. In this study, a novel Rab1 homolog (EcRab1) from Epinephelus coioides was cloned, and its roles during virus infection and host immune responses were investigated. EcRab1 encoded a 202 amino acid polypeptide, showing 98% and 78% identity to Epinephelus lanceolatus and Homo sapiens, respectively. After challenge with RGNNV or poly(I:C), the transcription of EcRab1 was altered both in vitro and in vivo, implying that EcRab1 was involved in virus infection. Subcellular localization showed that EcRab1 was displayed as punctate structures in the cytoplasm, which was affected by EcRab1 mutants. The dominant negative (DN) EcRab1, enabling EcRab1 to remain in the GDP-binding state, caused EcRab1 to be diffusely distributed in the cytoplasm. Constitutively active (CA) EcRab1, enabling EcRab1 to remain in the GTP-binding state, induced larger cluster structures of EcRab1. During the late stage of RGNNV infection, some EcRab1 co-localized with RGNNV, and the size of EcRab1 clusters was enlarged. Importantly, overexpression of EcRab1 significantly inhibited RGNNV infection, and knockdown of EcRab1 promoted RGNNV infection. Furthermore, EcRab1 inhibited the entry of RGNNV to host cells. Compared with EcRab1, overexpression of DN EcRab1 or CA EcRab1 also promoted RGNNV infection, suggesting that EcRab1 regulated RGNNV infection, depending on the cycles of GTP- and GDP-binding states. In addition, EcRab1 positively regulated interferon (IFN) immune and inflammatory responses. Taken together, these results suggest that EcRab1 affects RGNNV infection, possibly by regulating host immunity. Our study furthers the understanding of Rab1 function during virus infection, thus helping to design new antiviral strategies.
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Affiliation(s)
- Lingfeng Guan
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Xiaozhi Wen
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Zihan Zhang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Liqun Wang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Xinyue Zhang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Min Yang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Shaowen Wang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, 511464, China.
| | - Qiwei Qin
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, 511464, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 519000, China.
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8
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Thibodeau MC, Harris NJ, Jenkins ML, Parson MAH, Evans JT, Scott MK, Shaw AL, Pokorný D, Leonard TA, Burke JE. Molecular basis for the recruitment of the Rab effector protein WDR44 by the GTPase Rab11. J Biol Chem 2023; 299:102764. [PMID: 36463963 PMCID: PMC9808001 DOI: 10.1016/j.jbc.2022.102764] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/22/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022] Open
Abstract
The formation of complexes between Rab11 and its effectors regulates multiple aspects of membrane trafficking, including recycling and ciliogenesis. WD repeat-containing protein 44 (WDR44) is a structurally uncharacterized Rab11 effector that regulates ciliogenesis by competing with prociliogenesis factors for Rab11 binding. Here, we present a detailed biochemical and biophysical characterization of the WDR44-Rab11 complex and define specific residues mediating binding. Using AlphaFold2 modeling and hydrogen/deuterium exchange mass spectrometry, we generated a molecular model of the Rab11-WDR44 complex. The Rab11-binding domain of WDR44 interacts with switch I, switch II, and the interswitch region of Rab11. Extensive mutagenesis of evolutionarily conserved residues in WDR44 at the interface identified numerous complex-disrupting mutations. Using hydrogen/deuterium exchange mass spectrometry, we found that the dynamics of the WDR44-Rab11 interface are distinct from the Rab11 effector FIP3, with WDR44 forming a more extensive interface with the switch II helix of Rab11 compared with FIP3. The WDR44 interaction was specific to Rab11 over evolutionarily similar Rabs, with mutations defining the molecular basis of Rab11 specificity. Finally, WDR44 can be phosphorylated by Sgk3, with this leading to reorganization of the Rab11-binding surface on WDR44. Overall, our results provide molecular detail on how WDR44 interacts with Rab11 and how Rab11 can form distinct effector complexes that regulate membrane trafficking events.
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Affiliation(s)
- Matthew C Thibodeau
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Noah J Harris
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Matthew A H Parson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - John T Evans
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Mackenzie K Scott
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Alexandria L Shaw
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada; Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Daniel Pokorný
- Max Perutz Labs, Department of Structural and Computational Biology, Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Thomas A Leonard
- Max Perutz Labs, Department of Structural and Computational Biology, Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada; Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada.
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