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Zhao X, Quintremil S, Rodriguez Castro ED, Cui H, Moraga D, Wang T, Vallee RB, Solmaz SR. Molecular mechanism for recognition of the cargo adapter Rab6 GTP by the dynein adapter BicD2. Life Sci Alliance 2024; 7:e202302430. [PMID: 38719748 PMCID: PMC11077774 DOI: 10.26508/lsa.202302430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/12/2024] Open
Abstract
Rab6 is a key modulator of protein secretion. The dynein adapter Bicaudal D2 (BicD2) recruits the motors cytoplasmic dynein and kinesin-1 to Rab6GTP-positive vesicles for transport; however, it is unknown how BicD2 recognizes Rab6. Here, we establish a structural model for recognition of Rab6GTP by BicD2, using structure prediction and mutagenesis. The binding site of BicD2 spans two regions of Rab6 that undergo structural changes upon the transition from the GDP- to GTP-bound state, and several hydrophobic interface residues are rearranged, explaining the increased affinity of the active GTP-bound state. Mutations of Rab6GTP that abolish binding to BicD2 also result in reduced co-migration of Rab6GTP/BicD2 in cells, validating our model. These mutations also severely diminished the motility of Rab6-positive vesicles in cells, highlighting the importance of the Rab6GTP/BicD2 interaction for overall motility of the multi-motor complex that contains both kinesin-1 and dynein. Our results provide insights into trafficking of secretory and Golgi-derived vesicles and will help devise therapies for diseases caused by BicD2 mutations, which selectively affect the affinity to Rab6 and other cargoes.
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Affiliation(s)
- Xiaoxin Zhao
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
| | - Sebastian Quintremil
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | | | - Heying Cui
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
| | - David Moraga
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
| | - Tingyao Wang
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
| | - Richard B Vallee
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Sozanne R Solmaz
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
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Scala M, Tomati V, Ferla M, Lena M, Cohen JS, Fatemi A, Brokamp E, Bican A, Phillips JA, Koziura ME, Nicouleau M, Rio M, Siquier K, Boddaert N, Musante I, Tamburro S, Baldassari S, Iacomino M, Scudieri P, Rosenfeld JA, Bellus G, Reed S, Al Saif H, Russo RS, Walsh MB, Cantagrel V, Crunk A, Gustincich S, Ruggiero SM, Fitzgerald MP, Helbig I, Striano P, Severino M, Salpietro V, Pedemonte N, Zara F. De novo variants in DENND5B cause a neurodevelopmental disorder. Am J Hum Genet 2024; 111:529-543. [PMID: 38387458 PMCID: PMC10940048 DOI: 10.1016/j.ajhg.2024.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/24/2024] Open
Abstract
The Rab family of guanosine triphosphatases (GTPases) includes key regulators of intracellular transport and membrane trafficking targeting specific steps in exocytic, endocytic, and recycling pathways. DENND5B (Rab6-interacting Protein 1B-like protein, R6IP1B) is the longest isoform of DENND5, an evolutionarily conserved DENN domain-containing guanine nucleotide exchange factor (GEF) that is highly expressed in the brain. Through exome sequencing and international matchmaking platforms, we identified five de novo variants in DENND5B in a cohort of five unrelated individuals with neurodevelopmental phenotypes featuring cognitive impairment, dysmorphism, abnormal behavior, variable epilepsy, white matter abnormalities, and cortical gyration defects. We used biochemical assays and confocal microscopy to assess the impact of DENND5B variants on protein accumulation and distribution. Then, exploiting fluorescent lipid cargoes coupled to high-content imaging and analysis in living cells, we investigated whether DENND5B variants affected the dynamics of vesicle-mediated intracellular transport of specific cargoes. We further generated an in silico model to investigate the consequences of DENND5B variants on the DENND5B-RAB39A interaction. Biochemical analysis showed decreased protein levels of DENND5B mutants in various cell types. Functional investigation of DENND5B variants revealed defective intracellular vesicle trafficking, with significant impairment of lipid uptake and distribution. Although none of the variants affected the DENND5B-RAB39A interface, all were predicted to disrupt protein folding. Overall, our findings indicate that DENND5B variants perturb intracellular membrane trafficking pathways and cause a complex neurodevelopmental syndrome with variable epilepsy and white matter involvement.
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Affiliation(s)
- Marcello Scala
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy; Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy; UOC Genetica Medica, IRCCS Giannina Gaslini, Genoa, Italy
| | - Valeria Tomati
- UOC Genetica Medica, IRCCS Giannina Gaslini, Genoa, Italy
| | - Matteo Ferla
- Oxford Protein Informatics Group, Department of Statistics, University of Oxford, Oxford, UK
| | - Mariateresa Lena
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Julie S Cohen
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ali Fatemi
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Elly Brokamp
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Anna Bican
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John A Phillips
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Mary E Koziura
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael Nicouleau
- Université Paris Cité, Imagine Institute, Developmental Brain Disorders Laboratory, INSERM UMR 1163, 75015 Paris, France
| | - Marlene Rio
- Université Paris Cité, Imagine Institute, Developmental Brain Disorders Laboratory, INSERM UMR 1163, 75015 Paris, France; Service de Génétique, Necker Enfants Malades University Hospital, Assistance Publique-Hôpitaux de Pairs, Paris, France
| | - Karine Siquier
- Université Paris Cité, Imagine Institute, Developmental Brain Disorders Laboratory, INSERM UMR 1163, 75015 Paris, France
| | - Nathalie Boddaert
- Département de Radiologie Pédiatrique, INSERM UMR 1163 and INSERM U1000, AP-HP, Hôpital Necker-Enfants Malades, Paris, France
| | - Ilaria Musante
- UOC Genetica Medica, IRCCS Giannina Gaslini, Genoa, Italy
| | | | | | | | - Paolo Scudieri
- UOC Genetica Medica, IRCCS Giannina Gaslini, Genoa, Italy
| | - Jill A Rosenfeld
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX, USA; Baylor Genetics Laboratories, Houston, TX, USA
| | - Gary Bellus
- Clinical Genetics, Geisinger Medical Center, Danville, PA 17822, USA
| | - Sara Reed
- Clinical Genetics, Geisinger Medical Center, Danville, PA 17822, USA
| | - Hind Al Saif
- Department of Human and Molecular Genetics, Division of Clinical Genetics, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | | | - Matthew B Walsh
- Department of Human Genetics, Emory University, Atlanta, GA 30322, USA
| | - Vincent Cantagrel
- Université Paris Cité, Imagine Institute, Developmental Brain Disorders Laboratory, INSERM UMR 1163, 75015 Paris, France
| | | | - Stefano Gustincich
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Sarah M Ruggiero
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Mark P Fitzgerald
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Ingo Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy; Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | | | - Vincenzo Salpietro
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy; Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.
| | | | - Federico Zara
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy; UOC Genetica Medica, IRCCS Giannina Gaslini, Genoa, Italy
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Bergeman MH, Velarde K, Glenn HL, Hogue IB. Herpes Simplex Virus 1 (HSV-1) Uses the Rab6 Post-Golgi Secretory Pathway For Viral Egress. bioRxiv 2023:2023.12.13.571414. [PMID: 38168379 PMCID: PMC10760111 DOI: 10.1101/2023.12.13.571414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Herpes Simplex Virus 1 (HSV-1) is an alpha herpesvirus that infects a majority of the world population. The mechanisms and cellular host factors involved in the intracellular transport and exocytosis of HSV-1 particles are not fully understood. To elucidate these late steps in the replication cycle, we developed a live-cell fluorescence microscopy assay of HSV-1 virion intracellular trafficking and exocytosis. This method allows us to track individual virus particles, and identify the precise moment and location of particle exocytosis using a pH-sensitive reporter. We show that HSV-1 uses the host Rab6 post-Golgi secretory pathway during egress. The small GTPase, Rab6, binds to nascent secretory vesicles at the trans-Golgi network and regulates vesicle trafficking and exocytosis at the plasma membrane. HSV-1 particles colocalize with Rab6a in the region of the Golgi, cotraffic with Rab6a to the cell periphery, and undergo exocytosis from Rab6a vesicles. Consistent with previous reports, we find that HSV-1 particles accumulate at preferential egress sites in infected cells. The Rab6a secretory pathway mediates this preferential/polarized egress, since Rab6a vesicles accumulate near the plasma membrane similarly in uninfected cells. These data suggest that, following particle envelopment, HSV-1 egress follows a pre-existing cellular secretory pathway to exit infected cells rather than novel, virus-induced mechanisms.
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Affiliation(s)
- Melissa H. Bergeman
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Kimberly Velarde
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Honor L. Glenn
- Center for Structural Discovery, Biodesign Institute, Arizona State University
| | - Ian B. Hogue
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University
- School of Life Sciences, Arizona State University, Tempe, Arizona
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G. Dornan L, C. Simpson J. Rab6-mediated retrograde trafficking from the Golgi: the trouble with tubules. Small GTPases 2023; 14:26-44. [PMID: 37488775 PMCID: PMC10392741 DOI: 10.1080/21541248.2023.2238330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/13/2023] [Accepted: 07/15/2023] [Indexed: 07/26/2023] Open
Abstract
Next year marks one-quarter of a century since the discovery of the so-called COPI-independent pathway, which operates between the Golgi apparatus and the endoplasmic reticulum (ER) in eukaryotic cells. Unlike almost all other intracellular trafficking pathways, this pathway is not regulated by the physical accumulation of multisubunit proteinaceous coat molecules, but instead by the small GTPase Rab6. What also sets it apart from other pathways is that the transport carriers themselves often take the form of tubules, rather than conventional vesicles. In this review, we assess the relevant literature that has accumulated to date, in an attempt to provide a concerted description of how this pathway is regulated. We discuss the possible cargo molecules that are carried in this pathway, and the likely mechanism of Rab6 tubule biogenesis, including how the cargo itself may play a critical role. We also provide perspective surrounding the various molecular motors of the kinesin, myosin and dynein families that have been implicated in driving Rab6-coated tubular membranes long distances through the cell prior to delivering their cargo to the ER. Finally, we also raise several important questions that require resolution, if we are to ultimately provide a comprehensive molecular description of how the COPI-independent pathway is controlled.
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Affiliation(s)
- Lucy G. Dornan
- Cell Screening Laboratory, UCD School of Biology & Environmental Science, University College Dublin, Dublin, Ireland
| | - Jeremy C. Simpson
- Cell Screening Laboratory, UCD School of Biology & Environmental Science, University College Dublin, Dublin, Ireland
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Guo RJ, Cao YF, Li EM, Xu LY. Multiple functions and dual characteristics of RAB11A in cancers. Biochim Biophys Acta Rev Cancer 2023; 1878:188966. [PMID: 37657681 DOI: 10.1016/j.bbcan.2023.188966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/05/2023] [Accepted: 08/05/2023] [Indexed: 09/03/2023]
Abstract
Vesicle trafficking is an unceasing and elaborate cellular process that functions in material transport and information delivery. Recent studies have identified the small GTPase, Ras-related protein in brain 11A (RAB11A), as a key regulator in this process. Aberrant RAB11A expression has been reported in several types of cancers, suggesting the important functions and characteristics of RAB11A in cancer. These discoveries are of great significance because therapeutic strategies based on the physiological and pathological status of RAB11A might make cancer treatment more effective, as the molecular mechanisms of cancer development have not been completely revealed. However, these studies on RAB11A have not been reviewed and discussed specifically. Therefore, we summarize and discuss the recent findings of RAB11A involvement in different biological processes, including endocytic recycling regulation, receptors and adhesion molecules recycling, exosome secretion, phagophore formation and cytokinesis, as well as regulatory mechanisms in several tumor types. Moreover, contradictory effects of RAB11A have also been observed in different types of cancers, implying the dual characteristics of RAB11A in cancer, which are either oncogenic or tumor-suppressive. This review on the functions and characteristics of RAB11A highlights the value of RAB11A in inducing multiple important phenotypes based on vesicle trafficking and therefore will offer insights for future studies to reveal the molecular mechanisms, clinical significance, and therapeutic targeting of RAB11A in different cancers.
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Affiliation(s)
- Rui-Jian Guo
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou 515041, Guangdong, PR China
| | - Yu-Fei Cao
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou 515041, Guangdong, PR China
| | - En-Min Li
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou 515041, Guangdong, PR China.
| | - Li-Yan Xu
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou 515041, Guangdong, PR China; Institute of Oncologic Pathology, Shantou University Medical College, Shantou 515041, Guangdong, PR China.
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Sultana P, Novotny J. Rab11 and Its Role in Neurodegenerative Diseases. ASN Neuro 2022; 14:17590914221142360. [PMID: 36464817 PMCID: PMC9726856 DOI: 10.1177/17590914221142360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022] Open
Abstract
Vesicles mediate the trafficking of membranes/proteins in the endocytic and secretory pathways. These pathways are regulated by small GTPases of the Rab family. Rab proteins belong to the Ras superfamily of GTPases, which are significantly involved in various intracellular trafficking and signaling processes in the nervous system. Rab11 is known to play a key role especially in recycling many proteins, including receptors important for signal transduction and preservation of functional activities of nerve cells. Rab11 activity is controlled by GEFs (guanine exchange factors) and GAPs (GTPase activating proteins), which regulate its function through modulating GTP/GDP exchange and the intrinsic GTPase activity, respectively. Rab11 is involved in the transport of several growth factor molecules important for the development and repair of neurons. Overexpression of Rab11 has been shown to significantly enhance vesicle trafficking. On the other hand, a reduced expression of Rab11 was observed in several neurodegenerative diseases. Current evidence appears to support the notion that Rab11 and its cognate proteins may be potential targets for therapeutic intervention. In this review, we briefly discuss the function of Rab11 and its related interaction partners in intracellular pathways that may be involved in neurodegenerative processes.
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Affiliation(s)
| | - Jiri Novotny
- Jiri Novotny, Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic.
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Moya-Alvarado G, Guerra MV, Tiburcio R, Bravo E, Bronfman FC. The Rab11-regulated endocytic pathway and BDNF/TrkB signaling: Roles in plasticity changes and neurodegenerative diseases. Neurobiol Dis 2022; 171:105796. [PMID: 35728773 DOI: 10.1016/j.nbd.2022.105796] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 05/10/2022] [Accepted: 06/14/2022] [Indexed: 02/08/2023] Open
Abstract
Neurons are highly polarized cells that rely on the intracellular transport of organelles. This process is regulated by molecular motors such as dynein and kinesins and the Rab family of monomeric GTPases that together help move cargo along microtubules in dendrites, somas, and axons. Rab5-Rab11 GTPases regulate receptor trafficking along early-recycling endosomes, which is a process that determines the intracellular signaling output of different signaling pathways, including those triggered by BDNF binding to its tyrosine kinase receptor TrkB. BDNF is a well-recognized neurotrophic factor that regulates experience-dependent plasticity in different circuits in the brain. The internalization of the BDNF/TrkB complex results in signaling endosomes that allow local signaling in dendrites and presynaptic terminals, nuclear signaling in somas and dynein-mediated long-distance signaling from axons to cell bodies. In this review, we briefly discuss the organization of the endocytic pathway and how Rab11-recycling endosomes interact with other endomembrane systems. We further expand upon the roles of the Rab11-recycling pathway in neuronal plasticity. Then, we discuss the BDNF/TrkB signaling pathways and their functional relationships with the postendocytic trafficking of BDNF, including axonal transport, emphasizing the role of BDNF signaling endosomes, particularly Rab5-Rab11 endosomes, in neuronal plasticity. Finally, we discuss the evidence indicating that the dysfunction of the early-recycling pathway impairs BDNF signaling, contributing to several neurodegenerative diseases.
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Detampel P, Tehranian S, Mukherjee P, Foret M, Fuerstenhaupt T, Darbandi A, Bogari N, Hlasny M, Jeje A, Olszewski MA, Ganguly A, Amrein M. Caveolin-initiated macropinocytosis is required for efficient silica nanoparticles' transcytosis across the alveolar epithelial barrier. Sci Rep 2022; 12:9474. [PMID: 35676405 PMCID: PMC9178038 DOI: 10.1038/s41598-022-13388-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 05/24/2022] [Indexed: 12/22/2022] Open
Abstract
Removal of particulate materials that would otherwise cumulate within the airspace and hinder the gas exchange is one of the central processes of maintaining lung homeostasis. While the importance of the particle uptake by alveolar macrophages and their expulsion via the airways mucociliary escalator is well established, very little is known about the alternative route for removing the particles via direct crossing the lung epithelium for transfer into the pulmonary lymph and bloodstream. This study dissected sequential mechanisms involved in nanoparticle transcytosis through the alveolar epithelial cell layer. By a combination of live cell, super resolution, and electron microscopy and RNA interference study, we have dissected temporal steps of nanoparticle transcytosis through alveolar epithelium. Our study revealed that caveolin is essential for the firm adhesion of the silica nanoparticle agglomerates to the apical membrane and their subsequent rapid internalization with the help of macropinocytic elements C-terminal-binding protein1 and Rabankyrin-5 but not dynamin. Actin, but not microtubules, played a major role in nanoparticle uptake and subsequent transportation. The compartments with nanoparticles were tethered to trans-Golgi network to be jointly transported along actin stress fibers across the cytoplasm, employing a myosin-dependent mechanism. The trans-Golgi nanoparticle transport machinery was positive to Rab6A, a marker linked to vesicle exocytosis. Exocytosis was primarily occurring at the basolateral plane of the alveolar epithelial cells. The high-proficiency novel caveolin and Rabankyrin-5 associated uptake and transcellular transport of nanoparticles across the AEC barrier supports its importance in clearance of amorphous silica and other types of non-inflammatory nanoparticles that are rapidly removed from the lungs following their inhalation.
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Affiliation(s)
- Pascal Detampel
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, Canada.,Division of Pharmaceutical Technology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Sara Tehranian
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, Canada
| | - Priyanka Mukherjee
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, Canada
| | - Morgan Foret
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, Canada
| | - Tobias Fuerstenhaupt
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, Canada
| | - Ali Darbandi
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, Canada
| | - Nawaf Bogari
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, Canada
| | - Magda Hlasny
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, Canada
| | - Ayodeji Jeje
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, Canada
| | - Michal A Olszewski
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, MI, USA.,Research Service, LTC Charles S. Kettles VA Medical Center, Ann Arbor, MI, USA
| | - Anutosh Ganguly
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, Canada. .,Department of Microbiology Immunology and Infectious Diseases, University of Calgary, Cumming School of Medicine, 3330 Hospital Drive, Calgary, AB, T2N4N1, Canada. .,Research Service, LTC Charles S. Kettles VA Medical Center, Ann Arbor, MI, USA. .,Department of Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA.
| | - Matthias Amrein
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, Canada.
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Bjørnestad SA, Guadagno NA, Kjos I, Progida C. Rab33b-exocyst interaction mediates localized secretion for focal adhesion turnover and cell migration. iScience 2022; 25:104250. [PMID: 35521520 PMCID: PMC9061791 DOI: 10.1016/j.isci.2022.104250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 02/17/2022] [Accepted: 04/08/2022] [Indexed: 12/19/2022] Open
Abstract
Rab proteins are well known regulators of intracellular trafficking; however, more and more studies point to their function also in other cellular processes, including cell migration. In this work, we have performed an siRNA screen to identify Rab proteins that influence cell migration. The screen revealed Rab33b as the strongest candidate that affected cell motility. Rab33b has been previously reported to localize at the Golgi apparatus to regulate Golgi-to-ER retrograde trafficking and Golgi homeostasis. We revealed that Rab33b also mediates post-Golgi transport to the plasma membrane. We further identified Exoc6, a subunit of the exocyst complex, as an interactor of Rab33b. Moreover, our data indicate that Rab33b regulates focal adhesion dynamics by modulating the delivery of cargo such as integrins to focal adhesions. Altogether, our results demonstrate a role for Rab33b in cell migration by regulating the delivery of integrins to focal adhesions through the interaction with Exoc6. RNAi screen reveals a role for Rab33b in cell migration Rab33b influences focal adhesion dynamics Rab33b interacts with the exocyst subunit Exoc6 Rab33b together with Exoc6 mediates the delivery of β1 integrin to adhesion points
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Yang M, Johnsson P, Bräutigam L, Yang XR, Thrane K, Gao J, Tobin NP, Zhou Y, Yu R, Nagy N, Engström PG, Tuominen R, Eriksson H, Lundeberg J, Tucker MA, Goldstein AM, Egyhazi-Brage S, Zhao J, Cao Y, Höiom V. Novel loss-of-function variant in DENND5A impedes melanosomal cargo transport and predisposes to familial cutaneous melanoma. Genet Med 2022; 24:157-169. [PMID: 34906508 PMCID: PMC10617683 DOI: 10.1016/j.gim.2021.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/05/2021] [Accepted: 09/10/2021] [Indexed: 11/18/2022] Open
Abstract
PURPOSE More than half of the familial cutaneous melanomas have unknown genetic predisposition. This study aims at characterizing a novel melanoma susceptibility gene. METHODS We performed exome and targeted sequencing in melanoma-prone families without any known melanoma susceptibility genes. We analyzed the expression of candidate gene DENND5A in melanoma samples in relation to pigmentation and UV signature. Functional studies were carried out using microscopic approaches and zebrafish model. RESULTS We identified a novel DENND5A truncating variant that segregated with melanoma in a Swedish family and 2 additional rare DENND5A variants, 1 of which segregated with the disease in an American family. We found that DENND5A is significantly enriched in pigmented melanoma tissue. Our functional studies show that loss of DENND5A function leads to decrease in melanin content in vitro and pigmentation defects in vivo. Mechanistically, harboring the truncating variant or being suppressed leads to DENND5A losing its interaction with SNX1 and its ability to transport the SNX1-associated vesicles from melanosomes. Consequently, untethered SNX1-premelanosome protein and redundant tyrosinase are redirected to lysosomal degradation by default, causing decrease in melanin content. CONCLUSION Our findings provide evidence of a physiological role of DENND5A in the skin context and link its variants to melanoma susceptibility.
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Affiliation(s)
- Muyi Yang
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Per Johnsson
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden; Ludwig Institute for Cancer Research, Stockholm, Sweden
| | - Lars Bräutigam
- Comparative Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Xiaohong R Yang
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, MD
| | - Kim Thrane
- Department of Gene Technology, SciLifeLab, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Jiwei Gao
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Nicholas P Tobin
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Yitian Zhou
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Rong Yu
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Noemi Nagy
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Pär G Engström
- Department of Biochemistry and Biophysics, National Bioinformatics Infrastructure Sweden, SciLifeLab, Stockholm University, Stockholm, Sweden
| | - Rainer Tuominen
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Hanna Eriksson
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden; Karolinska University Hospital, Stockholm, Sweden
| | - Joakim Lundeberg
- Department of Gene Technology, SciLifeLab, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Margaret A Tucker
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, MD
| | - Alisa M Goldstein
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, MD
| | | | - Jian Zhao
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.
| | - Yihai Cao
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Veronica Höiom
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden; Karolinska University Hospital, Stockholm, Sweden.
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11
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Capitani N, Baldari CT. F-Actin Dynamics in the Regulation of Endosomal Recycling and Immune Synapse Assembly. Front Cell Dev Biol 2021; 9:670882. [PMID: 34249926 PMCID: PMC8265274 DOI: 10.3389/fcell.2021.670882] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/24/2021] [Indexed: 12/24/2022] Open
Abstract
Membrane proteins endocytosed at the cell surface as vesicular cargoes are sorted at early endosomes for delivery to lysosomes for degradation or alternatively recycled to different cellular destinations. Cargo recycling is orchestrated by multimolecular complexes that include the retromer, retriever, and the WASH complex, which promote the polymerization of new actin filaments at early endosomes. These endosomal actin pools play a key role at different steps of the recycling process, from cargo segregation to specific endosomal subdomains to the generation and mobility of tubulo-vesicular transport carriers. Local F-actin pools also participate in the complex redistribution of endomembranes and organelles that leads to the acquisition of cell polarity. Here, we will present an overview of the contribution of endosomal F-actin to T-cell polarization during assembly of the immune synapse, a specialized membrane domain that T cells form at the contact with cognate antigen-presenting cells.
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Affiliation(s)
- Nagaja Capitani
- Department of Life Sciences, University of Siena, Siena, Italy
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12
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Yang L, Liu G, Li X, Xia Z, Wang Y, Lin W, Zhang W, Zhang W, Li X. Small GTPase RAB6 deficiency promotes alveolar progenitor cell renewal and attenuates PM2.5-induced lung injury and fibrosis. Cell Death Dis 2020; 11:827. [PMID: 33012781 PMCID: PMC7533251 DOI: 10.1038/s41419-020-03027-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/14/2022]
Abstract
Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease characterized by chronic non-specific inflammation of the interstitial lung and extensive deposition of collagen fibers leading to destruction of lung function. Studies have demonstrated that exposure to fine particulate matter (PM2.5) increases the risk of IPF. In order to recover from PM2.5-induced lung injury, alveolar epithelial cells need to be repaired and regenerated to maintain lung function. Type 2 alveolar epithelial cells (AEC2) are stem cells in the adult lung that contribute to the lung repair process through complex signaling. Our previous studies demonstrated that RAB6, a RAS family member lowly expressed in lung cancer, inhibited lung cancer stem cell self-renewal, but it is unclear whether or not and how RAB6 may regulate AEC2 cell proliferation and self-renewal in PM2.5-induced pulmonary fibrosis. Here, we demonstrated that knockout of RAB6 inhibited pulmonary fibrosis, oxidative stress, and AEC2 cell death in PM2.5-injured mice. In addition, knockout of RAB6 decreased Dickkopf 1(DKK1) autocrine and activated proliferation, self-renewal, and wnt/β-catenin signaling of PM2.5-injured AEC2 cells. RAB6 overexpression increased DKK1 autocrine and inhibited proliferation, self-renewal and wnt/β-catenin signaling in AEC2 cells in vitro. Furthermore, DKK1 inhibitors promoted proliferation, self-renewal and wnt/β-catenin signaling of RAB6 overexpressing AEC2 cells, and attenuated PM2.5-induced pulmonary fibrosis in mice. These data establish RAB6 as a regulator of DKK1 autocrine and wnt/β-catenin signal that serves to regulate AEC2 cell proliferation and self-renewal, and suggest a mechanism that RAB6 disruption may promote AEC2 cell proliferation and self-renewal to enhance lung repair following PM2.5 injury.
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Affiliation(s)
- Lawei Yang
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, China.,Clinical Research Center, Affiliated Hospital of Guangdong Medical University, 524001, Zhanjiang, China
| | - Gang Liu
- Clinical Research Center, Affiliated Hospital of Guangdong Medical University, 524001, Zhanjiang, China
| | - Xiaomin Li
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, China
| | - Zhengyuan Xia
- Clinical Research Center, Affiliated Hospital of Guangdong Medical University, 524001, Zhanjiang, China.,Department of Anesthesiology, Affiliated Hospital of Guangdong Medical University, 524001, Zhanjiang, China.,Department of Anesthesiology, The University of Hong Kong, Hong Kong, China
| | - Yahong Wang
- Clinical Research Center, Affiliated Hospital of Guangdong Medical University, 524001, Zhanjiang, China
| | - Weihao Lin
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, China
| | - Wei Zhang
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, China
| | - Wenjuan Zhang
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, China
| | - Xuenong Li
- Department of Pathology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, China.
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13
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Chauhan IS, Marwa S, Rao GS, Singh N. Antiparasitic dibenzalacetone inhibits the GTPase activity of Rab6 protein of Leishmania donovani (LdRab6), a potential target for its antileishmanial effect. Parasitol Res 2020; 119:2991-3003. [PMID: 32748038 DOI: 10.1007/s00436-020-06810-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/08/2020] [Indexed: 10/23/2022]
Abstract
Visceral leishmaniasis (VL, also known as kala-azar) is a vector borne disease caused by obligate intracellular protozoan parasite Leishmania donovani. To overcome the limitations of currently available drugs for VL, molecular target-based study is a promising tool to develop new drugs to treat this neglected tropical disease. One such target we recently identified from L. donovani (Ld) genome (WGS, clinical Indian isolate; BHU 1220, AVPQ01000001) is a small GTP-binding protein, Rab6 protein. We now report a specific inhibitor of the GTPase activity of Rab6 protein of L. donovani (LdRab6) without restricting host enzyme activity. First, to understand the nature of LdRab6 protein, we generated recombinant LdRab6 mutant proteins (rLdRab6) by systematically introducing deletion (two cysteine residues at C-terminal) and mutations [single amino acid substitutions in the conserved region of GTP (Q84L)/GDP(T38N) coding sequence]. The GTPase activity of rLdRab6:GTP and rLdRab6:GDP locked mutant proteins showed ~ 8-fold and ~ 1.5-fold decreases in enzyme activity, respectively, compared to the wild type enzyme activity. The mutant protein rLdRab6:ΔC inhibited the GTPase activity. Sequence alignment analysis of Rab6 protein of L. donovani with Homo sapiens showed identical amino acids in the G conserved region (GTP/GDP-binding sites) but it differed in the C-terminal region. We then evaluated the inhibitory activity of trans-dibenzalacetone (DBA, a synthetic analog of curcumin with strong antileishmanial activity reported earlier by us) in the GTPase activity of LdRab6 protein. Comparative molecular docking analysis of DBA and specific inhibitors of Rab proteins (Lovastatin, BFA, Zoledronate, and NE10790) indicated that DBA had optimum binding affinity with LdRab6 protein. This was further confirmed by the GTPase activity of DBA-treated LdRab6 which showed a basal GTP level significantly lower than that of the wild-type rLdRab6. The results confirm that DBA inhibits the GTPase activity of LdRab6 protein from L. donovani (LdRab6), a potential target for its antileishmanial effect.
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14
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Iwaki A, Moriwaki K, Sobajima T, Taniguchi M, Yoshimura SI, Kunii M, Kanda S, Kamada Y, Miyoshi E, Harada A. Loss of Rab6a in the small intestine causes lipid accumulation and epithelial cell death from lactation. FASEB J 2020; 34:9450-9465. [PMID: 32496646 DOI: 10.1096/fj.202000028r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 04/24/2020] [Accepted: 05/05/2020] [Indexed: 11/11/2022]
Abstract
Intestinal epithelial cells (IECs) are not only responsible for the digestion and absorption of dietary substrates but also function as a first line of host defense against commensal and pathogenic luminal bacteria. Disruption of the epithelial layer causes malnutrition and enteritis. Rab6 is a small GTPase localized to the Golgi, where it regulates anterograde and retrograde transport by interacting with various effector proteins. Here, we generated mice with IEC-specific deletion of Rab6a (Rab6a∆IEC mice). While Rab6aΔIEC mice were born at the Mendelian ratio, they started to show IEC death, inflammation, and bleeding in the small intestine shortly after birth, and these changes culminated in early postnatal death. We further found massive lipid accumulation in the IECs of Rab6a∆IEC neonates. In contrast to Rab6a∆IEC neonates, knockout embryos did not show any of these abnormalities. Lipid accumulation and IEC death became evident when Rab6a∆IEC embryos were nursed by a foster mother, suggesting that dietary milk-derived lipids accumulated in Rab6a-deficient IECs and triggered IEC death. These results indicate that Rab6a plays a crucial role in regulating the lipid transport and maintaining tissue integrity.
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Affiliation(s)
- Ayano Iwaki
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Suita, Japan.,Department of Molecular Biochemistry and Clinical Investigation, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Kenta Moriwaki
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Tomoaki Sobajima
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Suita, Japan.,Department of Molecular Biochemistry and Clinical Investigation, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Manabu Taniguchi
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Shin-Ichiro Yoshimura
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Masataka Kunii
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Satoshi Kanda
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yoshihiro Kamada
- Department of Molecular Biochemistry and Clinical Investigation, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Eiji Miyoshi
- Department of Molecular Biochemistry and Clinical Investigation, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Akihiro Harada
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Suita, Japan
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15
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Abstract
The small GTPase Arf4-based ciliary membrane-targeting complex recognizes specific targeting signals within sensory receptors and regulates their directed movement to primary cilia. Activated Arf4 directly binds the VxPx ciliary-targeting signal (CTS) of the light-sensing receptor rhodopsin. Recent findings revealed that at the trans-Golgi, marked by the small GTPase Rab6, activated Arf4 forms a functional complex with rhodopsin and the Arf guanine nucleotide exchange factor (GEF) GBF1, providing positive feedback that drives further Arf4 activation in ciliary trafficking. Arf4 function is conserved across diverse cell types; however, it appears that not all its aspects are conserved across species, as mouse Arf4 is a natural mutant in the conserved α3 helix, which is essential for its interaction with rhodopsin. Generally, activated Arf4 regulates the assembly of the targeting nexus containing the Arf GAP ASAP1 and the Rab11a-FIP3-Rabin8 dual effector complex, which controls the assembly of the highly conserved Rab11a-Rabin8-Rab8 ciliary-targeting module. It was recently found that this module interacts with the R-SNARE VAMP7, likely in its activated, c-Src-phosphorylated form. Rab11 and Rab8 bind VAMP7 regulatory longin domain (LD), whereas Rabin8 interacts with the SNARE domain, capturing VAMP7 for delivery to the ciliary base and subsequent pairing with the cognate SNAREs syntaxin 3 and SNAP-25. This review will focus on the implications of these novel findings that further illuminate the role of well-ordered Arf and Rab interaction networks in targeting of sensory receptors to primary cilia. Abbreviations: CTS: Ciliary-Targeting Signal; GAP: GTPase Activating Protein; GEF: Guanine Nucleotide Exchange Factor; RTC(s), Rhodopsin Transport Carrier(s); SNARE: Soluble N-ethylmaleimide-sensitive Factor Attachment Protein Receptor; TGN: Trans-Golgi Network.
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Affiliation(s)
- Dusanka Deretic
- Departments of Surgery, Division of Ophthalmology, University of New Mexico , Albuquerque, NM, USA.,Cell Biology and Physiology, University of New Mexico , Albuquerque, NM, USA
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University , Aarhus, Denmark
| | - Theresa Fresquez
- Departments of Surgery, Division of Ophthalmology, University of New Mexico , Albuquerque, NM, USA
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16
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Vestre K, Kjos I, Guadagno NA, Borg Distefano M, Kohler F, Fenaroli F, Bakke O, Progida C. Rab6 regulates cell migration and invasion by recruiting Cdc42 and modulating its activity. Cell Mol Life Sci 2019; 76:2593-614. [DOI: 10.1007/s00018-019-03057-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 02/08/2019] [Accepted: 02/26/2019] [Indexed: 12/22/2022]
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17
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Abstract
The Golgi apparatus is a central sorting station in the cell. It receives newly synthesized molecules from the endoplasmic reticulum and directs them to different subcellular destinations, such as the plasma membrane or the endocytic pathway. Importantly, in the last few years, it has emerged that the maintenance of Golgi structure is connected to the proper regulation of membrane trafficking. Rab proteins are small GTPases that are considered to be the master regulators of the intracellular membrane trafficking. Several of the over 60 human Rabs are involved in the regulation of transport pathways at the Golgi as well as in the maintenance of its architecture. This chapter will summarize the different roles of Rab GTPases at the Golgi, both as regulators of membrane transport, scaffold, and tethering proteins and in preserving the structure and function of this organelle.
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18
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Prince E, Kroeger B, Gligorov D, Wilson C, Eaton S, Karch F, Brankatschk M, Maeda RK. Rab-mediated trafficking in the secondary cells of Drosophila male accessory glands and its role in fecundity. Traffic 2018; 20:137-151. [PMID: 30426623 PMCID: PMC6492190 DOI: 10.1111/tra.12622] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 11/01/2018] [Accepted: 11/06/2018] [Indexed: 12/16/2022]
Abstract
The male seminal fluid contains factors that affect female post‐mating behavior and physiology. In Drosophila, most of these factors are secreted by the two epithelial cell types that make up the male accessory gland: the main and secondary cells. Although secondary cells represent only ~4% of the cells of the accessory gland, their contribution to the male seminal fluid is essential for sustaining the female post‐mating response. To better understand the function of the secondary cells, we investigated their molecular organization, particularly with respect to the intracellular membrane transport machinery. We determined that large vacuole‐like structures found in the secondary cells are trafficking hubs labeled by Rab6, 7, 11 and 19. Furthermore, these organelles require Rab6 for their formation and many are essential in the process of creating the long‐term postmating behavior of females. In order to better serve the intracellular membrane and protein trafficking communities, we have created a searchable, online, open‐access imaging resource to display our complete findings regarding Rab localization in the accessory gland.
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Affiliation(s)
- Elodie Prince
- Department of Genetics and Evolution, Section of Biology, Sciences Faculty, University of Geneva, Geneva, Switzerland
| | - Benjamin Kroeger
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Dragan Gligorov
- Department of Genetics and Evolution, Section of Biology, Sciences Faculty, University of Geneva, Geneva, Switzerland
| | - Clive Wilson
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Suzanne Eaton
- Biotechnology Center of the TU Dresden, Dresden, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - François Karch
- Department of Genetics and Evolution, Section of Biology, Sciences Faculty, University of Geneva, Geneva, Switzerland
| | - Marko Brankatschk
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Robert K Maeda
- Department of Genetics and Evolution, Section of Biology, Sciences Faculty, University of Geneva, Geneva, Switzerland
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19
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Renna L, Stefano G, Slabaugh E, Wormsbaecher C, Sulpizio A, Zienkiewicz K, Brandizzi F. TGNap1 is required for microtubule-dependent homeostasis of a subpopulation of the plant trans-Golgi network. Nat Commun 2018. [PMID: 30552321 DOI: 10.1038/s41467-018-07662-7664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023] Open
Abstract
Defining convergent and divergent mechanisms underlying the biogenesis and function of endomembrane organelles is fundamentally important in cell biology. In all eukaryotes, the Trans-Golgi Network (TGN) is the hub where the exocytic and endocytic pathways converge. To gain knowledge in the mechanisms underlying TGN biogenesis and function, we characterized TGNap1, a protein encoded by a plant gene of unknown function conserved with metazoans. We demonstrate that TGNap1 is a TGN protein required for the homeostasis of biosynthetic and endocytic traffic pathways. We also show that TGNap1 binds Rab6, YIP4 and microtubules. Finally, we establish that TGNap1 contributes to microtubule-dependent biogenesis, tracking and function of a TGN subset, likely through interaction with Rab6 and YIP4. Our results identify an important trafficking determinant at the plant TGN and reveal an unexpected reliance of post-Golgi traffic homeostasis and organelle biogenesis on microtubules in plants.
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Affiliation(s)
- Luciana Renna
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
| | - Giovanni Stefano
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Erin Slabaugh
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | - Clarissa Wormsbaecher
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, 43210, USA
| | - Alan Sulpizio
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14850, USA
| | - Krzysztof Zienkiewicz
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Department of Plant Biochemistry, Georg-August-University, Albrecht-von-Haller-Institute for Plant Sciences, 37073, Göttingen, Germany
| | - Federica Brandizzi
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA.
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA.
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20
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Renna L, Stefano G, Slabaugh E, Wormsbaecher C, Sulpizio A, Zienkiewicz K, Brandizzi F. TGNap1 is required for microtubule-dependent homeostasis of a subpopulation of the plant trans-Golgi network. Nat Commun 2018; 9:5313. [PMID: 30552321 PMCID: PMC6294250 DOI: 10.1038/s41467-018-07662-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 11/08/2018] [Indexed: 11/09/2022] Open
Abstract
Defining convergent and divergent mechanisms underlying the biogenesis and function of endomembrane organelles is fundamentally important in cell biology. In all eukaryotes, the Trans-Golgi Network (TGN) is the hub where the exocytic and endocytic pathways converge. To gain knowledge in the mechanisms underlying TGN biogenesis and function, we characterized TGNap1, a protein encoded by a plant gene of unknown function conserved with metazoans. We demonstrate that TGNap1 is a TGN protein required for the homeostasis of biosynthetic and endocytic traffic pathways. We also show that TGNap1 binds Rab6, YIP4 and microtubules. Finally, we establish that TGNap1 contributes to microtubule-dependent biogenesis, tracking and function of a TGN subset, likely through interaction with Rab6 and YIP4. Our results identify an important trafficking determinant at the plant TGN and reveal an unexpected reliance of post-Golgi traffic homeostasis and organelle biogenesis on microtubules in plants.
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Affiliation(s)
- Luciana Renna
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
| | - Giovanni Stefano
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Erin Slabaugh
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | - Clarissa Wormsbaecher
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, 43210, USA
| | - Alan Sulpizio
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14850, USA
| | - Krzysztof Zienkiewicz
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Department of Plant Biochemistry, Georg-August-University, Albrecht-von-Haller-Institute for Plant Sciences, 37073, Göttingen, Germany
| | - Federica Brandizzi
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA.
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA.
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21
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Ayala CI, Kim J, Neufeld TP. Rab6 promotes insulin receptor and cathepsin trafficking to regulate autophagy induction and activity in Drosophila. J Cell Sci 2018; 131:jcs.216127. [PMID: 30111579 DOI: 10.1242/jcs.216127] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 08/02/2018] [Indexed: 01/07/2023] Open
Abstract
The self-degradative process of autophagy is important for energy homeostasis and cytoplasmic renewal. This lysosome-mediated pathway is negatively regulated by the target of rapamycin kinase (TOR) under basal conditions, and requires the vesicle trafficking machinery regulated by Rab GTPases. However, the interactions between autophagy, TOR and Rab proteins remain incompletely understood in vivo Here, we identify Rab6 as a critical regulator of the balance between TOR signaling and autolysosome function. Loss of Rab6 causes an accumulation of enlarged autophagic vesicles resulting in part from a failure to deliver lysosomal hydrolases, rendering autolysosomes with a reduced degradative capacity and impaired turnover. Additionally, Rab6-deficient cells are reduced in size and display defective insulin-TOR signaling as a result of mis-sorting and internalization of the insulin receptor. Our findings suggest that Rab6 acts to maintain the reciprocal regulation between autophagy and TOR activity during distinct nutrient states, thereby balancing autophagosome production and turnover to avoid autophagic stress.
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Affiliation(s)
- Carlos I Ayala
- Department of Genetics, Cell Biology and Development, 6-160 Jackson Hall, 321 Church St. SE, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jung Kim
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Thomas P Neufeld
- Department of Genetics, Cell Biology and Development, 6-160 Jackson Hall, 321 Church St. SE, University of Minnesota, Minneapolis, MN 55455, USA
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22
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Bärlocher K, Welin A, Hilbi H. Formation of the Legionella Replicative Compartment at the Crossroads of Retrograde Trafficking. Front Cell Infect Microbiol 2017; 7:482. [PMID: 29226112 PMCID: PMC5706426 DOI: 10.3389/fcimb.2017.00482] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/06/2017] [Indexed: 12/13/2022] Open
Abstract
Retrograde trafficking from the endosomal system through the Golgi apparatus back to the endoplasmic reticulum is an essential pathway in eukaryotic cells, serving to maintain organelle identity and to recycle empty cargo receptors delivered by the secretory pathway. Intracellular replication of several bacterial pathogens, including Legionella pneumophila, is restricted by the retrograde trafficking pathway. L. pneumophila employs the Icm/Dot type IV secretion system (T4SS) to form the replication-permissive Legionella-containing vacuole (LCV), which is decorated with multiple components of the retrograde trafficking machinery as well as retrograde cargo receptors. The L. pneumophila effector protein RidL is secreted by the T4SS and interferes with retrograde trafficking. Here, we review recent evidence that the LCV interacts with the retrograde trafficking pathway, discuss the possible sites of action and function of RidL in the retrograde route, and put forth the hypothesis that the LCV is an acceptor compartment of retrograde transport vesicles.
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Affiliation(s)
- Kevin Bärlocher
- Institute of Medical Microbiology, University of Zürich, Zurich, Switzerland
| | - Amanda Welin
- Institute of Medical Microbiology, University of Zürich, Zurich, Switzerland
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zürich, Zurich, Switzerland
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23
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Abstract
Rab proteins regulate vesicular transport in eukaryotic cells and establish connections to various cellular structures and processes by interacting with so-called effector molecules. Several of these effectors are known to not only bind a single Rab protein, but to be able to bind multiple different Rabs simultaneously. In this review we will give a short overview of effectors in general and (putative) functions of the aforementioned multivalent Rab:effector interactions.
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Affiliation(s)
- Amrita Rai
- 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
| | - Matthias P Müller
- a Department of Structural Biochemistry , Max Planck Institute of Molecular Physiology , Dortmund , Germany
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24
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Rai A, Oprisko A, Campos J, Fu Y, Friese T, Itzen A, Goody RS, Gazdag EM, Müller MP. bMERB domains are bivalent Rab8 family effectors evolved by gene duplication. eLife 2016; 5. [PMID: 27552051 PMCID: PMC5026484 DOI: 10.7554/elife.18675] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/22/2016] [Indexed: 12/11/2022] Open
Abstract
In their active GTP-bound form, Rab proteins interact with proteins termed effector molecules. In this study, we have thoroughly characterized a Rab effector domain that is present in proteins of the Mical and EHBP families, both known to act in endosomal trafficking. Within our study, we show that these effectors display a preference for Rab8 family proteins (Rab8, 10, 13 and 15) and that some of the effector domains can bind two Rab proteins via separate binding sites. Structural analysis allowed us to explain the specificity towards Rab8 family members and the presence of two similar Rab binding sites that must have evolved via gene duplication. This study is the first to thoroughly characterize a Rab effector protein that contains two separate Rab binding sites within a single domain, allowing Micals and EHBPs to bind two Rabs simultaneously, thus suggesting previously unknown functions of these effector molecules in endosomal trafficking. DOI:http://dx.doi.org/10.7554/eLife.18675.001
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Affiliation(s)
- Amrita Rai
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Anastasia Oprisko
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Jeremy Campos
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Yangxue Fu
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Timon Friese
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Aymelt Itzen
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technische Universität München, Garching, Germany
| | - Roger S Goody
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Emerich Mihai Gazdag
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Matthias P Müller
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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Klinkert K, Echard A. Rab35 GTPase: A Central Regulator of Phosphoinositides and F-actin in Endocytic Recycling and Beyond. Traffic 2016; 17:1063-77. [PMID: 27329675 DOI: 10.1111/tra.12422] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/12/2016] [Accepted: 06/12/2016] [Indexed: 12/11/2022]
Abstract
Rab35 is one of the first discovered members of the large Rab GTPase family, yet it received little attention for 10 years being considered merely as a Rab1-like GTPase. In 2006, Rab35 was recognized as a unique Rab GTPase localized both at the plasma membrane and on endosomes, playing essential roles in endocytic recycling and cytokinesis. Since then, Rab35 has become one of the most studied Rabs involved in a growing number of cellular functions, including endosomal trafficking, exosome release, phagocytosis, cell migration, immunological synapse formation and neurite outgrowth. Recently, Rab35 has been acknowledged as an oncogenic GTPase with activating mutations being found in cancer patients. In this review, we provide a comprehensive summary of known Rab35-dependent cellular functions and detail the few Rab35 effectors characterized so far. We also review how the Rab35 GTP/GDP cycle is regulated, and emphasize a newly discovered mechanism that controls its tight activation on newborn endosomes. We propose that the involvement of Rab35 in such diverse and apparently unrelated cellular functions can be explained by the central role of this GTPase in regulating phosphoinositides and F-actin, both on endosomes and at the plasma membrane.
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Affiliation(s)
- Kerstin Klinkert
- Membrane Traffic and Cell Division Lab, Cell Biology and Infection Department, Institut Pasteur, 25-28 rue du Dr Roux, 75724, Paris, France.,Centre National de la Recherche Scientifique, UMR3691, 75015, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 06, Institut de formation doctorale, 75252, Paris, France
| | - Arnaud Echard
- Membrane Traffic and Cell Division Lab, Cell Biology and Infection Department, Institut Pasteur, 25-28 rue du Dr Roux, 75724, Paris, France. .,Centre National de la Recherche Scientifique, UMR3691, 75015, Paris, France.
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26
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Abstract
Retromer is an evolutionarily conserved multimeric protein complex that mediates intracellular transport of various vesicular cargoes and functions in a wide variety of cellular processes including polarized trafficking, developmental signaling and lysosome biogenesis. Through its interaction with the Rab GTPases and their effectors, membrane lipids, molecular motors, the endocytic machinery and actin nucleation promoting factors, retromer regulates sorting and trafficking of transmembrane proteins from endosomes to the trans-Golgi network (TGN) and the plasma membrane. In this review, I highlight recent progress in the understanding of retromer-mediated protein sorting and vesicle trafficking and discuss how retromer contributes to a diverse set of developmental, physiological and pathological processes.
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Affiliation(s)
- Jia-Jia Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Beijing 100101, China.
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27
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Abstract
Many viruses exploit specific arms of the endomembrane system. The unique composition of each arm prompts the development of remarkably specific interactions between viruses and sub-organelles. This review focuses on the viral–host interactions occurring on the endocytic recycling compartment (ERC), and mediated by its regulatory Ras-related in brain (Rab) GTPase Rab11. This protein regulates trafficking from the ERC and the trans-Golgi network to the plasma membrane. Such transport comprises intricate networks of proteins/lipids operating sequentially from the membrane of origin up to the cell surface. Rab11 is also emerging as a critical factor in an increasing number of infections by major animal viruses, including pathogens that provoke human disease. Understanding the interplay between the ERC and viruses is a milestone in human health. Rab11 has been associated with several steps of the viral lifecycles by unclear processes that use sophisticated diversified host machinery. For this reason, we first explore the state-of-the-art on processes regulating membrane composition and trafficking. Subsequently, this review outlines viral interactions with the ERC, highlighting current knowledge on viral-host binding partners. Finally, using examples from the few mechanistic studies available we emphasize how ERC functions are adjusted during infection to remodel cytoskeleton dynamics, innate immunity and membrane composition.
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Affiliation(s)
- Sílvia Vale-Costa
- Cell Biology of Viral Infection Lab, Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, 2780-156 Oeiras, Portugal.
| | - Maria João Amorim
- Cell Biology of Viral Infection Lab, Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, 2780-156 Oeiras, Portugal.
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28
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Choi JY, Shin YC, Yoon JH, Kim CM, Lee JH, Jeon JH, Park HH. Molecular mechanism of constitutively active Rab11A was revealed by crystal structure of Rab11A S20V. FEBS Lett 2016; 590:819-27. [PMID: 26879265 DOI: 10.1002/1873-3468.12100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/02/2016] [Accepted: 02/05/2016] [Indexed: 11/06/2022]
Abstract
Rab11A is a small GTP-binding protein involved in the regulation of vesicle trafficking during recycling of endosomes. Substitution of S20 to V (S20V) at Rab11A inhibits the GTP hydrolysis activity of Rab11A. This mutation is known to be constitutively in an active form. Here, we report the crystal structure of the human Rab11A S20V mutant form complexed with GTP at a resolution of 2.4 Å. Without adding any substrate, Rab11A contained non-hydrolyzed natural substrate GTP in the nucleotide binding pocket with Mg(2+). In our observations, substituted V20 of Rab11A was found to interfere with proper localization of the water molecule, which mediated GTP hydrolysis, resulting in GTP being locked in an active form of Rab11A S20V.
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Affiliation(s)
- Jae Young Choi
- School of Biotechnology and Graduate School of Biochemistry at Yeungnam University, Gyeongsan, South Korea
| | - Young-Cheul Shin
- Department of Physiology, Department of Biomedical Sciences, and Institute of Dermatological Science, Seoul National University College of Medicine, South Korea
| | - Jong Hwan Yoon
- School of Biotechnology and Graduate School of Biochemistry at Yeungnam University, Gyeongsan, South Korea
| | - Chang Min Kim
- School of Biotechnology and Graduate School of Biochemistry at Yeungnam University, Gyeongsan, South Korea
| | - Jun Hyuck Lee
- Division of Polar Life Sciences, Korea Polar Research Institute, Inchon, South Korea
| | - Ju-Hong Jeon
- Department of Physiology, Department of Biomedical Sciences, and Institute of Dermatological Science, Seoul National University College of Medicine, South Korea
| | - Hyun Ho Park
- School of Biotechnology and Graduate School of Biochemistry at Yeungnam University, Gyeongsan, South Korea
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29
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Abstract
GTPases of the RAB family are key regulators of multiple steps of membrane trafficking. Several members of the RAB GTPase family have been implicated in mitotic progression. In this review, we will first focus on the function of endosome-associated RAB GTPases reported in early steps of mitosis, spindle pole maturation, and during cytokinesis. Second, we will discuss the role of Golgi-associated RAB GTPases at the metaphase/anaphase transition and during cytokinesis.
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Affiliation(s)
- Stéphanie Miserey-Lenkei
- Institut Curie, PSL Research University, Molecular Mechanisms of Intracellular Transport Group, CNRS UMR 144 Paris, France
| | - María I Colombo
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo Mendoza, Argentina
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30
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Bardin S, Miserey-Lenkei S, Hurbain I, Garcia-Castillo D, Raposo G, Goud B. Phenotypic characterisation of RAB6A knockout mouse embryonic fibroblasts. Biol Cell 2015; 107:427-39. [PMID: 26304202 DOI: 10.1111/boc.201400083] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 08/18/2015] [Indexed: 01/08/2023]
Abstract
BACKGROUND INFORMATION Rab6 is one of the most conserved Rab GTPaes throughout evolution and the most abundant Rab protein associated with the Golgi complex. The two ubiquitous Rab isoforms, Rab6A and Rab6A', that are generated by alternative splicing of the RAB6A gene, regulate several transport steps at the Golgi level, including retrograde transport between endosomes and Golgi, anterograde transport between Golgi and the plasma membrane, and intra-Golgi and Golgi to endoplasmic reticulum transport. RESULTS We have generated mice with a conditional null allele of RAB6A. Mice homozygous for the RAB6A null allele died at an early stage of embryonic development. Mouse embryonic fibroblasts (MEFs) were isolated from RAB6A(loxP/loxP) Rosa26-CreERT2 and incubated with 4-hydroxy tamoxifen, resulting in the efficient depletion of Rab6A and Rab6A'. We show that Rab6 depletion affects cell growth, alters Golgi morphology and decreases the Golgi-associated levels of some known Rab6 effectors such as Bicaudal-D and myosin II. We also show that Rab6 depletion protects MEFs against ricin toxin and delays VSV-G secretion. CONCLUSIONS Our study shows that RAB6 is an essential gene required for normal embryonic development. We confirm in MEF cells most of the functions previously attributed to the two ubiquitous Rab6 isoforms.
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Affiliation(s)
- Sabine Bardin
- Institut Curie, PSL Research University and CNRS UMR 144, Paris, 75248, France
| | | | - Ilse Hurbain
- Institut Curie, PSL Research University and CNRS UMR 144, Paris, 75248, France
| | - Daniela Garcia-Castillo
- Institut Curie, PSL Research University, CNRS UMR 3666 and INSERM U1143, Paris, 75248, France
| | - Graça Raposo
- Institut Curie, PSL Research University and CNRS UMR 144, Paris, 75248, France
| | - Bruno Goud
- Institut Curie, PSL Research University and CNRS UMR 144, Paris, 75248, France
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31
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Lall P, Lindsay AJ, Hanscom S, Kecman T, Taglauer ES, McVeigh UM, Franklin E, McCaffrey MW, Khan AR. Structure-Function Analyses of the Interactions between Rab11 and Rab14 Small GTPases with Their Shared Effector Rab Coupling Protein (RCP). J Biol Chem 2015; 290:18817-32. [PMID: 26032412 DOI: 10.1074/jbc.m114.612366] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Indexed: 01/05/2023] Open
Abstract
Rab GTPases recruit effector proteins, via their GTP-dependent switch regions, to distinct subcellular compartments. Rab11 and Rab25 are closely related small GTPases that bind to common effectors termed the Rab11 family of interacting proteins (FIPs). The FIPs are organized into two subclasses (class I and class II) based on sequence and domain organization, and both subclasses contain a highly conserved Rab-binding domain at their C termini. Yeast two-hybrid and biochemical studies have revealed that the more distantly related Rab14 also interacts with class I FIPs. Here, we perform detailed structural, thermodynamic, and cellular analyses of the interactions between Rab14 and one of the class I FIPs, the Rab-coupling protein (RCP), to clarify the molecular aspects of the interaction. We find that Rab14 indeed binds to RCP, albeit with reduced affinity relative to conventional Rab11-FIP and Rab25-FIP complexes. However, in vivo, Rab11 recruits RCP onto biological membranes. Furthermore, biophysical analyses reveal a noncanonical 1:2 stoichiometry between Rab14-RCP in dilute solutions, in contrast to Rab11/25 complexes. The structure of Rab14-RCP reveals that Rab14 interacts with the canonical Rab-binding domain and also provides insight into the unusual properties of the complex. Finally, we show that both the Rab coupling protein and Rab14 function in neuritogenesis.
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Affiliation(s)
- Patrick Lall
- From the School of Biochemistry and Immunology, Trinity College, Dublin 2 and
| | - Andrew J Lindsay
- the Molecular Cell Biology Laboratory, School of Biochemistry and Cell Biology, Biosciences Institute, University College Cork, Cork, Ireland
| | - Sara Hanscom
- the Molecular Cell Biology Laboratory, School of Biochemistry and Cell Biology, Biosciences Institute, University College Cork, Cork, Ireland
| | - Tea Kecman
- From the School of Biochemistry and Immunology, Trinity College, Dublin 2 and
| | | | - Una M McVeigh
- From the School of Biochemistry and Immunology, Trinity College, Dublin 2 and
| | - Edward Franklin
- From the School of Biochemistry and Immunology, Trinity College, Dublin 2 and
| | - Mary W McCaffrey
- the Molecular Cell Biology Laboratory, School of Biochemistry and Cell Biology, Biosciences Institute, University College Cork, Cork, Ireland
| | - Amir R Khan
- From the School of Biochemistry and Immunology, Trinity College, Dublin 2 and
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32
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Galea G, Bexiga MG, Panarella A, O'Neill ED, Simpson JC. A high-content screening microscopy approach to dissect the role of Rab proteins in Golgi-to-ER retrograde trafficking. J Cell Sci 2015; 128:2339-49. [PMID: 25999475 DOI: 10.1242/jcs.167973] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 05/18/2015] [Indexed: 12/24/2022] Open
Abstract
Here, we describe a high-content microscopy-based screen that allowed us to systematically assess and rank proteins involved in Golgi-to-endoplasmic reticulum (ER) retrograde transport in mammalian cells. Using a cell line stably expressing a GFP-tagged Golgi enzyme, we used brefeldin A treatment to stimulate the production of Golgi-to-ER carriers and then quantitatively analysed populations of cells for changes in this trafficking event. Systematic RNA interference (RNAi)-based depletion of 58 Rab GTPase proteins and 12 Rab accessory proteins of the PRAF, YIPF and YIF protein families revealed that nine of these were strong regulators. In addition to demonstrating roles for Rab1a, Rab1b, Rab2a, and Rab6a or Rab6a' in this transport step, we also identified Rab10 and Rab11a as playing a role and being physically present on a proportion of the Golgi-to-ER tubular intermediates. Combinatorial depletions of Rab proteins also revealed previously undescribed functional co-operation and physical co-occurrence between several Rab proteins. Our approach therefore provides a novel and robust strategy for a more complete investigation of the molecular components required to regulate Golgi-to-ER transport in mammalian cells.
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Affiliation(s)
- George Galea
- School of Biology and Environmental Science and UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Mariana G Bexiga
- School of Biology and Environmental Science and UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Angela Panarella
- School of Biology and Environmental Science and UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Elaine D O'Neill
- School of Biology and Environmental Science and UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Jeremy C Simpson
- School of Biology and Environmental Science and UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
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33
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Li Y, Xu J, Xiong H, Ma Z, Wang Z, Kipreos ET, Dalton S, Zhao S. Cancer driver candidate genes AVL9, DENND5A and NUPL1 contribute to MDCK cystogenesis. Oncoscience 2014; 1:854-865. [PMID: 25621300 PMCID: PMC4303893 DOI: 10.18632/oncoscience.107] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 12/14/2014] [Indexed: 12/12/2022] Open
Abstract
AVL9, DENND5A and NUPL1 are among the cancer driver candidate genes previously identified via dog-human comparison, and may function in epithelial cell polarity as indicated by bioinformatics analysis. To better understand their cellular functions and roles in cancer, we knocked down each gene in MDCKII cells through shRNA and performed three-dimensional culture. Compared to the control, the knockdown clones developed significantly more abnormal cysts, e.g., cysts with the lumen harboring dead and/or live cells, or cysts having multiple lumens. Further analysis revealed that abnormalities initiated at the first cell division and persisted throughout the entire cystogenesis process. For NUPL1-knockdown cells, abnormal cytogenesis largely arose from faulty cell divisions, notably monopolar spindles or spindles with poorly separated poles. For AVL9- or DENND5A-knockdown cells, abnormalities originated from both aberrant intracellular trafficking and defective mitosis. Moreover, while all knockdown clones displayed an accelerated rate of both cell proliferation and death, only AVL9- and DENND5A-knockdowns, but not NUPL1-knockdown, promoted cell migration. These observations indicate that NUPL1 contributes to bipolar spindle formation, whereas AVL9 and DENND5A participate in both intracellular trafficking and cell cycle progression. Our study shed lights on these genes' normal cellular functions and on how their alteration contributes to carcinogenesis.
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Affiliation(s)
- Yaping Li
- Department of Biochemistry and Molecular Biology, Institute of Bioinformatics, University of Georgia, Athens
| | - Jianing Xu
- Department of Biochemistry and Molecular Biology, Institute of Bioinformatics, University of Georgia, Athens.,Current Address: Human Oncology & Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York
| | - Huan Xiong
- Department of Biochemistry and Molecular Biology, Institute of Bioinformatics, University of Georgia, Athens
| | - Zhongyao Ma
- Department of Biochemistry and Molecular Biology, Institute of Bioinformatics, University of Georgia, Athens
| | - Zhenghe Wang
- Department of Genetics & Genome Sciences and Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio
| | | | - Stephen Dalton
- Department of Biochemistry and Molecular Biology, Institute of Bioinformatics, University of Georgia, Athens
| | - Shaying Zhao
- Department of Biochemistry and Molecular Biology, Institute of Bioinformatics, University of Georgia, Athens
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34
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Ailion M, Hannemann M, Dalton S, Pappas A, Watanabe S, Hegermann J, Liu Q, Han HF, Gu M, Goulding MQ, Sasidharan N, Schuske K, Hullett P, Eimer S, Jorgensen EM. Two Rab2 interactors regulate dense-core vesicle maturation. Neuron 2014; 82:167-80. [PMID: 24698274 DOI: 10.1016/j.neuron.2014.02.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2014] [Indexed: 12/14/2022]
Abstract
Peptide neuromodulators are released from a unique organelle: the dense-core vesicle. Dense-core vesicles are generated at the trans-Golgi and then sort cargo during maturation before being secreted. To identify proteins that act in this pathway, we performed a genetic screen in Caenorhabditis elegans for mutants defective in dense-core vesicle function. We identified two conserved Rab2-binding proteins: RUND-1, a RUN domain protein, and CCCP-1, a coiled-coil protein. RUND-1 and CCCP-1 colocalize with RAB-2 at the Golgi, and rab-2, rund-1, and cccp-1 mutants have similar defects in sorting soluble and transmembrane dense-core vesicle cargos. RUND-1 also interacts with the Rab2 GAP protein TBC-8 and the BAR domain protein RIC-19, a RAB-2 effector. In summary, a pathway of conserved proteins controls the maturation of dense-core vesicles at the trans-Golgi network.
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Affiliation(s)
- Michael Ailion
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA; Department of Biochemistry, University of Washington, Seattle WA, 98195, USA.
| | - Mandy Hannemann
- European Neuroscience Institute, 37077 Göttingen, Germany; International Max Planck Research School Molecular Biology, 37077 Göttingen, Germany
| | - Susan Dalton
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Andrea Pappas
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Shigeki Watanabe
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Jan Hegermann
- European Neuroscience Institute, 37077 Göttingen, Germany; DFG research Center for Molecular Physiology of the Brain (CMPB), 37077 Göttingen, Germany
| | - Qiang Liu
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Hsiao-Fen Han
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Mingyu Gu
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Morgan Q Goulding
- Department of Biochemistry, University of Washington, Seattle WA, 98195, USA
| | | | - Kim Schuske
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Patrick Hullett
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Stefan Eimer
- European Neuroscience Institute, 37077 Göttingen, Germany; DFG research Center for Molecular Physiology of the Brain (CMPB), 37077 Göttingen, Germany
| | - Erik M Jorgensen
- Howard Hughes Medical Institute, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA.
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35
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Khan AR, Ménétrey J. Structural biology of Arf and Rab GTPases' effector recruitment and specificity. Structure 2014; 21:1284-97. [PMID: 23931141 DOI: 10.1016/j.str.2013.06.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 05/30/2013] [Accepted: 06/05/2013] [Indexed: 11/15/2022]
Abstract
Arf and Rab proteins, members of small GTPases superfamily, localize to specific subcellular compartments and regulate intracellular trafficking. To carry out their cellular functions, Arfs/Rabs interact with numerous and structurally diverse effector proteins. Over the years, a number of Arf/Rab:effector complexes have been crystallized and their structures reveal shared binding modes including α-helical packing, β-β complementation, and heterotetrameric assemblies. We review available structural information and provide a framework for in-depth analysis of complexes. The unifying features that we identify are organized into a classification scheme for different modes of Arf/Rab:effector interactions, which includes "all-α-helical," "mixed α-helical," "β-β zipping," and "bivalent" modes of binding. Additionally, we highlight structural determinants that are the basis of effector specificity. We conclude by expanding on functional implications that are emerging from available structural information under our proposed classification scheme.
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Affiliation(s)
- Amir R Khan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
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36
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Lindsay AJ, Jollivet F, Horgan CP, Khan AR, Raposo G, McCaffrey MW, Goud B. Identification and characterization of multiple novel Rab-myosin Va interactions. Mol Biol Cell 2013; 24:3420-34. [PMID: 24006491 PMCID: PMC3814135 DOI: 10.1091/mbc.e13-05-0236] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
A systematic screen of the entire human Rab GTPase family for interactions with myosin Va identified 10 novel Rab partners for myosin Va, all of which belong to the endocytic recycling and post-Golgi secretory membrane network. However, Rab10 and Rab11 appear to be the major determinants of its recruitment to intracellular membranes. Myosin Va is a widely expressed actin-based motor protein that binds members of the Rab GTPase family (3A, 8A, 10, 11A, 27A) and is implicated in many intracellular trafficking processes. To our knowledge, myosin Va has not been tested in a systematic screen for interactions with the entire Rab GTPase family. To that end, we report a yeast two-hybrid screen of all human Rabs for myosin Va-binding ability and reveal 10 novel interactions (3B, 3C, 3D, 6A, 6A′, 6B, 11B, 14, 25, 39B), which include interactions with three new Rab subfamilies (Rab6, Rab14, Rab39B). Of interest, myosin Va interacts with only a subset of the Rabs associated with the endocytic recycling and post-Golgi secretory systems. We demonstrate that myosin Va has three distinct Rab-binding domains on disparate regions of the motor (central stalk, an alternatively spliced exon, and the globular tail). Although the total pool of myosin Va is shared by several Rabs, Rab10 and Rab11 appear to be the major determinants of its recruitment to intracellular membranes. We also present evidence that myosin Va is necessary for maintaining a peripheral distribution of Rab11- and Rab14-positive endosomes.
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Affiliation(s)
- Andrew J Lindsay
- Molecular Cell Biology Laboratory, School of Biochemistry and Cell Biology, Biosciences Institute, University College Cork, Cork, Ireland Centre de Recherche, Molecular Mechanisms of Intracellular Transport, Institut Curie, CNRS UMR144, F-75248 Paris, France School of Biochemistry and Immunology, Trinity College, Dublin 2, Ireland Structure and Membrane Compartments, Institut Curie, CNRS UMR144, F-75248 Paris, France Cell and Tissue Imaging Facility (PICT-IBiSA), Institut Curie, CNRS UMR144, F-75248 Paris, France
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37
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Abstract
The superfamily of small GTPases serves as a signal transducer to regulate a diverse array of cellular functions. The members of this superfamily are structurally and functionally classified into at least 5 groups (Ras, Rho/Rac, Rab, Arf, and Ran) and they are involved in the control of cell proliferation and differentiation, regulation of the actin cytoskeleton, membrane trafficking, and nuclear transport. It is widely reported that members of the Rab family participate in the control of intracellular membrane trafficking through the interaction with specific effector molecules. However, many Rabs and other small GTPases have also been shown to function in cell division. In this review, we discuss current knowledge about Rab proteins regulating different stages of the cell cycle, such as the congregation and segregation of chromosomes (during metaphase) and the final stage of cell division known as cytokinesis, in which a cell is cleaved originating 2 daughter cells.
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Affiliation(s)
- Rodrigo Militello
- Laboratorio de Biología Celular y Molecular; Instituto de Histología y Embriología (IHEM)-CONICET; Facultad de Ciencias Médicas; Universidad Nacional de Cuyo; Mendoza, Argentina
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38
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Abstract
Comprising over 60 members, Rab proteins constitute the largest branch of the Ras superfamily of low-molecular-mass G-proteins. This protein family have been primarily implicated in various aspects of intracellular membrane trafficking processes. On the basis of distinct subfamily-specific sequence motifs, many Rabs have been grouped into subfamilies. The Rab11 GTPase subfamily comprises three members: Rab11a, Rab11b and Rab25/Rab11c, which, between them, have been demonstrated to bind more than 30 proteins. In the present paper, we review the function of the Rab11 subfamily. We describe their localization and primary functional roles within the cell and their implication, to date, in disease processes. We also summarize the protein machinery currently known to regulate or mediate their functions and the cargo molecules which they have been shown to transport.
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39
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Abstract
The Ras-superfamily of small G proteins is a family of GTP hydrolases that is regulated by GTP/GDP binding states. One member of the Ras-superfamily, Rab, is involved in the regulation of vesicle trafficking, which is critical to endocytosis, biosynthesis, secretion, cell differentiation and cell growth. The active form of the Rab proteins, which contains GTP, can recruit specific binding partners, such as sorting adaptors, tethering factors, kinases, phosphatases and motor proteins, thereby influencing vesicle formation, transport, and tethering. Many Rab proteins share the same interacting partners and perform unique roles in specific locations. Because functional loss of the Rab pathways has been implicated in a variety of diseases, the Rab GTPase family has been extensively investigated. In this review, we summarize Rab GTPase- mediated membrane trafficking while focusing on the structures of Rab protein and Rab-effector complexes. This review provides detailed information that helps explain how the Rab GTPase family is involved in membrane trafficking.
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Affiliation(s)
- Hyun Ho Park
- School of Biotechnology and Graduate School of Biochemistry, Yeungnam University, Gyeongsan 712-749, Korea.
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40
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Niu Y, Zhang C, Sun Z, Hong Z, Li K, Sun D, Yang Y, Tian C, Gong W, Liu J. PtdIns(4)P regulates retromer–motor interaction to facilitate dynein–cargo dissociation at the trans-Golgi network. Nat Cell Biol 2013; 15:417-29. [DOI: 10.1038/ncb2710] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 02/14/2013] [Indexed: 02/08/2023]
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41
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Militello RD, Munafó DB, Berón W, López LA, Monier S, Goud B, Colombo MI. Rab24 is required for normal cell division. Traffic 2013; 14:502-18. [PMID: 23387408 DOI: 10.1111/tra.12057] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 02/04/2013] [Accepted: 02/06/2013] [Indexed: 12/18/2022]
Abstract
Rab24 is an atypical member of the Rab GTPase family whose distribution in interphase cells has been characterized; however, its function remains largely unknown. In this study, we have analyzed the distribution of Rab24 throughout cell division. We have observed that Rab24 was located at the mitotic spindle in metaphase, at the midbody during telophase and in the furrow during cytokinesis. We have also observed partial co-localization of Rab24 and tubulin and demonstrated its association to microtubules. Interestingly, more than 90% of transiently transfected HeLa cells with Rab24 presented abnormal nuclear connections (i.e., chromatin bridges). Furthermore, in CHO cells stably transfected with GFP-Rab24wt, we observed a large percentage of binucleated and multinucleated cells. In addition, these cells presented an extremely large size and multiple failures in mitosis, as aberrant spindle formation (metaphase), delayed chromosomes (telophase) and multiple cytokinesis. A marked increase in binucleated, multinucleated and multilobulated nucleus formation was observed in HeLa cells depleted of Rab24. We also present evidence that a fraction of Rab24 associates with microtubules. In addition, Rab24 knock down resulted in misalignment of chromosomes and abnormal spindle formation in metaphase leading to the appearance of delayed chromosomes during late telophase and failures in cytokinesis. Our findings suggest that an adequate level of Rab24 is necessary for normal cell division. In summary, Rab24 modulates several mitotic events, including chromosome segregation and cytokinesis, perhaps through the interaction with microtubules.
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Affiliation(s)
- Rodrigo D Militello
- Laboratorio de Biología Celular y Molecular- Instituto de Histología y Embriología (IHEM), Facultad de Ciencias Médicas, Universidad Nacional de Cuyo-CONICET, Mendoza, Argentina
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42
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Schulz M, Brandner S, Eberhagen C, Eckardt-Schupp F, Larsen MR, Andrae U. Quantitative phosphoproteomic analysis of early alterations in protein phosphorylation by 2,3,7,8-tetrachlorodibenzo-p-dioxin. J Proteome Res 2013; 12:866-82. [PMID: 23298284 DOI: 10.1021/pr3009429] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A comprehensive quantitative analysis of changes in protein phosphorylation preceding or accompanying transcriptional activation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in 5L rat hepatoma cells was performed using the SILAC approach. Following exposure of the cells to DMSO or 1 nM TCDD for 0.5 to 2 h, 5648 phosphorylated peptides corresponding to 2156 phosphoproteins were identified. Eight peptides exhibited a statistically significantly altered phosphorylation because of TCDD exposure and 22 showed a regulation factor of ≥ 1.5 in one of the experiments per time point. The vast majority of the TCCD-induced phosphorylation changes had not been reported before. The transcription factor ARNT, the obligate partner for gene activation by the TCDD-bound Ah receptor, exhibited an up-regulation of its Ser77 phosphorylation, a modification known to control the differential binding of ARNT homodimers and heterodimers to different enhancers suggesting that this phosphorylation represents a novel mechanism contributing to the alteration of gene expression by TCDD. Other proteins with altered phosphorylation included, among others, various transcriptional coregulators previously unknown to participate in TCDD-induced gene activation, regulators of small GTPases of the Ras superfamily, UBX domain-containing proteins and the oncogenic protein LYRIC. The results open up new directions for research on the molecular mechanisms of dioxin action and toxicity.
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Affiliation(s)
- Melanie Schulz
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
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43
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Abstract
Rabs comprise the largest member of the Ras superfamily of small GTPases with over 60 proteins in mammals and 11 proteins in yeast. Like all small GTPases, Rabs oscillate between an inactive GDP-bound conformation and an active GTP-bound state that is tethered to lipid membranes via a C-terminal prenylation site on conserved cysteine residues. In their active state, Rabs regulate various aspects of membrane trafficking, including vesicle formation, transport, docking, and fusion. The critical element of biological activity is the recruitment of cytosolic effector proteins to specific endomembranes by active Rabs. The importance of Rabs in cellular processes is apparent from their links to genetic disorders, immunodeficiency, cancer, and pathogen invasion. During the last decade, numerous structures of complexes have shed light on the molecular basis for Rab/effector specificity and their topological organization on subcellular membranes. Here, I review the known structures of Rab/effector complexes and their modes of oligomerization. This is followed by a brief discussion on the thermodynamics of effector recruitment, which has not been documented sufficiently in previous reviews. A summary of diseases associated with Rab/effector trafficking pathways concludes this chapter.
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Affiliation(s)
- Amir R Khan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
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44
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Lachance V, Degrandmaison J, Marois S, Robitaille M, Génier S, Nadeau S, Angers S, Parent JL. Ubiquitination and activation of a Rab GTPase promoted by a β2-Adrenergic Receptor/HACE1 complex. J Cell Sci 2013; 127:111-23. [DOI: 10.1242/jcs.132944] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We and others have shown that trafficking of G protein-coupled receptors is regulated by Rab GTPases. Cargo-mediated regulation of vesicular transport has received great attention lately. Rab GTPases, forming the largest branch of the Ras GTPase superfamily, regulate almost every step of vesicle-mediated trafficking. Rab GTPases are well-recognized targets of human diseases but their regulation and the mechanisms connecting them to cargo proteins are still poorly understood. Herein, we show by overexpression/depletion studies that HACE1, a HECT domain-containing ubiquitin ligase, promotes the recycling of the β2-adrenergic receptor (β2AR), a prototypical G protein-coupled receptor, through a Rab11a-dependent mechanism. Interestingly, the β2AR in conjunction with HACE1 triggered ubiquitination of Rab11a, as observed by Western blot analysis. LC-MS/MS experiments determined that Rab11a is ubiquitnatied on Lys145. A Rab11a-K145R mutant failed to undergo β2AR/HACE1-induced ubiquitination and inhibited the HACE1-mediated recycling of the β2AR. Rab11a, but not Rab11a-K145R, was activated by β2AR/HACE1 indicating that ubiquitination of Lys145 is involved in Rab11a activation. β2AR/HACE1 co-expression also potentiated ubiquitination of Rab6a and Rab8a, but not of other Rab GTPases that were tested. We report a novel regulatory mechanism of Rab GTPases by their ubiquitination with associated functional effects demonstrated on Rab11a. This partakes into a new pathway whereby a cargo protein, like a G protein-coupled receptor, can regulate its own trafficking by inducing the ubiquitination and activation of a Rab GTPase.
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45
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Henaff D, Radtke K, Lippé R. Herpesviruses exploit several host compartments for envelopment. Traffic 2012; 13:1443-9. [PMID: 22805610 DOI: 10.1111/j.1600-0854.2012.01399.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 07/13/2012] [Accepted: 07/17/2012] [Indexed: 01/16/2023]
Abstract
Enveloped viruses acquire their host-derived membrane at a variety of intracellular locations. Herpesviruses are complex entities that undergo several budding and fusion events during an infection. All members of this large family are believed to share a similar life cycle. However, they seemingly differ in terms of acquisition of their mature envelope. Herpes simplex virus is often believed to bud into an existing intracellular compartment, while the related cytomegalovirus may acquire its final envelope from a novel virus-induced assembly compartment. This review focuses on recent advances in the characterization of cellular compartment(s) potentially contributing to herpes virion final envelopment. It also examines the common points between seemingly distinct envelopment pathways and highlights the dynamic nature of intracellular compartments in the context of herpesvirus infections.
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Affiliation(s)
- Daniel Henaff
- Department of Pathology and Cell Biology, University of Montreal, Montreal, QC, Canada
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46
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Shin YC, Yoon JH, Jang TH, Kim SY, Heo WD, So I, Jeon JH, Park HH. Crystal structure of Rab6A'(Q72L) mutant reveals unexpected GDP/Mg²⁺ binding with opened GTP-binding domain. Biochem Biophys Res Commun 2012; 424:269-73. [PMID: 22750005 DOI: 10.1016/j.bbrc.2012.06.102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 06/20/2012] [Indexed: 01/14/2023]
Abstract
The Ras small G protein-superfamily is a family of GTP hydrolases whose activity is regulated by GTP/GDP binding states. Rab6A, a member of the Ras superfamily, is involved in the regulation of vesicle trafficking, which is critical for endocytosis, biosynthesis, secretion, cell differentiation and cell growth. Rab6A exists in two isoforms, termed RabA and Rab6A'. Substitution of Gln72 to Leu72 (Q72L) at Rab6 family blocks GTP hydrolysis activity and this mutation usually causes the Rab6 protein to be constitutively in an active form. Here, we report the crystal structure of the human Rab6A'(Q72L) mutant form at 1.9Å resolution. Unexpectedly, we found that Rab6A'(Q72L) possesses GDP/Mg(2+) in the GTP binding pockets, which is formed by a flexible switch I and switch II. Large conformational changes were also detected in the switch I and switch II regions. Our structure revealed that the non-hydrolysable, constitutively active form of Rab6A' can accommodate GDP/Mg(2+) in the open conformation.
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47
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Fernandes H, Franklin E, Jollivet F, Bliedtner K, Khan AR. Mapping the interactions between a RUN domain from DENND5/Rab6IP1 and sorting nexin 1. PLoS One 2012; 7:e35637. [PMID: 22558185 PMCID: PMC3338420 DOI: 10.1371/journal.pone.0035637] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 03/19/2012] [Indexed: 12/03/2022] Open
Abstract
Eukaryotic cells have developed a diverse repertoire of Rab GTPases to regulate vesicle trafficking pathways. Together with their effector proteins, Rabs mediate various aspects of vesicle formation, tethering, docking and fusion, but details of the biological roles elicited by effectors are largely unknown. Human Rab6 is involved in the trafficking of vesicles at the level of Golgi via interactions with numerous effector proteins. We have previously determined the crystal structure of Rab6 in complex with DENND5, alternatively called Rab6IP1, which comprises two RUN domains (RUN1 and RUN2) separated by a PLAT domain. The structure of Rab6/RUN1-PLAT (Rab6/R1P) revealed the molecular basis for Golgi recruitment of DENND5 via the RUN1 domain, but the functional role of the RUN2 domain has not been well characterized. Here we show that a soluble DENND5 construct encompassing the RUN2 domain binds to the N-terminal region of sorting nexin 1 by surface plasmon resonance analyses.
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Affiliation(s)
| | - Edward Franklin
- School of Biochemistry and Immunology, Trinity College, Dublin, Ireland
| | - Florence Jollivet
- School of Biochemistry and Immunology, Trinity College, Dublin, Ireland
| | | | - Amir R. Khan
- School of Biochemistry and Immunology, Trinity College, Dublin, Ireland
- * E-mail:
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48
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Abstract
Members of the Rab or ARF/Sar branches of the Ras GTPase superfamily regulate almost every step of intracellular membrane traffic. A rapidly growing body of evidence indicates that these GTPases do not act as lone agents but are networked to one another through a variety of mechanisms to coordinate the individual events of one stage of transport and to link together the different stages of an entire transport pathway. These mechanisms include guanine nucleotide exchange factor (GEF) cascades, GTPase-activating protein (GAP) cascades, effectors that bind to multiple GTPases, and positive-feedback loops generated by exchange factor-effector interactions. Together these mechanisms can lead to an ordered series of transitions from one GTPase to the next. As each GTPase recruits a unique set of effectors, these transitions help to define changes in the functionality of the membrane compartments with which they are associated.
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Affiliation(s)
- Emi Mizuno-Yamasaki
- Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan.
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49
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Abstract
The endo-lysosomal system is an interconnected tubulo-vesicular network that acts as a sorting station to process and distribute internalised cargo. This network accepts cargoes from both the plasma membrane and the biosynthetic pathway, and directs these cargos either towards the lysosome for degradation, the peri-nuclear recycling endosome for return to the cell surface, or to the trans-Golgi network. These intracellular membranes are variously enriched in different phosphoinositides that help to shape compartmental identity. These lipids act to localise a number of phosphoinositide-binding proteins that function as sorting machineries to regulate endosomal cargo sorting. Herein we discuss regulation of these machineries by phosphoinositides and explore how phosphoinositide-switching contributes toward sorting decisions made at this platform.
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Affiliation(s)
- Peter J Cullen
- Henry Wellcome Integrated Signaling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, BS8 1TD, Bristol, United Kingdom,
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50
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Lachance V, Cartier A, Génier S, Munger S, Germain P, Labrecque P, Parent JL. Regulation of β2-adrenergic receptor maturation and anterograde trafficking by an interaction with Rab geranylgeranyltransferase: modulation of Rab geranylgeranylation by the receptor. J Biol Chem 2011; 286:40802-13. [PMID: 21990357 DOI: 10.1074/jbc.m111.267815] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Previous reports by us and others demonstrated that G protein-coupled receptors interact functionally with Rab GTPases. Here, we show that the β(2)-adrenergic receptor (β(2)AR) interacts with the Rab geranylgeranyltransferase α-subunit (RGGTA). Confocal microscopy showed that β(2)AR co-localizes with RGGTA in intracellular compartments and at the plasma membrane. Site-directed mutagenesis revealed that RGGTA binds to the L(339)L(340) motif in the β(2)AR C terminus known to be involved in the transport of the receptor from the endoplasmic reticulum to the cell surface. Modulation of the cellular levels of RGGTA protein by overexpression or siRNA-mediated knockdown of the endogenous protein demonstrated that RGGTA has a positive role in the maturation and anterograde trafficking of the β(2)AR, which requires the interaction of RGGTA with the β(2)AR L(339)L(340) motif. Furthermore, the β(2)AR modulates the geranylgeranylation of Rab6a, Rab8a, and Rab11a, but not of other Rab proteins tested in this study. Regulation of Rab geranylgeranylation by the β(2)AR was dependent on the RGGTA-interacting L(339)L(340) motif. Interestingly, a RGGTA-Y107F mutant was unable to regulate Rab geranylgeranylation but still promoted β(2)AR maturation, suggesting that RGGTA may have functions independent of Rab geranylgeranylation. We demonstrate for the first time an interaction between a transmembrane receptor and RGGTA which regulates the maturation and anterograde transport of the receptor, as well as geranylgeranylation of Rab GTPases.
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Affiliation(s)
- Véronik Lachance
- Service de Rhumatologie, Département de Médecine, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, the Centre de Recherche Clinique Étienne-Le Bel, and the Institut de Pharmacologie de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4
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