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Meshref M, Ghaith HS, Hammad MA, Shalaby MMM, Ayasra F, Monib FA, Attia MS, Ebada MA, Elsayed H, Shalash A, Bahbah EI. The Role of RIN3 Gene in Alzheimer's Disease Pathogenesis: a Comprehensive Review. Mol Neurobiol 2024; 61:3528-3544. [PMID: 37995081 PMCID: PMC11087354 DOI: 10.1007/s12035-023-03802-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 11/10/2023] [Indexed: 11/24/2023]
Abstract
Alzheimer's disease (AD) is a globally prevalent form of dementia that impacts diverse populations and is characterized by progressive neurodegeneration and impairments in executive memory. Although the exact mechanisms underlying AD pathogenesis remain unclear, it is commonly accepted that the aggregation of misfolded proteins, such as amyloid plaques and neurofibrillary tau tangles, plays a critical role. Additionally, AD is a multifactorial condition influenced by various genetic factors and can manifest as either early-onset AD (EOAD) or late-onset AD (LOAD), each associated with specific gene variants. One gene of particular interest in both EOAD and LOAD is RIN3, a guanine nucleotide exchange factor. This gene plays a multifaceted role in AD pathogenesis. Firstly, upregulation of RIN3 can result in endosomal enlargement and dysfunction, thereby facilitating the accumulation of beta-amyloid (Aβ) peptides in the brain. Secondly, RIN3 has been shown to impact the PICLAM pathway, affecting transcytosis across the blood-brain barrier. Lastly, RIN3 has implications for immune-mediated responses, notably through its influence on the PTK2B gene. This review aims to provide a concise overview of AD and delve into the role of the RIN3 gene in its pathogenesis.
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Affiliation(s)
- Mostafa Meshref
- Department of Neurology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt
| | | | | | | | - Faris Ayasra
- Faculty of Medicine, The Hashemite University, Zarqa, Jordan
| | | | - Mohamed S Attia
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | | | - Hanaa Elsayed
- Faculty of Medicine, Zagazig University, Zagazig, Egypt
| | - Ali Shalash
- Department of Neurology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Eshak I Bahbah
- Faculty of Medicine, Al-Azhar University, Damietta, Egypt.
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Cabana VC, Bouchard AY, Sénécal AM, Ghilarducci K, Kourrich S, Cappadocia L, Lussier MP. RNF13 Dileucine Motif Variants L311S and L312P Interfere with Endosomal Localization and AP-3 Complex Association. Cells 2021; 10:cells10113063. [PMID: 34831286 PMCID: PMC8620429 DOI: 10.3390/cells10113063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 12/24/2022] Open
Abstract
Developmental and epileptic encephalopathies (DEE) are rare and serious neurological disorders characterized by severe epilepsy with refractory seizures and a significant developmental delay. Recently, DEE73 was linked to genetic alterations of the RNF13 gene, which convert positions 311 or 312 in the RNF13 protein from leucine to serine or proline, respectively (L311S and L312P). Using a fluorescence microscopy approach to investigate the molecular and cellular mechanisms affected by RNF13 protein variants, the current study shows that wild-type RNF13 localizes extensively with endosomes and lysosomes, while L311S and L312P do not extensively colocalize with the lysosomal marker Lamp1. Our results show that RNF13 L311S and L312P proteins affect the size of endosomal vesicles along with the temporal and spatial progression of fluorescently labeled epidermal growth factor, but not transferrin, in the endolysosomal system. Furthermore, GST-pulldown and co-immunoprecipitation show that RNF13 variants disrupt association with AP-3 complex. Knockdown of AP-3 complex subunit AP3D1 alters the lysosomal localization of wild-type RNF13 and similarly affects the size of endosomal vesicles. Importantly, our study provides a first step toward understanding the cellular and molecular mechanism altered by DEE73-associated genetic variations of RNF13.
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Affiliation(s)
- Valérie C. Cabana
- Département de Chimie, Université du Québec à Montréal, Montréal, QC H2X 2J6, Canada; (V.C.C.); (A.Y.B.); (A.M.S.); (K.G.); (L.C.)
- Centre d’Excellence en Recherche sur les Maladies Orphelines—Fondation Courtois (CERMO-FC), Université du Québec à Montréal, Montréal, QC H2X 3Y7, Canada;
| | - Antoine Y. Bouchard
- Département de Chimie, Université du Québec à Montréal, Montréal, QC H2X 2J6, Canada; (V.C.C.); (A.Y.B.); (A.M.S.); (K.G.); (L.C.)
- Centre d’Excellence en Recherche sur les Maladies Orphelines—Fondation Courtois (CERMO-FC), Université du Québec à Montréal, Montréal, QC H2X 3Y7, Canada;
| | - Audrey M. Sénécal
- Département de Chimie, Université du Québec à Montréal, Montréal, QC H2X 2J6, Canada; (V.C.C.); (A.Y.B.); (A.M.S.); (K.G.); (L.C.)
- Centre d’Excellence en Recherche sur les Maladies Orphelines—Fondation Courtois (CERMO-FC), Université du Québec à Montréal, Montréal, QC H2X 3Y7, Canada;
| | - Kim Ghilarducci
- Département de Chimie, Université du Québec à Montréal, Montréal, QC H2X 2J6, Canada; (V.C.C.); (A.Y.B.); (A.M.S.); (K.G.); (L.C.)
- Centre d’Excellence en Recherche sur les Maladies Orphelines—Fondation Courtois (CERMO-FC), Université du Québec à Montréal, Montréal, QC H2X 3Y7, Canada;
| | - Saïd Kourrich
- Centre d’Excellence en Recherche sur les Maladies Orphelines—Fondation Courtois (CERMO-FC), Université du Québec à Montréal, Montréal, QC H2X 3Y7, Canada;
- Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Laurent Cappadocia
- Département de Chimie, Université du Québec à Montréal, Montréal, QC H2X 2J6, Canada; (V.C.C.); (A.Y.B.); (A.M.S.); (K.G.); (L.C.)
- Centre d’Excellence en Recherche sur les Maladies Orphelines—Fondation Courtois (CERMO-FC), Université du Québec à Montréal, Montréal, QC H2X 3Y7, Canada;
| | - Marc P. Lussier
- Département de Chimie, Université du Québec à Montréal, Montréal, QC H2X 2J6, Canada; (V.C.C.); (A.Y.B.); (A.M.S.); (K.G.); (L.C.)
- Centre d’Excellence en Recherche sur les Maladies Orphelines—Fondation Courtois (CERMO-FC), Université du Québec à Montréal, Montréal, QC H2X 3Y7, Canada;
- Correspondence: ; Tel.: +1-(514)-987-3000 (ext. 5591); Fax: +1-(514)-987-4054
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Parkinson G, Roboti P, Zhang L, Taylor S, Woodman P. His domain protein tyrosine phosphatase and Rabaptin-5 couple endo-lysosomal sorting of EGFR with endosomal maturation. J Cell Sci 2021; 134:272512. [PMID: 34657963 PMCID: PMC8627557 DOI: 10.1242/jcs.259192] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/13/2021] [Indexed: 01/20/2023] Open
Abstract
His domain protein tyrosine phosphatase (HD-PTP; also known as PTPN23) collaborates with endosomal sorting complexes required for transport (ESCRTs) to sort endosomal cargo into intralumenal vesicles, forming the multivesicular body (MVB). Completion of MVB sorting is accompanied by maturation of the endosome into a late endosome, an event that requires inactivation of the early endosomal GTPase Rab5 (herein referring to generically to all isoforms). Here, we show that HD-PTP links ESCRT function with endosomal maturation. HD-PTP depletion prevents MVB sorting, while also blocking cargo from exiting Rab5-rich endosomes. HD-PTP-depleted cells contain hyperphosphorylated Rabaptin-5 (also known as RABEP1), a cofactor for the Rab5 guanine nucleotide exchange factor Rabex-5 (also known as RABGEF1), although HD-PTP is unlikely to directly dephosphorylate Rabaptin-5. In addition, HD-PTP-depleted cells exhibit Rabaptin-5-dependent hyperactivation of Rab5. HD-PTP binds directly to Rabaptin-5, between its Rabex-5- and Rab5-binding domains. This binding reaction involves the ESCRT-0/ESCRT-III binding site in HD-PTP, which is competed for by an ESCRT-III peptide. Jointly, these findings indicate that HD-PTP may alternatively scaffold ESCRTs and modulate Rabex-5–Rabaptin-5 activity, thereby helping to coordinate the completion of MVB sorting with endosomal maturation. Summary: Sorting of endocytic cargo to the multivesicular body is accompanied by endosomal maturation. Here, we provide a potential mechanism by which these two processes are linked.
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Affiliation(s)
- Gabrielle Parkinson
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Peristera Roboti
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Ling Zhang
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Sandra Taylor
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Philip Woodman
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
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Borchers AC, Langemeyer L, Ungermann C. Who's in control? Principles of Rab GTPase activation in endolysosomal membrane trafficking and beyond. J Cell Biol 2021; 220:212549. [PMID: 34383013 PMCID: PMC8366711 DOI: 10.1083/jcb.202105120] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/08/2021] [Accepted: 07/08/2021] [Indexed: 12/12/2022] Open
Abstract
The eukaryotic endomembrane system consists of multiple interconnected organelles. Rab GTPases are organelle-specific markers that give identity to these membranes by recruiting transport and trafficking proteins. During transport processes or along organelle maturation, one Rab is replaced by another, a process termed Rab cascade, which requires at its center a Rab-specific guanine nucleotide exchange factor (GEF). The endolysosomal system serves here as a prime example for a Rab cascade. Along with endosomal maturation, the endosomal Rab5 recruits and activates the Rab7-specific GEF Mon1-Ccz1, resulting in Rab7 activation on endosomes and subsequent fusion of endosomes with lysosomes. In this review, we focus on the current idea of Mon1-Ccz1 recruitment and activation in the endolysosomal and autophagic pathway. We compare identified principles to other GTPase cascades on endomembranes, highlight the importance of regulation, and evaluate in this context the strength and relevance of recent developments in in vitro analyses to understand the underlying foundation of organelle biogenesis and maturation.
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Affiliation(s)
- Ann-Christin Borchers
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany.,Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
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Peterson TA, Piper RC. Deconvolution of Multiple Rab Binding Domains Using the Batch Yeast 2-Hybrid Method DEEPN. Methods Mol Biol 2021; 2293:117-141. [PMID: 34453714 PMCID: PMC8524840 DOI: 10.1007/978-1-0716-1346-7_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A hallmark of functionally significant interactions between Rab proteins and their targets is whether that binding depends on the type of nucleotide bound to the Rab GTPase. A system that can directly compare those sets of interactions mediated by a Rab in its GTP-bound conformation versus its GDP bound conformation would provide a direct route to finding biologically relevant partners. Comprehensive large-scale yeast 2-hybrid assays allow a potential method to compare one interactome against another provided that the same set of potentially interacting partners is interrogated between samples. Here we describe the use of such a yeast 2-hybrid system that lends itself toward comparing pairs of Rab mutants, locked in either their GTP or GDP conformation. Importantly, using a complex library of protein fragments as potential binding ("prey") partners, identification of interacting proteins as well as the domain(s) mediating those interactions can be determined using a series of sequence analyses and binary validation experiments.
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Affiliation(s)
- Tabitha A Peterson
- Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Robert C Piper
- Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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White Spot Syndrome Virus Benefits from Endosomal Trafficking, Substantially Facilitated by a Valosin-Containing Protein, To Escape Autophagic Elimination and Propagate in the Crustacean Cherax quadricarinatus. J Virol 2020; 94:JVI.01570-20. [PMID: 32967962 DOI: 10.1128/jvi.01570-20] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/15/2020] [Indexed: 12/19/2022] Open
Abstract
As the most severely lethal viral pathogen for crustaceans in both brackish water and freshwater, white spot syndrome virus (WSSV) has a mechanism of infection that remains largely unknown, which profoundly limits the control of WSSV disease. By using a hematopoietic tissue (Hpt) stem cell culture from the red claw crayfish Cherax quadricarinatus suitable for WSSV propagation in vitro, the intracellular trafficking of live WSSV, in which the acidic-pH-dependent endosomal environment was a prerequisite for WSSV fusion, was determined for the first time via live-cell imaging. When the acidic pH within the endosome was alkalized by chemicals, the intracellular WSSV virions were detained in dysfunctional endosomes, resulting in appreciable blocking of the viral infection. Furthermore, disrupted valosin-containing protein (C. quadricarinatus VCP [CqVCP]) activity resulted in considerable aggregation of endocytic WSSV virions in the disordered endosomes, which subsequently recruited autophagosomes, likely by binding to CqGABARAP via CqVCP, to eliminate the aggregated virions within the dysfunctional endosomes. Importantly, both autophagic sorting and the degradation of intracellular WSSV virions were clearly enhanced in Hpt cells with increased autophagic activity, demonstrating that autophagy played a defensive role against WSSV infection. Intriguingly, most of the endocytic WSSV virions were directed to the endosomal delivery system facilitated by CqVCP activity so that they avoided autophagy degradation and successfully delivered the viral genome into Hpt cell nuclei, which was followed by the propagation of progeny virions. These findings will benefit anti-WSSV target design against the most severe viral disease currently affecting farmed crustaceans.IMPORTANCE White spot disease is currently the most devastating viral disease in farmed crustaceans, such as shrimp and crayfish, and has resulted in a severe ecological problem for both brackish water and freshwater aquaculture areas worldwide. Efficient antiviral control of WSSV disease is still lacking due to our limited knowledge of its pathogenesis. Importantly, research on the WSSV infection mechanism is also quite meaningful for the elucidation of viral pathogenesis and virus-host coevolution, as WSSV is one of the largest animal viruses, in terms of genome size, that infects only crustaceans. Here, we found that most of the endocytic WSSV virions were directed to the endosomal delivery system, strongly facilitated by CqVCP, so that they avoided autophagic degradation and successfully delivered the viral genome into the Hpt cell nucleus for propagation. Our data point to a virus-sorting model that might also explain the escape of other enveloped DNA viruses.
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Formation and Maturation of the Phagosome: A Key Mechanism in Innate Immunity against Intracellular Bacterial Infection. Microorganisms 2020; 8:microorganisms8091298. [PMID: 32854338 PMCID: PMC7564318 DOI: 10.3390/microorganisms8091298] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 02/07/2023] Open
Abstract
Phagocytosis is an essential mechanism in innate immune defense, and in maintaining homeostasis to eliminate apoptotic cells or microbes, such as Mycobacterium tuberculosis, Salmonella enterica, Streptococcus pyogenes and Legionella pneumophila. After internalizing microbial pathogens via phagocytosis, phagosomes undergo a series of ‘maturation’ steps, to form an increasingly acidified compartment and subsequently fuse with the lysosome to develop into phagolysosomes and effectively eliminate the invading pathogens. Through this mechanism, phagocytes, including macrophages, neutrophils and dendritic cells, are involved in the processing of microbial pathogens and antigen presentation to T cells to initiate adaptive immune responses. Therefore, phagocytosis plays a role in the bridge between innate and adaptive immunity. However, intracellular bacteria have evolved diverse strategies to survive and replicate within hosts. In this review, we describe the sequential stages in the phagocytosis process. We also discuss the immune evasion strategies used by pathogens to regulate phagosome maturation during intracellular bacterial infection, and indicate that these might be used for the development of potential therapeutic strategies for infectious diseases.
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Abstract
With over 30% of current medications targeting this family of proteins, G-protein-coupled receptors (GPCRs) remain invaluable therapeutic targets. However, due to their unique physicochemical properties, their low abundance, and the lack of highly specific antibodies, GPCRs are still challenging to study in vivo. To overcome these limitations, we combined here transgenic mouse models and proteomic analyses in order to resolve the interactome of the δ-opioid receptor (DOPr) in its native in vivo environment. Given its analgesic properties and milder undesired effects than most clinically prescribed opioids, DOPr is a promising alternative therapeutic target for chronic pain management. However, the molecular and cellular mechanisms regulating its signaling and trafficking remain poorly characterized. We thus performed liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses on brain homogenates of our newly generated knockin mouse expressing a FLAG-tagged version of DOPr and revealed several endogenous DOPr interactors involved in protein folding, trafficking, and signal transduction. The interactions with a few identified partners such as VPS41, ARF6, Rabaptin-5, and Rab10 were validated. We report an approach to characterize in vivo interacting proteins of GPCRs, the largest family of membrane receptors with crucial implications in virtually all physiological systems.
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Tubbesing K, Ward J, Abini-Agbomson R, Malhotra A, Rudkouskaya A, Warren J, Lamar J, Martino N, Adam AP, Barroso M. Complex Rab4-Mediated Regulation of Endosomal Size and EGFR Activation. Mol Cancer Res 2020; 18:757-773. [PMID: 32019812 PMCID: PMC7526990 DOI: 10.1158/1541-7786.mcr-19-0052] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 09/24/2019] [Accepted: 01/30/2020] [Indexed: 11/16/2022]
Abstract
Early sorting endosomes are responsible for the trafficking and function of transferrin receptor (TfR) and EGFR. These receptors play important roles in iron uptake and signaling and are critical for breast cancer development. However, the role of morphology, receptor composition, and signaling of early endosomes in breast cancer remains poorly understood. A novel population of enlarged early endosomes was identified in breast cancer cells and tumor xenografts but not in noncancerous MCF10A cells. Quantitative analysis of endosomal morphology, cargo sorting, EGFR activation, and Rab GTPase regulation was performed using super-resolution and confocal microscopy followed by 3D rendering. MDA-MB-231 breast cancer cells have fewer, but larger EEA1-positive early endosomes compared with MCF10A cells. Live-cell imaging indicated dysregulated cargo sorting, because EGF and Tf traffic together via enlarged endosomes in MDA-MB-231, but not in MCF10A. Large EEA1-positive MDA-MB-231 endosomes exhibited prolonged and increased EGF-induced activation of EGFR upon phosphorylation at tyrosine-1068 (EGFR-p1068). Rab4A overexpression in MCF10A cells produced EEA1-positive enlarged endosomes that displayed prolonged and amplified EGF-induced EGFR-p1068 activation. Knockdown of Rab4A lead to increased endosomal size in MCF10A, but not in MDA-MB-231 cells. Nevertheless, Rab4A knockdown resulted in enhanced EGF-induced activation of EGFR-p1068 in MDA-MB-231 as well as downstream signaling in MCF10A cells. Altogether, this extensive characterization of early endosomes in breast cancer cells has identified a Rab4-modulated enlarged early endosomal compartment as the site of prolonged and increased EGFR activation. IMPLICATIONS: Enlarged early endosomes play a Rab4-modulated role in regulation of EGFR activation in breast cancer cells.
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Affiliation(s)
- Kate Tubbesing
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - Jamie Ward
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - Raymond Abini-Agbomson
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - Aditi Malhotra
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - Alena Rudkouskaya
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - Janine Warren
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - John Lamar
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - Nina Martino
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - Alejandro P Adam
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
- Department of Ophthalmology, Albany Medical College, Albany, New York
| | - Margarida Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York.
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Bezeljak U, Loya H, Kaczmarek B, Saunders TE, Loose M. Stochastic activation and bistability in a Rab GTPase regulatory network. Proc Natl Acad Sci U S A 2020; 117:6540-6549. [PMID: 32161136 PMCID: PMC7104049 DOI: 10.1073/pnas.1921027117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The eukaryotic endomembrane system is controlled by small GTPases of the Rab family, which are activated at defined times and locations in a switch-like manner. While this switch is well understood for an individual protein, how regulatory networks produce intracellular activity patterns is currently not known. Here, we combine in vitro reconstitution experiments with computational modeling to study a minimal Rab5 activation network. We find that the molecular interactions in this system give rise to a positive feedback and bistable collective switching of Rab5. Furthermore, we find that switching near the critical point is intrinsically stochastic and provide evidence that controlling the inactive population of Rab5 on the membrane can shape the network response. Notably, we demonstrate that collective switching can spread on the membrane surface as a traveling wave of Rab5 activation. Together, our findings reveal how biochemical signaling networks control vesicle trafficking pathways and how their nonequilibrium properties define the spatiotemporal organization of the cell.
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Affiliation(s)
- Urban Bezeljak
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Hrushikesh Loya
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Beata Kaczmarek
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Timothy E Saunders
- Mechanobiology Institute, National University of Singapore, Singapore 119077;
- Department of Biological Sciences, National University of Singapore, Singapore 119077
| | - Martin Loose
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria;
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Liu W, Han J, Shi S, Dai Y, He J. TUFT1 promotes metastasis and chemoresistance in triple negative breast cancer through the TUFT1/Rab5/Rac1 pathway. Cancer Cell Int 2019; 19:242. [PMID: 31572059 PMCID: PMC6757435 DOI: 10.1186/s12935-019-0961-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/13/2019] [Indexed: 12/19/2022] Open
Abstract
Background Triple negative breast cancer (TNBC) is a breast cancer (BC) subtype that is characterized by its strong invasion and a high risk of metastasis. However, the specific mechanisms underlying these phenotypes are unclear. TUFT1 plays an important role in BC and impacts the proliferation and survival of BC cells. Recent studies have shown that TUFT1 mediates intracellular lysosome localization and vesicle transport by regulating Rab GTPase, but the relevance of this activity in TNBC is unknown. Therefore, our aim was to systematically study the role of TUFT1 in the metastasis and chemoresistance of TNBC. Methods We measured TUFT1, Rab5-GTP, and Rac1-GTP expression levels in samples of human TNBC by immunohistochemistry (IHC) and conducted univariate and multivariate analyses. shRNA-mediated knockdown and overexpression, combined with transwell assays, co-immunoprecipitation, a nude mouse xenograft tumor model, and GTP activity assays were used for further mechanistic studies. Results TUFT1 expression was positively correlated with Rab5-GTP and Rac1-GTP in the TNBC samples, and co-expression of TUFT1 and Rab5-GTP predicted poor prognosis in TNBC patients who were treated with chemotherapy. Mechanism studies showed that TUFT1 could activate Rab5 by binding to p85α, leading to activation of Rac1 through recruitment of Tiam1, and concurrent down-regulation of the NF-κB pathway and proapoptotic factors, ultimately promoting metastasis and chemoresistance in TNBC cells. Conclusions Our findings suggest that the TUFT1/Rab5/Rac1 pathway may be a potential target for the effective treatment of TNBC.
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Affiliation(s)
- Weiguang Liu
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, 056000 Hebei China
| | - Jianjun Han
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, 056000 Hebei China
| | - Sufang Shi
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, 056000 Hebei China
| | - Yuna Dai
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, 056000 Hebei China
| | - Jianchao He
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, 056000 Hebei China
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Liu W, Chen G, Sun L, Zhang Y, Han J, Dai Y, He J, Shi S, Chen B. TUFT1 Promotes Triple Negative Breast Cancer Metastasis, Stemness, and Chemoresistance by Up-Regulating the Rac1/β-Catenin Pathway. Front Oncol 2019; 9:617. [PMID: 31338333 PMCID: PMC6629836 DOI: 10.3389/fonc.2019.00617] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 06/24/2019] [Indexed: 12/26/2022] Open
Abstract
Objectives: Triple negative breast cancer (TNBC) is a subtype of breast cancer with stronger invasion and metastasis, but its specific mechanism of action is still unclear. Tuft1 plays an important regulatory role in the survival of breast cancer cells; however, its role in regulating TNBC metastatic potential has not been well-characterized. Our aim was therefore to systematically study the mechanism of TUFT1 in the metastasis, stemness, and chemoresistance of TNBC and provide new predictors and targets for BC treatment. Methods: We used western blotting and IHC to measure TUFT1and Rac1-GTP expression levels in both human BC samples and cell lines. A combination of shRNA, migration/invasion assays, sphere formation assay, apoptosis assays, nude mouse xenograft tumor model, and GTP activity assays was used for further mechanistic studies. Results: We demonstrated that silencing TUFT1 in TNBC cells significantly inhibited cell metastasis and stemness in vitro. A nude mouse xenograft tumor model revealed that TUFT1 knockdown greatly decreased spontaneous lung metastasis of TNBC tumors. Mechanism studies showed that TUFT1 promoted tumor cell metastasis and stemness by up-regulating the Rac1/β-catenin pathway. Moreover, mechanistic studies indicated that the lack of TUFT1 expression in TNBC cells conferred more sensitive to chemotherapy and increased cell apoptosis via down-regulating the Rac1/β-catenin signaling pathway. Further, TUFT1 expression positively correlated with Rac1-GTP in TNBC samples, and co-expression of TUFT1 and Rac1-GTP predicted poor prognosis in TNBC patients who treated with chemotherapy. Conclusion: Our findings suggest that TUFT1/Rac1/β-catenin pathway may provide a potential target for more effective treatment of TNBC.
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Affiliation(s)
- Weiguang Liu
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, China
| | - Guanglei Chen
- Department of Breast Surgery, Shengjing Hospital of China Medical University, Shenyang, China
| | - Lisha Sun
- Department of Breast Surgery, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yue Zhang
- Department of Physiology, Dalian Medical University, Dalian, China
| | - Jianjun Han
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, China
| | - Yuna Dai
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, China
| | - Jianchao He
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, China
| | - Sufang Shi
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, China
| | - Bo Chen
- Department of Breast Surgery, The First Hospital of China Medical University, Shenyang, China
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13
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Piedade GS, Schirmer CM, Goren O, Zhang H, Aghajanian A, Faber JE, Griessenauer CJ. Cerebral Collateral Circulation: A Review in the Context of Ischemic Stroke and Mechanical Thrombectomy. World Neurosurg 2019; 122:33-42. [PMID: 30342266 DOI: 10.1016/j.wneu.2018.10.066] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/06/2018] [Accepted: 10/08/2018] [Indexed: 01/28/2023]
Abstract
The pial (leptomenigeal) collateral circulation is a key determinant of functional outcome after mechanical thrombectomy after large-vessel ischemic stroke. Patients with good collateral blood flow benefit up to 24 hours after stroke onset, whereas those with poor collateral flow evidence less or no benefit. However, clues to why collateral flow varies so widely among patients have remained elusive. Recent findings in animal studies, which are currently being tested for confirmation in humans, have found that naturally occurring variants of a novel "collateral gene," Rabep2, result in large differences in the extent of anatomic collaterals and thus blood flow and infarct size in mice after stroke. The comprehension of collagerogenesis in humans and the evaluation of collateral status could aid in identifying patients who will benefit not only from mechanical thrombectomy in the extended time window but also from any reperfusion strategy. We performed a literature review focused on radiographic, clinical, and genetic aspects of the collateral circulation.
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Affiliation(s)
- Guilherme Santos Piedade
- Department of Neurosurgery, Geisinger, Pennsylvania, USA; Department of Neurosurgery, University of Düsseldorf, Düsseldorf, Germany
| | | | - Oded Goren
- Department of Neurosurgery, Geisinger, Pennsylvania, USA
| | - Hua Zhang
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Amir Aghajanian
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - James E Faber
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Christoph J Griessenauer
- Department of Neurosurgery, Geisinger, Pennsylvania, USA; Research Institute of Neurointervention, Paracelsus Medical University, Salzburg, Austria; Department of Neurosurgery, Paracelsus Medical University, Salzburg, Austria.
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14
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Nag S, Rani S, Mahanty S, Bissig C, Arora P, Azevedo C, Saiardi A, van der Sluijs P, Delevoye C, van Niel G, Raposo G, Setty SRG. Rab4A organizes endosomal domains for sorting cargo to lysosome-related organelles. J Cell Sci 2018; 131:jcs.216226. [PMID: 30154210 PMCID: PMC6151265 DOI: 10.1242/jcs.216226] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 08/08/2018] [Indexed: 12/13/2022] Open
Abstract
Sorting endosomes (SEs) are the regulatory hubs for sorting cargo to multiple organelles, including lysosome-related organelles, such as melanosomes in melanocytes. In parallel, melanosome biogenesis is initiated from SEs with the processing and sequential transport of melanocyte-specific proteins toward maturing melanosomes. However, the mechanism of cargo segregation on SEs is largely unknown. Here, RNAi screening in melanocytes revealed that knockdown of Rab4A results in defective melanosome maturation. Rab4A-depletion increases the number of vacuolar endosomes and disturbs the cargo sorting, which in turn lead to the mislocalization of melanosomal proteins to lysosomes, cell surface and exosomes. Rab4A localizes to the SEs and forms an endosomal complex with the adaptor AP-3, the effector rabenosyn-5 and the motor KIF3, which possibly coordinates cargo segregation on SEs. Consistent with this, inactivation of rabenosyn-5, KIF3A or KIF3B phenocopied the defects observed in Rab4A-knockdown melanocytes. Further, rabenosyn-5 was found to associate with rabaptin-5 or Rabip4/4' (isoforms encoded by Rufy1) and differentially regulate cargo sorting from SEs. Thus, Rab4A acts a key regulator of cargo segregation on SEs.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Sudeshna Nag
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560 012
| | - Shikha Rani
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560 012
| | - Sarmistha Mahanty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560 012
| | - Christin Bissig
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, F-75005, Paris, France
| | - Pooja Arora
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560 012
| | - Cristina Azevedo
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Adolfo Saiardi
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Peter van der Sluijs
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Cedric Delevoye
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, F-75005, Paris, France.,Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), F-75005, Paris, France
| | - Guillaume van Niel
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, F-75005, Paris, France.,Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), F-75005, Paris, France
| | - Graca Raposo
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, F-75005, Paris, France.,Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), F-75005, Paris, France
| | - Subba Rao Gangi Setty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560 012
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15
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Langemeyer L, Fröhlich F, Ungermann C. Rab GTPase Function in Endosome and Lysosome Biogenesis. Trends Cell Biol 2018; 28:957-970. [PMID: 30025982 DOI: 10.1016/j.tcb.2018.06.007] [Citation(s) in RCA: 244] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/15/2018] [Accepted: 06/25/2018] [Indexed: 10/28/2022]
Abstract
Eukaryotic cells maintain a highly organized endolysosomal system. This system regulates the protein and lipid content of the plasma membrane, it participates in the intracellular quality control machinery and is needed for the efficient removal of damaged organelles. This complex network comprises an endosomal membrane system that feeds into the lysosomes, yet also allows recycling of membrane proteins, and probably lipids. Moreover, lysosomal degradation provides the cell with macromolecules for further growth. In this review, we focus primarily on the role of the small Rab GTPases Rab5 and Rab7 as organelle markers and interactors of multiple effectors on endosomes and lysosomes and highlight their role in membrane dynamics, particularly fusion along the endolysosomal pathway.
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Affiliation(s)
- Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Florian Fröhlich
- Department of Biology/Chemistry, Molecular Membrane Biology Group, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany; Center of Cellular Nanoanalytics of the University of Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany; Department of Biology/Chemistry, Molecular Membrane Biology Group, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany; Center of Cellular Nanoanalytics of the University of Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany.
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16
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Pylypenko O, Hammich H, Yu IM, Houdusse A. Rab GTPases and their interacting protein partners: Structural insights into Rab functional diversity. Small GTPases 2018. [PMID: 28632484 DOI: 10.1080/215412481336191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023] Open
Abstract
Rab molecular switches are key players in defining membrane identity and regulating intracellular trafficking events in eukaryotic cells. In spite of their global structural similarity, Rab-family members acquired particular features that allow them to perform specific cellular functions. The overall fold and local sequence conservations enable them to utilize a common machinery for prenylation and recycling; while individual Rab structural differences determine interactions with specific partners such as GEFs, GAPs and effector proteins. These interactions orchestrate the spatiotemporal regulation of Rab localization and their turning ON and OFF, leading to tightly controlled Rab-specific functionalities such as membrane composition modifications, recruitment of molecular motors for intracellular trafficking, or recruitment of scaffold proteins that mediate interactions with downstream partners, as well as actin cytoskeleton regulation. In this review we summarize structural information on Rab GTPases and their complexes with protein partners in the context of partner binding specificity and functional outcomes of their interactions in the cell.
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Affiliation(s)
- Olena Pylypenko
- a Structural Motility, Institut Curie , PSL Research University, CNRS, UMR 144 , Paris , France
| | - Hussein Hammich
- a Structural Motility, Institut Curie , PSL Research University, CNRS, UMR 144 , Paris , France
- b Sorbonne Universités , UPMC Univ Paris 06, Sorbonne Universités, IFD , Paris , France
| | - I-Mei Yu
- a Structural Motility, Institut Curie , PSL Research University, CNRS, UMR 144 , Paris , France
| | - Anne Houdusse
- a Structural Motility, Institut Curie , PSL Research University, CNRS, UMR 144 , Paris , France
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17
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Moore R, Pujol MG, Zhu Z, Smythe E. Interplay of Endocytosis and Growth Factor Receptor Signalling. ENDOCYTOSIS AND SIGNALING 2018; 57:181-202. [DOI: 10.1007/978-3-319-96704-2_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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18
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Early Endosome Morphology in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1074:335-343. [PMID: 29721961 DOI: 10.1007/978-3-319-75402-4_41] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Early endosomes are organelles that receive macromolecules and solutes from the extracellular environment. The major function of early endosomes is to sort these cargos into recycling and degradative compartments of the cell. Degradation of the cargo involves maturation of early endosomes into late endosomes, which, after acquisition of hydrolytic enzymes, form lysosomes. Endosome maturation involves recruitment of specific proteins and lipids to the early endosomal membrane, which drives changes in endosome morphology. Defects in early endosome maturation are generally accompanied by alterations in morphology, such as increase in volume and/or number. Enlarged early endosomes have been observed in Alzheimer's disease and Niemann Pick Disease type C, which also exhibit defects in endocytic sorting. This article discusses the mechanisms that regulate early endosome morphology and highlights the potential importance of endosome maturation in the retinal pigment epithelium.
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19
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Podinovskaia M, Spang A. The Endosomal Network: Mediators and Regulators of Endosome Maturation. ENDOCYTOSIS AND SIGNALING 2018; 57:1-38. [DOI: 10.1007/978-3-319-96704-2_1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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20
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Pylypenko O, Hammich H, Yu IM, Houdusse A. Rab GTPases and their interacting protein partners: Structural insights into Rab functional diversity. Small GTPases 2017. [PMID: 28632484 PMCID: PMC5902227 DOI: 10.1080/21541248.2017.1336191] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Rab molecular switches are key players in defining membrane identity and regulating intracellular trafficking events in eukaryotic cells. In spite of their global structural similarity, Rab-family members acquired particular features that allow them to perform specific cellular functions. The overall fold and local sequence conservations enable them to utilize a common machinery for prenylation and recycling; while individual Rab structural differences determine interactions with specific partners such as GEFs, GAPs and effector proteins. These interactions orchestrate the spatiotemporal regulation of Rab localization and their turning ON and OFF, leading to tightly controlled Rab-specific functionalities such as membrane composition modifications, recruitment of molecular motors for intracellular trafficking, or recruitment of scaffold proteins that mediate interactions with downstream partners, as well as actin cytoskeleton regulation. In this review we summarize structural information on Rab GTPases and their complexes with protein partners in the context of partner binding specificity and functional outcomes of their interactions in the cell.
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Affiliation(s)
- Olena Pylypenko
- a Structural Motility, Institut Curie , PSL Research University, CNRS, UMR 144 , Paris , France
| | - Hussein Hammich
- a Structural Motility, Institut Curie , PSL Research University, CNRS, UMR 144 , Paris , France.,b Sorbonne Universités , UPMC Univ Paris 06, Sorbonne Universités, IFD , Paris , France
| | - I-Mei Yu
- a Structural Motility, Institut Curie , PSL Research University, CNRS, UMR 144 , Paris , France
| | - Anne Houdusse
- a Structural Motility, Institut Curie , PSL Research University, CNRS, UMR 144 , Paris , France
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21
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CMTM3 decreases EGFR expression and EGF-mediated tumorigenicity by promoting Rab5 activity in gastric cancer. Cancer Lett 2017; 386:77-86. [DOI: 10.1016/j.canlet.2016.11.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/27/2016] [Accepted: 11/10/2016] [Indexed: 02/06/2023]
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22
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Abstract
Rab GTPases act as organizers of protein networks defining identities and functions of organelles of the endocytic and secretory pathways. Various modes of coordination between different Rabs drive the timely maturation and conversion of membranes. Endosomal Rab5 has been known as the prime example for self-activation via a feedback loop recruiting Rabaptin5, which is complexed with the Rab5 exchange factor Rabex5, and couples to Rab4-GTP. Among other effectors, Rab5 also recruits the Mon1/SAND1-Ccz1 complex that both activates Rab7 and dissociates Rabex5 for Rab5-to-Rab7 conversion of early-to-late endosomes. A detailed deletion analysis now revealed 2 separate binding sites each for Rab4-GTP and Rab5-GTP and indicates a feedforward mechanism of Rab5 activation. Rabaptin5/Rabex5 is recruited to endosomal membranes positive for Rab4-GTP and ubiquitinated cargo (binding to the ubiquitin binding site of Rabex5). This mechanism also suggests additional criteria for Rab5 inactivation concomitant with increasing Rab7-GTP levels. The disappearance of ubiquitinated cargo upon ESCRT-mediated formation of intraluminal vesicles and inactivation of Rab4 may also contribute to loss of Rab5 activation. Rabaptin5/Rabex5 thus may integrate several cues of maturation to perform Rab conversion. Furthermore Rab5 binding to Rabaptin5 appears to prevent uncontrolled progression to late endosomes.
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Affiliation(s)
- Simone Kälin
- a Biozentrum, University of Basel , Basel, Switzerland
| | | | - Martin Spiess
- a Biozentrum, University of Basel , Basel, Switzerland
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23
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Lucitti JL, Sealock R, Buckley BK, Zhang H, Xiao L, Dudley AC, Faber JE. Variants of Rab GTPase-Effector Binding Protein-2 Cause Variation in the Collateral Circulation and Severity of Stroke. Stroke 2016; 47:3022-3031. [PMID: 27811335 DOI: 10.1161/strokeaha.116.014160] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 08/23/2016] [Accepted: 09/21/2016] [Indexed: 12/29/2022]
Abstract
BACKGROUND AND PURPOSE The extent (number and diameter) of collateral vessels varies widely and is a major determinant, along with arteriogenesis (collateral remodeling), of variation in severity of tissue injury after large artery occlusion. Differences in genetic background underlie the majority of the variation in collateral extent in mice, through alterations in collaterogenesis (embryonic collateral formation). In brain and other tissues, ≈80% of the variation in collateral extent among different mouse strains has been linked to a region on chromosome 7. We recently used congenic (CNG) fine mapping of C57BL/6 (B6, high extent) and BALB/cByJ (BC, low extent) mice to narrow the region to a 737 Kb locus, Dce1. Herein, we report the causal gene. METHODS We used additional CNG mapping and knockout mice to narrow the number of candidate genes. Subsequent inspection identified a nonsynonymous single nucleotide polymorphism between B6 and BC within Rabep2 (rs33080487). We then created B6 mice with the BC single nucleotide polymorphism at this locus plus 3 other lines for predicted alteration or knockout of Rabep2 using gene editing. RESULTS The single amino acid change caused by rs33080487 accounted for the difference in collateral extent and infarct volume between B6 and BC mice attributable to Dce1. Mechanistically, variants of Rabep2 altered collaterogenesis during embryogenesis but had no effect on angiogenesis examined in vivo and in vitro. Rabep2 deficiency altered endosome trafficking known to be involved in VEGF-A→VEGFR2 signaling required for collaterogenesis. CONCLUSIONS Naturally occurring variants of Rabep2 are major determinants of variation in collateral extent and stroke severity in mice.
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Affiliation(s)
- Jennifer L Lucitti
- From the Department of Cell Biology and Physiology, The McAllister Heart Institute, University of North Carolina, Chapel Hill
| | - Robert Sealock
- From the Department of Cell Biology and Physiology, The McAllister Heart Institute, University of North Carolina, Chapel Hill
| | - Brian K Buckley
- From the Department of Cell Biology and Physiology, The McAllister Heart Institute, University of North Carolina, Chapel Hill
| | - Hua Zhang
- From the Department of Cell Biology and Physiology, The McAllister Heart Institute, University of North Carolina, Chapel Hill
| | - Lin Xiao
- From the Department of Cell Biology and Physiology, The McAllister Heart Institute, University of North Carolina, Chapel Hill
| | - Andrew C Dudley
- From the Department of Cell Biology and Physiology, The McAllister Heart Institute, University of North Carolina, Chapel Hill
| | - James E Faber
- From the Department of Cell Biology and Physiology, The McAllister Heart Institute, University of North Carolina, Chapel Hill.
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24
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Ishida M, E Oguchi M, Fukuda M. Multiple Types of Guanine Nucleotide Exchange Factors (GEFs) for Rab Small GTPases. Cell Struct Funct 2016; 41:61-79. [PMID: 27246931 DOI: 10.1247/csf.16008] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Rab small GTPases are highly conserved master regulators of membrane traffic in all eukaryotes. The same as the activation and inactivation of other small GTPases, the activation and inactivation of Rabs are tightly controlled by specific GEFs (guanine nucleotide exchange factors) and GAPs (GTPase-activating proteins), respectively. Although almost all Rab-GAPs reported thus far have a TBC (Tre-2/Bub2/Cdc16)/Rab-GAP domain in common, recent accumulating evidence has indicated the existence of a number of structurally unrelated types of Rab-GEFs, including DENN proteins, VPS9 proteins, Sec2 proteins, TRAPP complexes, heterodimer GEFs (Mon1-Ccz1, HPS1-HPS4 (BLOC-3 complex), Ric1-Rgp1 and Rab3GAP1/2), and other GEFs (e.g., REI-1 and RPGR). In this review article we provide an up-to-date overview of the structures and functions of all putative Rab-GEFs in mammals, with a special focus on their substrate Rabs, interacting proteins, associations with genetic diseases, and intracellular localizations.
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Affiliation(s)
- Morié Ishida
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University
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