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Ahmad N, Fazeli W, Schließke S, Lesca G, Gokce-Samar Z, Mekbib KY, Jin SC, Burton J, Hoganson G, Petersen A, Gracie S, Granger L, Bartels E, Oppermann H, Kundishora A, Till M, Milleret-Pignot C, Dangerfield S, Viskochil D, Anderson KJ, Palculict TB, Schnur RE, Wentzensen IM, Tiller GE, Kahle KT, Kunz WS, Burkart S, Simons M, Sticht H, Abou Jamra R, Neuser S. De Novo Variants in RAB11B Cause Various Degrees of Global Developmental Delay and Intellectual Disability in Children. Pediatr Neurol 2023; 148:164-171. [PMID: 37734130 DOI: 10.1016/j.pediatrneurol.2023.08.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 07/20/2023] [Accepted: 08/15/2023] [Indexed: 09/23/2023]
Abstract
BACKGROUND RAB11B was described previously once with a severe form of intellectual disability. We aim at validation and delineation of the role of RAB11B in neurodevelopmental disorders. METHODS We present seven novel individuals with disease-associated variants in RAB11B when compared with the six cases described in the literature. We performed a cross-sectional analysis to identify the clinical spectrum and the core phenotype. Additionally, structural effects of the variants were assessed by molecular modeling. RESULTS Seven distinct de novo missense variants were identified, three of them recurrent (p.(Gly21Arg), p.(Val22Met), and p.(Ala68Thr)). Molecular modeling suggests that those variants either affect the nucleotide binding (at amino acid positions 21, 22, 33, 68) or the interaction with effector molecules (at positions 72 and 75). Our data confirmed the main manifestations as neurodevelopmental disorder with intellectual disability (85%), muscular hypotonia (83%), structural brain anomalies (77%), and visual impairment (70%). Combined analysis indicates a genotype-phenotype correlation; variants impacting the nucleotide binding cause a severe phenotype with intellectual disability, and variants outside the binding pocket lead to a milder phenotype with epilepsy. CONCLUSIONS We confirm that disease-associated missense variants in RAB11B cause a neurodevelopmental disorder and suggest a genotype-phenotype correlation based on the impact on nucleotide binding functionality of RAB11B.
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Affiliation(s)
- Natalie Ahmad
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Walid Fazeli
- Department of Pediatric Neurology, University Hospital Bonn, Bonn, Germany
| | - Sophia Schließke
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Gaetan Lesca
- Department of Medical Genetics, Lyon University Hospital, University of Lyon, UCB1, Lyon, France
| | | | - Kedous Y Mekbib
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut; Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts
| | - Sheng Chih Jin
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri
| | - Jennifer Burton
- University of Illinois College of Medicine, Peoria, Illinois
| | - George Hoganson
- University of Illinois College of Medicine, Peoria, Illinois
| | - Andrea Petersen
- Department of Genetics and Metabolism, Randall Children's Hospital, Portland, Oregon
| | - Sara Gracie
- Department of Genetics and Metabolism, Randall Children's Hospital, Portland, Oregon
| | - Leslie Granger
- Department of Genetics and Metabolism, Randall Children's Hospital, Portland, Oregon
| | - Enrika Bartels
- Institute of Clinical Genetics and Tumor Genetics, Bonn, Germany
| | - Henry Oppermann
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Adam Kundishora
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut
| | - Marianne Till
- Department of Medical Genetics, Lyon University Hospital, University of Lyon, UCB1, Lyon, France
| | | | | | | | - Katherine J Anderson
- University of Utah, Salt Lake City, Utah; Department of Pediatrics, University of Vermont Medical Center, Burlington, Vermont
| | | | | | | | - George E Tiller
- Department of Genetics, Kaiser Permanente, Los Angeles, California
| | - Kristopher T Kahle
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Wolfram S Kunz
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Sebastian Burkart
- Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany
| | - Matias Simons
- Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany
| | - Heinrich Sticht
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Rami Abou Jamra
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Sonja Neuser
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany.
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García-Dorival I, Cuesta-Geijo MÁ, Galindo I, Del Puerto A, Barrado-Gil L, Urquiza J, Alonso C. Elucidation of the Cellular Interactome of African Swine Fever Virus Fusion Proteins and Identification of Potential Therapeutic Targets. Viruses 2023; 15:v15051098. [PMID: 37243184 DOI: 10.3390/v15051098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/26/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023] Open
Abstract
African swine fever virus (ASFV) encodes more than 150 proteins, most of them of unknown function. We used a high-throughput proteomic analysis to elucidate the interactome of four ASFV proteins, which potentially mediate a critical step of the infection cycle, the fusion and endosomal exit of the virions. Using affinity purification and mass spectrometry, we were able to identify potential interacting partners for those ASFV proteins P34, E199L, MGF360-15R and E248R. Representative molecular pathways for these proteins were intracellular and Golgi vesicle transport, endoplasmic reticulum organization, lipid biosynthesis, and cholesterol metabolism. Rab geranyl geranylation emerged as a significant hit, and also Rab proteins, which are crucial regulators of the endocytic pathway and interactors of both p34 and E199L. Rab proteins co-ordinate a tight regulation of the endocytic pathway that is necessary for ASFV infection. Moreover, several interactors were proteins involved in the molecular exchange at ER membrane contacts. These ASFV fusion proteins shared interacting partners, suggesting potential common functions. Membrane trafficking and lipid metabolism were important categories, as we found significant interactions with several enzymes of the lipid metabolism. These targets were confirmed using specific inhibitors with antiviral effect in cell lines and macrophages.
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Affiliation(s)
- Isabel García-Dorival
- Departmento de Biotecnología, INIA-CSIC, Centro Nacional Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Ctra. de la Coruña Km 7.5, 28040 Madrid, Spain
| | - Miguel Ángel Cuesta-Geijo
- Departmento de Biotecnología, INIA-CSIC, Centro Nacional Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Ctra. de la Coruña Km 7.5, 28040 Madrid, Spain
| | - Inmaculada Galindo
- Departmento de Biotecnología, INIA-CSIC, Centro Nacional Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Ctra. de la Coruña Km 7.5, 28040 Madrid, Spain
| | - Ana Del Puerto
- Departmento de Biotecnología, INIA-CSIC, Centro Nacional Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Ctra. de la Coruña Km 7.5, 28040 Madrid, Spain
| | - Lucía Barrado-Gil
- Departmento de Biotecnología, INIA-CSIC, Centro Nacional Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Ctra. de la Coruña Km 7.5, 28040 Madrid, Spain
| | - Jesús Urquiza
- Departmento de Biotecnología, INIA-CSIC, Centro Nacional Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Ctra. de la Coruña Km 7.5, 28040 Madrid, Spain
| | - Covadonga Alonso
- Departmento de Biotecnología, INIA-CSIC, Centro Nacional Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Ctra. de la Coruña Km 7.5, 28040 Madrid, Spain
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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] [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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4
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Giannaki M, Ludwig C, Heermann S, Roussa E. Regulation of electrogenic Na + /HCO 3 - cotransporter 1 (NBCe1) function and its dependence on m-TOR mediated phosphorylation of Ser 245. J Cell Physiol 2021; 237:1372-1388. [PMID: 34642952 DOI: 10.1002/jcp.30601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 09/09/2021] [Accepted: 10/01/2021] [Indexed: 11/09/2022]
Abstract
Astrocytes are pivotal responders to alterations of extracellular pH, primarily by regulation of their principal acid-base transporter, the membrane-bound electrogenic Na+ /bicarbonate cotransporter 1 (NBCe1). Here, we describe amammalian target of rapamycin (mTOR)-dependent and NBCe1-mediated astroglial response to extracellular acidosis. Using primary mouse cortical astrocytes, we investigated the effect of long-term extracellular metabolic acidosis on regulation of NBCe1 and elucidated the underlying molecular mechanisms by immunoblotting, biotinylation of surface proteins, intracellular H+ recording using the H+ -sensitive dye 2',7'-bis-(carboxyethyl)-5-(and-6)-carboxyfluorescein, and phosphoproteomic analysis. The results showed significant increase of NBCe1-mediated recovery of intracellular pH from acidification in WT astrocytes, but not in cortical astrocytes from NBCe1-deficient mice. Acidosis-induced upregulation of NBCe1 activity was prevented following inhibition of mTOR signaling by rapamycin. Yet, during acidosis or following exposure of astrocytes to rapamycin, surface protein abundance of NBCe1 remained -unchanged. Mutational analysis in HeLa cells suggested that NBCe1 activity was dependent on phosphorylation state of Ser245 , a residue conserved in all NBCe1 variants. Moreover, phosphorylation state of Ser245 is regulated by mTOR and is inversely correlated with NBCe1 transport activity. Our results identify pSer245 as a novel regulator of NBCe1 functional expression. We propose that context-dependent and mTOR-mediated multisite phosphorylation of serine residues of NBCe1 is likely to be a potent mechanism contributing to the response of astrocytes to acid/base challenges during pathophysiological conditions.
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Affiliation(s)
- Marina Giannaki
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Medical Faculty, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Christina Ludwig
- Bavarian Center for Biomolecular Mass Spectrometry (BayBioMS), Technical University of Munich (TUM), Freising, Germany
| | - Stephan Heermann
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Medical Faculty, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Eleni Roussa
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Medical Faculty, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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Cai L, Zhang J, Hongyun W, Zhu Y, Zhang X, Liang W. Rab11B participates in erythrocyte storage lesion of under-collected whole blood. Transfus Apher Sci 2020; 60:103034. [PMID: 33341364 DOI: 10.1016/j.transci.2020.103034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/05/2020] [Accepted: 11/07/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVES The storage lesion of the red blood cell affects the life span of RBC and the quality of blood component. The elucidation of this mechanism is helpful to reduce the storage damage of RBC and improve the efficacy and safety of blood transfusion. The aim of this study was to discover the potential molecular mechanism of erythrocyte storage lesion with Under-collected whole blood (UC-WB) model. METHODS The label-free MS/MS quantitative method was used to identify the differential proteins of erythrocyte membrane proteins and the difference of Rab11B, V-ATPase and plasma GDI2 protein expression were further verified by western blot at the end of blood storage. RESULTS A total of 12 Rab proteins and 3 interacting effector proteins were identified among the membrane protein of normal WB and UC-WB, including 5 differential Rab proteins and 2 interacting effector proteins. Compared with normal WB, the expression of membrane Rab11B protein and ATP6V1B1/2 subunit of V-ATPases protein as well as the plasma GDI2 protein of UC-WB increased at the end of storage period. CONCLUSION Rab protein might be related to RBC storage lesions, Rab11B participates in the RBC storage lesion through Rab11B/V-ATPases pathways.
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Affiliation(s)
- Li Cai
- Jiangsu Province Blood Center, China
| | - Jingjing Zhang
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, China
| | | | - Yi Zhu
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, China
| | - Xiongfei Zhang
- School of Medicine and Holistic Integrative Medicine, Nanjing University of Chinese Medicine, China.
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Li D, Bradley T, Cain DW, Pedroza-Pacheco I, Aggelakopoulou M, Parks R, Barr M, Xia SM, Scearce R, Bowman C, Stevens G, Newman A, Hora B, Chen Y, Riebe K, Wang Y, Sempowski G, Saunders KO, Borrow P, Haynes BF. RAB11FIP5-Deficient Mice Exhibit Cytokine-Related Transcriptomic Signatures. Immunohorizons 2020; 4:713-728. [PMID: 33172842 PMCID: PMC8050958 DOI: 10.4049/immunohorizons.2000088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 11/19/2022] Open
Abstract
Rab11 recycling endosomes are involved in immunological synaptic functions, but the roles of Rab11 family–interacting protein 5 (Rab11Fip5), one of the Rab11 effectors, in the immune system remain obscure. Our previous study demonstrated that RAB11FIP5 transcripts are significantly elevated in PBMCs from HIV-1–infected individuals, making broadly HIV-1–neutralizing Abs compared with those without broadly neutralizing Abs; however, the role of Rab11FiP5 in immune functions remains unclear. In this study, a RAB11FIP5 gene knockout (RAB11FIP5−/−) mouse model was employed to study the role of Rab11Fip5 in immune responses. RAB11FIP5−/− mice exhibited no perturbation in lymphoid tissue cell subsets, and Rab11Fip5 was not required for serum Ab induction following HIV-1 envelope immunization, Ab transcytosis to mucosal sites, or survival after influenza challenge. However, differences were observed in multiple transcripts, including cytokine genes, in lymphocyte subsets from envelope-immunized RAB11FIP5−/− versus control mice. These included alterations in several genes in NK cells that mirrored observations in NKs from HIV-infected humans expressing less RAB11FIP5, although Rab11Fip5 was dispensable for NK cell cytolytic activity. Notably, immunized RAB11FIP5−/− mice had lower IL4 expression in CD4+ T follicular helper cells and showed lower TNF expression in CD8+ T cells. Likewise, TNF-α production by human CD8+ T cells correlated with PBMC RAB11FIP5 expression. These observations in RAB11FIP5−/− mice suggest a role for Rab11Fip5 in regulating cytokine responses.
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Affiliation(s)
- Dapeng Li
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710;
| | - Todd Bradley
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710.,Department of Medicine, Duke University School of Medicine, Durham, NC 27710
| | - Derek W Cain
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710.,Department of Medicine, Duke University School of Medicine, Durham, NC 27710
| | - Isabela Pedroza-Pacheco
- Nuffield Department of Clinical Medicine, University of Oxford, OX3 7FZ Oxford, United Kingdom
| | - Maria Aggelakopoulou
- Nuffield Department of Clinical Medicine, University of Oxford, OX3 7FZ Oxford, United Kingdom
| | - Robert Parks
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
| | - Maggie Barr
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
| | - Shi-Mao Xia
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
| | - Richard Scearce
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
| | - Cindy Bowman
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
| | - Grace Stevens
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
| | - Amanda Newman
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
| | - Bhavna Hora
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
| | - Yue Chen
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
| | - Kristina Riebe
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
| | - Yunfei Wang
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
| | - Gregory Sempowski
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
| | - Kevin O Saunders
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710.,Department of Immunology, Duke University School of Medicine, Durham, NC 27710; and.,Department of Surgery, Duke University, Durham, NC 27710
| | - Persephone Borrow
- Nuffield Department of Clinical Medicine, University of Oxford, OX3 7FZ Oxford, United Kingdom
| | - Barton F Haynes
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710; .,Department of Medicine, Duke University School of Medicine, Durham, NC 27710.,Department of Immunology, Duke University School of Medicine, Durham, NC 27710; and
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Kluge M, Namkoong E, Khakipoor S, Park K, Roussa E. Differential regulation of vacuolar H + -ATPase subunits by transforming growth factor-β1 in salivary ducts. J Cell Physiol 2019; 234:15061-15079. [PMID: 30648263 DOI: 10.1002/jcp.28147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 12/20/2018] [Indexed: 01/24/2023]
Abstract
Bicarbonate concentration in saliva is controlled by the action of acid-base transporters in salivary duct cells. We show for the first time expression of ATP6V1B1 in submandibular gland and introduce transforming growth factor-beta (TGF-β) as a novel regulator of V-ATPase subunits. Using QRT-PCR, immunoblotting, biotinylation of surface proteins, immunofluorescence, chromatin immunoprecipitation, and intracellular H(+ ) recording with H(+ )-sensitive dye 2',7'-bis-(carboxyethyl)-5-(and-6)-carboxyfluorescein we show that in the human submandibular gland (HSG) cell line, activation of TGF-β signaling upregulates ATP6V1E1 and ATP6V1B2, downregulates ATP6V1B1, and has no effect on ATP6V1A. TGF-β1 effects on ATP6V1B1 are mediated through the canonical, the soluble adenylate cyclase, and ERK signaling. A CREB binding sequence was identified in the ATP6V1B1 promoter and CREB binding decreased after TGF-β1 treatment. Following acidosis, a bafilomycin-sensitive and Na+ -independent cell pH recovery was observed in HSG cells, an effect that was not influenced after disruption of acidic lysosomes. Moreover, neutralization of TGF-βs, inhibition of TGF-β receptor, or inhibition of the canonical pathway decreased membrane expression of ATP6V1A and prevented the acidosis-induced increased V-ATPase activity. The results suggest multiple modes of action of TGF-β1 on V-ATPase subunits in HSG cells: TGF-β1 may regulate transcription or protein synthesis of certain subunits and trafficking of other subunits in a context-dependent manner. Moreover, surface V-ATPase is active in salivary duct cells and involved in intracellular pH regulation following acidosis.
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Affiliation(s)
- Milena Kluge
- Department of Molecular Embryology, Faculty of Medicine, Institute of Anatomy and Cell Biology, University of Freiburg, Freiburg, Germany
| | - Eun Namkoong
- Department of Physiology, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Shokoufeh Khakipoor
- Department of Molecular Embryology, Faculty of Medicine, Institute of Anatomy and Cell Biology, University of Freiburg, Freiburg, Germany
| | - Kyungpyo Park
- Department of Physiology, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Eleni Roussa
- Department of Molecular Embryology, Faculty of Medicine, Institute of Anatomy and Cell Biology, University of Freiburg, Freiburg, Germany
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Khakipoor S, Giannaki M, Theparambil SM, Zecha J, Küster B, Heermann S, Deitmer JW, Roussa E. Functional expression of electrogenic sodium bicarbonate cotransporter 1 (NBCe1) in mouse cortical astrocytes is dependent on S255‐257 and regulated by mTOR. Glia 2019; 67:2264-2278. [DOI: 10.1002/glia.23682] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 06/23/2019] [Accepted: 07/03/2019] [Indexed: 01/14/2023]
Affiliation(s)
- Shokoufeh Khakipoor
- Department of Molecular Embryology, Faculty of Medicine Institute of Anatomy and Cell Biology, Albert‐Ludwigs‐Universität Freiburg Freiburg Germany
| | - Marina Giannaki
- Department of Molecular Embryology, Faculty of Medicine Institute of Anatomy and Cell Biology, Albert‐Ludwigs‐Universität Freiburg Freiburg Germany
| | - Shefeeq M. Theparambil
- Department of General Zoology, FB Biology University of Kaiserslautern Kaiserslautern Germany
| | - Jana Zecha
- Chair of Proteomics and Bioanalytics Technical University of Munich Freising Germany
| | - Bernhard Küster
- Chair of Proteomics and Bioanalytics Technical University of Munich Freising Germany
- Bavarian Biomolecular Mass Spectrometry Center (BayBioMS) Technical University of Munich Freising Germany
| | - Stephan Heermann
- Department of Molecular Embryology, Faculty of Medicine Institute of Anatomy and Cell Biology, Albert‐Ludwigs‐Universität Freiburg Freiburg Germany
| | - Joachim W. Deitmer
- Department of General Zoology, FB Biology University of Kaiserslautern Kaiserslautern Germany
| | - Eleni Roussa
- Department of Molecular Embryology, Faculty of Medicine Institute of Anatomy and Cell Biology, Albert‐Ludwigs‐Universität Freiburg Freiburg Germany
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9
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Baldini N, Avnet S. The Effects of Systemic and Local Acidosis on Insulin Resistance and Signaling. Int J Mol Sci 2018; 20:ijms20010126. [PMID: 30598026 PMCID: PMC6337415 DOI: 10.3390/ijms20010126] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 12/12/2018] [Accepted: 12/23/2018] [Indexed: 12/14/2022] Open
Abstract
Most pathological conditions that cause local or systemic acidosis by overcoming the buffering activities of body fluids overlap with those diseases that are characterized by glucose metabolic disorders, including diabetes mellitus, inflammation, and cancer. This simple observation suggests the existence of a strong relationship between acidosis and insulin metabolism or insulin receptor signaling. In this review, we summarized the current knowledge on the activity of insulin on the induction of acidosis and, vice versa, on the effects of changes of extracellular and intracellular pH on insulin resistance. Insulin influences acidosis by promoting glycolysis. Although with an unclear mechanism, the lowering of pH, in turn, inhibits insulin sensitivity or activity. In addition to ketoacidosis that is frequently associated with diabetes, other important and more complex factors are involved in this delicate feedback mechanism. Among these, in this review we discussed the acid-mediated inhibiting effects on insulin binding affinity to its receptor, on glycolysis, on the recycling of glucose transporters, and on insulin secretion via transforming growth factor β (TGF-β) activity by pancreatic β-cells. Finally, we revised current data available on the mutual interaction between insulin signaling and the activity of ion/proton transporters and pH sensors, and on how acidosis may enhance insulin resistance through the Nuclear Factor kappa B (NF-κB) inflammatory pathway.
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Affiliation(s)
- Nicola Baldini
- Orthopaedic Pathophysiology and Regenerative Medicine Unit, Istituto Ortopedico Rizzoli IRCCS, 40136 Bologna, Italy.
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 401223 Bologna, Italy.
| | - Sofia Avnet
- Orthopaedic Pathophysiology and Regenerative Medicine Unit, Istituto Ortopedico Rizzoli IRCCS, 40136 Bologna, Italy.
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RAB11FIP5 Expression and Altered Natural Killer Cell Function Are Associated with Induction of HIV Broadly Neutralizing Antibody Responses. Cell 2018; 175:387-399.e17. [PMID: 30270043 PMCID: PMC6176872 DOI: 10.1016/j.cell.2018.08.064] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 07/09/2018] [Accepted: 08/29/2018] [Indexed: 12/25/2022]
Abstract
HIV-1 broadly neutralizing antibodies (bnAbs) are difficult to induce with vaccines but are generated in ∼50% of HIV-1-infected individuals. Understanding the molecular mechanisms of host control of bnAb induction is critical to vaccine design. Here, we performed a transcriptome analysis of blood mononuclear cells from 47 HIV-1-infected individuals who made bnAbs and 46 HIV-1-infected individuals who did not and identified in bnAb individuals upregulation of RAB11FIP5, encoding a Rab effector protein associated with recycling endosomes. Natural killer (NK) cells had the highest differential expression of RAB11FIP5, which was associated with greater dysregulation of NK cell subsets in bnAb subjects. NK cells from bnAb individuals had a more adaptive/dysfunctional phenotype and exhibited impaired degranulation and cytokine production that correlated with RAB11FIP5 transcript levels. Moreover, RAB11FIP5 overexpression modulated the function of NK cells. These data suggest that NK cells and Rab11 recycling endosomal transport are involved in regulation of HIV-1 bnAb development. Elevated RAB11FIP5 expression is associated with HIV-1 bnAb induction NK cells show the highest differential RAB11FIP5 expression NK cell subsets are more dysregulated in individuals developing bnAbs Rab11Fip5 regulates NK cell function
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11
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Gomi H, Osawa H, Uno R, Yasui T, Hosaka M, Torii S, Tsukise A. Canine Salivary Glands: Analysis of Rab and SNARE Protein Expression and SNARE Complex Formation With Diverse Tissue Properties. J Histochem Cytochem 2017; 65:637-653. [PMID: 28914590 DOI: 10.1369/0022155417732527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The comparative structure and expression of salivary components and vesicular transport proteins in the canine major salivary glands were investigated. Histochemical analysis revealed that the morphology of the five major salivary glands-parotid, submandibular, polystomatic sublingual, monostomatic sublingual, and zygomatic glands-was greatly diverse. Immunoblot analysis revealed that expression levels of α-amylase and antimicrobial proteins, such as lysozyme, lactoperoxidase, and lactoferrin, differed among the different glands. Similarly, Rab proteins (Rab3d, Rab11a, Rab11b, Rab27a, and Rab27b) and soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) proteins VAMP4, VAMP8, syntaxin-2, syntaxin-3, syntaxin-4, and syntaxin-6 were expressed at various levels in individual glands. mmunohistochemistry of Rab3d, Rab11b, Rab27b, VAMP4, VAMP8, syntaxin-4, and syntaxin-6 revealed their predominant expression in serous acinar cells, demilunes, and ductal cells. The VAMP4/syntaxin-6 SNARE complex, which is thought to be involved in the maturation of secretory granules in the Golgi field, was found more predominantly in the monostomatic sublingual gland than in the parotid gland. These results suggest that protein expression profiles in canine salivary glands differ among individual glands and reflect the properties of their specialized functions.
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Affiliation(s)
- Hiroshi Gomi
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Hiromi Osawa
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Rie Uno
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Tadashi Yasui
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Masahiro Hosaka
- Laboratory of Molecular Life Sciences, Department of Biotechnology, Akita Prefectural University, Akita, Japan
| | - Seiji Torii
- Laboratory of Secretion Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Azuma Tsukise
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
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12
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Roussa E, Speer JM, Chudotvorova I, Khakipoor S, Smirnov S, Rivera C, Krieglstein K. The membrane trafficking and functionality of the K+-Cl- co-transporter KCC2 is regulated by TGF-β2. J Cell Sci 2016; 129:3485-98. [PMID: 27505893 PMCID: PMC5047681 DOI: 10.1242/jcs.189860] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 08/02/2016] [Indexed: 02/02/2023] Open
Abstract
Functional activation of the neuronal K(+)-Cl(-) co-transporter KCC2 (also known as SLC12A5) is a prerequisite for shifting GABAA responses from depolarizing to hyperpolarizing during development. Here, we introduce transforming growth factor β2 (TGF-β2) as a new regulator of KCC2 membrane trafficking and functional activation. TGF-β2 controls membrane trafficking, surface expression and activity of KCC2 in developing and mature mouse primary hippocampal neurons, as determined by immunoblotting, immunofluorescence, biotinylation of surface proteins and KCC2-mediated Cl(-) extrusion. We also identify the signaling pathway from TGF-β2 to cAMP-response-element-binding protein (CREB) and Ras-associated binding protein 11b (Rab11b) as the underlying mechanism for TGF-β2-mediated KCC2 trafficking and functional activation. TGF-β2 increases colocalization and interaction of KCC2 with Rab11b, as determined by 3D stimulated emission depletion (STED) microscopy and co-immunoprecipitation, respectively, induces CREB phosphorylation, and enhances Rab11b gene expression. Loss of function of either CREB1 or Rab11b suppressed TGF-β2-dependent KCC2 trafficking, surface expression and functionality. Thus, TGF-β2 is a new regulatory factor for KCC2 functional activation and membrane trafficking, and a putative indispensable molecular determinant for the developmental shift of GABAergic transmission.
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Affiliation(s)
- Eleni Roussa
- Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Faculty of Medicine, University of Freiburg, Albertstrasse 17, Freiburg D-79104, Germany Institute of Anatomy and Cell Biology, Department of Neuroanatomy, Faculty of Medicine, University of Freiburg, Albertstrasse 17, Freiburg D-79104, Germany
| | - Jan Manuel Speer
- Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Faculty of Medicine, University of Freiburg, Albertstrasse 17, Freiburg D-79104, Germany
| | - Ilona Chudotvorova
- Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Faculty of Medicine, University of Freiburg, Albertstrasse 17, Freiburg D-79104, Germany
| | - Shokoufeh Khakipoor
- Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Faculty of Medicine, University of Freiburg, Albertstrasse 17, Freiburg D-79104, Germany
| | - Sergei Smirnov
- Institute of Biotechnology, University of Helsinki, Viikinkaari 9, Helsinki FIN-00014, Finland
| | - Claudio Rivera
- Institute of Biotechnology, University of Helsinki, Viikinkaari 9, Helsinki FIN-00014, Finland
| | - Kerstin Krieglstein
- Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Faculty of Medicine, University of Freiburg, Albertstrasse 17, Freiburg D-79104, Germany
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13
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Boal F, Hodgson LR, Reed SE, Yarwood SE, Just VJ, Stephens DJ, McCaffrey MW, Tavaré JM. Insulin promotes Rip11 accumulation at the plasma membrane by inhibiting a dynamin- and PI3-kinase-dependent, but Akt-independent, internalisation event. Cell Signal 2015; 28:74-82. [PMID: 26515129 PMCID: PMC4678287 DOI: 10.1016/j.cellsig.2015.10.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/23/2015] [Indexed: 12/11/2022]
Abstract
Rip11 is a Rab11 effector protein that has been shown to be important in controlling the trafficking of several intracellular cargoes, including the fatty acid transporter FAT/CD36, V-ATPase and the glucose transporter GLUT4. We have previously demonstrated that Rip11 translocates to the plasma membrane in response to insulin and here we examine the basis of this regulated phenomenon in more detail. We show that Rip11 rapidly recycles between the cell interior and surface, and that the ability of insulin to increase the appearance of Rip11 at the cell surface involves an inhibition of Rip11 internalisation from the plasma membrane. By contrast the hormone has no effect on the rate of Rip11 translocation towards the plasma membrane. The ability of insulin to inhibit Rip11 internalisation requires dynamin and class I PI3-kinases, but is independent of the activation of the protein kinase Akt; characteristics which are very similar to the mechanism by which insulin inhibits GLUT4 endocytosis.
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Affiliation(s)
- Frédéric Boal
- School of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK
| | - Lorna R Hodgson
- School of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK
| | - Sam E Reed
- School of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK
| | - Sophie E Yarwood
- School of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK
| | - Victoria J Just
- School of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK
| | - David J Stephens
- School of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK
| | - Mary W McCaffrey
- Molecular Cell Biology Laboratory, School of Biochemistry and Cell Biology, Biosciences Institute, University College Cork, Cork, Ireland
| | - Jeremy M Tavaré
- School of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK.
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14
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Abstract
Postsynaptic AMPA-type glutamate receptors (AMPARs) are among the major determinants of synaptic strength and can be trafficked into and out of synapses. Neuronal activity regulates AMPAR trafficking during synaptic plasticity to induce long-term changes in synaptic strength, including long-term potentiation (LTP) and long-term depression (LTD). Rab family GTPases regulate most membrane trafficking in eukaryotic cells; particularly, Rab11 and its effectors are implicated in mediating postsynaptic AMPAR insertion during LTP. To explore the synaptic function of Rab11Fip5, a neuronal Rab11 effector and a candidate autism-spectrum disorder gene, we performed shRNA-mediated knock-down and genetic knock-out (KO) studies. Surprisingly, we observed robust shRNA-induced synaptic phenotypes that were rescued by a Rab11Fip5 cDNA but that were nevertheless not observed in conditional KO neurons. Both in cultured neurons and acute slices, KO of Rab11Fip5 had no significant effect on basic parameters of synaptic transmission, indicating that Rab11Fip5 is not required for fundamental synaptic operations, such as neurotransmitter release or postsynaptic AMPAR insertion. KO of Rab11Fip5 did, however, abolish hippocampal LTD as measured both in acute slices or using a chemical LTD protocol in cultured neurons but did not affect hippocampal LTP. The Rab11Fip5 KO mice performed normally in several behavioral tasks, including fear conditioning, but showed enhanced contextual fear extinction. These are the first findings to suggest a requirement for Rab11Fip5, and presumably Rab11, during LTD.
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15
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Schrödl-Häußel M, Theparambil SM, Deitmer JW, Roussa E. Regulation of functional expression of the electrogenic sodium bicarbonate cotransporter 1, NBCe1 (SLC4A4), in mouse astrocytes. Glia 2015; 63:1226-39. [DOI: 10.1002/glia.22814] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 12/25/2022]
Affiliation(s)
- Magdalena Schrödl-Häußel
- Department of Molecular Embryology; Institute for Anatomy and Cell Biology, University of Freiburg; Freiburg Germany
| | - Shefeeq M. Theparambil
- Department of General Zoology; FB Biology, University of Kaiserslautern; Kaiserslautern Germany
| | - Joachim W. Deitmer
- Department of General Zoology; FB Biology, University of Kaiserslautern; Kaiserslautern Germany
| | - Eleni Roussa
- Department of Molecular Embryology; Institute for Anatomy and Cell Biology, University of Freiburg; Freiburg Germany
- Department of Neuroanatomy; University of Freiburg; Freiburg Germany
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16
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Breda C, Nugent ML, Estranero JG, Kyriacou CP, Outeiro TF, Steinert JR, Giorgini F. Rab11 modulates α-synuclein-mediated defects in synaptic transmission and behaviour. Hum Mol Genet 2015; 24:1077-91. [PMID: 25305083 PMCID: PMC4986550 DOI: 10.1093/hmg/ddu521] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 09/17/2014] [Accepted: 10/07/2014] [Indexed: 01/03/2023] Open
Abstract
A central pathological hallmark of Parkinson's disease (PD) is the presence of proteinaceous depositions known as Lewy bodies, which consist largely of the protein α-synuclein (aSyn). Mutations, multiplications and polymorphisms in the gene encoding aSyn are associated with familial forms of PD and susceptibility to idiopathic PD. Alterations in aSyn impair neuronal vesicle formation/transport, and likely contribute to PD pathogenesis by neuronal dysfunction and degeneration. aSyn is functionally associated with several Rab family GTPases, which perform various roles in vesicle trafficking. Here, we explore the role of the endosomal recycling factor Rab11 in the pathogenesis of PD using Drosophila models of aSyn toxicity. We find that aSyn induces synaptic potentiation at the larval neuromuscular junction by increasing synaptic vesicle (SV) size, and that these alterations are reversed by Rab11 overexpression. Furthermore, Rab11 decreases aSyn aggregation and ameliorates several aSyn-dependent phenotypes in both larvae and adult fruit flies, including locomotor activity, degeneration of dopaminergic neurons and shortened lifespan. This work emphasizes the importance of Rab11 in the modulation of SV size and consequent enhancement of synaptic function. Our results suggest that targeting Rab11 activity could have a therapeutic value in PD.
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Affiliation(s)
- Carlo Breda
- Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Marie L Nugent
- Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK, MRC Toxicology Unit, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK
| | - Jasper G Estranero
- Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK
| | | | - Tiago F Outeiro
- Department of NeuroDegeneration and Restorative Research, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Goettingen, Göttingen, Germany and Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
| | - Joern R Steinert
- MRC Toxicology Unit, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK
| | - Flaviano Giorgini
- Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK,
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17
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Yu S, Yehia G, Wang J, Stypulkowski E, Sakamori R, Jiang P, Hernandez-Enriquez B, Tran TS, Bonder EM, Guo W, Gao N. Global ablation of the mouse Rab11a gene impairs early embryogenesis and matrix metalloproteinase secretion. J Biol Chem 2014; 289:32030-32043. [PMID: 25271168 DOI: 10.1074/jbc.m113.538223] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Rab11a has been conceived as a prominent regulatory component of the recycling endosome, which acts as a nexus in the endo- and exocytotic networks. The precise in vivo role of Rab11a in mouse embryonic development is unknown. We globally ablated Rab11a and examined the phenotypic and molecular outcomes in Rab11a(null) blastocysts and mouse embryonic fibroblasts. Using multiple trafficking assays and complementation analyses, we determined, among multiple important membrane-associated and soluble cargos, the critical contribution of Rab11a vesicular traffic to the secretion of multiple soluble MMPs. Rab11a(null) embryos were able to properly form normal blastocysts but died at peri-implantation stages. Our data suggest that Rab11a critically controls mouse blastocyst development and soluble matrix metalloproteinase secretion.
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Affiliation(s)
- Shiyan Yu
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102
| | - Ghassan Yehia
- Transgenic Core Facility, Rutgers New Jersey Medical School, Newark, New Jersey 07103
| | - Juanfei Wang
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and
| | - Ewa Stypulkowski
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102
| | - Ryotaro Sakamori
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102
| | - Ping Jiang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| | | | - Tracy S Tran
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102
| | - Edward M Bonder
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and
| | - Nan Gao
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102,.
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18
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Giorgini F, Steinert JR. Rab11 as a modulator of synaptic transmission. Commun Integr Biol 2013; 6:e26807. [PMID: 24563714 PMCID: PMC3922788 DOI: 10.4161/cib.26807] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 10/12/2013] [Indexed: 01/07/2023] Open
Abstract
Many neurodegenerative disorders are characterized by synaptic dysfunction preceding general neuronal loss and subsequent cognitive or behavioral anomalies. Much recent research has been aimed at understanding the early underlying processes leading to dysfunction at the synapse, as this knowledge would likely inform interventions that could potentially slow progression and delay onset of disease. We have recently reported that synaptic dysfunction in a Drosophila melanogaster model of Huntington's disease (HD) can be prevented by enhanced neuronal expression of Rab11, a Rab family GTPase involved in endosomal recycling, which complements studies that have found disrupted Rab11 activity in several models of this disorder. Indeed, inhibition of Rab11 function in fibroblasts of HD patients has been observed to perturb vesicle formation from recycling endosomes. Therefore, our study investigated a potential role of Rab11 in synaptic dysfunction prior to the onset of HD symptoms, with the aim of finding a possible early intervention to disease progression. We found that Rab11 ameliorates synaptic dysfunction due to expression of mutant huntingtin-the causative protein in HD-by normalizing synaptic vesicle size, which consequently ameliorates locomotor deficits in Drosophila larvae. Here we further consider these results and the implications this work has on potential therapeutic intervention in HD and other neurodegenerative disorders.
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19
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Collaco AM, Geibel P, Lee BS, Geibel JP, Ameen NA. Functional vacuolar ATPase (V-ATPase) proton pumps traffic to the enterocyte brush border membrane and require CFTR. Am J Physiol Cell Physiol 2013; 305:C981-96. [PMID: 23986201 DOI: 10.1152/ajpcell.00067.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Vacuolar ATPases (V-ATPases) are highly conserved proton pumps that regulate organelle pH. Epithelial luminal pH is also regulated by cAMP-dependent traffic of specific subunits of the V-ATPase complex from endosomes into the apical membrane. In the intestine, cAMP-dependent traffic of cystic fibrosis transmembrane conductance regulator (CFTR) channels and the sodium hydrogen exchanger (NHE3) in the brush border regulate luminal pH. V-ATPase was found to colocalize with CFTR in intestinal CFTR high expresser (CHE) cells recently. Moreover, apical traffic of V-ATPase and CFTR in rat Brunner's glands was shown to be dependent on cAMP/PKA. These observations support a functional relationship between V-ATPase and CFTR in the intestine. The current study examined V-ATPase and CFTR distribution in intestines from wild-type, CFTR(-/-) mice and polarized intestinal CaCo-2BBe cells following cAMP stimulation and inhibition of CFTR/V-ATPase function. Coimmunoprecipitation studies examined V-ATPase interaction with CFTR. The pH-sensitive dye BCECF determined proton efflux and its dependence on V-ATPase/CFTR in intestinal cells. cAMP increased V-ATPase/CFTR colocalization in the apical domain of intestinal cells and redistributed the V-ATPase Voa1 and Voa2 trafficking subunits from the basolateral membrane to the brush border membrane. Voa1 and Voa2 subunits were localized to endosomes beneath the terminal web in untreated CFTR(-/-) intestine but redistributed to the subapical cytoplasm following cAMP treatment. Inhibition of CFTR or V-ATPase significantly decreased pHi in cells, confirming their functional interdependence. These data establish that V-ATPase traffics into the brush border membrane to regulate proton efflux and this activity is dependent on CFTR in the intestine.
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Affiliation(s)
- Anne M Collaco
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut
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20
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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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21
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Oehlke O, Speer JM, Roussa E. Variants of the electrogenic sodium bicarbonate cotransporter 1 (NBCe1) in mouse hippocampal neurons are regulated by extracellular pH changes: evidence for a Rab8a-dependent mechanism. Int J Biochem Cell Biol 2013; 45:1427-38. [PMID: 23583738 DOI: 10.1016/j.biocel.2013.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 03/25/2013] [Accepted: 04/03/2013] [Indexed: 11/24/2022]
Abstract
Changes in extracellular pH are common events in both pathological conditions and during normal brain function. In organs other than the brain, cells may respond to pH changes by trafficking of acid-base transporters. However, regulation of neuronal acid-base transporters during pH shifts is not understood. The aim of this study was to investigate regulatory mechanisms of the variants of the electrogenic sodium/bicarbonate cotransporter 1, NBCe1-A and NBCe1-B/C, in neurons following changes of extracellular pH. Therefore, primary mouse hippocampal neurons were exposed to extracellular acidosis or alkalosis. We show that acid-base changes regulated trafficking and membrane expression of neuronal NBCe1 but the underlying molecular cues were distinct for individual NBCe1 variants. Following extracellular acidosis NBCe1-A was recruited from intracellular pools to the plasma membrane, followed by increased membrane expression, whereas NBCe1-B/C was retrieved from the membrane. Extracellular alkalosis had no impact on NBCe1-A, but caused translocation of NBCe1-B/C toward the dendrites. We also show that acidosis-induced NBCe1-A, but not NBCe1-B/C, trafficking is mediated by Rab8a. Rab8a is expressed in hippocampal neurons, co-localizes, and interacts with NBCe1-A. Loss-of-function of Rab8a using specific siRNA prevented acidosis-induced redistribution of NBCe1-A. These data propose opposite recruitment pattern for NBCe1 variants in neurons following extracellular acid-base changes, implicating distinct physiological functions of individual NBCe1 variants, and introduce Rab8a as a novel molecular determinant and crucial mediator of acidosis-induced NBCe1 trafficking in neurons.
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Affiliation(s)
- Oliver Oehlke
- Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Albert-Ludwigs University Freiburg, Albertstrasse 17, D-79104 Freiburg, Germany.
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22
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Vandenberg LN, Morrie RD, Seebohm G, Lemire JM, Levin M. Rab GTPases are required for early orientation of the left-right axis in Xenopus. Mech Dev 2013; 130:254-71. [PMID: 23354119 PMCID: PMC10676213 DOI: 10.1016/j.mod.2012.11.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/14/2012] [Accepted: 11/16/2012] [Indexed: 02/04/2023]
Abstract
The earliest steps of left-right (LR) patterning in Xenopus embryos are driven by biased intracellular transport that ensures a consistently asymmetric localization of maternal ion channels and pumps in the first 2-4 blastomeres. The subsequent differential net efflux of ions by these transporters generates a bioelectrical asymmetry; this LR voltage gradient redistributes small signaling molecules along the LR axis that later regulate transcription of the normally left-sided Nodal. This system thus amplifies single cell chirality into a true left-right asymmetry across multi-cellular fields. Studies using molecular-genetic gain- and loss-of-function reagents have characterized many of the steps involved in this early pathway in Xenopus. Yet one key question remains: how is the chiral cytoskeletal architecture interpreted to localize ion transporters to the left or right side? Because Rab GTPases regulate nearly all aspects of membrane trafficking, we hypothesized that one or more Rab proteins were responsible for the directed, asymmetric shuttling of maternal ion channel or pump proteins. After performing a screen using dominant negative and wildtype (overexpressing) mRNAs for four different Rabs, we found that alterations in Rab11 expression randomize both asymmetric gene expression and organ situs. We also demonstrated that the asymmetric localization of two ion transporter subunits requires Rab11 function, and that Rab11 is closely associated with at least one of these subunits. Yet, importantly, we found that endogenous Rab11 mRNA and protein are expressed symmetrically in the early embryo. We conclude that Rab11-mediated transport is responsible for the movement of cargo within early blastomeres, and that Rab11 expression is required throughout the early embryo for proper LR patterning.
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Affiliation(s)
- Laura N. Vandenberg
- Center for Regenerative and Developmental Biology, and Biology Department, Tufts University Medford, MA 02155, United States
| | - Ryan D. Morrie
- Center for Regenerative and Developmental Biology, and Biology Department, Tufts University Medford, MA 02155, United States
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, Myocellular Electophysiology Group, University Hospital Münster, D-48149 Münster, Germany
| | - Joan M. Lemire
- Center for Regenerative and Developmental Biology, and Biology Department, Tufts University Medford, MA 02155, United States
| | - Michael Levin
- Center for Regenerative and Developmental Biology, and Biology Department, Tufts University Medford, MA 02155, United States
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23
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Baetz NW, Goldenring JR. Rab11-family interacting proteins define spatially and temporally distinct regions within the dynamic Rab11a-dependent recycling system. Mol Biol Cell 2013; 24:643-58. [PMID: 23283983 PMCID: PMC3583667 DOI: 10.1091/mbc.e12-09-0659] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Rab11-family interacting proteins (Rab11-FIPs) facilitate Rab11-dependent vesicle recycling. We hypothesized that Rab11-FIPs define discrete subdomains and carry out temporally distinct roles within the recycling system. We used live-cell deconvolution microscopy of HeLa cells expressing chimeric fluorescent Rab11-FIPs to examine Rab11-FIP localization, transferrin passage through Rab11-FIP-containing compartments, and overlap among Rab11-FIPs within the recycling system. FIP1A, FIP2, and FIP5 occupy widely distributed mobile tubules and vesicles, whereas FIP1B, FIP1C, and FIP3 localize to perinuclear tubules. Internalized transferrin entered Rab11-FIP-containing compartments within 5 min, reaching maximum colocalization with FIP1B and FIP2 early in the time course, whereas localization with FIP1A, FIP1C, FIP3, and FIP5 was delayed until 10 min or later. Whereas direct interactions with FIP1A were only observed for FIP1B and FIP1C, FIP1A also associated with membranes containing FIP3. Live-cell dual-expression studies of Rab11-FIPs revealed the tubular dynamics of Rab11-FIP-containing compartments and demonstrated a series of selective associations among Rab11-FIPs in real time. These findings suggest that Rab11-FIP1 proteins participate in spatially and temporally distinct steps of the recycling process along a complex and dynamic tubular network in which Rab11-FIPs occupy discrete domains.
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Affiliation(s)
- Nicholas W Baetz
- Section of Surgical Sciences and Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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24
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Rabconnectin3α promotes stable activity of the H+ pump on synaptic vesicles in hair cells. J Neurosci 2012; 32:11144-56. [PMID: 22875945 DOI: 10.1523/jneurosci.1705-12.2012] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Acidification of synaptic vesicles relies on the vacuolar-type ATPase (V-ATPase) and provides the electrochemical driving force for neurotransmitter exchange. The regulatory mechanisms that ensure assembly of the V-ATPase holoenzyme on synaptic vesicles are unknown. Rabconnectin3α (Rbc3α) is a potential candidate for regulation of V-ATPase activity because of its association with synaptic vesicles and its requirement for acidification of intracellular compartments. Here, we provide the first evidence for a role of Rbc3α in synaptic vesicle acidification and neurotransmission. In this study, we characterized mutant alleles of rbc3α isolated from a large-scale screen for zebrafish with auditory/vestibular defects. We show that Rbc3α is localized to basal regions of hair cells in which synaptic vesicles are present. To determine whether Rbc3α regulates V-ATPase activity, we examined the acidification of synaptic vesicles and localization of the V-ATPase in hair cells. In contrast to wild-type hair cells, we observed that synaptic vesicles had elevated pH, and a cytosolic subunit of the V-ATPase was no longer enriched in synaptic regions of mutant hair cells. As a consequence of defective acidification of synaptic vesicles, afferent neurons in rbc3α mutants had reduced firing rates and reduced accuracy of phase-locked action potentials in response to mechanical stimulation of hair cells. Collectively, our data suggest that Rbc3α modulates synaptic transmission in hair cells by promoting V-ATPase activity in synaptic vesicles.
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Oehlke O, Schlosshardt C, Feuerstein M, Roussa E. Acidosis-induced V-ATPase trafficking in salivary ducts is initiated by cAMP/PKA/CREB pathway via regulation of Rab11b expression. Int J Biochem Cell Biol 2012; 44:1254-65. [PMID: 22561749 DOI: 10.1016/j.biocel.2012.04.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 04/05/2012] [Accepted: 04/23/2012] [Indexed: 01/14/2023]
Abstract
Changes in systemic acid-base homeostasis cause a series of organ-specific cellular responses, among them changes of acid-base transporter activities, and recruitment or retrieval of these transporters from intracellular pools to the plasma membrane and vice versa. The purpose of this study was to investigate the impact of protein phosphorylation in the acidosis-induced translocation of vacuolar-type H(+)-ATPase (V-ATPase) in salivary ducts and to identify molecular targets. Therefore, the human submandibular gland cell line HSG was exposed to acidosis and V-ATPase trafficking was investigated in the presence or absence of inhibitors and activators of sAC/PKA and Src/ERK signaling pathways. Putative target genes have been identified by RT-PCR and immunoblotting, and validated by loss-of-function experiments. Acidosis caused activation of cAMP/PKA and Src signaling and inhibition of either pathway significantly impaired acidosis-induced V-ATPase redistribution and incorporation into the plasma membrane. Activation of ERK1/2 was Src-independent, whereas activation of PKA caused phosphorylation of cAMP response element-binding (CREB) and activation to regulate Rab11b transcription. Loss-of-function of CREB down-regulated Rab11b transcript and protein and significantly impaired acidosis-induced V-ATPase translocation in HSG cells. These data demonstrate that the cAMP/PKA/CREB signaling pathway initiates acidosis-induced V-ATPase trafficking in salivary ducts via regulation of Rab11b expression and provide first evidence for a molecular mechanism underlying cAMP/PKA-dependent transporter trafficking that could account for accumulation and activity of transporters in other cellular systems as well.
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Affiliation(s)
- Oliver Oehlke
- Institute for Anatomy and Cell Biology, Department of Molecular Embryology, University of Freiburg, Albertstrasse 17, D-79104 Freiburg, Germany.
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Xu M, Xia M, Li XX, Han WQ, Boini KM, Zhang F, Zhang Y, Ritter JK, Li PL. Requirement of translocated lysosomal V1 H(+)-ATPase for activation of membrane acid sphingomyelinase and raft clustering in coronary endothelial cells. Mol Biol Cell 2012; 23:1546-57. [PMID: 22357614 PMCID: PMC3327313 DOI: 10.1091/mbc.e11-09-0821] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The activation of translocated lysosomal H+-ATPase is attributed to FasL-induced formation and maintenance of an acid microenvironment around the endothelial cell membrane, which facilitates the activation of ASM and production of ceramide, thereby leading to MR clustering and redox signaling platform formation. Acid sphingomyelinase (ASM) mediates the formation of membrane raft (MR) redox signalosomes in a process that depends on a local acid microenvironment in coronary arterial endothelial cells (CAECs). However, it is not known how this local acid microenvironment is formed and maintained. The present study hypothesized that lysosomal V1 H+-ATPase provides a hospitable acid microenvironment for activation of ASM when lysosomes traffic and fuse into the cell membrane. Confocal microscopy showed that local pH change significantly affected MRs, with more fluorescent patches under low pH. Correspondingly, the ASM product, ceramide, increased locally in the cell membrane. Electron spin resonance assay showed that local pH increase significantly inhibited NADPH oxidase–mediated production of O2−. in CAECs. Direct confocal microscopy demonstrated that Fas ligand resulted in localized areas of decreased pH around CAEC membranes. The inhibitors of both lysosomal fusion and H+-ATPase apparently attenuated FasL-caused pH decrease. V1 H+-ATPase accumulation and activity on cell membranes were substantially suppressed by the inhibitors of lysosomal fusion or H+-ATPase. These results provide the first direct evidence that translocated lysosomal V1 H+-ATPase critically contributes to the formation of local acid microenvironment to facilitate activation of ASM and consequent MR aggregation, forming MR redox signalosomes and mediating redox signaling in CAECs.
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Affiliation(s)
- Ming Xu
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298, USA
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Li X, DiFiglia M. The recycling endosome and its role in neurological disorders. Prog Neurobiol 2011; 97:127-41. [PMID: 22037413 DOI: 10.1016/j.pneurobio.2011.10.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 10/14/2011] [Accepted: 10/17/2011] [Indexed: 02/08/2023]
Abstract
The recycling endosome (RE) is an organelle in the endocytic pathway where plasma membranes (proteins and lipids) internalized by endocytosis are processed back to the cell surface for reuse. Endocytic recycling is the primary way for the cell to maintain constituents of the plasma membrane (Griffiths et al., 1989), i.e., to maintain the abundance of receptors and transporters on cell surfaces. Membrane traffic through the RE is crucial for several key cellular processes including cytokinesis and cell migration. In polarized cells, including neurons, the RE is vital for the generation and maintenance of the polarity of the plasma membrane. Many RE dependent cargo molecules are known to be important for neuronal function and there is evidence that improper function of key proteins in RE-associated pathways may contribute to the pathogenesis of neurological disorders, including Huntington's disease. The function of the RE in neurons is poorly understood. Therefore, there is need to understand how membrane dynamics in RE-associated pathways are affected or participate in the development or progression of neurological diseases. This review summarizes advances in understanding endocytic recycling associated with the RE, challenges in elucidating molecular mechanisms underlying RE function, and evidence for RE dysfunction in neurological disorders.
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Affiliation(s)
- Xueyi Li
- Laboratory of Cellular Neurobiology and Department of Neurology, Massachusetts General Hospital, 114 16th Street, Charlestown, MA 02129, USA
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