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Chuaychob S, Lyu R, Tanaka M, Haginiwa A, Kitada A, Nakamura T, Yokokawa R. Mimicking angiogenic microenvironment of alveolar soft-part sarcoma in a microfluidic coculture vasculature chip. Proc Natl Acad Sci U S A 2024; 121:e2312472121. [PMID: 38502703 PMCID: PMC10990104 DOI: 10.1073/pnas.2312472121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 01/24/2024] [Indexed: 03/21/2024] Open
Abstract
Alveolar soft-part sarcoma (ASPS) is a slow-growing soft tissue sarcoma with high mortality rates that affects adolescents and young adults. ASPS resists conventional chemotherapy; thus, decades of research have elucidated pathogenic mechanisms driving the disease, particularly its angiogenic capacities. Integrated blood vessels that are rich in pericytes (PCs) and metastatic potential are distinctive of ASPS. To mimic ASPS angiogenic microenvironment, a microfluidic coculture vasculature chip has been developed as a three-dimensional (3D) spheroid composed of mouse ASPS, a layer of PCs, and endothelial cells (ECs). This ASPS-on-a-chip provided functional and morphological similarity as the in vivo mouse model to elucidate the cellular crosstalk within the tumor vasculature before metastasis. We successfully reproduce ASPS spheroid and leaky vessels representing the unique tumor vasculature to assess effective drug delivery into the core of a solid tumor. Furthermore, this ASPS angiogenesis model enabled us to investigate the role of proteins in the intracellular trafficking of bioactive signals from ASPS to PCs and ECs during angiogenesis, including Rab27a and Sytl2. The results can help to develop drugs targeting the crosstalk between ASPS and the adjacent cells in the tumoral microenvironment.
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Affiliation(s)
- Surachada Chuaychob
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto615-8540, Japan
| | - Ruyin Lyu
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto615-8540, Japan
| | - Miwa Tanaka
- Project for Cancer Epigenomics, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo135-8550, Japan
- Department of Experimental Pathology, Institute of Medical Science, Tokyo Medical University, Tokyo160-8402, Japan
| | - Ayumi Haginiwa
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto615-8540, Japan
| | - Atsuya Kitada
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto615-8540, Japan
| | - Takuro Nakamura
- Department of Experimental Pathology, Institute of Medical Science, Tokyo Medical University, Tokyo160-8402, Japan
| | - Ryuji Yokokawa
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto615-8540, Japan
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2
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Tanaka M, Chuaychob S, Homme M, Yamazaki Y, Lyu R, Yamashita K, Ae K, Matsumoto S, Kumegawa K, Maruyama R, Qu W, Miyagi Y, Yokokawa R, Nakamura T. ASPSCR1::TFE3 orchestrates the angiogenic program of alveolar soft part sarcoma. Nat Commun 2023; 14:1957. [PMID: 37029109 PMCID: PMC10082046 DOI: 10.1038/s41467-023-37049-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 03/01/2023] [Indexed: 04/09/2023] Open
Abstract
Alveolar soft part sarcoma (ASPS) is a soft part malignancy affecting adolescents and young adults. ASPS is characterized by a highly integrated vascular network, and its high metastatic potential indicates the importance of ASPS's prominent angiogenic activity. Here, we find that the expression of ASPSCR1::TFE3, the fusion transcription factor causatively associated with ASPS, is dispensable for in vitro tumor maintenance; however, it is required for in vivo tumor development via angiogenesis. ASPSCR1::TFE3 is frequently associated with super-enhancers (SEs) upon its DNA binding, and the loss of its expression induces SE-distribution dynamic modification related to genes belonging to the angiogenesis pathway. Using epigenomic CRISPR/dCas9 screening, we identify Pdgfb, Rab27a, Sytl2, and Vwf as critical targets associated with reduced enhancer activities due to the ASPSCR1::TFE3 loss. Upregulation of Rab27a and Sytl2 promotes angiogenic factor-trafficking to facilitate ASPS vascular network construction. ASPSCR1::TFE3 thus orchestrates higher ordered angiogenesis via modulating the SE activity.
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Affiliation(s)
- Miwa Tanaka
- Division of Carcinogenesis, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.
- Department of Experimental Pathology, Institute of Medical Science, Tokyo Medical University, Tokyo, Japan.
- Project for Cancer Epigenomics, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.
| | - Surachada Chuaychob
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Mizuki Homme
- Division of Carcinogenesis, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
- Division of Cell Biology, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Yukari Yamazaki
- Division of Carcinogenesis, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
- Department of Experimental Pathology, Institute of Medical Science, Tokyo Medical University, Tokyo, Japan
| | - Ruyin Lyu
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Kyoko Yamashita
- Division of Pathology, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Keisuke Ae
- Department of Orthopedic Oncology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Seiichi Matsumoto
- Department of Orthopedic Oncology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Kohei Kumegawa
- Project for Cancer Epigenomics, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Reo Maruyama
- Project for Cancer Epigenomics, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Wei Qu
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Yohei Miyagi
- Molecular Pathology and Genetics Division, Kanagawa Cancer Center Research Institute, Yokohama, Japan
| | - Ryuji Yokokawa
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Takuro Nakamura
- Division of Carcinogenesis, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.
- Department of Experimental Pathology, Institute of Medical Science, Tokyo Medical University, Tokyo, Japan.
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3
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Bauer KM, Nelson MC, Tang WW, Chiaro TR, Brown DG, Ghazaryan A, Lee SH, Weis AM, Hill JH, Klag KA, Tran VB, Thompson JW, Ramstead AG, Monts JK, Marvin JE, Alexander M, Voth WP, Stephens WZ, Ward DM, Petrey AC, Round JL, O'Connell RM. CD11c+ myeloid cell exosomes reduce intestinal inflammation during colitis. JCI Insight 2022; 7:159469. [PMID: 36214220 PMCID: PMC9675566 DOI: 10.1172/jci.insight.159469] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 08/19/2022] [Indexed: 01/25/2023] Open
Abstract
Intercellular communication is critical for homeostasis in mammalian systems, including the gastrointestinal (GI) tract. Exosomes are nanoscale lipid extracellular vesicles that mediate communication between many cell types. Notably, the roles of immune cell exosomes in regulating GI homeostasis and inflammation are largely uncharacterized. By generating mouse strains deficient in cell-specific exosome production, we demonstrate deletion of the small GTPase Rab27A in CD11c+ cells exacerbated murine colitis, which was reversible through administration of DC-derived exosomes. Profiling RNAs within colon exosomes revealed a distinct subset of miRNAs carried by colon- and DC-derived exosomes. Among antiinflammatory exosomal miRNAs, miR-146a was transferred from gut immune cells to myeloid and T cells through a Rab27-dependent mechanism, targeting Traf6, IRAK-1, and NLRP3 in macrophages. Further, we have identified a potentially novel mode of exosome-mediated DC and macrophage crosstalk that is capable of skewing gut macrophages toward an antiinflammatory phenotype. Assessing clinical samples, RAB27A, select miRNAs, and RNA-binding proteins that load exosomal miRNAs were dysregulated in ulcerative colitis patient samples, consistent with our preclinical mouse model findings. Together, our work reveals an exosome-mediated regulatory mechanism underlying gut inflammation and paves the way for potential use of miRNA-containing exosomes as a novel therapeutic for inflammatory bowel disease.
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Affiliation(s)
- Kaylyn M Bauer
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Morgan C Nelson
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - William W Tang
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Tyson R Chiaro
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - D Garrett Brown
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Arevik Ghazaryan
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Soh-Hyun Lee
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Allison M Weis
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Jennifer H Hill
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Kendra A Klag
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Van B Tran
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Jacob W Thompson
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Andrew G Ramstead
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Josh K Monts
- University of Utah Flow Cytometry Core, Salt Lake City, Utah, USA
| | - James E Marvin
- University of Utah Flow Cytometry Core, Salt Lake City, Utah, USA
| | - Margaret Alexander
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Warren P Voth
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - W Zac Stephens
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Diane M Ward
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA
| | - Aaron C Petrey
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA.,Department of Internal Medicine, Division of Gastroenterology, and
| | - June L Round
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA.,Hunstman Cancer Institute, University of Utah, Salt Lake City, Utah, USA
| | - Ryan M O'Connell
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City, Utah, USA.,Hunstman Cancer Institute, University of Utah, Salt Lake City, Utah, USA
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4
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Novel RAB27A Variant Associated with Late-Onset Hemophagocytic Lymphohistiocytosis Alters Effector Protein Binding. J Clin Immunol 2022; 42:1685-1695. [DOI: 10.1007/s10875-022-01315-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 06/22/2022] [Indexed: 11/25/2022]
Abstract
Abstract
Autosomal recessive mutations in RAB27A are associated with Griscelli syndrome type 2 (GS2), characterized by hypopigmentation and development of early-onset, potentially fatal hemophagocytic lymphohistiocytosis (HLH). We describe a 35-year old male who presented with recurrent fever, was diagnosed with Epstein-Barr virus-driven chronic lymphoproliferation, fulfilled clinical HLH criteria, and who carried a novel homozygous RAB27A c.551G > A p.(R184Q) variant. We aimed to evaluate the contribution of the identified RAB27A variant in regard to the clinical phenotype as well as cellular and biochemical function. The patient displayed normal pigmentation as well as RAB27A expression in blood-derived cells. However, patient NK and CD8+ T cell exocytosis was low. Ectopic expression of the RAB27A p.R184Q variant rescued melanosome distribution in mouse Rab27a-deficient melanocytes, but failed to increase exocytosis upon reconstitution of human RAB27A-deficient CD8+ T cells. Mechanistically, the RAB27A p.R184Q variant displayed reduced binding to SLP2A but augmented binding to MUNC13-4, two key effector proteins in immune cells. MUNC13-4 binding was particularly strong to an inactive RAB27A p.T23N/p.R184Q double mutant. RAB27A p.R184Q was expressed and could facilitate melanosome trafficking, but did not support lymphocyte exocytosis. The HLH-associated RAB27A variant increased Munc13-4 binding, potentially representing a novel mode of impairing RAB27A function selectively in hematopoietic cells.
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5
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Mastio J, Saeed MB, Wurzer H, Krecke M, Westerberg LS, Thomas C. Higher Incidence of B Cell Malignancies in Primary Immunodeficiencies: A Combination of Intrinsic Genomic Instability and Exocytosis Defects at the Immunological Synapse. Front Immunol 2020; 11:581119. [PMID: 33240268 PMCID: PMC7680899 DOI: 10.3389/fimmu.2020.581119] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/09/2020] [Indexed: 12/11/2022] Open
Abstract
Congenital defects of the immune system called primary immunodeficiency disorders (PID) describe a group of diseases characterized by a decrease, an absence, or a malfunction of at least one part of the immune system. As a result, PID patients are more prone to develop life-threatening complications, including cancer. PID currently include over 400 different disorders, however, the variety of PID-related cancers is narrow. We discuss here reasons for this clinical phenotype. Namely, PID can lead to cell intrinsic failure to control cell transformation, failure to activate tumor surveillance by cytotoxic cells or both. As the most frequent tumors seen among PID patients stem from faulty lymphocyte development leading to leukemia and lymphoma, we focus on the extensive genomic alterations needed to create the vast diversity of B and T lymphocytes with potential to recognize any pathogen and why defects in these processes lead to malignancies in the immunodeficient environment of PID patients. In the second part of the review, we discuss PID affecting tumor surveillance and especially membrane trafficking defects caused by altered exocytosis and regulation of the actin cytoskeleton. As an impairment of these membrane trafficking pathways often results in dysfunctional effector immune cells, tumor cell immune evasion is elevated in PID. By considering new anti-cancer treatment concepts, such as transfer of genetically engineered immune cells, restoration of anti-tumor immunity in PID patients could be an approach to complement standard therapies.
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Affiliation(s)
- Jérôme Mastio
- Department of Oncology, Cytoskeleton and Cancer Progression, Luxembourg Institute of Health, Luxembourg City, Luxembourg
| | - Mezida B Saeed
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Hannah Wurzer
- Department of Oncology, Cytoskeleton and Cancer Progression, Luxembourg Institute of Health, Luxembourg City, Luxembourg
| | - Max Krecke
- Department of Oncology, Cytoskeleton and Cancer Progression, Luxembourg Institute of Health, Luxembourg City, Luxembourg
| | - Lisa S Westerberg
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Clément Thomas
- Department of Oncology, Cytoskeleton and Cancer Progression, Luxembourg Institute of Health, Luxembourg City, Luxembourg
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6
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Kawata R, Oda S, Koya Y, Kajiyama H, Yokoi T. Macrophage-derived extracellular vesicles regulate concanavalin A-induced hepatitis by suppressing macrophage cytokine production. Toxicology 2020; 443:152544. [PMID: 32739513 DOI: 10.1016/j.tox.2020.152544] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/21/2020] [Accepted: 07/27/2020] [Indexed: 12/18/2022]
Abstract
Acute liver failure is a clinical syndrome of severe hepatic dysfunction. Immune cells play an important role in acute liver failure. In recent years, the immunoregulatory function of extracellular vesicles (EVs) has been reported; therefore, it is inferred that EVs play a role in immune-mediated hepatitis. In this study, we investigated the immunoregulatory function of EVs in concanavalin A (Con A)-induced hepatitis. The mouse model was prepared by a single intravenous administration of 15 mg/kg Con A, in which there was a significant increase in the serum EVs number. In an in vitro study, the number of secreted EVs was also significantly increased in Con A-treated RAW264.7 cells, a mouse macrophage cell line, but not in Hepa1-6 cells, a mouse hepatoma cell line. In an in vitro EVs treatment study, EVs from Con A-treated mouse serum and Con A-treated RAW264.7 cells suppressed inflammatory cytokine production in Con A-stimulated RAW264.7 cells. miRNA sequencing analysis showed that the expression of mmu-miR-122-5p and mmu-miR-148a-3p was commonly increased in these EVs and EVs-treated cells. The pathways enriched in the predicted miRNA target genes included inflammatory response pathways. The mRNA levels of the target genes in these pathways (mitogen-activated protein kinase, phosphoinositide 3-kinase/Akt and Rho/Rho-associated coiled-coil containing protein kinase pathways) were decreased in the EVs-treated cells. In an in vivo RNA interference study, the knockdown of liver RAB27A, an EVs secretion regulator, significantly exacerbated Con A-induced hepatitis. These data suggest that macrophage-derived EVs play an important role in Con A-induced hepatitis through immunoregulation.
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Affiliation(s)
- Reo Kawata
- Department of Drug Safety Sciences, Division of Clinical Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan; Department of Investigative Toxicology, Nonclinical Research Center, Tokushima Research Institute, Otsuka Pharmaceutical Co., Ltd., 463-10 Kagasuno, Kawauchi-cho, Tokushima, Japan.
| | - Shingo Oda
- Department of Drug Safety Sciences, Division of Clinical Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yoshihiro Koya
- Bell Research Center Obstetrics and Gynecology, Academic Research & Industrial-Academia Collaboration, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Hiroaki Kajiyama
- Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Tsuyoshi Yokoi
- Department of Drug Safety Sciences, Division of Clinical Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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7
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The Role of Lipopolysaccharide-Induced Extracellular Vesicles in Cardiac Cell Death. BIOLOGY 2019; 8:biology8040069. [PMID: 31547509 PMCID: PMC6955717 DOI: 10.3390/biology8040069] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 12/11/2022]
Abstract
Exosomes play a crucial role in the progression of infectious diseases, as exosome release and biogenesis are affected by external factors, such as pathogenic infections. Pyrogens may aide in the progression of diseases by triggering inflammation, endothelial cell injury, and arterial plaque rupture, all of which can lead to acute coronary disease, resulting in cardiac tissue death and the onset of a cardiac event (CE). To better understand the effects of Gram-negative bacterial infections on exosome composition and biogenesis, we examined exosome characteristics after treatment of AC16 human cardiomyocytes with lipopolysaccharide (LPS), which served as a model system for Gram-negative bacterial infection. Using increasing doses (0, 0.1, 1, or 10 µg) of LPS, we showed that treatment with LPS substantially altered the composition of AC16-derived exosomes. Both the relative size and the quantity (particles/mL) of exosomes were decreased significantly at all tested concentrations of LPS treatment compared to the untreated group. In addition, LPS administration reduced the expression of exosomal proteins that are related to exosomal biogenesis. Conversely, we observed an increase in immunomodulators present after LPS administration. This evaluation of the impact of LPS on cardiac cell death and exosome composition will yield new insight into the importance of exosomes in a variety of physiological and pathological processes as it relates to disease progression, diagnosis, and treatment.
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8
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Rab27a facilitates human parainfluenza virus type 2 growth by promoting cell surface transport of envelope proteins. Med Microbiol Immunol 2018; 207:141-150. [DOI: 10.1007/s00430-018-0536-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 01/20/2018] [Indexed: 01/03/2023]
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9
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Bustos MA, Lucchesi O, Ruete MC, Tomes CN. Membrane-permeable Rab27A is a regulator of the acrosome reaction: Role of geranylgeranylation and guanine nucleotides. Cell Signal 2018; 44:72-81. [PMID: 29337043 DOI: 10.1016/j.cellsig.2018.01.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 12/18/2017] [Accepted: 01/09/2018] [Indexed: 12/11/2022]
Abstract
The acrosome reaction is the regulated exocytosis of mammalian sperm's single secretory granule, essential for fertilization. It relies on small GTPases, the cAMP binding protein Epac, and the SNARE complex, among other components. Here, we describe a novel tool to investigate Rab27-related signaling pathways: a hybrid recombinant protein consisting of human Rab27A fused to TAT, a cell penetrating peptide. With this tool, we aimed to unravel the connection between Rab3, Rab27 and Rap1 in sperm exocytosis and to deepen our understanding about how isoprenylation and guanine nucleotides influence the behaviour of Rab27 in exocytosis. Our results show that TAT-Rab27A-GTP-γ-S permeated into live sperm and triggered acrosomal exocytosis per se when geraylgeranylated but inhibited it when not lipid-modified. Likewise, an impermeant version of Rab27A elicited exocytosis in streptolysin O-permeabilized - but not in non-permeabilized - cells when geranylgeranylated and active. When GDP-β-S substituted for GTP-γ-S, isoprenylated TAT-Rab27A inhibited the acrosome reaction triggered by progesterone and an Epac-selective cAMP analogue, whereas the non-isoprenylated protein did not. Geranylgeranylated TAT-Rab27A-GTP-γ-S promoted the exchange of GDP for GTP on Rab3 and Rap1 detected by far-immunofluorescence with Rab3-GTP and Rap1-GTP binding cassettes. In contrast, TAT-Rab27A lacking isoprenylation or loaded with GDP-β-S prevented the activation of Rab3 and Rap1 elicited by progesterone. Challenging streptolysin O-permeabilized human sperm with calcium increased the population of sperm with Rap1-GTP, Rab3-GTP and Rab27-GTP in the acrosomal region; pretreatment with anti-Rab27 antibodies prevented the activation of all three. The novel findings reported here include: the description of membrane permeant TAT-Rab27A as a trustworthy tool to unveil the regulation of the human sperm acrosome reaction by Rab27 under physiological conditions; that the activation of endogenous Rab27 is required for that of Rab3 and Rap1; and the connection between Epac and Rab27 and between Rab27 and the configuration of the SNARE complex. Moreover, we present direct evidence that Rab27A's lipid modification, and activation/inactivation status correlate with its stimulatory or inhibitory roles in exocytosis.
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Affiliation(s)
- Matías A Bustos
- Instituto de Histologia y Embriologia de Mendoza (IHEM) Dr. Mario H. Burgos-CONICET, Universidad Nacional de Cuyo, casilla de correo 56, 5500 Mendoza, Argentina
| | - Ornella Lucchesi
- Instituto de Histologia y Embriologia de Mendoza (IHEM) Dr. Mario H. Burgos-CONICET, Universidad Nacional de Cuyo, casilla de correo 56, 5500 Mendoza, Argentina
| | - María C Ruete
- Instituto de Histologia y Embriologia de Mendoza (IHEM) Dr. Mario H. Burgos-CONICET, Universidad Nacional de Cuyo, casilla de correo 56, 5500 Mendoza, Argentina
| | - Claudia N Tomes
- Instituto de Histologia y Embriologia de Mendoza (IHEM) Dr. Mario H. Burgos-CONICET, Universidad Nacional de Cuyo, casilla de correo 56, 5500 Mendoza, Argentina.
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10
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Lindemann C, Thomanek N, Hundt F, Lerari T, Meyer HE, Wolters D, Marcus K. Strategies in relative and absolute quantitative mass spectrometry based proteomics. Biol Chem 2017; 398:687-699. [DOI: 10.1515/hsz-2017-0104] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 02/28/2017] [Indexed: 11/15/2022]
Abstract
Abstract
Quantitative mass spectrometry approaches are used for absolute and relative quantification in global proteome studies. To date, relative and absolute quantification techniques are available that differ in quantification accuracy, proteome coverage, complexity and robustness. This review focuses on most common relative or absolute quantification strategies exemplified by three experimental studies. A label-free relative quantification approach was performed for the investigation of the membrane proteome of sensory cilia to the depth of olfactory receptors in Mus musculus. A SILAC-based relative quantification approach was successfully applied for the identification of core components and transient interactors of the peroxisomal importomer in Saccharomyces cerevisiae. Furthermore, AQUA using stable isotopes was exemplified to unraveling the prenylome influenced by novel prenyltransferase inhibitors. Characteristic enrichment and fragmentation strategies for a robust quantification of the prenylome are also summarized.
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11
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Khadilkar RJ, Ray A, Chetan DR, Sinha AR, Magadi SS, Kulkarni V, Inamdar MS. Differential modulation of the cellular and humoral immune responses in Drosophila is mediated by the endosomal ARF1-Asrij axis. Sci Rep 2017; 7:118. [PMID: 28273919 PMCID: PMC5427928 DOI: 10.1038/s41598-017-00118-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 01/10/2017] [Indexed: 12/15/2022] Open
Abstract
How multicellular organisms maintain immune homeostasis across various organs and cell types is an outstanding question in immune biology and cell signaling. In Drosophila, blood cells (hemocytes) respond to local and systemic cues to mount an immune response. While endosomal regulation of Drosophila hematopoiesis is reported, the role of endosomal proteins in cellular and humoral immunity is not well-studied. Here we demonstrate a functional role for endosomal proteins in immune homeostasis. We show that the ubiquitous trafficking protein ADP Ribosylation Factor 1 (ARF1) and the hemocyte-specific endosomal regulator Asrij differentially regulate humoral immunity. Asrij and ARF1 play an important role in regulating the cellular immune response by controlling the crystal cell melanization and phenoloxidase activity. ARF1 and Asrij mutants show reduced survival and lifespan upon infection, indicating perturbed immune homeostasis. The ARF1-Asrij axis suppresses the Toll pathway anti-microbial peptides (AMPs) by regulating ubiquitination of the inhibitor Cactus. The Imd pathway is inversely regulated- while ARF1 suppresses AMPs, Asrij is essential for AMP production. Several immune mutants have reduced Asrij expression, suggesting that Asrij co-ordinates with these pathways to regulate the immune response. Our study highlights the role of endosomal proteins in modulating the immune response by maintaining the balance of AMP production. Similar mechanisms can now be tested in mammalian hematopoiesis and immunity.
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Affiliation(s)
- Rohan J Khadilkar
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Arindam Ray
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - D R Chetan
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | | | - Srivathsa S Magadi
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Vani Kulkarni
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Maneesha S Inamdar
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India.
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12
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Yang YX, Li L. Identification of potential biomarkers of sepsis using bioinformatics analysis. Exp Ther Med 2017; 13:1689-1696. [PMID: 28565754 PMCID: PMC5443301 DOI: 10.3892/etm.2017.4178] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 09/22/2016] [Indexed: 01/02/2023] Open
Abstract
Sepsis is defined as the systemic inflammatory response to infection and is one of the leading causes of mortality in critically ill patients. The goal of the present study is to elucidate the molecular mechanism of sepsis. Transcription profile data (GSE12624) were downloaded that had a total of 70 samples (36 sepsis samples and 34 non-sepsis samples) from the Gene Expression Omnibus database. Protein-protein interaction network analysis was conducted in order to comprehensively understand the interactions of genes in all samples. Hierarchical clustering and analysis of covariance (ANCOVA) global test were performed to identify the differentially expressed clusters in the networks, followed by function and pathway enrichment analyses. Finally, a support vector machine (SVM) was performed to classify the clusters, and 10-fold cross-validation method was performed to evaluate the classification results. A total of 7,672 genes were obtained after preprocessing of the mRNA expression profile data. The PPI network of genes under sepsis and non-sepsis status collected 1,996/2,147 genes and 2,645/2,783 interactions. Moreover, following the ANCOVA global test (P<0.05), 24 differentially expressed clusters with 12 clusters in septic and 12 clusters in non-septic samples were identified. Finally, 207 biomarker genes, including CDC42, CSF3R, GCA, HMGB2, RHOG, SERPINB1, TYROBP SERPINA1, FCER1 G and S100P in the top six clusters, were collected using the SVM method. The SERPINA1, FCER1 G and S100P genes are thought to be potential biomarkers. Furthermore, Gene oncology terms, including the intracellular signaling cascade, regulation of programmed cell death, regulation of cell death, regulation of apoptosis and leukocyte activation may participate in sepsis.
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Affiliation(s)
- Yu-Xia Yang
- Department of Emergency Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Li Li
- Department of Emergency Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
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Zhang M, Bracaglia C, Prencipe G, Bemrich-Stolz CJ, Beukelman T, Dimmitt RA, Chatham WW, Zhang K, Li H, Walter MR, De Benedetti F, Grom AA, Cron RQ. A Heterozygous RAB27A Mutation Associated with Delayed Cytolytic Granule Polarization and Hemophagocytic Lymphohistiocytosis. THE JOURNAL OF IMMUNOLOGY 2016; 196:2492-503. [PMID: 26880764 DOI: 10.4049/jimmunol.1501284] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 01/12/2016] [Indexed: 11/19/2022]
Abstract
Frequently fatal, primary hemophagocytic lymphohistiocytosis (HLH) occurs in infancy resulting from homozygous mutations in NK and CD8 T cell cytolytic pathway genes. Secondary HLH presents after infancy and may be associated with heterozygous mutations in HLH genes. We report two unrelated teenagers with HLH and an identical heterozygous RAB27A mutation (c.259G→C). We explore the contribution of this Rab27A missense (p.A87P) mutation on NK cell cytolytic function by cloning it into a lentiviral expression vector prior to introduction into the human NK-92 cell line. NK cell degranulation (CD107a expression), target cell conjugation, and K562 target cell lysis was compared between mutant- and wild-type-transduced NK-92 cells. Polarization of granzyme B to the immunologic synapse and interaction of mutant Rab27A (p.A87P) with Munc13-4 were explored by confocal microscopy and proximity ligation assay, respectively. Overexpression of the RAB27A mutation had no effect on cell conjugate formation between the NK and target cells but decreased NK cell cytolytic activity and degranulation. Moreover, the mutant Rab27A protein decreased binding to Munc13-4 and delayed granzyme B polarization toward the immunologic synapse. This heterozygous RAB27A mutation blurs the genetic distinction between primary and secondary HLH by contributing to HLH via a partial dominant-negative effect.
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Affiliation(s)
- Mingce Zhang
- Division of Pediatric Rheumatology, University of Alabama at Birmingham, Birmingham, AL 35233
| | - Claudia Bracaglia
- Divisione di Reumatologia Pediatrica, Ospedale Pediatrico Bambino Gesù, 00165 Rome, Italy
| | - Giusi Prencipe
- Divisione di Reumatologia Pediatrica, Ospedale Pediatrico Bambino Gesù, 00165 Rome, Italy
| | - Christina J Bemrich-Stolz
- Division of Pediatric Hematology-Oncology, University of Alabama at Birmingham, Birmingham, AL 35233
| | - Timothy Beukelman
- Division of Pediatric Rheumatology, University of Alabama at Birmingham, Birmingham, AL 35233; Division of Clinical Immunology and Rheumatology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Reed A Dimmitt
- Division of Pediatric Gastroenterology, University of Alabama at Birmingham, Birmingham, AL 35233
| | - W Winn Chatham
- Division of Clinical Immunology and Rheumatology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Kejian Zhang
- Human Genetics, University of Cincinnati, Cincinnati, OH 45229
| | - Hao Li
- Division of Clinical Immunology and Rheumatology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Mark R Walter
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294; and
| | - Fabrizio De Benedetti
- Divisione di Reumatologia Pediatrica, Ospedale Pediatrico Bambino Gesù, 00165 Rome, Italy
| | - Alexei A Grom
- Division of Pediatric Rheumatology, University of Cincinnati, Cincinnati, OH 45229
| | - Randy Q Cron
- Division of Pediatric Rheumatology, University of Alabama at Birmingham, Birmingham, AL 35233; Division of Clinical Immunology and Rheumatology, University of Alabama at Birmingham, Birmingham, AL 35294;
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Patients with Griscelli syndrome and normal pigmentation identify RAB27A mutations that selectively disrupt MUNC13-4 binding. J Allergy Clin Immunol 2014; 135:1310-8.e1. [PMID: 25312756 PMCID: PMC4418747 DOI: 10.1016/j.jaci.2014.08.039] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 08/23/2014] [Accepted: 08/27/2014] [Indexed: 11/21/2022]
Abstract
BACKGROUND Familial hemophagocytic lymphohistiocytosis (FHL) is a rare and often fatal disorder characterized by defective cellular cytotoxicity and hyperinflammation, and the only cure known to date is hematopoietic stem cell transplantation. Mutations in RAB27A, LYST, and AP3B1 give rise to FHL associated with oculocutaneous albinism, and patients with FHL are usually only screened for mutations in these genes when albinism is observed. A number of patients with FHL and normal pigmentation remain without a genetic diagnosis. OBJECTIVE We asked whether patients with FHL with immunodeficiency but with normal pigmentation might sometimes have mutations that affected cellular cytotoxicity without affecting pigmentation. METHODS We carried out mutation analysis of RAB27A, LYST, and AP3B1 in patients with FHL with pigment dilution, as well as a cohort with no clinical evidence of pigment dilution but no mutations in the other known FHL-related genes (PRF1, STXBP2, and UNC13D). RESULTS We identify patients with Griscelli syndrome type 2 with biallelic mutations in RAB27A in the absence of albinism. All 6 patients carried mutations at amino acids R141, Y159, or S163 of Rab27a that disrupt the interaction of Rab27a with Munc13-4, without impairing the interaction between melanophilin and Rab27a. CONCLUSION These studies highlight the need for RAB27A sequencing in patients with FHL with normal pigmentation and identify a critical binding site for Munc13-4 on Rab27a, revealing the molecular basis of this interaction.
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Joung JY, Lee HY, Park J, Lee JY, Chang BH, No KT, Nam KY, Hwang JS. Identification of novel rab27a/melanophilin blockers by pharmacophore-based virtual screening. Appl Biochem Biotechnol 2013; 172:1882-97. [PMID: 24293275 DOI: 10.1007/s12010-013-0615-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 10/30/2013] [Indexed: 12/31/2022]
Abstract
Melanocytes are unique cells that produce specific melanin-containing intracellular organelles called melanosomes. Melanosomes are transported from the perinuclear area of melanocytes toward the plasma membrane as they become more melanized in order to increase skin pigmentation. In this vesicular trafficking of melanosomes, Rab27a, melanophilin, and myosin Va play crucial roles in linking melanosomes to actin-based motors. To identify novel compounds to inhibit binding interface between Rab27a and melanophilin, a pharmacophore model was built based on a modeled 3D structure of the protein complex that describes the essential binding residues in the intermolecular interaction. A pharmacophore model was employed to screen a chemical library database. Finally, 25 virtual hits were selected for biological evaluations. The biological activities of 11 analogues were evaluated in a second assay. Two compounds were identified as having concentration-dependent inhibitory activity. By analyzing structure-activity relationships of derivatives of BMD-20, two hydroxyl functional groups were found to be critical for blocking the intermolecular binding between Rab27a and melanophilin.
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Affiliation(s)
- Jong Young Joung
- Bioinformatics and Molecular Design Research Center, Seoul, 120-749, Republic of Korea
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16
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De Matteis MA, Vicinanza M, Venditti R, Wilson C. Cellular Assays for Drug Discovery in Genetic Disorders of Intracellular Trafficking. Annu Rev Genomics Hum Genet 2013; 14:159-90. [DOI: 10.1146/annurev-genom-091212-153415] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | | | | | - Cathal Wilson
- Telethon Institute of Genetics and Medicine, 80131 Naples, Italy;
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17
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Abstract
Intracellular membrane trafficking requires the complex interplay of several classes of trafficking proteins. Rab proteins, the largest subfamily of the Ras superfamily of small G-proteins, are central regulators of all aspects of intracellular trafficking processes including vesicle budding and uncoating, motility, tethering and fusion. In the present paper, we discuss the discovery, evolution and characterization of the Rab GTPase family. We examine their basic functional roles, their important structural features and the regulatory proteins which mediate Rab function. We speculate on outstanding issues in the field, such as the mechanisms of Rab membrane association and the co-ordinated interplay between distinct Rab proteins. Finally, we summarize the data implicating Rab proteins in an ever increasing number of diseases.
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Reissmann M, Ludwig A. Pleiotropic effects of coat colour-associated mutations in humans, mice and other mammals. Semin Cell Dev Biol 2013; 24:576-86. [PMID: 23583561 DOI: 10.1016/j.semcdb.2013.03.014] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 03/27/2013] [Accepted: 03/28/2013] [Indexed: 12/20/2022]
Abstract
The characterisation of the pleiotropic effects of coat colour-associated mutations in mammals illustrates that sensory organs and nerves are particularly affected by disorders because of the shared origin of melanocytes and neurocytes in the neural crest; e.g. the eye-colour is a valuable indicator of disorders in pigment production and eye dysfunctions. Disorders related to coat colour-associated alleles also occur in the skin (melanoma), reproductive tract and immune system. Additionally, the coat colour phenotype of an individual influences its general behaviour and fitness. Mutations in the same genes often produce similar coat colours and pleiotropic effects in different species (e.g., KIT [reproductive disorders, lethality], EDNRB [megacolon] and LYST [CHS]). Whereas similar disorders and similar-looking coat colour phenotypes sometimes have a different genetic background (e.g., deafness [EDN3/EDNRB, MITF, PAX and SNAI2] and visual diseases [OCA2, RAB38, SLC24A5, SLC45A2, TRPM1 and TYR]). The human predilection for fancy phenotypes that ignore disorders and genetic defects is a major driving force for the increase of pleiotropic effects in domestic species and laboratory subjects since domestication has commenced approximately 18,000 years ago.
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Key Words
- AS
- ASIP
- ATRN
- Agouti signalling protein
- Albino
- Angelman syndrome
- Attractin (mahogany)
- BLOC
- Biogenesis of lysosomal organelles complex
- CCSD
- CHS
- CSD
- CSNB
- Canine congenital sensorineural deafness
- Chediak-Higashi syndrome
- Coat colour gene
- Congenital sensorineural deafness
- Congenital stationary night blindness
- Disorder
- EDN3
- EDNRB
- Endothelin 3
- Endothelin receptor type B
- Epistasis
- Fitness
- GS
- Griscelli syndrome (type 1 or 2)
- HPS
- HSCR
- Hermansky-Pudlak syndrome with different types
- Hirschsprung disease
- IPE
- Iris pigment epithelium
- KIT
- KIT ligand (steel factor)
- KITLG
- LFS
- LYST
- Lavender foal syndrome
- Lethal
- Leucism
- Lysosomal trafficking regulator
- MC1R
- MCOA
- MCOLN3
- MGRN1
- MITF
- MYO5A
- Mahogunin ring finger 1 (E3 ubiquitin protein ligase)
- Melanocortin 1 receptor
- Melanoma
- Microphthalmia-associated transcription factor
- Mucolipin 3 (TRPML3)
- Multiple congenital ocular anomalies
- Myosin VA (heavy chain 12, myoxin)
- OA
- OCA
- OCA2
- OLWS
- OSTM1
- Ocular albinism
- Oculocutaneous albinism II (pink-eye dilution homolog)
- Oculocutaneous albinism type 1–4
- Osteopetrosis associated transmembrane protein 1 (Grey lethal osteopetrosis)
- Overo lethal white syndrome
- PAX3
- PMEL
- PWS
- Paired box 3
- Pleiotropy
- Prader-Willi syndrome
- Premelanosome protein (Pmel17, SILV)
- RAB27A
- RAB27A member RAS oncogene family
- RAB38
- RAB38 member RAS oncogene family
- RPE
- Reproduction
- Retinal pigmented epithelium
- SLC24A5
- SLC2A9
- SLC45A2
- SNAI2
- STX17
- Snail homolog 2 (Drosophila), (SLUG), SOX10, SRY (sex determining region Y)-box 10
- Solute carrier family 2 (facilitated glucose transporter), member 9
- Solute carrier family 24, member 5
- Solute carrier family 45, member 2, MATP
- Syntaxin 17
- TRPM1
- TYR
- Tameness
- Transient receptor potential cation channel, subfamily M, member 1 (melastatin-1)
- Tyrosinase, TYRP1, Tyrosinase-related protein 1
- V-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog, tyrosine kinase receptor (c-kit)
- WS
- Waardenburg syndrome (type 1, type 2 combined with Tietz syndrome type 3 Klein-Waardenburg syndrome, type 4 Waardenburg-Shah syndrome)
- alpha-melanocyte-stimulating hormone
- αMSH
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Affiliation(s)
- Monika Reissmann
- Humboldt University Berlin, Department for Crop and Animal Sciences, Berlin, Germany.
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Boztug K, Klein C. Genetics and Pathophysiology of Severe Congenital Neutropenia Syndromes Unrelated to Neutrophil Elastase. Hematol Oncol Clin North Am 2013; 27:43-60, vii. [DOI: 10.1016/j.hoc.2012.11.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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20
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Khan AR. Oligomerization of rab/effector complexes in the regulation of vesicle trafficking. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:579-614. [PMID: 23663983 DOI: 10.1016/b978-0-12-386931-9.00021-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Rabs comprise the largest member of the Ras superfamily of small GTPases with over 60 proteins in mammals and 11 proteins in yeast. Like all small GTPases, Rabs oscillate between an inactive GDP-bound conformation and an active GTP-bound state that is tethered to lipid membranes via a C-terminal prenylation site on conserved cysteine residues. In their active state, Rabs regulate various aspects of membrane trafficking, including vesicle formation, transport, docking, and fusion. The critical element of biological activity is the recruitment of cytosolic effector proteins to specific endomembranes by active Rabs. The importance of Rabs in cellular processes is apparent from their links to genetic disorders, immunodeficiency, cancer, and pathogen invasion. During the last decade, numerous structures of complexes have shed light on the molecular basis for Rab/effector specificity and their topological organization on subcellular membranes. Here, I review the known structures of Rab/effector complexes and their modes of oligomerization. This is followed by a brief discussion on the thermodynamics of effector recruitment, which has not been documented sufficiently in previous reviews. A summary of diseases associated with Rab/effector trafficking pathways concludes this chapter.
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Affiliation(s)
- Amir R Khan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
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21
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Ali MY, Previs SB, Trybus KM, Sweeney HL, Warshaw DM. Myosin VI has a one track mind versus myosin Va when moving on actin bundles or at an intersection. Traffic 2012; 14:70-81. [PMID: 23046080 DOI: 10.1111/tra.12017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 10/05/2012] [Accepted: 10/09/2012] [Indexed: 11/30/2022]
Abstract
Myosin VI (myoVI) and myosin Va (myoVa) serve roles both as intracellular cargo transporters and tethers/anchors. In both capacities, these motors bind to and processively travel along the actin cytoskeleton, a network of intersecting actin filaments and bundles that present directional challenges to these motors. Are myoVI and myoVa inherently different in their abilities to interact and maneuver through the complexities of the actin cytoskeleton? Thus, we created an in vitro model system of intersecting actin filaments and individual unipolar (fascin-actin) or mixed polarity (α-actinin-actin) bundles. The stepping dynamics of individual Qdot-labeled myoVI and myoVa motors were determined on these actin tracks. Interestingly, myoVI prefers to stay on the actin filament it is traveling on, while myoVa switches filaments with higher probability at an intersection or between filaments in a bundle. The structural basis for this maneuverability difference was assessed by expressing a myoVI chimera in which the single myoVI IQ was replaced with the longer, six IQ myoVa lever. The mutant behaved more like myoVI at actin intersections and on bundles, suggesting that a structural element other than the lever arm dictates myoVI's preference to stay on track, which may be critical to its role as an intracellular anchor.
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Affiliation(s)
- M Yusuf Ali
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05405, USA.
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Contemporary diagnostic methods for hemophagocytic lymphohistiocytic disorders. J Immunol Methods 2010; 364:1-13. [PMID: 21110979 DOI: 10.1016/j.jim.2010.11.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 10/10/2010] [Accepted: 11/16/2010] [Indexed: 12/26/2022]
Abstract
Hemophagocytic lymphohistiocytosis is a life-threatening multi-system hyperinflammatory disorder characterized by dysfunctional cytolytic lymphocyte responses, hypercytokinemia, and widespread lymphohistiocytic tissue infiltration and destruction. Diagnosis and definitive therapy are often delayed as clinical efforts are directed toward treatment of presumed overwhelming infection. Sporadic cases occur in association with underlying immune dysfunction related to autoimmune disease, malignancy, or severe infection. However, familial cases predominate with remarkable associations between underlying genetic defects and dysregulation of immune responses. Here, we review the genetic and immunologic basis of contemporary diagnostic methods for hemophagocytic lymphohistiocytosis.
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Abstract
The majority of cells of the immune system are specialized secretory cells, whose function depends on regulated exocytosis. The latter is mediated by vesicular transport involving the sorting of specialized cargo into the secretory granules (SGs), thereby generating the transport vesicles; their transport along the microtubules and eventually their signal-dependent fusion with the plasma membrane. Each of these steps is tightly controlled by mechanisms, which involve the participation of specific sorting signals on the cargo proteins and their recognition by cognate adaptor proteins, posttranslational modifications of the cargo proteins and multiple GTPases and SNARE proteins. In some of the cells (i.e. mast cells, T killer cells) an intimate connection exists between the secretory system and the endocytic one, whereby the SGs are lysosome related organelles (LROs) also referred to as secretory lysosomes. Herein, we discuss these mechanisms in health and disease states.
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Affiliation(s)
- Anat Benado
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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24
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Ohbayashi N, Mamishi S, Ishibashi K, Maruta Y, Pourakbari B, Tamizifar B, Mohammadpour M, Fukuda M, Parvaneh N. Functional characterization of two RAB27A missense mutations found in Griscelli syndrome type 2. Pigment Cell Melanoma Res 2010; 23:365-74. [PMID: 20370853 DOI: 10.1111/j.1755-148x.2010.00705.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human Griscelli syndrome type 2 (GS-2) is characterized by partial albinism and a severe immunologic disorder as a result of RAB27A mutations. In melanocytes, Rab27A forms a tripartite complex with a specific effector Slac2-a/melanophilin and myosin Va, and the complex regulates melanosome transport. Here, we report a novel homozygous missense mutation of Rab27A, i.e. K22R, in a Persian GS-2 patient and the results of analysis of the impact of the K22R mutation and the previously reported I44T mutation on protein function. Both mutations completely abolish Slac2-a/melanophilin binding activity but they affect the biochemical properties of Rab27A differently. The Rab27A(K22R) mutant lacks the GTP binding ability and exhibits cytosolic localization in melanocytes. By contrast, neither intrinsic GTPase activity nor melanosomal localization of Rab27A is affected by the I44T mutation, but the Rab27A(I44T) mutant is unable to recruit Slac2-a/melanophilin. Interestingly, the two mutations differently affect binding to other Rab27A effectors, Slp2-a, Slp4-a/granuphilin-a, and Munc13-4. The Rab27A(K22R) mutant normally binds Munc13-4, but not Slp2-a or Slp4-a, whereas the Rab27A(I44T) mutant shows reduced binding activity to Slp2-a and Munc13-4 but normally binds Slp4-a.
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Affiliation(s)
- Norihiko Ohbayashi
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi, Japan
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25
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Meeths M, Bryceson YT, Rudd E, Zheng C, Wood SM, Ramme K, Beutel K, Hasle H, Heilmann C, Hultenby K, Ljunggren HG, Fadeel B, Nordenskjöld M, Henter JI. Clinical presentation of Griscelli syndrome type 2 and spectrum of RAB27A mutations. Pediatr Blood Cancer 2010; 54:563-72. [PMID: 19953648 DOI: 10.1002/pbc.22357] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Griscelli syndrome type 2 (GS2) is an autosomal-recessive immunodeficiency caused by mutations in RAB27A, clinically characterized by partial albinism and haemophagocytic lymphohistocytosis (HLH). We evaluated the frequency of RAB27A mutations in 21 unrelated patients with haemophagocytic syndromes without mutations in familial HLH (FHL) causing genes or an established diagnosis of GS2. In addition, we report three patients with known GS2. Moreover, neurological involvement and RAB27A mutations in previously published patients with genetically verified GS2 are reviewed. PROCEDURE Mutation analysis of RAB27A was performed by direct DNA sequencing. NK cell activity was evaluated and microscopy of the hair was performed to confirm the diagnosis. RESULTS RAB27A mutations were found in 1 of the 21 families. This Swedish family had three affected children with heterozygous compound mutations consisting of a novel splice error mutation, [c.239G>C], and a nonsense mutation, [c.550C>T], p.R184X. The three additional children all carried homozygous RAB27A mutations, one of which is a novel splice error mutation, [c.240-2A>C]. Of note, five of the six patients displayed neurological symptoms, while three out of six patients displayed NK cell activity within normal reference values, albeit low. A literature review revealed that 67% of GS2 patients have been reported with neurological manifestations. CONCLUSIONS Identification of RAB27A mutations can facilitate prompt diagnosis and treatment, and aid genetic counselling and prenatal diagnosis. Since five of six patients studied herein initially were diagnosed as having FHL, we conclude that the diagnosis of GS2 may be overlooked, particularly in fair-haired patients with haemophagocytic syndromes.
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Affiliation(s)
- Marie Meeths
- Childhood Cancer Research Unit, Department of Woman and Child Health, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.
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26
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Van Gele M, Dynoodt P, Lambert J. Griscelli syndrome: a model system to study vesicular trafficking. Pigment Cell Melanoma Res 2009; 22:268-82. [DOI: 10.1111/j.1755-148x.2009.00558.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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27
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New findings in primary immunodeficiency. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009. [PMID: 19280851 DOI: 10.1007/978-0-387-79838-7_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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28
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[Griscelli-Prunieras syndrome: report of two cases]. An Pediatr (Barc) 2009; 70:164-7. [PMID: 19217573 DOI: 10.1016/j.anpedi.2008.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 10/06/2008] [Indexed: 11/21/2022] Open
Abstract
Griscelli-Prunieras syndrome (GS) is a rare autosomal recessive disorder characterized by partial albinism. His pathogenic mechanism is associated with defects in the packaging of melanin and other cellular proteins. GS is classified into 3 types based on the genetic and molecular features. Mutations in the genes which cause GS are known. We report two first cases described in Spain who presented a silver-gray sheen of the hair and a severe immune disorder. They were studied for mutations principally related to this syndrome. Two patients showed the Rab27a mutation (frequently associated with GS2). The natural disorder evolution differs considerably among the various forms, so a genetic study is essential in GS to achieve the most accurate prognosis and treatment possible.
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Abstract
PURPOSE OF REVIEW Severe congenital neutropenia has been a well known hematological condition for over 50 years. Over this long period of time, the variable genetic causes and associated sequelae of the disease have been ascertained, and successful treatment strategies developed. Over the past 2 years, however, new studies have added greatly to our understanding of the molecular basis of the disease, details of which are presented in this review. RECENT FINDINGS Recent studies have elucidated a role for the unfolded protein response in mediating the pathogenic effects of ELA2 mutations, the most common mutation in severe congenital neutropenia (SCN) as well as cyclic neutropenia. Genetic lesions in HAX1 have also been identified in the original Kostmann pedigree representing the autosomal recessive form of SCN. An emerging theme is the convergence of these and other genetic lesions underlying SCN in enhancing neutrophil apoptosis. Other studies have revealed the importance of multiple independent mutations in these and other genes in SCN. Finally, the key role for signal transducer and activator of transcription 5 in mediating the effects of granulocyte colony-stimulating factor receptor truncation mutations in the development of myelodysplastic syndrome/acute myeloid leukemia following SCN has been elucidated. SUMMARY As the full spectrum of molecular mutations causing neutropenia emerges, it is becoming possible to differentiate patients into subtypes with different prognoses, for whom tailored therapies are indicated.
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A newly identified isoform of Slp2a associates with Rab27a in cytotoxic T cells and participates to cytotoxic granule secretion. Blood 2008; 112:5052-62. [DOI: 10.1182/blood-2008-02-141069] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Abstract
Cytotoxic T lymphocytes (CTLs) and natural killer cells help control infections and tumors via a killing activity that is mediated by the release of cytotoxic granules. Granule secretion at the synapse formed between the CTL and the target cell leads to apoptosis of the latter. This process involves polarization of the CTL's secretory machinery and cytotoxic granules. The small GTPase Rab27a and the hMunc13-4 protein have been shown to be required for both granule maturation and granule docking and priming at the immunologic synapse. Using a tandem affinity purification technique, we identified a previously unknown hematopoietic form of Slp2a (Slp2a-hem) and determined that it is a specific effector of the active form of Rab27a. This interaction occurs in vivo in primary CTLs. We have shown that (1) Rab27a recruits Slp2a-hem on vesicular structures in peripheral CTLs and (2) following CTL-target cell conjugate formation, the Slp2a-hem/Rab27a complex colocalizes with perforin-containing granules at the immunologic synapse, where it binds to the plasma membrane through its C2 domains. The overexpression of a dominant-negative form of Slp2a-hem markedly impaired exocytosis of cytotoxic granules—indicating that Slp2a is required for cytotoxic granule docking at the immunologic synapse.
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Kukimoto-Niino M, Sakamoto A, Kanno E, Hanawa-Suetsugu K, Terada T, Shirouzu M, Fukuda M, Yokoyama S. Structural Basis for the Exclusive Specificity of Slac2-a/Melanophilin for the Rab27 GTPases. Structure 2008; 16:1478-90. [DOI: 10.1016/j.str.2008.07.014] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 06/12/2008] [Accepted: 07/02/2008] [Indexed: 11/30/2022]
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Chavas LM, Ihara K, Kawasaki M, Torii S, Uejima T, Kato R, Izumi T, Wakatsuki S. Elucidation of Rab27 Recruitment by Its Effectors: Structure of Rab27a Bound to Exophilin4/Slp2-a. Structure 2008; 16:1468-77. [DOI: 10.1016/j.str.2008.07.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 07/18/2008] [Accepted: 07/21/2008] [Indexed: 01/03/2023]
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Masri A, Bakri FG, Al-Hussaini M, Al-Hadidy A, Hirzallah R, de Saint Basile G, Hamamy H. Griscelli syndrome type 2: a rare and lethal disorder. J Child Neurol 2008; 23:964-7. [PMID: 18403584 DOI: 10.1177/0883073808315409] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Griscelli syndrome is a rare autosomal recessive disorder. It is characterized by pigment dilution and variable immune deficiency leading to increased susceptibility to certain infections and a tendency to develop a life-threatening hemophagocytic syndrome known as the accelerated phase. Griscelli syndrome is now classified into 3 types based on the genetic and molecular features. Primary neurological presentation without the accelerated phase is rare in type 2. In this article, the authors report a boy who was presented with seizures and diffuse white matter involvement unaccompanied by the other features of the accelerated phase. Mutation analysis in family members revealed the presence of a missense mutation in Rab27a gene. In addition to the rare presentation, this is the first case of Griscelli syndrome to be reported from Jordan.
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Affiliation(s)
- Amira Masri
- Department of Pediatrics, Division of child Neurology, Jordan University Hospital, Amman, Jordan.
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Ng EL, Tang BL. Rab GTPases and their roles in brain neurons and glia. ACTA ACUST UNITED AC 2008; 58:236-46. [PMID: 18485483 DOI: 10.1016/j.brainresrev.2008.04.006] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 02/29/2008] [Accepted: 04/06/2008] [Indexed: 12/19/2022]
Affiliation(s)
- Ee Ling Ng
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore
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35
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Knockdown of myosin Va isoforms by RNAi as a tool to block melanosome transport in primary human melanocytes. J Invest Dermatol 2008; 128:2474-84. [PMID: 18401430 DOI: 10.1038/jid.2008.100] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The movement of melanosomes, dense melanin-containing organelles, within human melanocytes is actin-dependent and mediated through the formation of a Rab27a-Slac2-a-myosin Va (MyoVa) protein complex. We previously showed that only the melanocyte-specific exon F isoforms of MyoVa are involved in melanosome transport to the dendrite extremities. Here, we investigate siRNA to downregulate the exon F-containing isoforms of MyoVa in primary human melanocytes. Efficient and specific knockdown of the MyoVa exon F isofoms were shown at both mRNA and protein levels. Further, a stable shRNA against the MyoVa exon F isoforms was prepared by using a lentiviral system to improve and confirm the silencing effect in hard-to-transfect melanocyte cells. Immunofluorescence microscopy shows that knockdown of the exon F isoforms results in blockade of intramelanocytic melanosome transport due to the inability to form the Rab27a-Slac2-a-MyoVa tripartite complex. Interestingly, the observed phenotypic effect (that is, perinuclear accumulation of melanosomes) is the same as that seen in melanocytes from patients with human Griscelli syndrome causing abnormal pigmentation. We conclude that our siRNA-based strategy provides a previously unreported tool to block the intracellular melanosome movement in primary human melanocytes and may become an innovative drug to treat hyperpigmentation.
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Higashio H, Nishimura N, Ishizaki H, Miyoshi J, Orita S, Sakane A, Sasaki T. Doc2α and Munc13-4 Regulate Ca2+-Dependent Secretory Lysosome Exocytosis in Mast Cells. THE JOURNAL OF IMMUNOLOGY 2008; 180:4774-84. [DOI: 10.4049/jimmunol.180.7.4774] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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37
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Rajadhyax M, Neti G, Crow Y, Tyagi A. Neurological presentation of Griscelli syndrome: obstructive hydrocephalus without haematological abnormalities or organomegaly. Brain Dev 2007; 29:247-50. [PMID: 17085000 DOI: 10.1016/j.braindev.2006.09.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2006] [Revised: 09/04/2006] [Accepted: 09/06/2006] [Indexed: 11/26/2022]
Abstract
Griscelli syndrome is a rare autosomal-recessive disorder characterised by partial albinism, immunodeficiency, organomegaly and accelerated phases. During accelerated phases, pancytopenia, haemophagocytosis, hypoproteinemeia occur which may be accompanied by neurological deterioration. Primary neurological presentation is rare and we report a case that presented with obstructive hydrocephalus and infiltrative lesions in the brain unaccompanied by other features of accelerated phase. Biopsy of these lesions demonstrated sinus histiocytosis. Electron microscopy of hair shaft and genetic studies established the diagnosis of Griscelli disease with RAB 27A mutation.
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Affiliation(s)
- Mamata Rajadhyax
- Department of Paediatric Neurology, Genetics and Neurosurgery, Leeds General Infirmary, UK.
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38
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Handley MTW, Haynes LP, Burgoyne RD. Differential dynamics of Rab3A and Rab27A on secretory granules. J Cell Sci 2007; 120:973-84. [PMID: 17311845 PMCID: PMC1855981 DOI: 10.1242/jcs.03406] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
We have assessed the dynamics of the association of Rab3A and Rab27A with secretory granules at various stages of their life in PC12 cells. Endogenous Rab3A colocalised with the secretory granule marker secretogranin II (SGII) and expressed EGFP-Rab3A and ECFP-Rab27A colocalised with one another. The extent of colocalisation between EGFP-Rab3A or EGFP-Rab27 and SGII increased after longer times post transfection suggesting that these Rab proteins are preferentially recruited to newly synthesised granules. Following the release of immature secretory granules from the trans-Golgi network, Rab3A and Rab27A became associated with the immature granules after a lag period of around 20 minutes. Rab dynamics on granules were analysed in fluorescence recovery after photobleaching (FRAP) experiments. The recovery profile of EGFP-Rab27A was comparable to that of ppANF-EGFP, whereas the recovery profile of EGFP-Rab3A was significantly faster, indicating that Rab3A but not Rab27A might be rapidly exchanged between granules and cytosol. Inhibition of heat-shock protein 90 with 10 muM geldanamycin did not affect the exchange process or regulated exocytosis. Rab dynamics during stimulation with 300 muM ATP were analysed in live cells. Loss of granular ppANF-EGFP fluorescence was seen at the cell periphery after stimulation but only limited changes in EGFP-Rab3A and EGFP-Rab27A fluorescence was observed, indicating that the Rab proteins do not immediately dissociate or disperse on stimulation. The data suggest potentially distinct roles for Rab3A and Rab27A and we suggest that the finding that young secretory granules have a higher capacity for binding Rab3A and Rab27A is functionally important for preferential exocytosis from these granules.
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Affiliation(s)
- Mark T W Handley
- The Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
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Gazit R, Aker M, Elboim M, Achdout H, Katz G, Wolf DG, Katzav S, Mandelboim O. NK cytotoxicity mediated by CD16 but not by NKp30 is functional in Griscelli syndrome. Blood 2007; 109:4306-12. [PMID: 17255357 DOI: 10.1182/blood-2006-09-047159] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Abstract
Griscelli syndrome (GS) type 2 is an autosomal recessive disorder represented by pigment dilution and impaired cytotoxic T lymphocyte (CTL) activity. NK activity has been scarcely investigated in GS patients. Here, we describe a new patient, possessing a hemophagocytic syndrome with a homozygous Q118X nonsense RAB27A mutation. Single specific primer–polymerase chain reaction (SSP-PCR) was developed based on this mutation and is currently used in prenatal genetic analysis. As expected, CTLs in the patient are not functional and NK cytotoxicity against K562 or 721.221 cells is diminished. Surprisingly, however, we demonstrate that CD16-mediated killing is intact in this patient and is therefore RAB27A independent, whereas NKp30-mediated killing is impaired and is therefore RAB27A dependent. We further analyzed the signaling pathways of these 2 receptors and demonstrated phosphorylation of Vav1 after CD16 activation but not after NKp30 engagement. Thus, we identify a novel homozygous mutation in the RAB27A gene of a new GS patient, observe for the first time that some activating NK receptors function in GS patients, and demonstrate a functional dichotomy in the killing mediated by these human NK-activating receptors.
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Affiliation(s)
- Roi Gazit
- The Lautenberg Center for General and Tumor Immunology, Hadassah Medical School, Jerusalem, Israel
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40
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Zur Stadt U, Beutel K, Kolberg S, Schneppenheim R, Kabisch H, Janka G, Hennies HC. Mutation spectrum in children with primary hemophagocytic lymphohistiocytosis: molecular and functional analyses of PRF1, UNC13D, STX11, and RAB27A. Hum Mutat 2006; 27:62-8. [PMID: 16278825 DOI: 10.1002/humu.20274] [Citation(s) in RCA: 195] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Familial hemophagocytic lymphohistiocytosis (FHL) is an autosomal-recessive disease that affects young children. It presents as a severe hyperinflammatory syndrome with activated macrophages and T lymphocytes. Mutations in the perforin 1 gene (PRF1) were found in FHL-2 in 15-50% of all cases. Defective granule exocytosis caused by mutations in the hMunc13-4 gene (UNC13D) has been described in FHL-3. FHL-4 patients have mutations in STX11, a t-SNARE involved in intracellular trafficking. We analyzed a large group of 63 unrelated patients with FHL of different geographic origins (Turkey:32; Germany:23; others:8) for mutations in STX11, PRF1, and UNC13D. We identified mutations in 38 samples (20 in PRF1, 12 in UNC13D, and six in STX11). Of 32 patients from Turkey, 14 had mutations in PRF1, six had mutations in UNC13D, and six had mutations in STX11. The mutation Trp374X in PRF1 was found in 12 patients from Turkey and was associated with a very early onset of the disease below the age of 3 months in all cases. In contrast, three of 23 and four of 23 patients from Germany, and three of eight and two of eight from other origins showed mutations in PRF1 and UNC13D, respectively, but none in STX11. Thus, FHL-2, FHL-3, and FHL-4 account for 80% of the HLH cases of Turkish origin, and for 30% of German patients. Furthermore, we identified mutations in RAB27A in three patients with FHL-related Griscelli syndrome type 2. In functional studies using a mammalian two-hybrid system we found that missense mutations Ala87Pro in Rab27a and Leu403Pro in hMunc13-4 each prevented the formation of a stable hMunc13-4/Rab27a complex in vitro. Our findings demonstrate extensive genetic and allelic heterogeneity in FHL and delineate an approach for functionally characterizing missense mutations in RAB27A and UNC13D.
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Affiliation(s)
- Udo Zur Stadt
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg Eppendorf, Hamburg, Germany.
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41
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Ishida Y, David VA, Eizirik E, Schäffer AA, Neelam BA, Roelke ME, Hannah SS, O'Brien SJ, Menotti-Raymond M. A homozygous single-base deletion in MLPH causes the dilute coat color phenotype in the domestic cat. Genomics 2006; 88:698-705. [PMID: 16860533 DOI: 10.1016/j.ygeno.2006.06.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 06/09/2006] [Accepted: 06/12/2006] [Indexed: 11/22/2022]
Abstract
Three proteins have been described in humans and mice as being essential for even distribution, transport, and translocation of pigment granules, with defects in these molecules giving rise to lighter skin/coat color. The dilute phenotype in domestic cats affects both eumelanin and phaeomelanin pigment pathways; for example, black pigmentation combined with dilute appears gray and orange pigments appear cream. The dilute pigmentation segregates as a fully penetrant, autosomal recessive trait. We conducted classical linkage mapping with microsatellites in a large multigeneration pedigree of domestic cats and detected tight linkage for dilute on cat chromosome C1 (theta=0.08, LOD=10.81). Fine-mapping identified a genomic region exhibiting conserved synteny to human chromosome 2, which included one of the three dilute candidate genes, melanophilin (MLPH). Sequence analysis in dilute cats identified a single base pair deletion in exon 2 of MLPH transcripts that introduces a stop codon 11 amino acids downstream, resulting in the truncation of the bulk of the MLPH protein. The occurrence of this homozygous variant in 97 unrelated dilute cats representing 26 cat breeds and random-bred cats, along with 89 unrelated wild-type cats representing 29 breeds and random-bred cats, supports the finding that dilute is caused by this single mutation in MLPH (p<0.00001). Single-nucleotide polymorphism analyses in dilute individuals identified a single haplotype in dilute cats, suggesting that a single mutation event in MLPH gave rise to dilute in domestic cats.
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Affiliation(s)
- Yasuko Ishida
- Laboratory of Genomic Diversity, National Cancer Institute, Building 560, Room 11-38, Fort Detrick, Frederick, MD 21702, USA.
| | - Victor A David
- Laboratory of Genomic Diversity, National Cancer Institute, Building 560, Room 11-38, Fort Detrick, Frederick, MD 21702, USA
| | - Eduardo Eizirik
- Centro de Biologia Genômica e Molecular, PUCRS, Porto Alegre, RS 90619-900, Brazil
| | - Alejandro A Schäffer
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20894, USA
| | - Beena A Neelam
- Advanced Biomedical Computing Center, SAIC-Frederick, National Cancer Institute, Frederick, MD 21702, USA
| | - Melody E Roelke
- Laboratory of Genomic Diversity, SAIC-Frederick, National Cancer Institute, Frederick, MD 21702, USA
| | | | - Stephen J O'Brien
- Laboratory of Genomic Diversity, National Cancer Institute, Building 560, Room 11-38, Fort Detrick, Frederick, MD 21702, USA
| | - Marilyn Menotti-Raymond
- Laboratory of Genomic Diversity, National Cancer Institute, Building 560, Room 11-38, Fort Detrick, Frederick, MD 21702, USA.
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42
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Fairbank PD, Lee C, Ellis A, Hildebrand JD, Gross JM, Wallingford JB. Shroom2 (APXL) regulates melanosome biogenesis and localization in the retinal pigment epithelium. Development 2006; 133:4109-18. [PMID: 16987870 DOI: 10.1242/dev.02563] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Shroom family proteins have been implicated in the control of the actin cytoskeleton, but so far only a single family member has been studied in the context of developing embryos. Here, we show that the Shroom-family protein,Shroom2 (previously known as APXL) is both necessary and sufficient to govern the localization of pigment granules at the apical surface of epithelial cells. In Xenopus embryos that lack Shroom2 function, we observed defects in pigmentation of the eye that stem from failure of melanosomes to mature and to associate with the apical cell surface. Ectopic expression of Shroom2 in naïve epithelial cells facilitates apical pigment accumulation, and this activity specifically requires the Rab27a GTPase. Most interestingly, we find that Shroom2, like Shroom3 (previously called Shroom),is sufficient to induce a dramatic apical accumulation of the microtubule-nucleating protein γ-tubulin at the apical surfaces of naïve epithelial cells. Together, our data identify Shroom2 as a central regulator of RPE pigmentation, and suggest that, despite their diverse biological roles, Shroom family proteins share a common activity. Finally,because the locus encoding human SHROOM2 lies within the critical region for two distinct forms of ocular albinism, it is possible that SHROOM2mutations may be a contributing factor in these human visual system disorders.
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Affiliation(s)
- Pamela D Fairbank
- Section of Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA
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43
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Itoh T, Fukuda M. Identification of EPI64 as a GTPase-activating Protein Specific for Rab27A. J Biol Chem 2006. [DOI: 10.1016/s0021-9258(19)84097-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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44
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Itoh T, Fukuda M. Identification of EPI64 as a GTPase-activating protein specific for Rab27A. J Biol Chem 2006; 281:31823-31. [PMID: 16923811 DOI: 10.1074/jbc.m603808200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Small GTPase Rab27A plays a pivotal role in melanosome transport in melanocytes and in secretion by various secreting cells. Because the GTP- or GDP-locked mutant of Rab27A causes perinuclear aggregation of melanosomes, appropriate GTP-GDP cycling of Rab27A is essential for melanosome transport, and certain guanine nucleotide exchange factors and GTPase-activating proteins (GAPs) of Rab27A must be present in melanocytes. However, no such regulators of Rab27A have ever been identified. In this study we developed novel methods of rapidly screening 40 different TBC (Tre2/Bub2/Cdc16) proteins, putative Rab-GAPs, for Rab27A-GAP by: (i) searching for TBC proteins that induce melanosome aggregation in melanocytes; (ii) trapping GTP-Rab27A with a Rab27A effector domain (i.e. the SHD of Slac2-a) in cultured cells that express both Rab27A and TBC proteins; and (iii) measuring in vitro Rab27A-GAP activity. These methods allowed us to identify EPI64, previously characterized as an EBP50-binding protein that contains an orphan TBC domain, as a specific Rab27A-GAP. We further showed that mutations in the catalytic domain of EPI64 caused complete loss of its ability to induce melanosome aggregation. This is the first report of screening for Rab27A-GAP based on functional interactions, and our screening methods can be applied for other uncharacterized TBC proteins.
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Affiliation(s)
- Takashi Itoh
- Fukuda Initiative Research Unit, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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45
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Malhotra AK, Bhaskar G, Nanda M, Kabra M, Singh MK, Ramam M. Griscelli syndrome. J Am Acad Dermatol 2006; 55:337-40. [PMID: 16844525 DOI: 10.1016/j.jaad.2005.11.1056] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Revised: 11/01/2005] [Accepted: 11/01/2005] [Indexed: 10/22/2022]
Abstract
A 4-month-old child had silvery gray hair, light-colored skin, recurrent chest infections, hepatosplenomegaly, and episodes of pancytopenia and hemophagocytosis in the liver, spleen, and bone marrow. Light microscopy of hair showed characteristic large aggregates of pigment granules distributed irregularly along the hair shaft. Peripheral blood smear examination did not show giant granules in granulocytes. Enlarged hyperpigmented basal melanocytes with sparsely pigmented adjacent keratinocytes were seen on the skin biopsy specimen. On the basis of these clinical and laboratory findings, Griscelli syndrome was diagnosed. The child succumbed to infection during an accelerated phase of the disease.
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Affiliation(s)
- Amit Kumar Malhotra
- Department of Dermatology and Venereology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi
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46
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Fukuda M. Distinct Rab27A binding affinities of Slp2-a and Slac2-a/melanophilin: Hierarchy of Rab27A effectors. Biochem Biophys Res Commun 2006; 343:666-74. [PMID: 16554019 DOI: 10.1016/j.bbrc.2006.03.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Accepted: 03/01/2006] [Indexed: 11/22/2022]
Abstract
The small GTPase Rab27A has recently been shown to regulate melanosome transport in mammalian skin melanocytes through sequentially interacting with two Rab27A effectors, Slac2-a/melanophilin and Slp2-a. Although Slac2-a and Slp2-a contain a similar N-terminal Rab27A-binding domain (named SHD, Slp homology domain), nothing is known about the functional differences between the Slac2-a SHD and Slp2-a SHD. In this study, the Rab27A-binding affinity of ten putative Rab27A effector proteins has been investigated. It has been found that they could be classified into a low-affinity group (e.g., Slac2-a) and a high-affinity group (e.g., Slp2-a and Slp4-a) based on their Rab27A-binding affinity. Kinetic analysis of the GTP-Rab27A-binding to the SHD of Slp2-a, Slp4-a, and Slac2-a by surface plasmon resonance further indicated that the kinetic parameters of Rab27A for the Slp2-a SHD, Slp4-a SHD, and Slac2-a SHD consisted of a fast association rate constant (3.35 x 10(4), 2.06 x 10(4), and 2.11 x 10(4) M(-1) s(-1), respectively) and a slow dissociation rate constant (4.48 x 10(-4), 3.96 x 10(-4), and 2.37 x 10(-3) s(-1) respectively), and their equilibrium dissociation constants were determined to be 13.4, 19.2, and 112 nM, respectively. Our data suggest that distinct Rab27A binding activities of Slac2-a and Slp2-a ensure the order (or hierarchy) of Rab27A effectors that sequentially function in melanosome transport in melanocytes.
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Affiliation(s)
- Mitsunori Fukuda
- Fukuda Initiative Research Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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47
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Abstract
A 7-month-old Turkish boy presented with partial albinism and typical clinical features of an accelerated phase, suggesting the diagnosis of Griscelli syndrome. The diagnosis was confirmed by light microscopic evaluation of hair and a peripheral blood smear. Genetic analysis identified a mutation in the Rab27A gene. He was initiated immunosuppressive treatment but accelerated phase could not be ameliorated. He unfortunately died from multiorgan failure. The finding of partial albinism in children should alert clinicians to consider Griscelli syndrome since simple methods can confirm the diagnosis and early diagnosis is life-saving.
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Affiliation(s)
- Deniz Aslan
- Sections of Hematology, Department of Pediatrics, Faculty of Medicine, Gazi University, Ankara, Turkey.
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48
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Mahoney TR, Liu Q, Itoh T, Luo S, Hadwiger G, Vincent R, Wang ZW, Fukuda M, Nonet ML. Regulation of synaptic transmission by RAB-3 and RAB-27 in Caenorhabditis elegans. Mol Biol Cell 2006; 17:2617-25. [PMID: 16571673 PMCID: PMC1474797 DOI: 10.1091/mbc.e05-12-1170] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Rab small GTPases are involved in the transport of vesicles between different membranous organelles. RAB-3 is an exocytic Rab that plays a modulatory role in synaptic transmission. Unexpectedly, mutations in the Caenorhabditis elegans RAB-3 exchange factor homologue, aex-3, cause a more severe synaptic transmission defect as well as a defecation defect not seen in rab-3 mutants. We hypothesized that AEX-3 may regulate a second Rab that regulates these processes with RAB-3. We found that AEX-3 regulates another exocytic Rab, RAB-27. Here, we show that C. elegans RAB-27 is localized to synapse-rich regions pan-neuronally and is also expressed in intestinal cells. We identify aex-6 alleles as containing mutations in rab-27. Interestingly, aex-6 mutants exhibit the same defecation defect as aex-3 mutants. aex-6; rab-3 double mutants have behavioral and pharmacological defects similar to aex-3 mutants. In addition, we demonstrate that RBF-1 (rabphilin) is an effector of RAB-27. Therefore, our work demonstrates that AEX-3 regulates both RAB-3 and RAB-27, that both RAB-3 and RAB-27 regulate synaptic transmission, and that RAB-27 potentially acts through its effector RBF-1 to promote soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) function.
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Affiliation(s)
- Timothy R. Mahoney
- *Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Qiang Liu
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030; and
| | - Takashi Itoh
- Fukuda Initiative Research Unit, RIKEN, Wako, Saitama 351-0198, Japan
| | - Shuo Luo
- *Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Gayla Hadwiger
- *Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Rose Vincent
- *Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Zhao-Wen Wang
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030; and
| | - Mitsunori Fukuda
- Fukuda Initiative Research Unit, RIKEN, Wako, Saitama 351-0198, Japan
| | - Michael L. Nonet
- *Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110
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Abstract
Neutrophils are critical components of the innate immune response, and persistent neutropenia is associated with a marked susceptibility to infection. There are a number of inherited clinical syndromes in which neutropenia is a prominent feature. A study of these rare disorders has provided insight into the mechanisms regulating normal neutrophil homeostasis. Tremendous progress has been made at defining the genetic basis of these disorders. Herein, progress in understanding the genetic basis and molecular mechanisms of these disorders is discussed. We have focused our discussion on inherited disorders in which neutropenia is the sole or major hematopoietic defect.
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Affiliation(s)
- David S Grenda
- Division of Oncology, Washington University School of Medicine, Saint Louis, MO 63110, USA
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50
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Hong W. Cytotoxic T lymphocyte exocytosis: bring on the SNAREs! Trends Cell Biol 2005; 15:644-50. [PMID: 16260137 DOI: 10.1016/j.tcb.2005.10.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 08/05/2005] [Accepted: 10/04/2005] [Indexed: 02/03/2023]
Abstract
Despite our general understanding of membrane traffic, the molecular machinery at the immunological synapse (IS) that regulates exocytosis of lytic granules from cytotoxic T lymphocytes (CTLs) remains elusive. The identification of disease-causing mutations in the small GTPase Rab27a, priming factor Munc13-4 and fusion protein syntaxin11 has defined an important role for these proteins in CTL exocytosis. In addition, the demonstration of a direct interaction in vitro between Rab27a and Munc13-4 suggests the possibility that the Rab27a-Munc13-4 cascade might regulate CTL exocytosis by engaging SNAREs such as syntaxin11. We propose that these SNAREs are likely to mediate the fusion of lytic granules with the plasma membrane of the IS.
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Affiliation(s)
- Wanjin Hong
- Membrane Biology Laboratory, Institute of Molecular and Cell Biology, Proteos, 61 Biopolis Drive, Singapore 138673, Singapore.
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