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Stomatin modulates adipogenesis through the ERK pathway and regulates fatty acid uptake and lipid droplet growth. Nat Commun 2022; 13:4174. [PMID: 35854007 PMCID: PMC9296665 DOI: 10.1038/s41467-022-31825-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 07/01/2022] [Indexed: 11/08/2022] Open
Abstract
Regulation of fatty acid uptake, lipid production and storage, and metabolism of lipid droplets (LDs), is closely related to lipid homeostasis, adipocyte hypertrophy and obesity. We report here that stomatin, a major constituent of lipid raft, participates in adipogenesis and adipocyte maturation by modulating related signaling pathways. In adipocyte-like cells, increased stomatin promotes LD growth or enlargements by facilitating LD-LD fusion. It also promotes fatty acid uptake from extracellular environment by recruiting effector molecules, such as FAT/CD36 translocase, to lipid rafts to promote internalization of fatty acids. Stomatin transgenic mice fed with high-fat diet exhibit obesity, insulin resistance and hepatic impairments; however, such phenotypes are not seen in transgenic animals fed with regular diet. Inhibitions of stomatin by gene knockdown or OB-1 inhibit adipogenic differentiation and LD growth through downregulation of PPARγ pathway. Effects of stomatin on PPARγ involves ERK signaling; however, an alternate pathway may also exist. Stomatin is a component of lipid rafts. Here, Wu et al. show that stomatin modulates the differentiation and functions of adipocytes by regulating adipogenesis signaling and fatty acid influx such that with excessive calorie intake, increased stomatin induces adiposity.
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2
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Sato A, Rahman NIA, Shimizu A, Ogita H. Cell-to-cell contact-mediated regulation of tumor behavior in the tumor microenvironment. Cancer Sci 2021; 112:4005-4012. [PMID: 34420253 PMCID: PMC8486192 DOI: 10.1111/cas.15114] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/15/2021] [Accepted: 08/17/2021] [Indexed: 02/06/2023] Open
Abstract
Tumor growth and progression are complex processes mediated by mutual interactions between cancer cells and their surrounding stroma that include diverse cell types and acellular components, which form the tumor microenvironment. In this environment, direct intercellular communications play important roles in the regulation of the biological behaviors of tumors. However, the underlying molecular mechanisms are insufficiently defined. We used an in vitro coculture system to identify genes that were specifically expressed at higher levels in cancer cells associated with stromal cells. Major examples included epithelial membrane protein 1 (EMP1) and stomatin, which positively and negatively regulate tumor progression, respectively. EMP1 promotes tumor cell migration and metastasis via activation of the small GTPase Rac1, while stomatin strongly suppresses cell proliferation and induces apoptosis of cancer cells via inhibition of Akt signaling. Here we highlight important aspects of EMP1, stomatin, and their family members in cancer biology. Furthermore, we consider the molecules that participate in intercellular communications and signaling transduction between cancer cells and stromal cells, which may affect the phenotypes of cancer cells in the tumor microenvironment.
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Affiliation(s)
- Akira Sato
- Division of Molecular Medical BiochemistryDepartment of Biochemistry and Molecular BiologyShiga University of Medical ScienceOtsuJapan
| | - Nor Idayu A. Rahman
- Division of Molecular Medical BiochemistryDepartment of Biochemistry and Molecular BiologyShiga University of Medical ScienceOtsuJapan
| | - Akio Shimizu
- Division of Molecular Medical BiochemistryDepartment of Biochemistry and Molecular BiologyShiga University of Medical ScienceOtsuJapan
| | - Hisakazu Ogita
- Division of Molecular Medical BiochemistryDepartment of Biochemistry and Molecular BiologyShiga University of Medical ScienceOtsuJapan
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Rahman NIA, Sato A, Tsevelnorov K, Shimizu A, Komeno M, Ahmat Amin MKB, Molla MR, Soh JEC, Nguyen LKC, Wada A, Kawauchi A, Ogita H. Stomatin-Mediated Inhibition of the Akt Signaling Axis Suppresses Tumor Growth. Cancer Res 2021; 81:2318-2331. [PMID: 33757977 DOI: 10.1158/0008-5472.can-20-2331] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 02/16/2021] [Accepted: 03/11/2021] [Indexed: 11/16/2022]
Abstract
The growth and progression of cancers are crucially regulated by the tumor microenvironment where tumor cells and stromal cells are mutually associated. In this study, we found that stomatin expression was markedly upregulated by the interaction between prostate cancer cells and stromal cells. Stomatin suppressed cancer cell proliferation and enhanced apoptosis in vitro and inhibited xenograft tumor growth in vivo. Stomatin inhibited Akt activation, which is mediated by phosphoinositide-dependent protein kinase 1 (PDPK1). PDPK1 protein stability was maintained by its binding to HSP90. Stomatin interacted with PDPK1 and interfered with the PDPK1-HSP90 complex formation, resulting in decreased PDPK1 expression. Knockdown of stomatin in cancer cells elevated Akt activation and promoted cell increase by promoting the interaction between PDPK1 and HSP90. Clinically, stomatin expression levels were significantly decreased in human prostate cancer samples with high Gleason scores, and lower expression of stomatin was associated with higher recurrence of prostate cancer after the operation. Collectively, these findings demonstrate the tumor-suppressive effect of stromal-induced stomatin on cancer cells. SIGNIFICANCE: These findings reveal that interactions with stromal cells induce expression of stomatin in prostate cancer cells, which suppresses tumor growth via attenuation of the Akt signaling axis.
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Affiliation(s)
- Nor Idayu A Rahman
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Akira Sato
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan.
| | - Khurelbaatar Tsevelnorov
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Akio Shimizu
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Masahiro Komeno
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Mohammad Khusni Bin Ahmat Amin
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Md Rasel Molla
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Joanne Ern Chi Soh
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Le Kim Chi Nguyen
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Akinori Wada
- Department of Urology, Shiga University of Medical Science, Otsu, Japan
| | - Akihiro Kawauchi
- Department of Urology, Shiga University of Medical Science, Otsu, Japan
| | - Hisakazu Ogita
- Division of Molecular Medical Biochemistry, Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan.
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4
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Guizouarn H, Allegrini B. Erythroid glucose transport in health and disease. Pflugers Arch 2020; 472:1371-1383. [PMID: 32474749 DOI: 10.1007/s00424-020-02406-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/15/2020] [Accepted: 05/22/2020] [Indexed: 12/14/2022]
Abstract
Glucose transport is intimately linked to red blood cell physiology. Glucose is the unique energy source for these cells, and defects in glucose metabolism or transport activity are associated with impaired red blood cell morphology and deformability leading to reduced lifespan. In vertebrate erythrocytes, glucose transport is mediated by GLUT1 (in humans) or GLUT4 transporters. These proteins also account for dehydroascorbic acid (DHA) transport through erythrocyte membrane. The peculiarities of glucose transporters and the red blood cell pathologies involving GLUT1 are summarized in the present review.
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Affiliation(s)
- Hélène Guizouarn
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, 28 av. Valrose, 06100, Nice, France.
| | - Benoit Allegrini
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, 28 av. Valrose, 06100, Nice, France
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5
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Eidem HR, Steenwyk JL, Wisecaver JH, Capra JA, Abbot P, Rokas A. integRATE: a desirability-based data integration framework for the prioritization of candidate genes across heterogeneous omics and its application to preterm birth. BMC Med Genomics 2018; 11:107. [PMID: 30453955 PMCID: PMC6245874 DOI: 10.1186/s12920-018-0426-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 11/07/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The integration of high-quality, genome-wide analyses offers a robust approach to elucidating genetic factors involved in complex human diseases. Even though several methods exist to integrate heterogeneous omics data, most biologists still manually select candidate genes by examining the intersection of lists of candidates stemming from analyses of different types of omics data that have been generated by imposing hard (strict) thresholds on quantitative variables, such as P-values and fold changes, increasing the chance of missing potentially important candidates. METHODS To better facilitate the unbiased integration of heterogeneous omics data collected from diverse platforms and samples, we propose a desirability function framework for identifying candidate genes with strong evidence across data types as targets for follow-up functional analysis. Our approach is targeted towards disease systems with sparse, heterogeneous omics data, so we tested it on one such pathology: spontaneous preterm birth (sPTB). RESULTS We developed the software integRATE, which uses desirability functions to rank genes both within and across studies, identifying well-supported candidate genes according to the cumulative weight of biological evidence rather than based on imposition of hard thresholds of key variables. Integrating 10 sPTB omics studies identified both genes in pathways previously suspected to be involved in sPTB as well as novel genes never before linked to this syndrome. integRATE is available as an R package on GitHub ( https://github.com/haleyeidem/integRATE ). CONCLUSIONS Desirability-based data integration is a solution most applicable in biological research areas where omics data is especially heterogeneous and sparse, allowing for the prioritization of candidate genes that can be used to inform more targeted downstream functional analyses.
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Affiliation(s)
- Haley R. Eidem
- Department of Biological Sciences, Vanderbilt University, Nashville, TN USA
| | - Jacob L. Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, TN USA
| | - Jennifer H. Wisecaver
- Department of Biological Sciences, Vanderbilt University, Nashville, TN USA
- Department of Biochemistry, Purdue University, West Lafayette, IN USA
| | - John A. Capra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN USA
- Department of Biomedical Informatics, Vanderbilt University, Nashville, TN USA
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN USA
| | - Patrick Abbot
- Department of Biological Sciences, Vanderbilt University, Nashville, TN USA
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, TN USA
- Department of Biomedical Informatics, Vanderbilt University, Nashville, TN USA
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN USA
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6
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Structure-function analysis of human stomatin: A mutation study. PLoS One 2017; 12:e0178646. [PMID: 28575093 PMCID: PMC5456319 DOI: 10.1371/journal.pone.0178646] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 05/16/2017] [Indexed: 12/27/2022] Open
Abstract
Stomatin is an ancient, widely expressed, oligomeric, monotopic membrane protein that is associated with cholesterol-rich membranes/lipid rafts. It is part of the SPFH superfamily including stomatin-like proteins, prohibitins, flotillin/reggie proteins, bacterial HflK/C proteins and erlins. Biochemical features such as palmitoylation, oligomerization, and hydrophobic “hairpin” structure show similarity to caveolins and other integral scaffolding proteins. Recent structure analyses of the conserved PHB/SPFH domain revealed amino acid residues and subdomains that appear essential for the structure and function of stomatin. To test the significance of these residues and domains, we exchanged or deleted them, expressed respective GFP-tagged mutants, and studied their subcellular localization, molecular dynamics and biochemical properties. We show that stomatin is a cholesterol binding protein and that at least two domains are important for the association with cholesterol-rich membranes. The conserved, prominent coiled-coil domain is necessary for oligomerization, while association with cholesterol-rich membranes is also involved in oligomer formation. FRAP analyses indicate that the C-terminus is the dominant entity for lateral mobility and binding site for the cortical actin cytoskeleton.
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7
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Lee JH, Hsieh CF, Liu HW, Chen CY, Wu SC, Chen TW, Hsu CS, Liao YH, Yang CY, Shyu JF, Fischer WB, Lin CH. Lipid raft-associated stomatin enhances cell fusion. FASEB J 2016; 31:47-59. [PMID: 27663861 DOI: 10.1096/fj.201600643r] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 09/07/2016] [Indexed: 01/25/2023]
Abstract
Membrane fusions that occur during vesicle transport, virus infection, and tissue development, involve receptors that mediate membrane contact and initiate fusion and effectors that execute membrane reorganization and fusion pore formation. Some of these fusogenic receptors/effectors are preferentially recruited to lipid raft membrane microdomains. Therefore, major constituents of lipid rafts, such as stomatin, may be involved in the regulation of cell-cell fusion. Stomatin produced in cells can be released to the extracellular environment, either through protein refolding to pass across lipid bilayer or through exosome trafficking. We report that cells expressing more stomatin or exposed to exogenous stomatin are more prone to undergoing cell fusion. During osteoclastogenesis, depletion of stomatin inhibited cell fusion but had little effect on tartrate-resistant acid phosphatase production. Moreover, in stomatin transgenic mice, increased cell fusion leading to enhanced bone resorption and subsequent osteoporosis were observed. With its unique molecular topology, stomatin forms molecular assembly within lipid rafts or on the appositional plasma membranes, and promotes membrane fusion by modulating fusogenic protein engagement.-Lee, J.-H., Hsieh, C.-F., Liu, H.-W., Chen, C.-Y., Wu, S.-C., Chen, T.-W., Hsu, C.-S., Liao, Y.-H., Yang, C.-Y., Shyu, J.-F., Fischer, W. B., Lin, C.-H. Lipid raft-associated stomatin enhances cell fusion.
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Affiliation(s)
- Jui-Hao Lee
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan.,Institute of Microbiology and Immunology.,Institute of Biochemistry and Molecular Biology
| | | | - Hong-Wen Liu
- Institute of Microbiology and Immunology.,Chong Hin Loon Memorial Cancer and Biotherapy Research Center, and
| | - Chin-Yau Chen
- Institute of Microbiology and Immunology.,Department of Surgery, I-Lan, Taiwan
| | - Shao-Chin Wu
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
| | - Tung-Wei Chen
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
| | | | - Yu-Hsiu Liao
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
| | - Chih-Yung Yang
- Department of Education and Research, Taipei City Hospital, Taipei, Taiwan; and
| | - Jia-Fwu Shyu
- Department of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan
| | - Wolfgang B Fischer
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
| | - Chi-Hung Lin
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan; .,Institute of Microbiology and Immunology.,Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
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8
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Brand J, Smith ESJ, Schwefel D, Lapatsina L, Poole K, Omerbašić D, Kozlenkov A, Behlke J, Lewin GR, Daumke O. A stomatin dimer modulates the activity of acid-sensing ion channels. EMBO J 2012; 31:3635-46. [PMID: 22850675 PMCID: PMC3433786 DOI: 10.1038/emboj.2012.203] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 07/06/2012] [Indexed: 12/14/2022] Open
Abstract
Stomatins govern membrane trafficking and ion channel activity. The banana-shaped stomatin-domain dimmers oligomerize into a cylindrical structure. A dynamic hydrophobic pocket at the concave side of the dimer mediates repression of acid-sensing ion channel 3 (ASIC3) activity. Stomatin proteins oligomerize at membranes and have been implicated in ion channel regulation and membrane trafficking. To obtain mechanistic insights into their function, we determined three crystal structures of the conserved stomatin domain of mouse stomatin that assembles into a banana-shaped dimer. We show that dimerization is crucial for the repression of acid-sensing ion channel 3 (ASIC3) activity. A hydrophobic pocket at the inside of the concave surface is open in the presence of an internal peptide ligand and closes in the absence of this ligand, and we demonstrate a function of this pocket in the inhibition of ASIC3 activity. In one crystal form, stomatin assembles via two conserved surfaces into a cylindrical oligomer, and these oligomerization surfaces are also essential for the inhibition of ASIC3-mediated currents. The assembly mode of stomatin uncovered in this study might serve as a model to understand oligomerization processes of related membrane-remodelling proteins, such as flotillin and prohibitin.
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Affiliation(s)
- Janko Brand
- Max-Delbrück Center for Molecular Medicine, Crystallography Department, Berlin, Germany
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9
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Stomatin-domain proteins. Eur J Cell Biol 2012; 91:240-5. [DOI: 10.1016/j.ejcb.2011.01.018] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Revised: 01/26/2011] [Accepted: 01/27/2011] [Indexed: 11/18/2022] Open
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10
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Gilligan DM, Finney GL, Rynes E, Maccoss MJ, Lambert AJ, Peters LL, Robledo RF, Wooden JM. Comparative proteomics reveals deficiency of NHE-1 (Slc9a1) in RBCs from the beta-adducin knockout mouse model of hemolytic anemia. Blood Cells Mol Dis 2011; 47:85-94. [PMID: 21592827 DOI: 10.1016/j.bcmd.2011.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 03/22/2011] [Indexed: 11/29/2022]
Abstract
Hemolytic anemia is one of the most common inherited disorders. To identify candidate proteins involved in hemolytic anemia pathophysiology, we utilized a label-free comparative proteomic approach to detect differences in RBCs from normal and beta-adducin (Add2) knock-out mice. We detected 7 proteins that were decreased and 48 proteins that were increased in the beta-adducin knock-out RBC ghost. Since hemolytic anemias are characterized by reticulocytosis, we compared reticulocyte-enriched samples from phenylhydrazine-treated mice with mature RBCs from untreated mice. Label-free analysis identified 47 proteins that were increased in the reticulocyte-enriched samples and 21 proteins that were decreased. Among the proteins increased in Add2 knockout RBCs, only 11 were also found increased in reticulocytes. Among the proteins decreased in Add2 knockout RBCs, beta- and alpha-adducin showed the greatest intensity difference, followed by NHE-1 (Slc9a1), the sodium-hydrogen exchanger. We verified these mass spectrometry results by immunoblot. This is the first example of a deficiency of NHE-1 in hemolytic anemia and suggests new insights into the mechanisms leading to fragile RBCs. Our use of label-free comparative proteomics to make this discovery demonstrates the usefulness of this approach as opposed to metabolic or chemical isotopic labeling of mice.
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Affiliation(s)
- Diana M Gilligan
- Department of Medicine, Upstate Medical University, Syracuse, NY, USA.
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11
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Pan PW, Käyrä K, Leinonen J, Nissinen M, Parkkila S, Rajaniemi H. Gene expression profiling in the submandibular gland, stomach, and duodenum of CAVI-deficient mice. Transgenic Res 2010; 20:675-98. [PMID: 20835760 DOI: 10.1007/s11248-010-9441-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2010] [Accepted: 09/01/2010] [Indexed: 12/31/2022]
Abstract
Carbonic anhydrase VI (CAVI) is the only secreted isozyme of the α-carbonic anhydrase family, which catalyzes the reversible reaction [Formula in text]. It appears that CAVI protects teeth and gastrointestinal mucosa by neutralizing excess acidity. However, the evidence for this physiological function is limited, and CAVI may have additional functions that have yet to be discovered. To explore the functions of CAVI more fully, we generated Car6 (-/-) mice and analyzed Car6 (-/-) mutant phenotypes. We also examined transcriptomic responses to CAVI deficiency in the submandibular gland, stomach, and duodenum of Car6 (-/-) mice. Car6 (-/-) mice were viable and fertile and had a normal life span. Histological analyses indicated a greater number of lymphoid follicles in the small intestinal Peyer's patches. A total of 94, 56, and 127 genes were up- or down-regulated in the submandibular gland, stomach, and duodenum of Car6 (-/-) mice, respectively. The functional clustering of differentially expressed genes revealed a number of altered biological processes. In the duodenum, the significantly affected biological pathways included the immune system process and retinol metabolic processes. The response to oxidative stress and brown fat cell differentiation changed remarkably in the submandibular gland. Notably, the submandibular gland, stomach, and duodenum shared one important transcriptional susceptibility pathway: catabolic process. Real-time PCR confirmed an altered expression in 14 of the 16 selected genes. The generation and of Car6 (-/-) mice and examination of the effects of CAVI deficiency on gene transcription have revealed several affected clusters of biological processes, which implicate CAVI in catabolic processes and the immune system response.
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Affiliation(s)
- Pei-wen Pan
- Institute of Medical Technology, University of Tampere, Biokatu 6, 33520, Tampere, Finland.
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12
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Genome-wide identification of TAL1's functional targets: insights into its mechanisms of action in primary erythroid cells. Genome Res 2010; 20:1064-83. [PMID: 20566737 DOI: 10.1101/gr.104935.110] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Coordination of cellular processes through the establishment of tissue-specific gene expression programs is essential for lineage maturation. The basic helix-loop-helix hemopoietic transcriptional regulator TAL1 (formerly SCL) is required for terminal differentiation of red blood cells. To gain insight into TAL1 function and mechanisms of action in erythropoiesis, we performed ChIP-sequencing and gene expression analyses from primary fetal liver erythroid cells. We show that TAL1 coordinates expression of genes in most known red cell-specific processes. The majority of TAL1's genomic targets require direct DNA-binding activity. However, one-fifth of TAL1's target sequences, mainly among those showing high affinity for TAL1, can recruit the factor independently of its DNA binding activity. An unbiased DNA motif search of sequences bound by TAL1 identified CAGNTG as TAL1-preferred E-box motif in erythroid cells. Novel motifs were also characterized that may help distinguish activated from repressed genes and suggest a new mechanism by which TAL1 may be recruited to DNA. Finally, analysis of recruitment of GATA1, a protein partner of TAL1, to sequences occupied by TAL1 suggests that TAL1's binding is necessary prior or simultaneous to that of GATA1. This work provides the framework to study regulatory networks leading to erythroid terminal maturation and to model mechanisms of action of tissue-specific transcription factors.
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13
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KOMATSU T, SATO K, OTSUKA Y, ARASHIKI N, TANAKA K, TAMAHARA S, ONO KI, INABA M. Parallel Reductions in Stomatin and Na,K-ATPase through the Exosomal Pathway during Reticulocyte Maturation in Dogs: Stomatin as a Genotypic and Phenotypic Marker of High K+ and Low K+ Red Cells. J Vet Med Sci 2010; 72:893-901. [DOI: 10.1292/jvms.10-0030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Tomohiko KOMATSU
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University
| | - Kota SATO
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University
| | - Yayoi OTSUKA
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University
| | - Nobuto ARASHIKI
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University
| | - Kohei TANAKA
- Laboratory of Clinical Pathobiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo
| | - Satoshi TAMAHARA
- Laboratory of Clinical Pathobiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo
| | - Ken-ichiro ONO
- Laboratory of Clinical Pathobiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo
| | - Mutsumi INABA
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University
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14
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Hereditary stomatocytosis and cation leaky red cells — Recent developments. Blood Cells Mol Dis 2009; 42:216-22. [DOI: 10.1016/j.bcmd.2009.01.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Accepted: 01/20/2009] [Indexed: 12/22/2022]
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15
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The Glut1 and Glut4 glucose transporters are differentially expressed during perinatal and postnatal erythropoiesis. Blood 2008; 112:4729-38. [DOI: 10.1182/blood-2008-05-159269] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Glucose is a major source of energy for living organisms, and its transport in vertebrates is a universally conserved property. Of all cell lineages, human erythrocytes express the highest level of the Glut1 glucose transporter with more than 200 000 molecules per cell. However, we recently reported that erythrocyte Glut1 expression is a specific trait of vitamin C–deficient mammalian species, comprising only higher primates, guinea pigs, and fruit bats. Here, we show that in all other tested mammalian species, Glut1 was transiently expressed in erythrocytes during the neonatal period. Glut1 was up-regulated during the erythroblast stage of erythroid differentiation and was present on the vast majority of murine red blood cells (RBCs) at birth. Notably though, Glut1 was not induced in adult mice undergoing anemia-induced erythropoiesis, and under these conditions, the up-regulation of a distinct transporter, Glut4, was responsible for an increased glucose transport. Sp3 and Sp1 transcriptions factors have been proposed to regulate Glut1 transcription, and we find that the concomitant repression of Glut1 and induction of Glut4 was associated with a significantly augmented Sp3/Sp1 ratio. Glucose transporter expression patterns in mice and human erythrocytes are therefore distinct. In mice, there is a postnatal switch from Glut1 to Glut4, with Glut4 further up-regulated under anemic conditions.
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16
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Montel-Hagen A, Kinet S, Manel N, Mongellaz C, Prohaska R, Battini JL, Delaunay J, Sitbon M, Taylor N. Erythrocyte Glut1 Triggers Dehydroascorbic Acid Uptake in Mammals Unable to Synthesize Vitamin C. Cell 2008; 132:1039-48. [DOI: 10.1016/j.cell.2008.01.042] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Revised: 12/05/2007] [Accepted: 01/28/2008] [Indexed: 10/22/2022]
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17
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Martinez-Salgado C, Benckendorff AG, Chiang LY, Wang R, Milenkovic N, Wetzel C, Hu J, Stucky CL, Parra MG, Mohandas N, Lewin GR. Stomatin and sensory neuron mechanotransduction. J Neurophysiol 2007; 98:3802-8. [PMID: 17942620 DOI: 10.1152/jn.00860.2007] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Somatic sensory neurons of the dorsal root ganglia are necessary for a large part of our mechanosensory experience. However, we only have a good knowledge of the molecules required for mechanotransduction in simple invertebrates such as the nematode Caenorhabiditis elegans. In C. elegans, a number of so-called mec genes have been isolated that are required for the transduction of body touch. One such gene, mec-2 codes for an integral membrane protein of the stomatin family, a large group of genes with a stomatin homology domain. Using stomatin null mutant mice, we have tested the hypothesis that the founding member of this family, stomatin might play a role in the transduction of mechanical stimuli by primary sensory neurons. We used the in vitro mouse skin nerve preparation to record from a large population of low- and high-threshold mechanoreceptors with myelinated A-fiber (n = 553) and unmyelinated C-fiber (n = 157) axons. One subtype of mechanoreceptor, the d-hair receptor, which is a rapidly adapting mechanoreceptor, had reduced sensitivity to mechanical stimulation in the absence of stomatin. Other cutaneous mechanoreceptors, including nociceptive C-fibers were not affected by the absence of a functional stomatin protein. Patch-clamp analysis of presumptive D-hair receptor mechanoreceptive neurons, which were identified by a characteristic rosette morphology in culture, showed no change in membrane excitability in the absence of the stomatin protein. We conclude that stomatin is required for normal mechanotransduction in a subpopulation of vertebrate sensory neurons.
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Affiliation(s)
- Carlos Martinez-Salgado
- Department of Neuroscience, Max-Delbrück Center for Molecular Medicine and Charité Universitätsmedizin Berlin, Robert-Rössle Str, Berlin-Buch, Germany
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18
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Carroll BT, Dubyak GR, Sedensky MM, Morgan PG. Sulfated signal from ASJ sensory neurons modulates stomatin-dependent coordination in Caenorhabditis elegans. J Biol Chem 2006; 281:35989-96. [PMID: 16973616 DOI: 10.1074/jbc.m606086200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The neuronal stomatin-like proteins UNC-1 and UNC-24 play important roles in the nervous system of Caenorhabditis elegans. These neuronal stomatin-like proteins are putative chaperone proteins that can modify volatile anesthetic sensitivity and disrupt coordinated locomotion. A suppressor of unc-1 and unc-24, named ssu-1(fc73) (for suppressor of stomatin uncoordination), suppresses three phenotypes of neuronal stomatin-like protein deficiency as follows: volatile anesthetic sensitivity, uncoordinated locomotion, and a constitutive alternative developmental phenotype known as dauer. Here we provide the first phenotypic characterization of ssu-1, predicted to be the only C. elegans cytosolic alcohol sulfotransferase, a family of enzymes that catalyze a sulfate linkage with the alcohol group of small molecules for the purposes of detoxification or modification of signaling. In vitro enzyme analysis of bacterially expressed SSU-1 demonstrates sulfotransferase activity and thus confirms the function predicted by protein sequence similarities. Whereas unc-1 is expressed in the majority of neurons of C. elegans, expression of SSU-1 protein in only the two ASJ amphid interneurons is sufficient to restore the wild type phenotype. This work demonstrates that SSU-1 is a functional sulfotransferase that likely modifies endocrine signaling in C. elegans. The expression of SSU-1 in the ASJ neurons refines the understanding of the function of these cells and supports their classification as endocrine tissue. The relationship of unc-1, unc-24, and ssu-1 is the first association of neuronal stomatin-like proteins sharing regulatory roles with a sulfotransferase enzyme.
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Affiliation(s)
- Bryan T Carroll
- Department of Genetics, Case School of Medicine, Cleveland, Ohio 44106, USA
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19
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Abstract
The red cell membrane is one of the best known membranes in terms of structure, function and genetic disorders. As any plasma membrane it mediates transport functions. It also provides the erythrocytes with their resilience and deformability. Many of the proteins and the genes performing these functions are known in great detail, although some disease-responsible genes are yet to be elucidated. Basic knowledge has shed light on important groups of genetic disorders. The latter include (i) the disorders of the red cell mechanics: hereditary spherocytosis, hereditary elliptocytosis and poikilocytosis, and (ii) the disorders of the passive flux of the monovalent cations across the membrane: the stomacytoses and allied conditions. Reciprocally, many information have come from genetics abnormalities. We will review the mutation-disease relationship. A number of points will be underscored: widespread weak alleles modulate the expression of the SPTA1 gene, encoding the alpha-chain of spectrin; mutations in the anion exchanger can give rise to an array of distinct nosological entities, including a renal condition; splenectomy is banned in the stomatocytoses; a variety of stomatocyosis is part of a pleiotropic syndrome that may includes perinatal fetal liquid effusions. The diagnosis, follow-up and treatment of the involved diseases have gradually improved.
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Affiliation(s)
- Jean Delaunay
- AP-HP, Hôpital de Bicêtre, Service d'Hématologie, INSERM Unité 779, Faculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, France.
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20
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Fricke B, Parsons SF, Knöpfle G, von Düring M, Stewart GW. Stomatin is mis-trafficked in the erythrocytes of overhydrated hereditary stomatocytosis, and is absent from normal primitive yolk sac-derived erythrocytes. Br J Haematol 2005; 131:265-77. [PMID: 16197460 DOI: 10.1111/j.1365-2141.2005.05742.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The 32 kD lipid-raft-associated membrane protein 'stomatin' is deficient from the erythrocyte membrane in the Na+-K+ leaky haemolytic anaemia, overhydrated hereditary stomatocytosis (OHSt). To date, no mutation in the gene coding for this protein has so far been found in OHSt. In this study, we have analysed the distribution of stomatin in both cultured erythroid cells from OHSt patients and in normal embryological and fetal erythroid development. In erythroid cell cultures from OHSt patients, stomatin-immunoreactivity (stomatin-IR) was present in progenitor cells but remained restricted to the area of the multivesicular complexes and the nucleus in the developing cells and was not seen in the plasma membrane. This could be consistent with the idea that stomatin is an innocent passenger in a more fundamental trafficking abnormality. In normal embryonic development, we found that, in extraembryonic (yolk sac) erythropoiesis, neither the nucleated red cells nor their enucleated mature derivatives displayed any stomatin-IR. In contrast, all haemangiopoietic progenitor cells of intraembryonic haematopoiesis, starting with the mesodermal precursors in the aorta-gonad-mesonephros region, exhibited strong stomatin-IR. The significance of this observation on these poorly understood cells is currently unclear.
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Affiliation(s)
- Britta Fricke
- Department of Neuroanatomy, Ruhr University, Bochum, Germany
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21
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Paltrinieri S, Comazzi S, Ceciliani F, Prohaska R, Bonfanti U. Stomatocytosis of Standard Schnauzers is not associated with stomatin deficiency. Vet J 2005; 173:200-3. [PMID: 16168686 DOI: 10.1016/j.tvjl.2005.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Stomatocytosis resembles human overhydrated hereditary stomatocytosis (OHSt), a disease characterised by a reduced or absent stomatin expression. The objective of this report was to investigate the expression level of stomatin in erythrocytes from Standard Schnauzers with stomatocytosis. Routine haematology, intraerythrocytic Na(+)/K(+) concentration and stomatin expression were evaluated in blood from twelve Standard Schnauzers and from three controls. SDS-PAGE and Western blotting on isolated integral membrane proteins were used to investigate stomatin expression. Circulating stomatocytes, macrocytosis, anisocytosis, increased erythrocyte fragility and high intracellular sodium and potassium concentrations were found in 10/12 dogs from the same breeding line although stomatin levels were similar to those of controls. In spite of the clinico-pathological similarities between human and canine stomatocytosis, erythrocytes from affected dogs do not lack stomatin and the expression level of this protein cannot therefore be used to diagnose hereditary stomatocytosis in Standard Schnauzers.
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Affiliation(s)
- Saverio Paltrinieri
- Department of Veterinary Pathology, Hygiene and Public Health, Unit of Veterinary General Pathology and Parasitology, University of Milan Via Celoria 10, 20133, Milan, Italy.
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22
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Abstract
While our understanding of lipid microdomains has advanced in recent years, many aspects of their formation and dynamics are still unclear. In particular, the molecular determinants that facilitate the partitioning of integral membrane proteins into lipid raft domains are yet to be clarified. This review focuses on a family of raft-associated integral membrane proteins, termed flotillins, which belongs to a larger class of integral membrane proteins that carry an evolutionarily conserved domain called the prohibitin homology (PHB) domain. A number of studies now suggest that eucaryotic proteins carrying this domain have affinity for lipid raft domains. The PHB domain is carried by a diverse array of proteins including stomatin, podocin, the archetypal PHB protein, prohibitin, lower eucaryotic proteins such as the Dictyostelium discoideum proteins vacuolin A and vacuolin B and the Caenorhabditis elegans proteins unc-1, unc-24 and mec-2. The presence of this domain in some procaryotic proteins suggests that the PHB domain may constitute a primordial lipid recognition motif. Recent work has provided new insights into the trafficking and targeting of flotillin and other PHB domain proteins. While the function of this large family of proteins remains unclear, studies of the C. elegans PHB proteins suggest possible links to a class of volatile anaesthetics raising the possibility that these lipophilic agents could influence lipid raft domains. This review will discuss recent insights into the cell biology of flotillins and the large family of evolutionarily conserved PHB domain proteins.
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Affiliation(s)
- Isabel C Morrow
- Institute for Molecular Bioscience, Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Queensland 4072, Australia
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23
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Abstract
A mosquito sterol carrier protein-2, AeSCP-2, has been shown to aid in the uptake of cholesterol in mosquito cells. The discovery of chemical inhibitors of AeSCP-2 is reported here. AeSCP-2 inhibitors (SCPIs) belong to several chemotypes of hydrophobic compounds. Those inhibitors competed with cholesterol for AeSCP-2, binding with relatively high binding affinities. In cultured insect cells, SCPIs reduced cholesterol uptake by as much as 30% at 1-5 microM concentrations. SCPIs were potent larvicides to the yellow fever mosquito, Aedes aegypti, and to the tobacco hornworm, Manduca sexta, with 50% lethal doses (LD50s) of 5-21 microM and 0.013-15 ng/mg diet, respectively. The results indicate that sterol carrier protein-2 has functional similarity in two different insect species.
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Affiliation(s)
- Min-sik Kim
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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24
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Delaunay J. The hereditary stomatocytoses: genetic disorders of the red cell membrane permeability to monovalent cations. Semin Hematol 2004; 41:165-72. [PMID: 15071792 DOI: 10.1053/j.seminhematol.2004.02.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The hereditary stomatocytoses are mostly accounted for by genetic disorders of red cell membrane permeability to monovalent cations. These conditions, all very rare, are comprised of a hemolytic anemia, frequently macrocytosis, and the presence of abnormally shaped red blood cells. The key test for diagnosis is osmotic gradient ektacytometry, which measures the osmotic resistance and hydration of the red blood cell; the curve depicting the temperature dependence of the cation leak is also important. Syndromes include familial pseudohyperkalemia (FP), which is devoid of hematological features, dehydrated hereditary stomatocytosis (DHS), and overhydrated hereditary stomatocytosis (OHS). Some forms of DHS may be a pleiotropic, showing pseudohyperkalemia and/or perinatal edema. Perinatal edema, if not properly treated, may be lethal but may also resolve spontaneously prior to or shortly after birth and never reappear. Hereditary cryohydrocytosis, type 1 (CHC 1) is characterized by a dramatic resumption of the leak in vitro as the temperature approaches 0 degrees C; cell hydration seems unaltered. In OHS, stomatin, a membrane protein, is sharply reduced; however, this is a secondary event and the primarily mutated protein remains unknown. Hereditary cryohydrocytosis, type 2 (CHC 2) presents similar to OHS, except that the leak dramatically increases close to 0 degrees C. In addition, hematological manifestations are associated with neurological disorders. Of critical practical importance is that splenectomy in DHS or OHS causes thromboembolic events that may be fatal. The genes involved in hereditary stomatocytoses have yet to be identified. Apart from the 16q24-qter locus, related to subsets of DHS and FP, and a chromosome 2 locus assigned to a single case of FP, gene mapping has been difficult. The eventual discovery of individual genes will clarify complicated classification of the stomatocytoses, now based solely on phenotype.
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MESH Headings
- Anemia, Hemolytic, Congenital/diagnosis
- Anemia, Hemolytic, Congenital/genetics
- Anemia, Hemolytic, Congenital/metabolism
- Anemia, Hemolytic, Congenital/therapy
- Blood Proteins/genetics
- Blood Proteins/metabolism
- Cations, Monovalent/metabolism
- Cell Membrane Permeability/genetics
- Cell Membrane Permeability/physiology
- Chromosomes, Human, Pair 16/genetics
- Chromosomes, Human, Pair 2/genetics
- Erythrocytes, Abnormal/metabolism
- Exons/genetics
- Female
- Humans
- Hyperkalemia/genetics
- Hyperkalemia/metabolism
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Potassium/metabolism
- RNA Precursors/genetics
- RNA Precursors/metabolism
- RNA Splicing/genetics
- Sodium/metabolism
- Splenectomy/mortality
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Affiliation(s)
- Jean Delaunay
- Service d'Hématologie, d'Immunologie et de Cytogénétique, Hôpital de Bicêtre, Faculté de Médecine Paris-Sud, INSERM U-473, 84 rue du Général-Leclerc, 94273 Le Kremlin-Bicêtre, France
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25
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Price MP, Thompson RJ, Eshcol JO, Wemmie JA, Benson CJ. Stomatin modulates gating of acid-sensing ion channels. J Biol Chem 2004; 279:53886-91. [PMID: 15471860 DOI: 10.1074/jbc.m407708200] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are H(+)-gated members of the degenerin/epithelial Na(+) channel (DEG/ENaC) family in vertebrate neurons. Several ASICs are expressed in sensory neurons, where they play a role in responses to nociceptive, taste, and mechanical stimuli; others are expressed in central neurons, where they participate in synaptic plasticity and some forms of learning. Stomatin is an integral membrane protein found in lipid/protein-rich microdomains, and it is believed to regulate the function of ion channels and transporters. In Caenorhabditis elegans, stomatin homologs interact with DEG/ENaC channels, which together are necessary for normal mechanosensation in the worm. Therefore, we asked whether stomatin interacts with and modulates the function of ASICs. We found that stomatin co-immunoprecipitated and co-localized with ASIC proteins in heterologous cells. Moreover, stomatin altered the function of ASIC channels. Stomatin potently reduced acid-evoked currents generated by ASIC3 without changing steady state protein levels or the amount of ASIC3 expressed at the cell surface. In contrast, stomatin accelerated the desensitization rate of ASIC2 and heteromeric ASICs, whereas current amplitude was unaffected. These data suggest that stomatin binds to and alters the gating of ASICs. Our findings indicate that modulation of DEG/ENaC channels by stomatin-like proteins is evolutionarily conserved and may have important implications for mammalian nociception and mechanosensation.
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Affiliation(s)
- Margaret P Price
- Department of Internal Medicine, University of Iowa College of Medicine, 200 Hawkins Dr., Iowa City, IA 52242, USA
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26
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Syntichaki P, Tavernarakis N. Genetic Models of Mechanotransduction: The NematodeCaenorhabditis elegans. Physiol Rev 2004; 84:1097-153. [PMID: 15383649 DOI: 10.1152/physrev.00043.2003] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Mechanotransduction, the conversion of a mechanical stimulus into a biological response, constitutes the basis for a plethora of fundamental biological processes such as the senses of touch, balance, and hearing and contributes critically to development and homeostasis in all organisms. Despite this profound importance in biology, we know remarkably little about how mechanical input forces delivered to a cell are interpreted to an extensive repertoire of output physiological responses. Recent, elegant genetic and electrophysiological studies have shown that specialized macromolecular complexes, encompassing mechanically gated ion channels, play a central role in the transformation of mechanical forces into a cellular signal, which takes place in mechanosensory organs of diverse organisms. These complexes are highly efficient sensors, closely entangled with their surrounding environment. Such association appears essential for proper channel gating and provides proximity of the mechanosensory apparatus to the source of triggering mechanical energy. Genetic and molecular evidence collected in model organisms such as the nematode worm Caenorhabditis elegans, the fruit fly Drosophila melanogaster, and the mouse highlight two distinct classes of mechanically gated ion channels: the degenerin (DEG)/epithelial Na+channel (ENaC) family and the transient receptor potential (TRP) family of ion channels. In addition to the core channel proteins, several other potentially interacting molecules have in some cases been identified, which are likely parts of the mechanotransducing apparatus. Based on cumulative data, a model of the sensory mechanotransducer has emerged that encompasses our current understanding of the process and fulfills the structural requirements dictated by its dedicated function. It remains to be seen how general this model is and whether it will withstand the impiteous test of time.
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Affiliation(s)
- Popi Syntichaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Vassilika Vouton, PO Box 1527, Heraklion 71110, Crete, Greece
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27
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Abstract
PURPOSE OF REVIEW To summarize recent findings in the study of the 'hereditary stomatocytoses and allied disorders', diseases in which the red cell membrane leaks Na and K, disturbing the osmotic homeostasis of the cell. RECENT FINDINGS Recent work has emphasized the diversity of these conditions, especially evident in the variations in temperature dependence of the cation leak. The association between the dehydrated, xerocytic form that maps to chromosome 16, with perinatal ascites is confirmed. Two cases that may represent a new hematoneurologic syndrome have been recognized. SUMMARY These leaky-membrane diseases fall into three main categories. The 'dehydrated' or xerocytic form maps to chromosome 16 and shows a minimal leak, and can show an excess of phosphatidylcholine in the membrane. Some of these xerocytic cases show a syndrome of self-limiting perinatal ascites of unknown cause. A second group shows very variable temperature dependence in the cation leak. The most severe 'overhydrated' form shows very leaky cells and the 32 kD stomatin protein is missing, although the gene is not mutated. This deficiency seems to be the result of a trafficking problem. The protein is associated with cholesterol and sphingomyelin-rich 'rafts' and may be some kind of partner protein for a membrane-bound proteolytic system.
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Affiliation(s)
- Gordon W Stewart
- Department of Medicine, Rayne Institute, University College London, University Street, London, UK.
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28
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Green JB, Fricke B, Chetty MC, von Düring M, Preston GF, Stewart GW. Eukaryotic and prokaryotic stomatins: the proteolytic link. Blood Cells Mol Dis 2004; 32:411-22. [PMID: 15121101 DOI: 10.1016/j.bcmd.2004.01.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2004] [Indexed: 11/29/2022]
Abstract
The 32kD membrane protein stomatin was first studied because it is deficient from the red cell membrane in two forms of the class of haemolytic anaemias known as "hereditary stomatocytosis." The hallmark of these conditions is a plasma membrane leak to the monovalent cations Na+ and K+: the protein is missing only in the most severely leaky of these conditions. No mutation has ever been found in the stomatin gene in these conditions. Stomatin-like proteins have been identified in all three domains of biology, yet their function remains enigmatic. Although the murine knock-out is without phenotype, we have identified a family showing a splicing defect in the stomatin mRNA, in which affected children showed a catastrophic multisystem disease not inconsistent with the now-known wide tissue distribution of stomatin. We report here a study of strongly homologous stomatin-like genes in prokaryotes, which reveals a close connection with a never-studied gene erroneously known as "nfed." This gene codes for a hydrophobic protein with a probable serine protease motif. It is possible that these stomatin-like genes and those which are known as"nfed" form an operon, suggesting that the two protein products are aimed at a common function. The corollary is that stomatin could be a partner protein for a membrane-bound proteolytic process, in both prokaryotes and in eukaryotes generally: this idea is consistent with experimental evidence.
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Affiliation(s)
- Jasper B Green
- Department of Medicine, Rayne Institute, University College London, University Street, London WC1E 6JJ, UK
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29
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Fricke B, Jarvis HG, Reid CDL, Aguilar-Martinez P, Robert A, Quittet P, Chetty M, Pizzey A, Cynober T, Lande WF, Mentzer WC, Düring M, Winter S, Delaunay J, Stewart GW. Four new cases of stomatin-deficient hereditary stomatocytosis syndrome: association of the stomatin-deficient cryohydrocytosis variant with neurological dysfunction. Br J Haematol 2004; 125:796-803. [PMID: 15180870 DOI: 10.1111/j.1365-2141.2004.04965.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This report concerns congenitally Na(+)-K(+) leaky red cells of the 'hereditary stomatocytosis' class. Three new isolated cases and one new pedigree are described, and one previously reported case is expanded. In all cases, Western blotting of red cell membranes revealed a deficiency in the 32 kDa membrane protein, stomatin. All showed pronounced cation leaks at 37 degrees C with markedly abnormal intracellular Na(+) and K(+) concentrations, like all other such stomatin-deficient cases. Consistent with recent findings in two previously described British pedigrees, immunocytochemistry demonstrated that the deficiency of stomatin was not complete. On typical blood films, some red cells showed positive stomatin immunoreactivity, while most were negative, although in one case only a minority were negative. All platelets and neutrophils were stomatin positive. The cases differed markedly between themselves with regard to the temperature dependence of the passive leak to K(+). Three showed a simple monotonic temperature dependence, while two showed a minimum at around 20-25 degrees C, such that the cells were extremely leaky at 0 degrees C, giving the phenotype known as 'cryohydrocytosis'. These patients are the only two known cases of stomatin-deficient cryohydrocytosis. Both showed a congenital syndrome of mental retardation, seizures, cataracts and massive hepatosplenomegaly, probably defining a new haemato-neurological syndrome.
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Affiliation(s)
- Britta Fricke
- Abteilung fuer Neuroanatomie, Institut fuer Anatomie, Bochum, Germany
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30
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Argent AC, Chetty MC, Fricke B, Bertrand Y, Philippe N, Khogali S, von Düring M, Delaunay J, Stewart GW. A family showing recessively inherited multisystem pathology with aberrant splicing of the erythrocyte Band 7.2b ('stomatin') gene. J Inherit Metab Dis 2004; 27:29-46. [PMID: 14970744 DOI: 10.1023/b:boli.0000016624.21475.de] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The case of a French child, born of consanguineous parents of Tunisian origin, is described. He showed a severe multisystem disease with dyserythropoietic, sideroblastic anaemia, delayed neurological development with hypotonia and convulsions, salt-losing nephropathy, chronic watery diarrhoea, lactic acidosis with mitochondrial dysfunction, brittle hair, hypergammaglobulinaemia, fatty liver with intermittent transaminasaemia, and terminal pulmonary fibrosis. Two siblings, of both sexes, were stillborn; two more lived only a short time. One sister is alive and well. SDS gel analysis of the red cell membranes showed a deficiency within 'Band 7' at 32 kDa. Analysis of the gene encoding 'stomatin', or 'erythrocyte membrane protein 7.2b', the principal protein of 'Band 7', revealed a complex series of aberrant spliceforms centred around exon 3, for which no explanatory genomic lesion could be found. The true underlying molecular cause of this condition remains obscure, but it suggests that the stomatin gene should be studied in other cases.
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Affiliation(s)
- A C Argent
- Department of Medicine, University College London School of Medicine, Rayne Institute, London, UK
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31
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Hiller NL, Akompong T, Morrow JS, Holder AA, Haldar K. Identification of a stomatin orthologue in vacuoles induced in human erythrocytes by malaria parasites. A role for microbial raft proteins in apicomplexan vacuole biogenesis. J Biol Chem 2003; 278:48413-21. [PMID: 12968029 DOI: 10.1074/jbc.m307266200] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
When the human malaria parasite Plasmodium falciparum infects erythrocytes, proteins associated with host-derived detergent-resistant membrane (DRM) rafts are selectively recruited into the newly formed vacuole, but parasite proteins that contribute to raft-based vacuole development are unknown. In mammalian cells, DRM-associated integral membrane proteins such as caveolin-1 and flotillin-1 that form oligomers have been linked to the formation of DRM-based invaginations called caveolae. Here we show that the P. falciparum genome does not encode caveolins or flotillins but does contain an orthologue of human band 7 stomatin, a protein known to oligomerize, associate with non-caveolar DRMs and is distantly related to flotillins. Stomatins are members of a large protein family conserved in evolution and P. falciparum (Pf) stomatin appears to be a prokaryotic-like molecule. Evidence is presented that it associates with DRMs and may oligomerize, suggesting that these features are conserved in the stomatin family. Further, Pfstomatin is an integral membrane protein concentrated at the apical end of extracellular parasites, where it co-localizes with invasion-associated rhoptry organelles. A resident rhoptry protein, RhopH2 also resides in DRMs. This provides the first evidence that rhoptries of an apicomplexan parasite contain DRM rafts. Further, when the parasite invades erythrocytes, rhoptry Pfstomatin and RhopH2 are inserted into the newly formed vacuole. Thus, like caveolin-1 and flotillin-1, a stomatin may also associate with non-clathrin coated, DRM-enriched vacuoles. We propose a new model of invasion and vacuole formation involving DRM-based interactions of both host and parasite molecules.
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Affiliation(s)
- N Luisa Hiller
- Department of Pathology, Northwestern University, Chicago, Illinois 60611, USA
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32
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Fricke B, Argent AC, Chetty MC, Pizzey AR, Turner EJ, Ho MM, Iolascon A, von Düring M, Stewart GW. The "stomatin" gene and protein in overhydrated hereditary stomatocytosis. Blood 2003; 102:2268-77. [PMID: 12750157 DOI: 10.1182/blood-2002-06-1705] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In overhydrated hereditary stomatocytosis (OHSt), Coomassie- and silver-stained polyacrylamide gels show an apparently complete deficit of the 32-kDa membrane protein, stomatin. We have used an antistomatin antibody to examine peripheral blood films, bone marrow, splenic tissue, and hepatic tissue from these patients by immunocytochemistry. This technique revealed that, in fact, some red cells did show positive stomatin immunoreactivity; and consistent with this result, Western blot analysis of the red cell membranes confirmed that about one twentieth to one fiftieth of the normal amount of stomatin was in fact present. Flow cytometry, combining immunoreactive quantitation of stomatin expression with thiazole orange staining for reticulocytes, showed that in OHSt, it was the young cells that had more stomatin. Magnetic-activated cell separation studies, using beads to which an anti-transferrin receptor antibody was conjugated, confirmed that in OHSt there was a correspondence between expression of stomatin and the transferrin receptor. Immunocytochemistry and Western blotting revealed that in OHSt patients, the protein was present in spleen, liver, neutrophils, platelets, monocytes, and about 50% of the peripheral lymphocytes, with the same distribution as in healthy controls. Neither Southern blots, nor direct sequencing of multiple subclones of the cDNA, nor sequencing of amplicons from genomic DNA revealed any significant abnormality in stomatin gene sequence in these patients. The deficiency of stomatin from red cells appears to be due to a loss of stomatin from these red cells on maturation in the bone marrow and in the circulation.
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Affiliation(s)
- Britta Fricke
- Departments of Medicine and Haematology, University College London, Rayne Institute, University Street, London WC1E 6JJ, United Kingdom
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33
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Abstract
The molecular mechanisms for the transduction of light and chemical signals in animals are fairly well understood. In contrast, the processes by which the senses of touch, balance, hearing, and proprioception are transduced are still largely unknown. Biochemical approaches to identify transduction components are difficult to use with mechanosensory systems, but genetic approaches are proving more successful. Genetic research in several organisms has demonstrated the importance of cytoskeletal, extracellular, and membrane components for sensory mechanotransduction. In particular, researchers have identified channel proteins in the DEG/ENaC and TRP families that are necessary for signaling in a variety of mechanosensory cells. Proof that these proteins are components of the transduction channel, however, is incomplete.
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Affiliation(s)
- Glen G Ernstrom
- Department of Biological Sciences, 1012 Fairchild Center, Columbia University, 1212 Amsterdam Avenue, New York, NY 10027, USA.
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34
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Morrow IC, Rea S, Martin S, Prior IA, Prohaska R, Hancock JF, James DE, Parton RG. Flotillin-1/reggie-2 traffics to surface raft domains via a novel golgi-independent pathway. Identification of a novel membrane targeting domain and a role for palmitoylation. J Biol Chem 2002; 277:48834-41. [PMID: 12370178 DOI: 10.1074/jbc.m209082200] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Flotillins are lipid raft-associated proteins, which have been implicated in neuronal regeneration and insulin signaling. We now show that newly synthesized flotillin-1 reaches the plasma membrane via a Sar1-independent and brefeldin A-resistant targeting pathway. Consistent with post-translational membrane association of flotillin, protease sensitivity experiments suggest that flotillin-1 is not a transmembrane protein but is associated with the cytoplasmic face of the plasma membrane. The N terminus of flotillin contains a prohibitin-like domain (PHB), which shows homology to a number of proteins associated with raft domains including stomatin, podocin, and prohibitin. We show that the PHB domain of flotillin can efficiently target a heterologous protein, green fluorescent protein, to the plasma membrane. Another PHB-containing protein, stomatin, traffics to the plasma membrane via the conventional secretory pathway. Plasma membrane association of both full-length flotillin and the green fluorescent protein-tagged PHB domain of flotillin is dependent on palmitoylation and requires a conserved cysteine residue, Cys-34, in the PHB domain. The results identify a novel targeting mechanism for plasma membrane association of flotillin-1 involving a Golgi-independent trafficking pathway, the PHB domain, and palmitoylation.
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Affiliation(s)
- Isabel C Morrow
- Institute for Molecular Bioscience and Centre for Functional and Applied Genomics, University of Queensland, St. Lucia, Australia
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35
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Feuk‐Lagerstedt E, Samuelsson M, Mosgoeller W, Movitz C, Rosqvist Å, Bergström J, Larsson T, Steiner M, Prohaska R, Karlsson A. The presence of stomatin in detergent‐insoluble domains of neutrophil granule membranes. J Leukoc Biol 2002. [DOI: 10.1189/jlb.72.5.970] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Elisabeth Feuk‐Lagerstedt
- The Phagocyte Research Laboratory, Department of Rheumatology and Inflammation Research, Austria and
| | - Marie Samuelsson
- The Phagocyte Research Laboratory, Department of Rheumatology and Inflammation Research, Austria and
| | | | - Charlotta Movitz
- The Phagocyte Research Laboratory, Department of Rheumatology and Inflammation Research, Austria and
| | - Åsa Rosqvist
- The Phagocyte Research Laboratory, Department of Rheumatology and Inflammation Research, Austria and
| | - Jörgen Bergström
- Institute of Medical Biochemistry, Göteborg University, Sweden; and Institutes of Vienna, Austria
| | - Thomas Larsson
- Institute of Medical Biochemistry, Göteborg University, Sweden; and Institutes of Vienna, Austria
| | | | | | - Anna Karlsson
- The Phagocyte Research Laboratory, Department of Rheumatology and Inflammation Research, Austria and
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36
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Mairhofer M, Steiner M, Mosgoeller W, Prohaska R, Salzer U. Stomatin is a major lipid-raft component of platelet alpha granules. Blood 2002; 100:897-904. [PMID: 12130500 DOI: 10.1182/blood.v100.3.897] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipid rafts are detergent-resistant, cholesterol- and sphingolipid-rich membrane domains that are involved in important cellular processes such as signal transduction and intracellular trafficking. Stomatin, a major lipid-raft component of erythrocytes and epithelial cells, is also an abundant platelet protein. Microscopical methods and subcellular fractionation showed that stomatin is located mainly at the alpha-granular membrane. The lipid-raft marker proteins flotillin-1 and flotillin-2 were also present in platelets but excluded from alpha granules. Stomatin and the flotillins were associated with Triton X-100-insoluble lipid rafts. Whereas stomatin was partly soluble in Triton X-100, it was insoluble in the detergents Lubrol and 3-[(3-cholamidopropyl)dimethylamonio]-1-propyl sulfonate (CHAPS). Flotation experiments after CHAPS lysis of platelets revealed a distinct set of lipid-raft-associated proteins, which were identified by matrix-assisted laser desorption/ionization mass spectrometry as stomatin, flotillin-1, flotillin-2, CD36, CD9, integrin alpha(IIb)beta(3), and the glucose transporter GLUT-3. Stomatin, the flotillins, and CD36 were exclusively present in this lipid-raft fraction. Activation of platelets by calcium ionophore A23187 or thrombin led to translocation of stomatin to the plasma membrane, cleavage by calpain, and specific sorting into released microvesicles. In conclusion, this study demonstrated the existence of alpha-granular lipid rafts and suggests an important role for stomatin in the organization and function of alpha granules.
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Affiliation(s)
- Mario Mairhofer
- Institute of Medical Biochemistry, Vienna Biocenter, University of Vienna, Austria
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37
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Affiliation(s)
- H A Nash
- Laboratory of Molecular Biology, National Institute of Mental Health, Building 36/Room 1B08, 9000 Rockville Pike, Bethesda, MD 20892-4034, USA
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38
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Zhang JZ, Abbud W, Prohaska R, Ismail-Beigi F. Overexpression of stomatin depresses GLUT-1 glucose transporter activity. Am J Physiol Cell Physiol 2001; 280:C1277-83. [PMID: 11287341 DOI: 10.1152/ajpcell.2001.280.5.c1277] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We showed previously that GLUT-1 glucose transporter is associated with stomatin (band 7.2b) in human red blood cell membranes and in Clone 9 cells. We show here that in a mixed population of stably transfected cells, overexpression of either murine or human stomatin resulted in 35-50% reduction in the basal rate of glucose transport. Moreover, there was a correlation between increased expression of stomatin and depression in the rate of glucose transport. In two clones chosen for further study, the ~10% and ~70% reduction in basal rate of glucose transport was associated with increases in stomatin mRNA and protein expression without a detectable change in GLUT-1 content in plasma membranes of either clone. In the clone overexpressing high levels of stomatin, immunoprecipitated GLUT-1 was associated with a large amount of stomatin as a coimmunoprecipitant. Employing extracts of cells overexpressing human stomatin, we found that stomatin bound to the glutathione-S-transferase (GST) fusion protein containing the COOH-terminal 42-amino acid segment of GLUT-1 but not to GST alone or a GST fusion protein containing the 66-amino acid central loop of GLUT-1. Rat stomatin cDNA was cloned by RT-PCR and found to be highly homologous to mouse (97%) and human (86%) stomatins. These results suggest that overexpression of stomatin results in a depression in the basal rate of glucose transport by decreasing the "intrinsic" activity of GLUT-1, probably through protein-protein interaction.
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Affiliation(s)
- J Z Zhang
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4951, USA
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39
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Sedensky MM, Siefker JM, Morgan PG. Model organisms: new insights into ion channel and transporter function. Stomatin homologues interact in Caenorhabditis elegans. Am J Physiol Cell Physiol 2001; 280:C1340-8. [PMID: 11287347 DOI: 10.1152/ajpcell.2001.280.5.c1340] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In C. elegans the protein UNC-1 is a major determinant of anesthetic sensitivity and is a close homologue of the mammalian protein stomatin. In humans stomatin is missing from erythrocyte membranes in the hemolytic disease overhydrated hereditary stomatocytosis, despite an apparently normal stomatin gene. Overhydrated hereditary stomatocytosis is characterized by alteration of the normal transmembrane gradients of sodium and potassium. Stomatin has been shown to interact genetically with sodium channels. It is also postulated that stomatin is important in the organization of lipid rafts. We demonstrate here that antibodies against UNC-1 stain the major nerve tracts of Caenorhabditis elegans, with very intense staining of the nerve ring. We also found that a gene encoding a stomatin-like protein, UNC-24, affects anesthetic sensitivity and is genetically epistatic to unc-1. In the absence of UNC-24, the staining of the nerve ring by anti-UNC-1 is abolished, despite normal transcriptional levels of the unc-1 mRNA. Western blots indicate that UNC-24 probably affects the stability of the UNC-1 protein. UNC-24 may therefore be necessary for the correct placement of UNC-1 in the cell membrane and organization of lipid rafts.
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Affiliation(s)
- M M Sedensky
- Department of Anesthesiology, University Hospitals and Case Western Reserve University, Cleveland, Ohio 44106, USA
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40
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Salzer U, Prohaska R. Stomatin, flotillin-1, and flotillin-2 are major integral proteins of erythrocyte lipid rafts. Blood 2001; 97:1141-3. [PMID: 11159550 DOI: 10.1182/blood.v97.4.1141] [Citation(s) in RCA: 261] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipid rafts are sphingolipid- and cholesterol-rich membrane microdomains that are insoluble in nonionic detergents, have a low buoyant density, and preferentially contain lipid-modified proteins, like glycosyl phosphatidylinositol (GPI)-anchored proteins. The lipid rafts were isolated from human erythrocytes and major protein components were identified. Apart from the GPI-anchored proteins, the most abundant integral proteins were found to be the distantly related membrane proteins stomatin (band 7.2b), flotillin-1, and flotillin-2. Flotillins, already described as lipid raft components in neurons and caveolae-associated proteins in A498 kidney cells, have not been recognized as red cell components yet. In addition, it was shown that the major cytoskeletal proteins, spectrin, actin, band 4.1, and band 4.2, are partly associated with the lipid rafts. Stomatin and the flotillins are present as independently organized high-order oligomers, suggesting that these complexes act as separate scaffolding components at the cytoplasmic face of erythrocyte lipid rafts.
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Affiliation(s)
- U Salzer
- Institute of Medical Biochemistry, University of Vienna, Vienna Biocenter, Vienna, Austria
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41
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Garin J, Diez R, Kieffer S, Dermine JF, Duclos S, Gagnon E, Sadoul R, Rondeau C, Desjardins M. The phagosome proteome: insight into phagosome functions. J Cell Biol 2001; 152:165-80. [PMID: 11149929 PMCID: PMC2193653 DOI: 10.1083/jcb.152.1.165] [Citation(s) in RCA: 550] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Phagosomes are key organelles for the innate ability of macrophages to participate in tissue remodeling, clear apoptotic cells, and restrict the spread of intracellular pathogens. To understand the functions of phagosomes, we initiated the systematic identification of their proteins. Using a proteomic approach, we identified >140 proteins associated with latex bead-containing phagosomes. Among these were hydrolases, proton pump ATPase subunits, and proteins of the fusion machinery, validating our approach. A series of unexpected proteins not previously described along the endocytic/phagocytic pathways were also identified, including the apoptotic proteins galectin3, Alix, and TRAIL, the anti-apoptotic protein 14-3-3, the lipid raft-enriched flotillin-1, the anti-microbial molecule lactadherin, and the small GTPase rab14. In addition, 24 spots from which the peptide masses could not be matched to entries in any database potentially represent new phagosomal proteins. The elaboration of a two-dimensional gel database of >160 identified spots allowed us to analyze how phagosome composition is modulated during phagolysosome biogenesis. Remarkably, during this process, hydrolases are not delivered in bulk to phagosomes, but are instead acquired sequentially. The systematic characterization of phagosome proteins provided new insights into phagosome functions and the protein or groups of proteins involved in and regulating these functions.
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Affiliation(s)
- Jérome Garin
- Laboratoire de Chimie des protéines, Commissariat a l'Energie Atomique, 38054 Grenoble, France
| | - Roberto Diez
- Département de Pathologie et Biologie Cellulaire, Université de Montréal, Montréal, Quebec, Canada, H3C 3J7
| | - Sylvie Kieffer
- Laboratoire de Chimie des protéines, Commissariat a l'Energie Atomique, 38054 Grenoble, France
| | - Jean-François Dermine
- Département de Pathologie et Biologie Cellulaire, Université de Montréal, Montréal, Quebec, Canada, H3C 3J7
| | - Sophie Duclos
- Département de Pathologie et Biologie Cellulaire, Université de Montréal, Montréal, Quebec, Canada, H3C 3J7
| | - Etienne Gagnon
- Département de Pathologie et Biologie Cellulaire, Université de Montréal, Montréal, Quebec, Canada, H3C 3J7
| | - Remy Sadoul
- Neurodégénérescence et Plasticité, Hopital A. Michallon, Centre Hospitalier Universitaire, 38043 Grenoble, France
| | - Christiane Rondeau
- Département de Pathologie et Biologie Cellulaire, Université de Montréal, Montréal, Quebec, Canada, H3C 3J7
| | - Michel Desjardins
- Département de Pathologie et Biologie Cellulaire, Université de Montréal, Montréal, Quebec, Canada, H3C 3J7
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42
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Wang Y, Morrow JS. Identification and characterization of human SLP-2, a novel homologue of stomatin (band 7.2b) present in erythrocytes and other tissues. J Biol Chem 2000; 275:8062-71. [PMID: 10713127 DOI: 10.1074/jbc.275.11.8062] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human stomatin (band 7.2b) is a 31-kDa erythrocyte membrane protein of unknown function but implicated in the control of ion channel permeability, mechanoreception, and lipid domain organization. Although absent in erythrocytes from patients with hereditary stomatocytosis, stomatin is not linked to this disorder. A second stomatin homologue, termed SLP-1, has been identified in nonerythroid tissues, and other stomatin related proteins are found in Drosophila, Caenorhabditis elegans, and plants. We now report the cloning and characterization of a new and unusual stomatin homologue, human SLP-2 (stomatin-like protein 2). SLP-2 is encoded by an approximately 1.5-kilobase mRNA (GenBank(TM) accession no. AF190167). The gene for human SLP-2, HUSLP2, is present on chromosome 9p13. Its derived amino acid sequence predicts a 38,537-kDa protein that is overall approximately 20% similar to human stomatin. Northern and Western blots for SLP-1 and SLP-2 reveal a wide but incompletely overlapping tissue distribution. Unlike SLP-1, SLP-2 is also present in mature human erythrocytes ( approximately 4,000 +/- 5,600 (+/- 2 S.D.) copies/cell). SLP-2 lacks a characteristic NH(2)-terminal hydrophobic domain found in other stomatin homologues and (unlike stomatin) is fully extractable from erythrocyte membranes by NaOH, pH 11. SLP-2 partitions into both Triton X-100-soluble and -insoluble pools in erythrocyte ghost membranes or when expressed in cultured COS cells and migrates anomalously on SDS-polyacrylamide gel electrophoresis analysis with apparent mobilities of approximately 45,500, 44,600, and 34,300 M(r). The smallest of these protein bands is believed to represent the product of alternative translation initiated at AUGs beginning with nt 217 or 391, although this point has not been rigorously proven. Collectively, these findings identify a novel and unusual member of the stomatin gene superfamily that interacts with the peripheral erythrocyte cytoskeleton and presumably other integral membrane proteins but not directly with the membrane bilayer. We hypothesize that SLP-2 may link stomatin or other integral membrane proteins to the peripheral cytoskeleton and thereby play a role in regulating ion channel conductances or the organization of sphingolipid and cholesterol-rich lipid rafts.
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Affiliation(s)
- Y Wang
- Department of Pathology Yale University School of Medicine, New Haven, Connecticut 06510, USA
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43
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Mohandas N, Gascard P. What do mouse gene knockouts tell us about the structure and function of the red cell membrane? Best Pract Res Clin Haematol 1999; 12:605-20. [PMID: 10895255 DOI: 10.1053/beha.1999.0044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Recent development of knockout mice with targeted deletion of specific genes encoding various red cell membrane proteins has added valuable armamentarium to red cell membrane structure-function studies. In this chapter we will summarize the various recent developments regarding the structure and function of the red cell membrane derived from studies using knockout mice. In addition to being expressed in red cells, all major red cell membrane proteins are also expressed in cells of various tissues. The potential use of knockout mice to decipher the biological functions of red cell membrane proteins in non-erythroid cells is also explored.
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Affiliation(s)
- N Mohandas
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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44
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Abstract
Rhesus (Rh) antigens are defined by a complex association of membrane polypeptides that are missing or severely deficient from the red cells of rare Rhnull individuals who suffer a clinical syndrome of varying severity characterized by abnormalities of the red cell shape, cation transport and membrane phospholipid organization. The Rhnull phenotype is an inherited condition that may arise from homozygosity either for a 'suppressor' gene unrelated to the RH locus ('regulator type') or for a silent allele at the RH locus itself ('amorph type'). A current model suggests that the proteins of the Rh complex (Rh, RhAG, CD47, LW, GPB) are assembled by non-covalent bonds and that it is not assembled or transported to the cell surface when one subunit is missing. Rh and RhAG proteins belong to the same protein family and are quantitatively the major components that form the core of the complex, which is firmly linked to the membrane skeleton. Molecular analysis of Rhnull individuals has revealed that abnormalities occur only at the RHAG and RH loci, without alteration of the genes encoding the accessory chains. Mutations of the RHAG gene, but not of RH, occur in all Rhnull individuals of the regulator type (including Rhmod) investigated so far (13 cases), strongly suggesting that RHAG mutants act as 'suppressors' and not as transcriptional regulators of the RH genes and that variable expression of the RHAG alleles may account for the Rhmod phenotypes (exhibiting weak expression of Rh antigens). Conversely, mutations of the RHCE gene, but not of RHAG, occur in two unrelated Rhnull individuals of the amorph type, supporting the view that RH mutants result from a 'silent' allele at the RH locus. These findings strongly support the Rh complex model since when either the Rh or RhAG protein is missing, the assembly and/or transport of the Rh complex is defective. Transcriptional as well as post-transcriptional mechanisms may account for the molecular abnormalities, but experimental evidence based on expression models is required to test these hypotheses, in the hope that they may help to clarify the biological role of the Rh proteins in the red cell membrane.
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Affiliation(s)
- J P Cartron
- INSERM Unité U76, Institut National de la Transfusion Sanguine, Paris, France
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45
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Stewart GW, Turner EJ. The hereditary stomatocytoses and allied disorders: congenital disorders of erythrocyte membrane permeability to Na and K. Best Pract Res Clin Haematol 1999; 12:707-27. [PMID: 10895260 DOI: 10.1053/beha.1999.0049] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The hereditary stomatocytoses and allied disorders are a set of dominantly inherited haemolytic anaemias in which the plasma membrane of the red cell 'leaks' sodium and potassium. There are about 10 different forms of these conditions, ranging from a moderately severe haemolytic anaemia to minor conditions in which the haematology is essentially normal, but where the patients present with pseudohyperkalaemia, due to leakage of K from the red cells on cooling to room temperature. Frequently misdiagnosed as atypical hereditary spherocytosis, these conditions can show marked thrombotic complications after splenectomy, which should be avoided. Laboratory studies of these conditions have drawn attention to a 32 kDa membrane protein, stomatin, which seems to act as a regulator of Na and K transport in human and animal tissues generally, but mutations in this gene do not cause these diseases. Genetic mapping in some kindreds, but not all, points to a mutation locus on chromosome 16.
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Affiliation(s)
- G W Stewart
- Department of Medicine, University College of London, Rayne Institute, UK.
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46
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Zhang JZ, Hayashi H, Ebina Y, Prohaska R, Ismail-Beigi F. Association of stomatin (band 7.2b) with Glut1 glucose transporter. Arch Biochem Biophys 1999; 372:173-8. [PMID: 10562431 DOI: 10.1006/abbi.1999.1489] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Employing a monoclonal antibody directed against the C-terminal peptide of glucose transporter molecule 1 (Glut1), we identified a approximately 30-kDa polypeptide which coimmunoprecipitated with Glut1 from sample of human red blood cells (RBC) membranes. The approximately 30-kDa polypeptide reacted with an antibody directed against stomatin, an integral plasma membrane protein which is also present at a high abundance in the human RBC plasma membrane. Likewise, employing anti-stomatin antibody, we found that Glut1 coimmunoprecipitated with stomatin from samples of RBC membranes. However, neither band 3, which is the most abundant integral membrane protein in the RBC, nor actin coimmunoprecipitated with Glut1, indicating a specific interaction between Glut1 and stomatin. Similar to the results obtained in the RBC, Glut1 and stomatin immunoprecipitated with each other in lysates of Clone 9 cells, a rat liver cell line in which Glut1 is expressed at approximately 1/200 the level present in RBC. Employing conditions that resulted in immunoprecipitation of approximately 10% of Glut1 in RBC membranes led to a approximately 3% coimmunoprecipitation of stomatin. A mixed population of Clone 9 cells stably transfected with a plasmid overexpressing the mouse stomatin exhibited 30 +/- 3% reduction in the basal rate of glucose transport compared to control cells or cells stably transfected with the empty vector. The above results suggest that stomatin is closely associated with Glut1 in the plasma membrane and that overexpression of stomatin results in a depression in the basal rate of glucose transport.
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Affiliation(s)
- J Z Zhang
- Departments of Medicine and of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, 44106-4951, USA
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47
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Salzer U, Kubicek M, Prohaska R. Isolation, molecular characterization, and tissue-specific expression of ECP-51 and ECP-54 (TIP49), two homologous, interacting erythroid cytosolic proteins. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1446:365-70. [PMID: 10524211 DOI: 10.1016/s0167-4781(99)00104-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We isolated two proteins, ECP-51 and ECP-54, from human erythrocyte cytosol by affinity chromatography using a peptide of the integral membrane protein stomatin as bait. Partial amino acid sequence information obtained by microsequencing allowed us to clone the respective cDNAs. Analysis of the nucleotide sequences revealed that ECP-51 and ECP-54 are homologous (44.2% amino acid identity) and contain ATP-binding sites. ECP-54 was identified as TIP49/RUVBL1/NMP238, which is a component of a large nuclear protein complex, possibly the RNA polymerase II holoenzyme; ECP-51 is a novel protein. Using the two-hybrid system, we showed that these proteins interact with each other. The interaction of ECP-51 and ECP-54 with the stomatin peptide and the localization to the nucleus and cytoplasm suggest an additional function for these proteins as chaperone components.
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Affiliation(s)
- U Salzer
- Institute of Biochemistry, Medical Faculty, University of Vienna, Austria
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