151
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Endocytosis of gene delivery vectors: from clathrin-dependent to lipid raft-mediated endocytosis. Mol Ther 2013; 21:1118-30. [PMID: 23587924 DOI: 10.1038/mt.2013.54] [Citation(s) in RCA: 226] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The ideal nonviral vector delivers its nucleic acid cargo to a specific intracellular target. Vectors enter cells mainly through endocytosis and are distributed to various intracellular organelles. Recent advances in microscopy, lipidomics, and proteomics confirm that the cell membrane is composed of clusters of lipids, organized in the form of lipid raft domains, together with non-raft domains that comprise a generally disordered lipid milieu. The binding of a nonviral vector to either region can determine the pathway for its endocytic uptake and subsequent intracellular itinerary. Given this model of the cell membrane structure, endocytic pathways should be reclassified in relation to lipid rafts. In this review, we attempt to assess the currently recognized endocytic pathways in mammalian cells. The endocytic pathways are classified in relation to the membrane regions that make up the primary endocytic vesicles. This review covers the well-recognized clathrin-mediated endocytosis (CME), phagocytosis, and macropinocytosis in addition to the less addressed pathways that take place in lipid rafts. These include caveolae-mediated, flotillin-dependent, GTPase regulator associated with focal adhesion kinase-1 (GRAF1)-dependent, adenosine diphosphate-ribosylation factor 6 (Arf6)-dependent, and RhoA-dependent endocytic pathways. We summarize the regulators associated with each uptake pathway and methods for interfering with these regulators are discussed. The fate of endocytic vesicles resulting from each endocytic uptake pathway is highlighted.
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152
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Chou CT, Bhawal UK, Watanabe N, Kuboyama N, Chang WJ, Lee SY, Abiko Y. Expression of caveolin-1 in the early phase of beta-TCP implanted in dog mandible. J Biomed Mater Res B Appl Biomater 2013; 101:804-12. [PMID: 23401359 DOI: 10.1002/jbm.b.32884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 10/31/2012] [Accepted: 11/25/2012] [Indexed: 11/05/2022]
Abstract
Caveolin is an essential and signature protein of caveolae. Caveolin-1 participates in signal transduction processes by acting as a scaffolding protein that concentrates, organizes and functional regulates signalling molecules within caveolar membranes. Beta-tricalcium phosphate (β-TCP) has been widely used for scaffold in tissue engineering due to its high biodegradability, osteoconductivity, easy manipulation, and lack of histotoxicity. To better understand the role of caveolin-1 in bone homeostasis and response to β-TCP scaffold, β-TCP was implanted into the dog mandible defects in beagle dogs, and gene expression profiles were examined focused on the molecular components involved in caveolin-1 regulation. Here we showed the quantitative imageology analysis characterized using in vivo micro-computed tomography (CT) images at 4 and 7 days after β-TCP implanted in dog mandibles. The bone reformation by using the β-TCP scaffolds began within 4 days of surgery, and was healing well at 7 days after surgery. Higher mRNA level of caveolin-1 was observed in β-TCP-implanted Beagle dog mandibles compared with controls at day 4 and day 7 post-surgery. The enhancement of caveolin-1 by β-TCP was further confirmed by immunohistochemistry and immunofluorescence analysis. We further revealed increased Smad7 and Phospho Stat3 expression in β-TCP-implanted specimens. Taken together, these results suggest that the enhancement of caveolin-1 play an important role in accelerating bone formation by β-TCP.
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Affiliation(s)
- Cherng-Tzeh Chou
- Department of Biochemistry and Molecular Biology, Nihon University School of Dentistry at Matsudo, Chiba 271-8587, Japan
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153
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Taira J, Higashimoto Y. Caveolin-1 interacts with protein phosphatase 5 and modulates its activity in prostate cancer cells. Biochem Biophys Res Commun 2013; 431:724-8. [PMID: 23352616 DOI: 10.1016/j.bbrc.2013.01.051] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 01/12/2013] [Indexed: 12/31/2022]
Abstract
Caveolin-1 is highly expressed in prostate cancer cells, and is implicated in disease progression. Here, we identified protein phosphatase 5 (PP5) as a novel cellular binding partner of caveolin-1 using a pull-down approach in combination with mass spectrometry-based proteomic analyses. In situ proximity ligation assays demonstrated co-localization and physical interaction of caveolin-1 and PP5 in the cytoplasm of PC-3 human prostate cancer cells. Using yeast two-hybrid analysis, we found that caveolin-1 interacted with the catalytic domain of PP5. We also found that PP5 activity was elevated about 1.7-fold in the presence of 2 μM caveolin-1, and that the scaffolding domain of caveolin-1 is required for this activation. Our results suggest that caveolin-1 is a novel physiological activator of PP5.
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Affiliation(s)
- Junichi Taira
- Department of Chemistry, Kurume University School of Medicine, Kurume 830-0011, Japan
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154
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Inder KL, Davis M, Hill MM. Ripples in the pond--using a systems approach to decipher the cellular functions of membrane microdomains. MOLECULAR BIOSYSTEMS 2013; 9:330-8. [PMID: 23322173 DOI: 10.1039/c2mb25300c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Membrane microdomains such as lipid rafts and caveolae regulate a myriad of cellular functions including cell signalling, protein trafficking, cell viability, and cell movement. They have been implicated in diseases such as cancer, diabetes and Alzheimer's disease, highlighting the essential role they play in cell processes. Despite much research and debate on the size, composition and dynamics of membrane microdomains, the molecular mechanism(s) of their action remain poorly understood. Most studies have dealt solely with the content and properties of the membrane microdomain as an entity in itself. However, recent work shows that membrane microdomain disruption has wide ranging effects on other subcellular compartments, and the cell as a whole. Hence we propose that a systems approach incorporating many cellular attributes such as subcellular localisation is required in order to understand the global impact of microdomains on cell function. Although analysis of sub-proteome changes already provides additional insight, we further propose biological network analysis of functional proteomics data to capture effects at the systems level. In this review, we highlight the use of protein-protein interactions networks and mixed networks to portray and visualize the relationships between proteins within and between subcellular fractions. Such a systems analysis will be required to improve our understanding of the full cellular function of membrane microdomains.
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155
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PrP octarepeats region determined the interaction with caveolin-1 and phosphorylation of caveolin-1 and Fyn. Med Microbiol Immunol 2013; 202:215-27. [PMID: 23283514 DOI: 10.1007/s00430-012-0284-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 12/12/2012] [Indexed: 01/15/2023]
Abstract
Caveolin-1 is one of the major constituents of caveolae. Both Cav-1 and PrP are plasma membrane proteins, which show active capacities for molecular interactions with many other proteins or agents, including themselves. Using yeast two-hybrid system and immunoprecipitation, we reconfirmed the molecular interaction between human Cav-1 and PrP. With co-immunoprecipitation tests, PrP(C)-Cav-1 and PrP(Sc)-Cav-1 complexes were identified in the brain homogenates of normal and scrapie agent 263K-infected hamsters, respectively. Transient expression of wild-type PrP (PrP-PG5) in HEK293 cells did not change the situation of Cav-1 and subsequent signal transduction pathways, while cross-linking of the expressed PrP with specific antibody induced remarkable colocalization of PrP and Cav-1 on the plasma membrane and significant increases of phosphorylated Cav-1 and phosphorylated Fyn. With deleted and inserted PrP mutants within octarepeat region, we observed obvious octarepeat-associated phenomena, including lower binding capacity with Cav-1 in vitro, unable to co-localize with Cav-1 in the cells and to induce up-regulation of p-Cav-1 and p-Fyn when removal of octarepeats in the context of full-length PrP. Moreover, we found that treatment on HEK293 cells with fibrous form of recombinant PrP protein led to up-regulating the levels of p-Cav-1 and p-Fyn. Our data here provide strong evidence that octarepeats of PrP are critical for the interaction between PrP and Cav-1. Significant alterations in the cultured cells, either the distributions of PrP and Cav-1 morphologically or the up-regulations of p-Cav-1 and p-Fyn, induced by antibody-mediated cross-linking or fibrous forms of PrP may suggest a possible internalization process of PrP(Sc).
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156
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Mandarin fish caveolin 1 interaction with major capsid protein of infectious spleen and kidney necrosis virus and its role in early stages of infection. J Virol 2013; 87:3027-38. [PMID: 23283951 DOI: 10.1128/jvi.00552-12] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Infectious spleen and kidney necrosis virus (ISKNV) is the type species of the genus Megalocytivirus from the family Iridoviridae. ISKNV is one of the major agents that cause mortality and economic losses to the freshwater fish culture industry in Asian countries, particularly for mandarin fish (Siniperca chuatsi). In the present study, we report that the interaction of mandarin fish caveolin 1 (mCav-1) with the ISKNV major capsid protein (MCP) was detected by using a virus overlay assay and confirmed by pulldown assay and coimmunoprecipitation. This interaction was independent of the classic caveolin 1 scaffolding domain (CSD), which is responsible for interacting with several signaling proteins and receptors. Confocal immunofluorescence microscopy showed that ISKNV MCP colocalized with mCav-1 in the perinuclear region of virus-infected mandarin fish fry (MFF-1) cells, which appeared as soon as 4 h postinfection. Subcellular fractionation analysis showed that ISKNV MCP was associated with caveolae in the early stages of viral infection. RNA interference silencing of mCav-1 did not change virus-cell binding but efficiently inhibited the entry of virions into the cell. Taken together, these results suggested that mCav-1 plays an important role in the early stages of ISKNV infection.
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157
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Kline CF, Mohler PJ. Evolving form to fit function: cardiomyocyte intercalated disc and transverse-tubule membranes. CURRENT TOPICS IN MEMBRANES 2013; 72:121-58. [PMID: 24210429 DOI: 10.1016/b978-0-12-417027-8.00004-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The vertebrate cardiac myocyte has evolved a highly organized cellular membrane architecture and cell-cell contacts in order to effectively transmit precisely timed and homogeneous depolarizing waves without failure (>2 billion times/human life span). Two unique specialized membrane domains, the intercalated disc and the transverse tubule (T-tubule), function to ensure the rapid and coordinated propagation of the action potential throughout the heart. Based on their critical roles in structure, signaling, and electric inter- and intracellular communication, it is not surprising that dysfunction in these membrane structures is associated with aberrant vertebrate physiology, resulting in potentially fatal congenital and acquired disease. This chapter will review the fundamental components of cardiomyocyte intercalated disc and transverse-tubule membranes with a focus on linking dysfunction in these membranes with human cardiovascular disease.
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Affiliation(s)
- Crystal F Kline
- The Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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158
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The Role of Cholesterol in Prostate Cancer. Prostate Cancer 2013. [DOI: 10.1007/978-1-4614-6828-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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159
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Turk HF, Chapkin RS. Membrane lipid raft organization is uniquely modified by n-3 polyunsaturated fatty acids. Prostaglandins Leukot Essent Fatty Acids 2013; 88:43-7. [PMID: 22515942 PMCID: PMC3404206 DOI: 10.1016/j.plefa.2012.03.008] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 03/27/2012] [Accepted: 03/28/2012] [Indexed: 01/20/2023]
Abstract
Fish oil, enriched in bioactive n-3 polyunsaturated fatty acids (PUFA), has been shown to play a role in prevention of colon cancer. The effects of n-3 PUFA are pleiotropic and multifaceted, resulting in an incomplete understanding of their molecular mechanisms of action. Here, we focus on a highly conserved mechanism of n-3 PUFA, which is the alteration of the organization of the plasma membrane. We highlight recent work demonstrating that enrichment of n-3 PUFA in the plasma membrane alters the lateral organization of membrane signaling assemblies (i.e. lipid rafts). This mechanism is central for n-3 PUFA regulation of downstream signaling, T-cell activation, transcriptional activation, and cytokine secretion. We conclude that these studies provide strong evidence for a predominant mechanism by which n-3 PUFA function in colon cancer prevention.
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Affiliation(s)
- Harmony F Turk
- Program in Integrative Nutrition and Complex Diseases and the Center for Environmental and Rural Health, Texas A&M University, College Station, TX 77843, USA
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160
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Abstract
Tissue factor (TF) is a transmembrane glycoprotein and an essential component of the factor VIIa-TF enzymatic complex that triggers activation of the coagulation cascade. Formation of TF-FVIIa complexes on cell surfaces not only trigger the coagulation cascade but also transduce cell signaling via activation of protease-activated receptors. Tissue factor is expressed constitutively on cell surfaces of a variety of extravascular cell types, including fibroblasts and pericytes in and surrounding blood vessel walls and epithelial cells, but is generally absent on cells that come into contact with blood directly. However, TF expression could be induced in some blood cells, such as monocytes and endothelial cells, following an injury or pathological stimuli. Tissue factor is essential for hemostasis, but aberrant expression of TF leads to thrombosis. Therefore, a proper regulation of TF activity is critical for the maintenance of hemostatic balance and health in general. TF-FVIIa coagulant activity at the cell surface is influenced not only by TF protein expression levels but also independently by a variety of mechanisms, including alterations in membrane phospholipid composition and cholesterol content, thiol-dependent modifications of TF allosteric disulfide bonds, and other post-translational modifications of TF. In this article, we critically review the key literature on mechanisms by which TF coagulant activity is regulated at the cell surface in the absence of changes in TF protein levels with specific emphasis on recently published data and provide the authors' perspective on the subject.
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Affiliation(s)
- L V M Rao
- Department of Cellular and Molecular Biology, Center for Biomedical Research, The University of Texas Health Science Center, Tyler, TX, USA
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161
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Wu Q, Wu S. Lipid rafts association and anti-apoptotic function of prohibitin in ultraviolet B light-irradiated HaCaT keratinocytes. Exp Dermatol 2012; 21:640-2. [PMID: 22776003 DOI: 10.1111/j.1600-0625.2012.01547.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Upon UVB irradiation, an alternation of major lipid raft components can lead to the recruitment/activation of rafts-associated proteins and initiation of downstream apoptotic signalling pathways. We used two-dimensional gel electrophoresis (2-DE) to identify potential regulators of UVB-induced apoptosis and mass spectrometry fingerprint analysis to identify proteins that are altered in the rafts after UVB irradiation. Our data show that levels of several proteins, including prohibitin (PHB), were changed in lipid rafts after UVB irradiation. We also demonstrate that while total PHB expression was not changed, the protein was enriched in lipid rafts after UVB irradiation. Reduced expression of PHB using siRNA knockdown resulted in an increase in cellular apoptosis after UVB irradiation. Based on these results, we propose that PHB protects keratinocytes from UVB-induced apoptosis.
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Affiliation(s)
- Qiong Wu
- Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, USA
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162
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Stary CM, Tsutsumi YM, Patel PM, Head BP, Patel HH, Roth DM. Caveolins: targeting pro-survival signaling in the heart and brain. Front Physiol 2012; 3:393. [PMID: 23060817 PMCID: PMC3464704 DOI: 10.3389/fphys.2012.00393] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 09/14/2012] [Indexed: 12/20/2022] Open
Abstract
The present review discusses intracellular signaling moieties specific to membrane lipid rafts (MLRs) and the scaffolding proteins caveolin and introduces current data promoting their potential role in the treatment of pathologies of the heart and brain. MLRs are discreet microdomains of the plasma membrane enriched in gylcosphingolipids and cholesterol that concentrate and localize signaling molecules. Caveolin proteins are necessary for the formation of MLRs, and are responsible for coordinating signaling events by scaffolding and enriching numerous signaling moieties in close proximity. Specifically in the heart and brain, caveolins are necessary for the cytoprotective phenomenon termed ischemic and anesthetic preconditioning. Targeted overexpression of caveolin in the heart and brain leads to induction of multiple pro-survival and pro-growth signaling pathways; thus, caveolins represent a potential novel therapeutic target for cardiac and neurological pathologies.
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Affiliation(s)
- Creed M Stary
- Department of Anesthesiology, Veterans Affairs San Diego Healthcare System, University of California San Diego, La Jolla, CA, USA
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163
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Garris DR, Novikova L, Garris BL, Lau YS. Hypercytolipidemia-induced nuclear lipoapoptosis: cytochemical analysis and integrated review of hypogonadal, diabetes-obesity syndrome-induced female reproductive axis disruption. Metab Syndr Relat Disord 2012; 2:198-209. [PMID: 18370687 DOI: 10.1089/met.2004.2.198] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Expression of the diabetes (db/db) mutation (i.e., leptin receptor defect) in C57BL/KsJ mice results in the functional suppression of the female pituitary-gonadal axis accompanied by premature utero-ovarian lipocytoatrophy. The current studies define the cytostructural, metabolic and endocrine disturbances associated with hypercytolipidemia and coincident nuclear lipoapoptosis following expression of the db/db-mutation. Adult, female C57BL/KsJ control (+/+ and +/? genotypes) and db/db mutant littermates were monitored for systemic alterations in blood glucose, insulin, luteinizing hormone (LH) and 17-B-estradiol (E2) concentrations associated with db/db-enhanced cytolipid depositions and TUNEL-labeled 3'-DNA fragmentation indexed nuclear lipoapoptosis. Obesity, hyperglycemia and hyperinsulinemia, in addition to depressed LH and E2 concentrations, characterized all db/db-mutants relative to control indices. Structural and cytochemical analysis of basophilic gonadotroph cells, ovarian follicular granulosa cells and uterine endometrial epithelial layers indicated that db/db mutants demonstrated prominent hypercytolipidemia relative to control cytoarchitecture profiles. Vasolipidemia and interstitial cytoadiposity were prominent in all db/db tissue compartments. In each affected cell type within the db/db pituitary-reproductive tract axis, hypercytolipidemia was localized with pronounced nuclear lipo-infiltration and 3'-DNA TUNEL-labeled fragmentation. These data indicate that coincident cytostructural, endocrine and metabolic disturbances associated with hypogonadal pituitary-reproductive tract hypercytolipidemia are functional manifestations of the expressed diabetes-obesity syndrome in db/db-mutants. The progressive vaso-, interstitial-, and cyto-lipidemic alterations in cytoarchitecture correlated with the coincident nuclear lipoapoptotic dissolution and pronounced organo-involution, alterations which contributed to the functional disruption of the pituitary-hypogonadal axis in C57BL/KsJ-db/db mice.
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Affiliation(s)
- David R Garris
- Divisions of Cell Biology and Biophysics and Pharmacology, Schools of Biological Sciences, Pharmacy and Medicine, University of Missouri-Kansas City, Kansas City, Missouri
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164
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Lokappa SB, Nagaraj R. Interaction of peptides spanning the transmembrane domain of caveolin-1 with model membranes. J Pept Sci 2012; 18:696-703. [DOI: 10.1002/psc.2457] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 08/29/2012] [Accepted: 08/30/2012] [Indexed: 01/17/2023]
Affiliation(s)
- Sowmya Bekshe Lokappa
- CSIR-Centre for Cellular and Molecular Biology; Uppal Road; Hyderabad; 500 007; India
| | - Ramakrishnan Nagaraj
- CSIR-Centre for Cellular and Molecular Biology; Uppal Road; Hyderabad; 500 007; India
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165
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Li X, Gulbins E, Zhang Y. Oxidative stress triggers Ca-dependent lysosome trafficking and activation of acid sphingomyelinase. Cell Physiol Biochem 2012; 30:815-26. [PMID: 22890197 PMCID: PMC3777434 DOI: 10.1159/000341460] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2012] [Indexed: 12/27/2022] Open
Abstract
Recent studies demonstrate that rapid translocation of the acid sphingomyelinase (ASM), a lysosomal hydrolase, to the outer leaflet of the cell membrane and concomitant release of ceramide constitute a common cellular signaling cascade to various stimuli including CD95 ligation, UV-irradiation, bacterial and viral infections. Reactive oxygen species (ROS) were shown to play a crucial role in regulating this signaling cascade at least for some bacterial infections and UV-irradiation. However, the precise role of ROS for regulation of ASM is unknown. Here, by confocal microscopy and flow cytometry analysis, we demonstrate that hydrogen peroxide (H(2)O(2)), a primary form of ROS in mammalian cells, induces very rapid translocation of ASM and formation of ceramide-enriched membrane platforms in the plasma membrane of Jurkat T cells. In parallel, H(2)O(2) triggers lysosome trafficking and fusion with the plasma membrane, i.e. lysosome exocytosis, as detected by exposure of a lysosome-associated protein, LAMP1. Depletion of intracellular Ca(2+) by cell permeable EGTA-AM inhibits H(2)O(2)-induced lysosome exocytosis, ASM translocation and formation of ceramide-enriched platforms. Pharmacological inhibition or genetic deficiency of ASM did not affect H(2)O(2)-induced lysosome exocytosis. These results indicate that ROS-induced membrane translocation of ASM is mediated by exocytosis of lysosomes, which is dependent on intracellular Ca(2+) release.
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Affiliation(s)
- Xiang Li
- Department of Pharmacology & Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, U.S.A
| | - Erich Gulbins
- Institute of Molecular Biology, University of Duisburg-Essen, Hufelandstr. 55, Essen, Germany
| | - Yang Zhang
- Department of Pharmacology & Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, U.S.A
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166
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Zagorac GB, Mahmutefendić H, Tomaš MI, Kučić N, Le Bouteiller P, Lučin P. Early endosomal rerouting of major histocompatibility class I conformers. J Cell Physiol 2012; 227:2953-64. [PMID: 21959869 DOI: 10.1002/jcp.23042] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Major histocompatibility class I (MHC-I) molecules are present at the cell surface both as fully conformed trimolecular complexes composed of heavy chain (HC), beta-2-microglobulin (β2m) and peptide, and various open forms, devoid of peptide and/or β2m (open MHC-I conformers). Fully conformed MHC-I complexes and open MHC-I conformers can be distinguished by well characterized monoclonal antibody reagents that recognize their conformational difference in the extracellular domain. In the present study, we used these tools in order to test whether conformational difference in the extracellular domain determines endocytic and endosomal route of plasma membrane (PM) proteins. We analyzed PM localization, internalization, endosomal trafficking, and recycling of human and murine MHC-I proteins on various cell lines. We have shown that fully conformed MHC-I and open MHC-I conformers segregate at the PM and during endosomal trafficking resulting in the exclusion of open MHC-I conformers from the recycling route. This segregation is associated with their partitioning into the membranes of different compositions. As a result, the open MHC-I conformers internalized with higher rate than fully conformed counterparts. Thus, our data suggest the existence of conformation-based protein sorting mechanism in the endosomal system.
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167
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Matrix metalloproteinase-2-mediated occludin degradation and caveolin-1-mediated claudin-5 redistribution contribute to blood-brain barrier damage in early ischemic stroke stage. J Neurosci 2012; 32:3044-57. [PMID: 22378877 DOI: 10.1523/jneurosci.6409-11.2012] [Citation(s) in RCA: 314] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Blood-brain barrier (BBB) disruption occurs early enough to be within the thrombolytic time window, and this early ischemic BBB damage is closely associated with hemorrhagic transformation and thus emerging as a promising target for reducing the hemorrhagic complications of thrombolytic stroke therapy. However, the mechanisms underlying early ischemic BBB damage remain poorly understood. Here, we investigated the early molecular events of ischemic BBB damage using in vitro oxygen-glucose deprivation (OGD) and in vivo rat middle cerebral artery occlusion (MCAO) models. Exposure of bEND3 monolayer to OGD for 2 h significantly increased its permeability to FITC-labeled dextran and promoted the secretion of metalloproteinase-2 and -9 (MMP-2/9) and cytosolic translocation of caveolin-1 (Cav-1). This same OGD treatment also led to rapid degradation of tight junction protein occludin and dissociation of claudin-5 from the cytoskeleton, which contributed to OGD-induced endothelial barrier disruption. Using selective MMP-2/9 inhibitor SB-3CT (2-[[(4-phenoxyphenyl)sulfonyl]methyl]-thiirane) or their neutralizing antibodies or Cav-1 siRNA, we found that MMP-2 was the major enzyme mediating OGD-induced occludin degradation, while Cav-1 was responsible for claudin-5 redistribution. The interaction between Cav-1 and claudin-5 was further confirmed by coimmunoprecipitation. Consistent with these in vitro findings, we observed fluorescence tracer extravasation, increased gelatinolytic activity, and elevated interstitial MMP-2 levels in ischemic subcortical tissue after 2 h MCAO. Moreover, occludin protein loss and claudin-5 redistribution were detected in ischemic cerebromicrovessels. These data indicate that cerebral ischemia initiates two rapid parallel processes, MMP-2-mediated occludin degradation and Cav-1-mediated claudin-5 redistribution, to cause BBB disruption at early stroke stages relevant to acute thrombolysis.
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168
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Arielly SS, Ariel M, Yehuda R, Scigelova M, Yehezkel G, Khalaila I. Quantitative analysis of caveolin-rich lipid raft proteins from primary and metastatic colorectal cancer clones. J Proteomics 2012; 75:2629-37. [PMID: 22484058 DOI: 10.1016/j.jprot.2012.03.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 01/26/2012] [Accepted: 03/08/2012] [Indexed: 12/26/2022]
Abstract
Caveolin-rich lipid rafts (CLRs) are thickened sections of the cell membrane that are composed of the integral membrane proteins caveolins together with saturated long chain fatty acids, cholesterol and lipids. Membrane proteins - lipid raft proteins in particular - may play important roles in cell signaling and cell-cell interaction. Due to their unique structure, CLRs seem to be the preferred docking site for specific proteins involved in focal adhesion and cancer metastasis. Our objective was thus to identify and quantify CLR proteins from primary and metastatic colorectal cancer (CRC) clones. We found differential expression of nine CLR proteins from primary and metastatic CRC clones. Among the identified proteins, an immune system inhibiting protein was significantly overexpressed in the metastatic clone, while cell adhesion and transport molecules were among the overexpressed proteins in the primary clone. All the identified CRL proteins are involved in tumorigenesis, specifically metastasis, and may thus serve as therapeutic targets. A novel concept for identification and quantification of CLR proteins with label-free mass spectrometry method was specifically examined in this study. Validation of the method against immunoblotting and FACS analysis indicates that it can be applied for the identification of novel biomarkers for cancer and metastasis.
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Affiliation(s)
- Shirley S Arielly
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
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169
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Chen Z, Bakhshi FR, Shajahan AN, Sharma T, Mao M, Trane A, Bernatchez P, van Nieuw Amerongen GP, Bonini MG, Skidgel RA, Malik AB, Minshall RD. Nitric oxide-dependent Src activation and resultant caveolin-1 phosphorylation promote eNOS/caveolin-1 binding and eNOS inhibition. Mol Biol Cell 2012; 23:1388-98. [PMID: 22323292 PMCID: PMC3315804 DOI: 10.1091/mbc.e11-09-0811] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The mechanism of caveolin-1–dependent eNOS inactivation is not clear. These studies reveal that NO-mediated Src kinase activation and caveolin-1 phosphorylation promote eNOS binding and inactivation, that is, eNOS negative feedback regulation. Endothelial nitric oxide synthase (eNOS)–mediated NO production plays a critical role in the regulation of vascular function and pathophysiology. Caveolin-1 (Cav-1) binding to eNOS holds eNOS in an inactive conformation; however, the mechanism of Cav-1–mediated inhibition of activated eNOS is unclear. Here the role of Src-dependent Cav-1 phosphorylation in eNOS negative feedback regulation is investigated. Using fluorescence resonance energy transfer (FRET) and coimmunoprecipitation analyses, we observed increased interaction between eNOS and Cav-1 following stimulation of endothelial cells with thrombin, vascular endothelial growth factor, and Ca2+ ionophore A23187, which is corroborated in isolated perfused mouse lung. The eNOS/Cav-1 interaction is blocked by eNOS inhibitor l-NG-nitroarginine methyl ester (hydrochloride) and Src kinase inhibitor 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo [3, 4-d] pyrimidine. We also observe increased binding of phosphomimicking Y14D-Cav-1 mutant transduced in human embryonic kidney cells overexpressing eNOS and reduced Ca2+-induced NO production compared to cells expressing the phosphodefective Y14F-Cav-1 mutant. Finally, Src FRET biosensor, eNOS small interfering RNA, and NO donor studies demonstrate NO-induced Src activation and Cav-1 phosphorylation at Tyr-14, resulting in increased eNOS/Cav-1 interaction and inhibition of eNOS activity. Taken together, these data suggest that activation of eNOS promotes Src-dependent Cav-1–Tyr-14 phosphorylation and eNOS/Cav-1 binding, that is, eNOS feedback inhibition.
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Affiliation(s)
- Zhenlong Chen
- Department of Pharmacology, University of Illinois, Chicago, IL 60612, USA
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170
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Annexin A2 is involved in the formation of hepatitis C virus replication complex on the lipid raft. J Virol 2012; 86:4139-50. [PMID: 22301157 DOI: 10.1128/jvi.06327-11] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The hepatitis C virus (HCV) RNA replicates in hepatic cells by forming a replication complex on the lipid raft (detergent-resistant membrane [DRM]). Replication complex formation requires various viral nonstructural (NS) proteins as well as host cellular proteins. In our previous study (C. K. Lai, K. S. Jeng, K. Machida, and M. M. Lai, J. Virol. 82:8838-8848, 2008), we found that a cellular protein, annexin A2 (Anxa2), interacts with NS3/NS4A. Since NS3/NS4A is a membranous protein and Anxa2 is known as a lipid raft-associated scaffold protein, we postulate that Anxa2 helps in the formation of the HCV replication complex on the lipid raft. Further studies showed that Anxa2 was localized at the HCV-induced membranous web and interacted with NS4B, NS5A, and NS5B and colocalized with them in the perinuclear region. The silencing of Anxa2 decreased the formation of membranous web-like structures and viral RNA replication. Subcellular fractionation and bimolecular fluorescence complementation analysis revealed that Anxa2 was partially associated with HCV at the lipid raft enriched with phosphatidylinositol-4-phosphate (PI4P) and caveolin-2. Further, the overexpression of Anxa2 in HCV-nonsusceptible HEK293 cells caused the enrichment of HCV NS proteins in the DRM fraction and increased the colony-forming ability of the HCV replicon. Since Anxa2 is known to induce the formation of the lipid raft microdomain, we propose that Anxa2 recruits HCV NS proteins and enriches them on the lipid raft to form the HCV replication complex.
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171
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Mialet-Perez J, D'Angelo R, Villeneuve C, Ordener C, Nègre-Salvayre A, Parini A, Vindis C. Serotonin 5-HT2A receptor-mediated hypertrophy is negatively regulated by caveolin-3 in cardiomyoblasts and neonatal cardiomyocytes. J Mol Cell Cardiol 2012; 52:502-10. [DOI: 10.1016/j.yjmcc.2011.07.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Revised: 07/19/2011] [Accepted: 07/21/2011] [Indexed: 01/10/2023]
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172
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Agnati LF, Guidolin D, Leo G, Guescini M, Pizzi M, Stocchi V, Spano PF, Ghidoni R, Ciruela F, Genedani S, Fuxe K. Possible new targets for GPCR modulation: allosteric interactions, plasma membrane domains, intercellular transfer and epigenetic mechanisms. J Recept Signal Transduct Res 2012; 31:315-31. [PMID: 21929287 DOI: 10.3109/10799893.2011.599393] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
It has been estimated that at least 50% of the drugs available on the market act on G-protein coupled receptors (GPCRs) and most of these are basically or agonists or antagonists of this type of receptors. Herein, we propose new putative targets for drug development based on recent data on GPCR allosterism and on the existence of receptor mosaics (RMs). The main target for drug development is still GPCRs, but the focus is not the orthosteric binding pocket. According to the mosaic model of the plasma membrane, we mainly discuss the possibility of indirect modulatory pharmacological actions on expression/function of GPCRs. In particular, the following two new targets will be analyzed: a) The possibility of pharmacological interventions on the roamer-type of volume transmission (VT), which allow the intercellular transfer of set of signal molecules such as GPCRs, tetraspanins and ribonucleic acids. Thus, there is the possibility of pharmacological interventions on the decoding capabilities of neurons and/or glial cells by means of an action on composition and release of micro-vesicles. b) The possibility of pharmacological interventions on epigenetic mechanisms by taking into account their inter-relationships with GPCRs. As a matter of fact, there are epigenetic changes that are characteristic of periods of developmental plasticity that could provide a target for therapeutic intervention in the event of brain damage. We believe that almost all the biochemical knowledge presently available on GPCRs can be used in the development of these new pharmacological approaches.
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173
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Chambaut-Guérin AM, Pairault J. Tumour necrosis factor α-induced adipose-related protein (TIARP): co-localization with caveolin-1. Biol Cell 2012; 97:339-47. [PMID: 15836432 DOI: 10.1042/bc20040062] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We previously identified TIARP (TNF(alpha)-induced adipose-related protein, where TNF(alpha) stands for tumour necrosis factor alpha), a novel plasma-membrane protein that is induced during 3T3-L1 preadipocytes differentiation by TNF(alpha). Whereas the biological function of TIARP is currently unknown, its protein sequence is reminiscent of transporter protein and/or NAD(P)/NAD(P)H-dependent oxidoreductase activities. We hypothesized that TIARP could be associated with the 3T3-L1 adipocyte plasma-membrane caveolae domains that contain many proteins involved in cellular trafficking and signalling processes. Studies by confocal microscopy showed that TIARP and caveolin-1, a major protein of caveolae, co-localized as patches at the plasma membrane. Immunoblot analysis of cell extracts indicated that TIARP was completely detergent-extractible from membranes, whereas caveolin-1 was present as both detergent-extractible and -insoluble pools. Since TIARP is compartmentalized with caveolin-1 within caveolae domains, we suggest this protein to be part of a signalling complex in association with caveolin-1 and regulatory proteins.
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Affiliation(s)
- Anne-Marie Chambaut-Guérin
- Laboratoire de Physiologie et Physiopathologie, Centre de Recherche Biomédicale des Cordeliers, UMR 7079 CNRS-Université Paris VI, 15 rue de l'Ecole de Médecine, 75270 Paris Cedex 06, France.
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174
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Caveolin-1 and breast cancer: a new clinical perspective. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 729:83-94. [PMID: 22411315 DOI: 10.1007/978-1-4614-1222-9_6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The current chapter focuses on the role of Caveolin-1 (Cav-1) in cellular growth with an emphasis on its implication in breast cancer initiation, progression, clinical prognosis and as a potential therapeutic target. The role of Cav-1 as a tumor suppressor in breast cancer has emerged in the past few years, with dual functions on both cancer epithelium as well as the cancer stroma. Its multiple functions as a regulator of estrogen signaling and kinase activity and its newly found role as an important factor controlling the dynamic relationship between cancer epithelia and stroma position Cav-1 as a new therapeutic target for the treatment of breast cancer.
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175
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Reeves VL, Thomas CM, Smart EJ. Lipid rafts, caveolae and GPI-linked proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 729:3-13. [PMID: 22411310 DOI: 10.1007/978-1-4614-1222-9_1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Lipid rafts and caveolae are specialized membrane microdomains enriched in sphingolipids and cholesterol. They function in a variety of cellular processes including but not limited to endocytosis, transcytosis, signal transduction and receptor recycling. Here, we outline the similarities and differences between lipid rafts and caveolae as well as discuss important components and functions of each.
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176
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Caveolae and the regulation of endocytosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 729:14-28. [PMID: 22411311 DOI: 10.1007/978-1-4614-1222-9_2] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Although clathrin-mediated endocytosis constitutes the main pathway for internalization of extracellular ligands and plasma membrane components it has generally been accepted that other uptake mechanisms-caveolae-mediated and noncaveolar raft-dependent endocytosis-also exist. During the last 20 years many papers have been published about caveolar endocytosis. These studies have fundamentally changed our view about the endocytotic role of caveolae. Views that caveolae are permanently static structures1 have been extensively considered and rejected. Although the initial steps leading to the pinching off of caveolae from the plasma membrane have been studied in details, there are still contradictory data about the intracellular trafficking of caveolae. It is still not entirely clear whether caveolar endocytosis represents an uptake pathway with distinct cellular compartments to avoid lysosomal degradation or ligands taken up by caveolae can also be targeted to late endosomes/lysosomes.In this chapter, we summarize the data available about caveolar endocytosis focusing on the intracellular route of caveolae and we provide data supporting that caveolar endocytosis can join the classical endocytotic pathway.
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177
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Sonnino S, Prioni S, Chigorno V, Prinetti A. Interactions Between Caveolin-1 and Sphingolipids, and Their Functional Relevance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 749:97-115. [DOI: 10.1007/978-1-4614-3381-1_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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178
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The role of lipid rafts in cancer cell adhesion and migration. Int J Cell Biol 2011; 2012:763283. [PMID: 22253629 PMCID: PMC3255102 DOI: 10.1155/2012/763283] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 09/20/2011] [Accepted: 09/21/2011] [Indexed: 01/06/2023] Open
Abstract
Lipid rafts are cholesterol-enriched microdomains of the cell membrane and possess a highly dynamic nature. They have been involved in various cellular functions including the regulation of cell adhesion and membrane signaling through proteins within lipid rafts. The dynamic features of the cancer cell surface may modulate the malignant phenotype of cancer, including adhesion disorders and aggressive phenotypes of migration and invasion. Recently, it was demonstrated that lipid rafts play critical roles in cancer cell adhesion and migration. This article summarizes the important roles of lipid rafts in cancer cell adhesion and migration, with a focus on the current state of knowledge. This article will improve the understanding of cancer progression and lead to the development of novel targets for cancer therapy.
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179
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Catalgol B, Kartal Ozer N. Lipid rafts and redox regulation of cellular signaling in cholesterol induced atherosclerosis. Curr Cardiol Rev 2011; 6:309-24. [PMID: 22043207 PMCID: PMC3083812 DOI: 10.2174/157340310793566181] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Revised: 06/13/2010] [Accepted: 06/17/2010] [Indexed: 02/06/2023] Open
Abstract
Redox mediated signaling mechanisms play crucial roles in the pathogenesis of several cardiovascular diseases. Atherosclerosis is one of the most important disorders induced mainly by hypercholesterolemia. Oxidation products and related signaling mechanisms are found within the characteristic biomarkers of atherosclerosis. Several studies have shown that redox signaling via lipid rafts play a significant role in the regulation of pathogenesis of many diseases including atherosclerosis. This review attempts to summarize redox signaling and lipid rafts in hypercholesterolemia induced atherosclerosis.
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Affiliation(s)
- Betul Catalgol
- Department of Biochemistry, Faculty of Medicine, Marmara University, 34668 Haydarpasa, Istanbul, Turkey
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180
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Sotgia F, Martinez-Outschoorn UE, Howell A, Pestell RG, Pavlides S, Lisanti MP. Caveolin-1 and cancer metabolism in the tumor microenvironment: markers, models, and mechanisms. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2011; 7:423-67. [PMID: 22077552 DOI: 10.1146/annurev-pathol-011811-120856] [Citation(s) in RCA: 224] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Caveolins are a family of membrane-bound scaffolding proteins that compartmentalize and negatively regulate signal transduction. Recent studies have implicated a loss of caveolin-1 (Cav-1) expression in the pathogenesis of human cancers. Loss of Cav-1 expression in cancer-associated fibroblasts results in an activated tumor microenvironment, thereby driving early tumor recurrence, metastasis, and poor clinical outcome in breast and prostate cancers. We describe various paracrine signaling mechanism(s) by which the loss of stromal Cav-1 promotes tumor progression, including fibrosis, extracellular matrix remodeling, and the metabolic/catabolic reprogramming of cancer-associated fibroblast, to fuel the growth of adjacent tumor cells. It appears that oxidative stress is the root cause of initiation of the loss of stromal Cav-1 via autophagy, which provides further impetus for the use of antioxidants in anticancer therapy. Finally, we discuss the functional role of Cav-1 in epithelial cancer cells.
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Affiliation(s)
- Federica Sotgia
- The Jefferson Stem Cell Biology and Regenerative Medicine Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
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181
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Salem AF, Bonuccelli G, Bevilacqua G, Arafat H, Pestell RG, Sotgia F, Lisanti MP. Caveolin-1 promotes pancreatic cancer cell differentiation and restores membranous E-cadherin via suppression of the epithelial-mesenchymal transition. Cell Cycle 2011; 10:3692-700. [PMID: 22041584 DOI: 10.4161/cc.10.21.17895] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Pancreatic cancer is one of the deadliest cancers due to early rapid metastasis and chemoresistance. Recently, epithelial to mesenchymal transition (EMT) was shown to play a key role in the pathogenesis of pancreatic cancer. To understand the role of caveolin-1 (Cav-1) in EMT, we over-expressed Cav-1 in a pancreatic cancer cell line, Panc 10.05, that does not normally express Cav-1. Here, we show that Cav-1 expression in pancreatic cancer cells induces an epithelial phenotype and promotes cell-cell contact, with increased expression of plasma membrane bound E-cadherin and beta-catenin. Mechanistically, Cav-1 induces Snail downregulation and decreased activation of AKT, MAPK and TGF-beta-Smad signaling pathways. In vitro, Cav-1 expression reduces cell migration and invasion, and attenuates doxorubicin-chemoresistance of pancreatic cancer cells. Importantly, in vivo studies revealed that Cav-1 expression greatly suppresses tumor formation in a xenograft model. Most interestingly, Panc/Cav-1 tumors displayed organized nests of differentiated cells that were totally absent in control tumors. Confirming our in vitro results, these nests of differentiated cells showed reexpression of E-cadherin and beta-catenin at the cell membrane. Thus, we provide evidence that Cav-1 functions as a crucial modulator of EMT and cell differentiation in pancreatic cancer.
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Affiliation(s)
- Ahmed F Salem
- Department of Stem Cell Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
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182
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Augsten M, Hackl H, Ebner B, Chemelli A, Glatter O, Marsche G, Lang U, Desoye G, Wadsack C. Fetal HDL/apoE: a novel regulator of gene expression in human placental endothelial cells. Physiol Genomics 2011; 43:1255-62. [DOI: 10.1152/physiolgenomics.00109.2011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Maternal lipoproteins have been studied extensively in human pregnancies, but little is known about the role of fetal lipoproteins. The vascularized human placenta interfaces between the mother and fetus to transfer nutrients for sustaining pregnancy. Unlike that of adults, fetal high-density lipoprotein (HDL), which is in contact with placental vessels, is characterized by a high proportion of apolipoprotein E (apoE). We hypothesize this unique composition of fetal HDL affects key functions of the growing fetal tissues. The aim was to identify genes regulated by apoE-HDL by incubating human placental endothelial cells (HPEC) with either fetal HDL or apoE-rich reconstituted HDL particles (apoE-rHDL). HPEC were exposed to 15 μg/ml fetal HDL, 15 μg/ml apoE-rHDL, or medium for 16 h, respectively. Microarray analysis determined genes regulated by fetal HDL and apoE. Characterization of HDL particles revealed a different hydrodynamic radius for apoE-rHDL (13.70 nm) compared with fetal HDL (18.11 nm). Stepwise gene clustering after microarray experiments identified 79 differentially expressed genes ( P < 0.05) when cells were exposed to HDL compared with controls. Among them 16 genes were downregulated, whereas five genes were upregulated by twofold, respectively. When HPEC were incubated with apoE-rHDL 18-fold more genes (1,417, 12% of transcripts) were regulated ( P < 0.05) in contrast to HDL. Thereof, 172 genes were downregulated and 376 genes upregulated (twofold). In the common subset of 38 genes regulated by both HDL particles, genes involved in cholesterol biosynthesis and cell protection prevailed. Strikingly, results suggest that HDL has the capability of regulating metallothioneins, which may have an effect on oxidative stress in HPEC.
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Affiliation(s)
- Manuela Augsten
- Clinic of Obstetrics and Gynaecology, Medical University of Graz, Graz
| | - Hubert Hackl
- Division of Bioinformatics, Biocenter, Innsbruck Medical University, Innsbruck
| | - Birgit Ebner
- Center of Medical Research, Medical University of Graz
| | - Angela Chemelli
- Department of Chemistry, Karl-Franzens University of Graz; and
| | - Otto Glatter
- Department of Chemistry, Karl-Franzens University of Graz; and
| | - Gunther Marsche
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - Uwe Lang
- Clinic of Obstetrics and Gynaecology, Medical University of Graz, Graz
| | - Gernot Desoye
- Clinic of Obstetrics and Gynaecology, Medical University of Graz, Graz
| | - Christian Wadsack
- Clinic of Obstetrics and Gynaecology, Medical University of Graz, Graz
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183
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Delgado-Coello B, Briones-Orta MA, Macías-Silva M, Mas-Oliva J. Cholesterol: recapitulation of its active role during liver regeneration. Liver Int 2011; 31:1271-84. [PMID: 21745289 DOI: 10.1111/j.1478-3231.2011.02542.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Liver regeneration is a compensatory hyperplasia produced by several stimuli that promotes proliferation in order to provide recovery of the liver mass and architecture. This process involves complex signalling cascades that receive feedback from autocrine and paracrine pathways, recognized by parenchymal as well as non-parenchymal cells. Nowadays the dynamic role of lipids in biological processes is widely recognized; however, a systematic analysis of their importance during liver regeneration is still missing. Therefore, in this review we address the role of lipids including the bioactive ones such as sphingolipids, but with special emphasis on cholesterol. Cholesterol is not only considered as a structural component but also as a relevant lipid involved in the control of the intermediate metabolism of different liver cell types such as hepatocytes, hepatic stellate cells and Kupffer cells. Cholesterol plays a significant role at the level of specific membrane domains, as well as modulating the expression of sterol-dependent proteins. Moreover, several enzymes related to the catabolism of cholesterol and whose activity is down regulated are related to the protection of liver tissue from toxicity during the process of regeneration. This review puts in perspective the necessity to study and understand the basic mechanisms involving lipids during the process of liver regeneration. On the other hand, the knowledge acquired in this area in the past years, can be considered invaluable in order to provide further insights into processes such as general organogenesis and several liver-related pathologies, including steatosis and fibrosis.
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Affiliation(s)
- Blanca Delgado-Coello
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, DF Mexico
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184
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Clarion L, Schindler M, de Weille J, Lolmède K, Laroche-Clary A, Uro-Coste E, Robert J, Mersel M, Bakalara N. 7β-Hydroxycholesterol-induced energy stress leads to sequential opposing signaling responses and to death of C6 glioblastoma cells. Biochem Pharmacol 2011; 83:37-46. [PMID: 21983033 DOI: 10.1016/j.bcp.2011.09.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 09/20/2011] [Accepted: 09/21/2011] [Indexed: 11/25/2022]
Abstract
7β-Hydroxycholesterol cytotoxicity has been shown in vivo and in vitro to be dependent on the accumulation of its esters. We show in our study, using a detergent-free raft preparation and LC/MS lipid content analysis, that membrane microdomains isolated from 7β-hydroxycholesterol-treated C6 cells have a reduced cholesterol: cholesterol ester ratio and accumulate 7keto-hydroxycholesterol, 7β-hydroxycholesterol and 7β-hydroxycholesterol esters. These modifications in lipid content are accompanied by a redistribution of flotillin-1 in the lipid rafts. Transient increases of AMPK phosphorylation and mitochondrial activity during the first 12 h of 7β-hydroxycholesterol treatment indicate that C6 cells undergo energy stress and increase oxidative phosphorylation. Even so, ATP levels are maintained during 15 h until glucose uptake decreases. The cell's answers to raft modifications and energy stress are sequential activations of different signaling pathways such as ERK, AMPK and PI3K/Akt. These pathways, known to be activated under energy stress conditions, are transiently activated at 6 h (ERK, AMPK) and 12 h (Akt) of treatment respectively suggesting a shift from cell survival to cell proliferation. The persistence of 7β-hydroxycholesterol-induced stress led after 24 h to P38 activation, loss of GSK3β activation and to cell death. Finally we demonstrate that the observed signaling responses depend on 7β-hydroxycholesterol esterification, confirming that esterification of 7β-hydroxycholesterol is essential for cytotoxicity.
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185
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Prinetti A, Cao T, Illuzzi G, Prioni S, Aureli M, Gagliano N, Tredici G, Rodriguez-Menendez V, Chigorno V, Sonnino S. A glycosphingolipid/caveolin-1 signaling complex inhibits motility of human ovarian carcinoma cells. J Biol Chem 2011; 286:40900-10. [PMID: 21949119 DOI: 10.1074/jbc.m111.286146] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The genetic (stable overexpression of sialyltransferase I, GM3 synthase) or pharmacological (selective pressure by N-(4-hydroxyphenyl)retinamide)) manipulation of A2780 human ovarian cancer cells allowed us to obtain clones characterized by higher GM3 synthase activity compared with wild-type cells. Clones with high GM3 synthase expression had elevated ganglioside levels, reduced in vitro cell motility, and enhanced expression of the membrane adaptor protein caveolin-1 with respect to wild-type cells. In high GM3 synthase-expressing clones, both depletion of gangliosides by treatment with the glucosylceramide synthase inhibitor D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol and silencing of caveolin-1 by siRNA were able to strongly increase in vitro cell motility. The motility of wild-type, low GM3 synthase-expressing cells was reduced in the presence of a Src inhibitor, and treatment of these cells with exogenous gangliosides, able to reduce their in vitro motility, inactivated c-Src kinase. Conversely, ganglioside depletion by D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol treatment or caveolin-1 silencing in high GM3 synthase-expressing cells led to c-Src kinase activation. In high GM3 synthase-expressing cells, caveolin-1 was associated with sphingolipids, integrin receptor subunits, p130(CAS), and c-Src forming a Triton X-100-insoluble noncaveolar signaling complex. These data suggest a role for gangliosides in regulating tumor cell motility by affecting the function of a signaling complex organized by caveolin-1, responsible for Src inactivation downstream to integrin receptors, and imply that GM3 synthase is a key target for the regulation of cell motility in human ovarian carcinoma.
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Affiliation(s)
- Alessandro Prinetti
- Department of Medical Chemistry, Biochemistry and Biotechnology, University of Milan, 20090 Segrate, Italy.
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186
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Biochemical and molecular aspects of vascular adrenergic regulation of blood pressure in the elderly. Int J Hypertens 2011; 2012:915057. [PMID: 21961055 PMCID: PMC3179865 DOI: 10.1155/2012/915057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 07/28/2011] [Indexed: 01/08/2023] Open
Abstract
Hypertension, orthostatic hypotension, arterial insufficiency, and atherosclerosis are common disorders in the elderly that lead to significant morbidity and mortality. One common factor to these conditions is an age-related decline in vascular beta-adrenergic receptor-mediated function and subsequent cAMP generation. Presently, there is no single cellular factor that can explain this age-related decline, and thus, the primary cause of this homeostatic imbalance is yet to be identified. However, the etiology is clearly associated with an age-related change in the ability of beta-adrenergic receptor to respond to agonist at the cellular level in the vasculature. This paper will review what is presently understood regarding the molecular and biochemical basis of age-impaired beta-adrenergic receptor-mediated signaling. A fundamental understanding of why β-AR-mediated vasorelaxation is impaired with age will provide new insights and innovative strategies for the management of multiple clinical disorders.
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187
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Patani N, Martin LA, Reis-Filho JS, Dowsett M. The role of caveolin-1 in human breast cancer. Breast Cancer Res Treat 2011; 131:1-15. [PMID: 21901387 DOI: 10.1007/s10549-011-1751-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 08/18/2011] [Indexed: 02/06/2023]
Abstract
Caveolin-1 is the essential constituent protein of specialised plasma membrane invaginations called caveolae. The unique topology of caveolin-1 facilitates the role of caveolae as molecular hubs, integrating the activity of a multitude of signalling molecules. Despite improvements in our understanding of caveolin-1 interactions and the function of caveolae, the relationship between dysfunctional caveolin-1 and tumourigenesis remains contentious. Perhaps most intriguing has been the demonstration of both oncogenic and tumour suppressor function within particular tumour types, including breast cancer. In this review, the biological and clinical relevance of caveolin-1 in human breast cancer are considered. Evidence is systematically presented for the potential tumour suppressor and oncogenic functions of caveolin-1. Specific reference is made to interactions between caveolin-1 and signalling pathways in the clinical and biological subtypes of breast cancer. Areas of controversy are discussed and technical considerations are highlighted. Translational implications and potential for specific therapeutic manipulation of caveolin-1 are evaluated in the context of evidence from in vitro and in vivo studies.
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Affiliation(s)
- Neill Patani
- The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research, London SW3 6JB, UK
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188
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Tomassian T, Humphries LA, Liu SD, Silva O, Brooks DG, Miceli MC. Caveolin-1 orchestrates TCR synaptic polarity, signal specificity, and function in CD8 T cells. THE JOURNAL OF IMMUNOLOGY 2011; 187:2993-3002. [PMID: 21849673 DOI: 10.4049/jimmunol.1101447] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
TCR engagement triggers the polarized recruitment of membrane, actin, and transducer assemblies within the T cell-APC contact that amplify and specify signaling cascades and T effector activity. We report that caveolin-1, a scaffold that regulates polarity and signaling in nonlymphoid cells, is required for optimal TCR-induced actin polymerization, synaptic membrane raft polarity, and function in CD8, but not CD4, T cells. In CD8(+) T cells, caveolin-1 ablation selectively impaired TCR-induced NFAT-dependent NFATc1 and cytokine gene expression, whereas caveolin-1 re-expression promoted NFATc1 gene expression. Alternatively, caveolin-1 ablation did not affect TCR-induced NF-κB-dependent Iκbα expression. Cav-1(-/-) mice did not efficiently promote CD8 immunity to lymphocytic choriomeningitis virus, nor did cav-1(-/-) OT-1(+) CD8(+) T cells efficiently respond to Listeria monocytogenes-OVA after transfer into wild-type hosts. Therefore, caveolin-1 is a T cell-intrinsic orchestrator of TCR-mediated membrane polarity and signal specificity selectively employed by CD8 T cells to customize TCR responsiveness.
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Affiliation(s)
- Tamar Tomassian
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine and College of Letters and Sciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
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189
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Zhang L, Wang Y, Wang L, Cao T, Hyuga S, Sato T, Wu Y, Yamagata S, Yamagata T. Ganglioside GD1a negatively regulates hepatocyte growth factor expression through caveolin-1 at the transcriptional level in murine osteosarcoma cells. Biochim Biophys Acta Gen Subj 2011; 1810:759-68. [DOI: 10.1016/j.bbagen.2011.04.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 04/10/2011] [Accepted: 04/20/2011] [Indexed: 01/24/2023]
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190
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Head BP, Hu Y, Finley JC, Saldana MD, Bonds JA, Miyanohara A, Niesman IR, Ali SS, Murray F, Insel PA, Roth DM, Patel HH, Patel PM. Neuron-targeted caveolin-1 protein enhances signaling and promotes arborization of primary neurons. J Biol Chem 2011; 286:33310-21. [PMID: 21799010 DOI: 10.1074/jbc.m111.255976] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Decreased expression of prosurvival and progrowth-stimulatory pathways, in addition to an environment that inhibits neuronal growth, contribute to the limited regenerative capacity in the central nervous system following injury or neurodegeneration. Membrane/lipid rafts, plasmalemmal microdomains enriched in cholesterol, sphingolipids, and the protein caveolin (Cav) are essential for synaptic development/stabilization and neuronal signaling. Cav-1 concentrates glutamate and neurotrophin receptors and prosurvival kinases and regulates cAMP formation. Here, we show that primary neurons that express a synapsin-driven Cav-1 vector (SynCav1) have increased raft formation, neurotransmitter and neurotrophin receptor expression, NMDA- and BDNF-mediated prosurvival kinase activation, agonist-stimulated cAMP formation, and dendritic growth. Moreover, expression of SynCav1 in Cav-1 KO neurons restores NMDA- and BDNF-mediated signaling and enhances dendritic growth. The enhanced dendritic growth occurred even in the presence of inhibitory cytokines (TNFα, IL-1β) and myelin-associated glycoproteins (MAG, Nogo). Targeting of Cav-1 to neurons thus enhances prosurvival and progrowth signaling and may be a novel means to repair the injured and neurodegenerative brain.
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Affiliation(s)
- Brian P Head
- Department of Anesthesiology, University of California, San Diego, La Jolla, California 92093, USA.
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191
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Arpaia E, Blaser H, Quintela-Fandino M, Duncan G, Leong HS, Ablack A, Nambiar SC, Lind EF, Silvester J, Fleming CK, Rufini A, Tusche MW, Brüstle A, Ohashi PS, Lewis JD, Mak TW. The interaction between caveolin-1 and Rho-GTPases promotes metastasis by controlling the expression of alpha5-integrin and the activation of Src, Ras and Erk. Oncogene 2011; 31:884-96. [PMID: 21765460 PMCID: PMC3289793 DOI: 10.1038/onc.2011.288] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Proteins containing a caveolin-binding domain (CBD), such as the Rho-GTPases, can interact with caveolin-1 (Cav1) through its caveolin scaffold domain. Rho-GTPases are important regulators of p130(Cas), which is crucial for both normal cell migration and Src kinase-mediated metastasis of cancer cells. However, although Rho-GTPases (particularly RhoC) and Cav1 have been linked to cancer progression and metastasis, the underlying molecular mechanisms are largely unknown. To investigate the function of Cav1-Rho-GTPase interaction in metastasis, we disrupted Cav1-Rho-GTPase binding in melanoma and mammary epithelial tumor cells by overexpressing CBD, and examined the loss-of-function of RhoC in metastatic cancer cells. Cancer cells overexpressing CBD or lacking RhoC had reduced p130(Cas) phosphorylation and Rac1 activation, resulting in an inhibition of migration and invasion in vitro. The activity of Src and the activation of its downstream targets FAK, Pyk2, Ras and extracellular signal-regulated kinase (Erk)1/2 were also impaired. A reduction in α5-integrin expression, which is required for binding to fibronectin and thus cell migration and survival, was observed in CBD-expressing cells and cells lacking RhoC. As a result of these defects, CBD-expressing melanoma cells had a reduced ability to metastasize in recipient mice, and impaired extravasation and survival in secondary sites in chicken embryos. Our data indicate that interaction between Cav1 and Rho-GTPases (most likely RhoC but not RhoA) promotes metastasis by stimulating α5-integrin expression and regulating the Src-dependent activation of p130(Cas)/Rac1, FAK/Pyk2 and Ras/Erk1/2 signaling cascades.
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Affiliation(s)
- E Arpaia
- The Campbell Family Institute for Breast Cancer Research, University Health Network, Toronto, Ontario, Canada
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192
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Taira J, Sugishima M, Kida Y, Oda E, Noguchi M, Higashimoto Y. Caveolin-1 is a competitive inhibitor of heme oxygenase-1 (HO-1) with heme: identification of a minimum sequence in caveolin-1 for binding to HO-1. Biochemistry 2011; 50:6824-31. [PMID: 21721581 DOI: 10.1021/bi200601t] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Heme oxygenase (HO) catalyzes the O(2)-dependent degradation of heme to biliverdin IXα, carbon monoxide (CO), and free ferrous iron through a multistep mechanism. Electrons required for HO catalysis in mammals are provided by NADPH-cytochrome P450 reductase. Recently, Kim et al. reported for the first time that HO, especially inducible HO-1, appears in caveolae and showed that caveolin-1, a principal isoform of the caveolin family, physically interacts with HO-1 [ Jung , N. H. et al. ( 2003 ) IUBMB Life 55 , 525 - 532 ; Kim , H. P. et al. ( 2004 ) FASEB J. 18 , 1080 - 1089 ]. In the present study, we confirmed by immunoprecipitation experiments that rat HO-1 and rat caveolin-1 (residues 1-101) directly interact with each other and that the HO-1 activity is inhibited by caveolin-1 (1-101). The 82-101 residues of caveolin-1 (CAV(82-101)), called the caveolin scaffolding domain, play essential roles in caveolin-related protein-protein interactions. The HO-1 activity is also inhibited by CAV(82-101) in a competitive manner with hemin, and a hemin titration experiment showed that CAV(82-101) interferes with hemin binding to HO-1. The enzyme kinetics and surface plasmon resonance experiments gave comparable K(i) and K(D) values of 5.2 and 1.0 μM for CAV(82-101), respectively, with respect to the interaction with HO-1. These observations indicated that CAV(82-101) and hemin share a common binding site within the HO-1 protein. The identified caveolin binding motif (FLLNIELF) of rat HO-1 is incomplete compared to the proposed consensus sequence. The affinity between HO-1 and CAV(82-101), however, was almost completely or remarkably eliminated by replacement of Phe(207) and/or Phe(214) with Ala, indicating that HO-1 binds to caveolin-1 via this motif. Among the peptide fragments derived from CAV(82-101), i.e., CAV(82-91), CAV(87-96), CAV(92-101), and CAV(97-101), CAV(92-101) and CAV(97-101) are able to inhibit the HO-1 activity to a similar extent; thus, the five-amino acid sequence (residues 97-101) is considered to be a minimum sequence for binding to HO-1.
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Affiliation(s)
- Junichi Taira
- Department of Chemistry, Kurume University School of Medicine, Kurume 830-0011, Japan
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193
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Sheriff DS, Ali EF. Perspective on plasma membrane cholesterol efflux and spermatozoal function. J Hum Reprod Sci 2011; 3:68-75. [PMID: 21209749 PMCID: PMC2970794 DOI: 10.4103/0974-1208.69337] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 07/29/2010] [Accepted: 08/05/2010] [Indexed: 01/05/2023] Open
Abstract
The process of sperm maturation, capacitation, and fertilization occur in different molecular milieu provided by epididymis and female reproductive tract including oviduct. The different tissue environment with different oxygen tension and temperature may still influence the process of sperm maturation and capacitation. Reactive oxygen species (ROS) is reported to be an initial switch that may activate the molecular process of capacitation. Therefore, the generation of reactive oxygen species and its possible physiological role depends upon a balance between its formation and degradation in an open environment provided by female reproductive tract. The sensitivity of the spermatozoa to the action of ROS may be due to its exposure for the first time to an oxygen rich external milieu compared to its internal milieu in the male reproductive tract. Reduced temperature in testicular environment coupled with reduced oxygen tension may be the right molecular environment for the process of spermatogenesis and spermiogenesis. The morphologically mature spermatozoa then may attain its motility in an environment provided by the caput epididymis wherein, the dyenin motor can become active. This ability to move forward will make the spermatozoa physiologically fit to undertake its sojourn in the competitive race of fertilization in a new oxygen rich female reproductive tract. The first encounter may be oxygen trigger or preconditioning of the spermatozoa with reactive oxygen species that may alter the spermatozoal function. Infertility is still one of the major global health problems that need medical attention. Apart from the development of artificial methods of reproduction and development of newer techniques in the field of andrology focuses attention on spermatozoal structure and metabolism. Therefore, understanding the molecular mechanisms involved in fertilization in general and that of sperm capacitation in particular may help lead to new and better techniques for enhancing fertility, identifying and treating certain forms of male infertility, and preventing conception. One remarkable insight is the importance of membrane cholesterol efflux in initiating transmembrane signaling events that confer fertilization competence. The identity of the physiologically relevant cholesterol acceptors and modulators of cholesterol efflux is therefore of great interest. Still, it is clear that cholesterol efflux represents only a part of this story. The involvement of phospholipid translocation in mediating dynamic changes in the membrane, rendering it conducive to transmembrane signaling, and the modulation of membrane components of signal transduction cascades by cholesterol or phospholipids will yield important insights into the links between environmental sensing and transmembrane signaling in the sperm. Understanding the membrane molecular events will ultimately provide new and exciting areas of investigation for the future
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194
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Al-Qusairi L, Laporte J. T-tubule biogenesis and triad formation in skeletal muscle and implication in human diseases. Skelet Muscle 2011; 1:26. [PMID: 21797990 PMCID: PMC3156648 DOI: 10.1186/2044-5040-1-26] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 07/13/2011] [Indexed: 12/25/2022] Open
Abstract
In skeletal muscle, the excitation-contraction (EC) coupling machinery mediates the translation of the action potential transmitted by the nerve into intracellular calcium release and muscle contraction. EC coupling requires a highly specialized membranous structure, the triad, composed of a central T-tubule surrounded by two terminal cisternae from the sarcoplasmic reticulum. While several proteins located on these structures have been identified, mechanisms governing T-tubule biogenesis and triad formation remain largely unknown. Here, we provide a description of triad structure and plasticity and review the role of proteins that have been linked to T-tubule biogenesis and triad formation and/or maintenance specifically in skeletal muscle: caveolin 3, amphiphysin 2, dysferlin, mitsugumins, junctophilins, myotubularin, ryanodine receptor, and dihydhropyridine Receptor. The importance of these proteins in triad biogenesis and subsequently in muscle contraction is sustained by studies on animal models and by the direct implication of most of these proteins in human myopathies.
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Affiliation(s)
- Lama Al-Qusairi
- Department of Translational Medecine and Neurogenetics, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), 1 rue Laurent Fries, 67404 Illkirch, France.
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195
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Heidari A, Behmanesh M, Sahraian M, Meshkani R, Darvish H, Najmabadi H, Ohadi M. The human caveolin 1 gene upstream purine complex and neurodegeneration—A common signature. J Neuroimmunol 2011; 236:106-10. [DOI: 10.1016/j.jneuroim.2011.05.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Revised: 05/08/2011] [Accepted: 05/09/2011] [Indexed: 11/17/2022]
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196
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Somara S, Bashllari D, Gilmont RR, Bitar KN. Real-time dynamic movement of caveolin-1 during smooth muscle contraction of human colon and aged rat colon transfected with caveolin-1 cDNA. Am J Physiol Gastrointest Liver Physiol 2011; 300:G1022-32. [PMID: 21372166 PMCID: PMC3119117 DOI: 10.1152/ajpgi.00301.2010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Caveolin-1 (cav-1) plays a key role in PKC-α and RhoA signaling pathways during acetylcholine (ACh)-induced contraction of colonic smooth muscle cells (CSMC). Aged rat CSMC showed sluggish contractility, concomitant with reduced expression of cav-1 with an associated reduction in activation of PKC-α and RhoA signaling pathway. Real-time monitoring of live human CSMC transfected with yellow fluorescent protein-tagged wild-type caveolin 1 cDNA (YFP-wt-cav-1) cDNA in the present study suggests that cav-1 cycles within and along the membrane in a synchronized, highly organized cytoskeletal path. These studies provide, for the first time, the advantages of real-time monitoring of the dynamic movement of caveolin in living cells. Rapid movement of cav-1 in response to ACh suggests its dynamic role in CSMC contraction. Human CSMC transfected with YFP-ΔTFT-cav-1 dominant negative cDNA show fluorescence in the cytosol of the CSMC and no movement of fluorescent cav-1 in response to ACh mimicking the response shown by aged rat CSMC. Transfection of CSMC from aged rat with YFP-wt-cav-1 cDNA restored the physiological contractile response to ACh as well as the dynamic movement of cav-1 along the organized cytoskeletal path observed in normal adult CSMC. To study the force generation by CSMC, three-dimensional colonic rings were bioengineered. Colonic bioengineered rings from aged CSMC showed reduced force generation compared with colonic bioengineered rings from adult CSMC. Colonic bioengineered rings from aged CSMC transfected with wt-cav-1 cDNA showed force generation similar to colonic bioengineered rings from adult rat CSMC. The data suggest that contraction in CSMC is dependent on cav-1 reorganization dynamics, which restores the physiological contractile response in aged CSMC. We hypothesize that dynamic movement of cav-1 is essential for physiological contractile response of colonic smooth muscle.
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Affiliation(s)
- Sita Somara
- Gastrointestinal Molecular Motors Laboratory, Department of Pediatrics, Gastroenterology, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Daniela Bashllari
- Gastrointestinal Molecular Motors Laboratory, Department of Pediatrics, Gastroenterology, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Robert R. Gilmont
- Gastrointestinal Molecular Motors Laboratory, Department of Pediatrics, Gastroenterology, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Khalil N. Bitar
- Gastrointestinal Molecular Motors Laboratory, Department of Pediatrics, Gastroenterology, University of Michigan Medical Center, Ann Arbor, Michigan
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197
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Cell-specific dual role of caveolin-1 in pulmonary hypertension. Pulm Med 2011; 2011:573432. [PMID: 21660237 PMCID: PMC3109422 DOI: 10.1155/2011/573432] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2011] [Accepted: 03/10/2011] [Indexed: 12/15/2022] Open
Abstract
A wide variety of cardiopulmonary and systemic diseases are known to lead to pulmonary hypertension (PH). A number of signaling pathways have been implicated in PH; however, the precise mechanism/s leading to PH is not yet clearly understood. Caveolin-1, a membrane scaffolding protein found in a number of cells including endothelial and smooth muscle cells, has been implicated in PH. Loss of endothelial caveolin-1 is reported in clinical and experimental forms of PH. Caveolin-1, also known as a tumor-suppressor factor, interacts with a number of transducing molecules that reside in or are recruited to caveolae, and it inhibits cell proliferative pathways. Not surprisingly, the rescue of endothelial caveolin-1 has been found not only to inhibit the activation of proliferative pathways but also to attenuate PH. Recently, it has emerged that during the progression of PH, enhanced expression of caveolin-1 occurs in smooth muscle cells, where it facilitates cell proliferation, thus contributing to worsening of the disease. This paper summarizes the cell-specific dual role of caveolin-1 in PH.
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198
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Wilson KA, Colavito SA, Schulz V, Wakefield PH, Sessa W, Tuck D, Stern DF. NFBD1/MDC1 regulates Cav1 and Cav2 independently of DNA damage and p53. Mol Cancer Res 2011; 9:766-81. [PMID: 21551225 DOI: 10.1158/1541-7786.mcr-10-0317] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
NFBD1/MDC1 is involved in DNA damage checkpoint signaling and DNA repair. NFBD1 binds to the chromatin component γH2AX at sites of DNA damage, causing amplification of ataxia telangiectasia-mutated gene (ATM) pathway signaling and recruitment of DNA repair factors. Residues 508-995 of NFBD1 possess transactivation activity, suggesting a possible role of NFBD1 in transcription. Furthermore, NFBD1 influences p53-mediated transcription in response to adriamycin. We sought to determine the role of NFBD1 in ionizing radiation (IR)-responsive transcription and if NFBD1 influences transcription independently of p53. Using microarray analysis, we identified genes altered upon NFBD1 knockdown. Surprisingly, most NFBD1 regulated genes are regulated in both the absence and presence of IR, thus pointing toward a novel function for NFBD1 outside of the DNA damage response. Furthermore, NFBD1 knockdown regulated genes mostly independent of p53 knockdown. These genes are involved in pathways including focal adhesion signaling, carbohydrate metabolism, and insulin signaling. We found that CAV1 and CAV2 mRNA and protein levels are reduced by both NFBD1 knockdown and knockout independently of IR and p53. NFBD1-depleted cells exhibit some similar phenotypes to Cav1-depleted cells. Furthermore, like Cav1-depletion, NFBD1 shRNA increases Erk phosphorylation. Thus, Cav1 could act as a mediator of the DNA-damage independent effects of NFBD1 in mitogenic signaling.
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Affiliation(s)
- Kathleen A Wilson
- Yale University, 333 Cedar Street, P.O. Box 208023, New Haven, CT 06520, USA
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199
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Kim BW, Lee CS, Yi JS, Lee JH, Lee JW, Choo HJ, Jung SY, Kim MS, Lee SW, Lee MS, Yoon G, Ko YG. Lipid raft proteome reveals that oxidative phosphorylation system is associated with the plasma membrane. Expert Rev Proteomics 2011; 7:849-66. [PMID: 21142887 DOI: 10.1586/epr.10.87] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Although accumulating proteomic analyses have supported the fact that mitochondrial oxidative phosphorylation (OXPHOS) complexes are localized in lipid rafts, which mediate cell signaling, immune response and host-pathogen interactions, there has been no in-depth study of the physiological functions of lipid-raft OXPHOS complexes. Here, we show that many subunits of OXPHOS complexes were identified from the lipid rafts of human adipocytes, C2C12 myotubes, Jurkat cells and surface biotin-labeled Jurkat cells via shotgun proteomic analysis. We discuss the findings of OXPHOS complexes in lipid rafts, the role of the surface ATP synthase complex as a receptor for various ligands and extracellular superoxide generation by plasma membrane oxidative phosphorylation complexes.
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Affiliation(s)
- Bong-Woo Kim
- College of Life Sciences and Biotechnology, Korea University, 1, 5-ka, Anam-dong, Sungbuk-ku, Seoul, Korea
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200
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Jean-Mairet RM, López-Menéndez C, Sánchez-Ruiloba L, Sacristán S, Rodríguez-Martínez M, Riol-Blanco L, Sánchez-Mateos P, Sánchez-Madrid F, Rodríguez-Fernández JL, Campanero MR, Iglesias T. The neuronal protein Kidins220/ARMS associates with ICAM-3 and other uropod components and regulates T-cell motility. Eur J Immunol 2011; 41:1035-46. [PMID: 21381019 DOI: 10.1002/eji.201040513] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 12/06/2010] [Accepted: 01/25/2011] [Indexed: 01/17/2023]
Abstract
Kinase D interacting substrate of 220 kDa (Kidins220), also known as ankyrin repeat-rich membrane spanning (ARMS), is a protein that is mainly expressed in brain and neural cells where its function is only starting to be characterized. Here, we show that Kidins220/ARMS is also expressed in T lymphocytes where it is highly concentrated at the uropod of polarized T cells. In this cellular model, Kidins220/ARMS colocalizes with typical uropod T-cell molecules and coimmunoprecipitates with ICAM-3. Furthermore, Kidins220/ARMS associates with raft domains at the uropod and coimmunoprecipitates with caveolin-1, a molecule we show here to be also expressed in T cells. Importantly, induction of morphological polarization in primary T lymphocytes and Jurkat cells enhances Kidins220/ARMS colocalization with ICAM-3. Conversely, disruption of cell polarity provokes Kidins220/ARMS redistribution from the uropod to other cellular regions and drastically impairs its association with ICAM-3 in a protein kinase C-dependent manner. Finally, Kidins220/ARMS knockdown in human polarized T-cell lines promotes both basal and stromal cell-derived factor-1α-induced directed migration, identifying a novel function for this molecule. Altogether, our findings show that Kidins220/ARMS is a novel component of the uropod involved in the regulation of T-cell motility, an essential process for the immune response.
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Affiliation(s)
- Roberto Martín Jean-Mairet
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
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