Cell-type and Tissue-specific Expression of Caveolin-2

Abstract

Caveolae are microdomains of the plasma membrane that have been implicated in organizing and compartmentalizing signal transducing molecules. Caveolin, a 21–24-kDa integral membrane protein, is a principal structural component of caveolae membranein vivo. Recently, we and other laboratories have identified a family of caveolin-related proteins; caveolin has been re-termed caveolin-1.Here, we examine the cell-type and tissue-specific expression of caveolin-2. For this purpose, we generated a novel mono-specific monoclonal antibody probe that recognizes only caveolin-2, but not caveolins-1 and -3. A survey of cell and tissue types demonstrates that the caveolin-2 protein is most abundantly expressed in endothelial cells, smooth muscle cells, skeletal myoblasts (L6, BC3H1, C2C12), fibroblasts, and 3T3-L1 cells differentiated to adipocytes. This pattern of caveolin-2 protein expression most closely resembles the cellular distribution of caveolin-1. In line with these observations, co-immunoprecipitation experiments with mono-specific antibodies directed against either caveolin-1 or caveolin-2 directly show that these molecules form a stable hetero-oligomeric complex. The in vivo relevance of this complex was further revealed by dual-labeling studies employing confocal laser scanning fluorescence microscopy. Our results indicate that caveolins 1 and 2 are strictly co-localized within the plasma membrane and other internal cellular membranes. Ultrastructurally, this pattern of caveolin-2 localization corresponds to caveolae membranes as seen by immunoelectron microscopy. Despite this strict co-localization, it appears that regulation of caveolin-2 expression occurs independently of the expression of either caveolin-1 or caveolin-3 as observed using two different model cell systems. Although caveolin-1 expression is down-regulated in response to oncogenic transformation of NIH 3T3 cells, caveolin-2 protein levels remain unchanged. Also, caveolin-2 protein levels remain unchanged during the differentiation of C2C12 cells from myoblasts to myotubes, while caveolin-3 levels are dramatically induced by this process. These results suggest that expression levels of caveolins 1, 2, and 3 can be independently up-regulated or down-regulated in response to a variety of distinct cellular cues. Caveolae are microdomains of the plasma membrane that have been implicated in organizing and compartmentalizing signal transducing molecules. Caveolin, a 21–24-kDa integral membrane protein, is a principal structural component of caveolae membranein vivo. Recently, we and other laboratories have identified a family of caveolin-related proteins; caveolin has been re-termed caveolin-1. Here, we examine the cell-type and tissue-specific expression of caveolin-2. For this purpose, we generated a novel mono-specific monoclonal antibody probe that recognizes only caveolin-2, but not caveolins-1 and -3. A survey of cell and tissue types demonstrates that the caveolin-2 protein is most abundantly expressed in endothelial cells, smooth muscle cells, skeletal myoblasts (L6, BC3H1, C2C12), fibroblasts, and 3T3-L1 cells differentiated to adipocytes. This pattern of caveolin-2 protein expression most closely resembles the cellular distribution of caveolin-1. In line with these observations, co-immunoprecipitation experiments with mono-specific antibodies directed against either caveolin-1 or caveolin-2 directly show that these molecules form a stable hetero-oligomeric complex. The in vivo relevance of this complex was further revealed by dual-labeling studies employing confocal laser scanning fluorescence microscopy. Our results indicate that caveolins 1 and 2 are strictly co-localized within the plasma membrane and other internal cellular membranes. Ultrastructurally, this pattern of caveolin-2 localization corresponds to caveolae membranes as seen by immunoelectron microscopy. Despite this strict co-localization, it appears that regulation of caveolin-2 expression occurs independently of the expression of either caveolin-1 or caveolin-3 as observed using two different model cell systems. Although caveolin-1 expression is down-regulated in response to oncogenic transformation of NIH 3T3 cells, caveolin-2 protein levels remain unchanged. Also, caveolin-2 protein levels remain unchanged during the differentiation of C2C12 cells from myoblasts to myotubes, while caveolin-3 levels are dramatically induced by this process. These results suggest that expression levels of caveolins 1, 2, and 3 can be independently up-regulated or down-regulated in response to a variety of distinct cellular cues. Caveolae are small omega-shaped indentations of the plasma membrane that have been implicated in signal transduction and vesicular transport processes (1Lisanti M.P. Scherer P. Tang Z.-L. Sargiacomo M. Trends Cell Biol. 1994; 4: 231-235Abstract Full Text PDF PubMed Scopus (597) Google Scholar, 2Couet J. Li S. Okamoto T. Scherer P.S. Lisanti M.P. Trends Cardiovasc. Med. 1997; 7: 103-110Crossref PubMed Scopus (111) Google Scholar). Caveolae are found in most cell types but are extremely abundant in terminally differentiated cell types: adipocytes (3Fan J.Y. Carpentier J.-L. van Obberghen E. Grunfeld C. Gorden P. Orci L. J. Cell Sci. 1983; 61: 219-230Crossref PubMed Google Scholar, 4Scherer P.E. Lisanti M.P. Baldini G. Sargiacomo M. Corley-Mastick C. Lodish H.F. J. Cell Biol. 1994; 127: 1233-1243Crossref PubMed Scopus (361) Google Scholar, 5Scherer P.E. Okamoto T. Chun M. Nishimoto I. Lodish H.F. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google and endothelial M. L. Cell and Google smooth muscle cells M. E. J. PubMed Scopus Google and M. S. J. 61: PubMed Scopus Google Scholar). Caveolin, a 21–24-kDa integral membrane protein, is a principal structural component of caveolae membranes in J. Biol. Full Text PDF PubMed Google Scholar, Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, Full Text PDF PubMed Scopus Google Scholar, T. P. M. J. Cell Biol. PubMed Scopus Google Scholar). of suggest that caveolin as a protein within caveolae membranes. a complex M. Scherer P.E. Tang Z.-L. E. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar, S. J. T. Biol. PubMed Scopus Google that is to the of caveolae membranes Tang Z.-L. Li S. Lisanti M.P. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google and expression of caveolin in cells is to the of E. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar, S. S. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, S. Okamoto T. Lisanti M.P. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). caveolin directly with M. J. T. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar, S. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google and M. P. S. PubMed Scopus Google it has been that the of the caveolae S. S. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). or of caveolin expression and caveolae occurs in NIH 3T3 cells by other Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). expression was in NIH 3T3 cells and with NIH 3T3 cells with as and In of caveolin protein expression revealed that the caveolin levels dramatically from to the cells that expressed or caveolin not as by Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). In caveolin expression levels with the of these cells to in the cells the of caveolin and caveolae the in These results caveolin as a Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). Recently, we have expressed caveolin in cells the of expression S. Okamoto T. Lisanti M.P. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). of caveolin expression was by and microscopy. Our results indicate that the caveolin protein is expressed using this and to the plasma of caveolin expression in and NIH 3T3 cells the of these cells in and in the of caveolae as seen by S. Okamoto T. Lisanti M.P. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). with of cell caveolin expression dramatically protein and of a S. Okamoto T. Lisanti M.P. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). to cell it appears that the of caveolin in be to to in cells S. Okamoto T. Lisanti M.P. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). In we that caveolin expression levels are down-regulated by two distinct oncogenic results indicate that of caveolin expression and caveolae be to the in cell S. Okamoto T. Lisanti M.P. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). directly with a variety of and a within caveolin has been that the of caveolin with and other This membrane of caveolin is to the of caveolin M. Scherer P.E. Tang Z.-L. E. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google and the of this the of caveolin with and S. Okamoto T. Chun M. Sargiacomo M. Nishimoto I. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, S. J. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Li S. Okamoto T. L. Sargiacomo M. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). This caveolin recognizes of these as and to with caveolin S. Okamoto T. Chun M. Sargiacomo M. Nishimoto I. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, S. J. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Li S. Okamoto T. L. Sargiacomo M. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). this caveolin is caveolin and the of caveolin with and we have this protein the or S. J. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, J. Li S. Okamoto T. T. Lisanti M.P. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). have that the caveolin other protein and to that molecules and J. Li S. Okamoto T. Scherer P.S. Lisanti M.P. Trends Cardiovasc. Med. 1997; 7: 103-110Crossref PubMed Scopus (111) Google Scholar, J. Li S. Okamoto T. T. Lisanti M.P. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). In caveolin as to the of signal transduction these molecules in the These the of caveolin expression to the of cells S. Okamoto T. Lisanti M.P. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). studies have that caveolin is only the of a family of caveolin proteins; caveolin has been re-termed caveolin-1. different caveolin and different of caveolin have been J. Li S. Okamoto T. Scherer P.S. Lisanti M.P. Trends Cardiovasc. Med. 1997; 7: 103-110Crossref PubMed Scopus (111) Google Scholar). are two of caveolin-1 and that in P.E. Tang Z.-L. Chun Sargiacomo M. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). The tissue distribution of caveolin-2 is extremely to caveolin-1 P.E. Okamoto T. Chun M. Nishimoto I. Lodish H.F. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). In caveolin-3 and protein are expressed in muscle tissue types and Scherer P.E. Tang Z.-L. Okamoto T. Li S. M. C. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Z.-L. Scherer P.E. Okamoto T. C. Nishimoto I. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, M. PubMed Scopus Google Scholar). Although caveolins-1 and are the of caveolin-2 has been by a of antibody Here, we have generated and a novel monoclonal probe that recognizes the caveolin-2 protein but not other of the caveolin this novel we the cell-type and tissue-specific expression of the caveolin-2 protein, is co-localization, and co-immunoprecipitation with a protein, and that caveolin-2 is to caveolae membranes as seen by immunoelectron microscopy. The and as we P.E. Okamoto T. Chun M. Nishimoto I. Lodish H.F. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar, Z.-L. Scherer P.E. Okamoto T. C. Nishimoto I. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, M. M. Tang Z.-L. Lisanti M.P. J. Cell Biol. PubMed Scopus Google Scholar). and as of of antibody directed against caveolin-1 A directed against caveolin-3 was as we Scherer P.E. Tang Z.-L. Okamoto T. Li S. M. C. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). The antibody was a from P.E. Scherer P.E. J. P. Lisanti M.P. Lodish H.F. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). A variety of other protein A monoclonal antibody to caveolin-2 was generated by of with a protein the caveolin-2 the of to with cells using Scholar). by and to by protein These antibodies in with and of or as P.E. Okamoto T. Chun M. Nishimoto I. Lodish H.F. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar, P.E. Tang Z.-L. Chun Sargiacomo M. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Z.-L. Scherer P.E. Okamoto T. C. Nishimoto I. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). These cells using cells expression was by by of and using the monoclonal recognizes the of in and with a tissue as P.E. Lisanti M.P. Baldini G. Sargiacomo M. Corley-Mastick C. Lodish H.F. J. Cell Biol. 1994; 127: 1233-1243Crossref PubMed Scopus (361) Google Scholar). to the was with antibodies directed against and 3T3-L1 with and in cells with and with in to with and with The cells with a of and directed against caveolin-1 and antibody and antibody The was while and antibody with with and observed a confocal fluorescence 3T3-L1 in and differentiated to the G. T. Lodish H.F. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). cells S. M. J. Biol. Full Text PDF PubMed Google from a of C2C12 cells C. 1983; Full Text PDF PubMed Scopus Google and a stable the cell myoblasts as S. M. J. Biol. Full Text PDF PubMed Google Scholar). cells in and and induced to in differentiation was by the of the cells to of the of caveolin-2 was as caveolin-1 M. Scherer P.E. Tang Z.-L. E. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). by with of was a and in a that the was in from the as by and to with to protein and to For as by the that we with and using as M.P. Tang Z.-L. Sargiacomo M. J. Cell Biol. PubMed Scopus Google with cells in a and to with or by and to with directed against caveolin-1 or caveolin-2 The as PubMed Scopus Google Scholar). in in in and using a and of and with a of and Cell Biol. PubMed Scopus Google Scholar). with antibodies and with protein A with a in from muscle with and 1 with and antibodies in and with antibody 2 further with and that and to antibody and are distinct with different in the of P.E. Okamoto T. Chun M. Nishimoto I. Lodish H.F. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google P.E. Tang Z.-L. Chun Sargiacomo M. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Z.-L. Scherer P.E. Okamoto T. C. Nishimoto I. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, M. PubMed Scopus Google Scholar). are antibody that caveolin-2. a protein the caveolin-2 protein was to a caveolin-2 monoclonal antibody demonstrates the of this novel it recognizes caveolin-2, but not caveolin-1 or -3. this novel probe can be in with other antibodies directed against caveolins-1 and P.E. Tang Z.-L. Chun Sargiacomo M. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Scherer P.E. Tang Z.-L. Okamoto T. Li S. M. C. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, L. J. Cell Biol. PubMed Scopus Google to the and expression of distinct caveolin family model cell to caveolin-2, we the expression of caveolin-2 in a variety of cell and cells The expression of caveolins-1 and are antibodies to the expressed to that caveolin-2 is most caveolin-1 a and caveolin-3 is found only within a cell line from skeletal caveolin-2 is most abundant in endothelial cells, smooth muscle cells, skeletal myoblasts and fibroblasts, and 3T3-L1 adipocytes. the expression of caveolin-2 protein most closely the distribution of caveolin-1. Also, it is to that myoblasts are the only cell line that caveolins the tissue distribution of caveolin-2 protein, we from a of different The tissue distribution of caveolins-1 are to protein in we these with is in and a of caveolin-2 expression in most tissue This is with that caveolin-2 is most abundant in differentiated 3T3-L1 and tissue P.E. Okamoto T. Chun M. Nishimoto I. Lodish H.F. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google and with that differentiated 3T3-L1 adipocytes are a of caveolae (3Fan J.Y. Carpentier J.-L. van Obberghen E. Grunfeld C. Gorden P. Orci L. J. Cell Sci. 1983; 61: 219-230Crossref PubMed Google P.E. Lisanti M.P. Baldini G. Sargiacomo M. Corley-Mastick C. Lodish H.F. J. Cell Biol. 1994; 127: 1233-1243Crossref PubMed Scopus (361) Google Scholar). 3T3-L1 a to differentiation (3Fan J.Y. Carpentier J.-L. van Obberghen E. Grunfeld C. Gorden P. Orci L. J. Cell Sci. 1983; 61: 219-230Crossref PubMed Google Scholar). These cells can be induced to a of from adipocytes. protein is induced 2 and of differentiation 3 that the expression of caveolin-2 is induced The expression of protein P. S. M. Baldini G. Lodish H.F. J. Biol. Full Text Full Text PDF PubMed Scopus Google is as a the differentiation 3 the the tissue and cellular of caveolins 1 and 2, we these two distinct caveolin in vivo. this we a of co-immunoprecipitation 3T3-L1 adipocytes and to with a directed against caveolin-1 that recognizes a that is not found in other caveolin family P.E. Tang Z.-L. Chun Sargiacomo M. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). These by using with directed against caveolin-2 and by using demonstrates that directed against caveolin-1 P.E. Tang Z.-L. Chun Sargiacomo M. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google can be to caveolins-1 and In directed against caveolin-2 can be to caveolins-1 and This is the that these antibodies are as by P.E. Tang Z.-L. Chun Sargiacomo M. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, and this it appears that caveolins 1 and 2 form a stable complex in vivo. the of caveolin-2 that a complex with a 3T3-L1 was two A was directly to the of caveolin-2 in the was with that of the with in a of the caveolin-2 signal by These results that the of caveolin-2 is with caveolin-1. further examine caveolins 1 and 2 are as a complex in cells, we with and directed against a of caveolin-1 These two antibodies experiments as in different of the antibodies with was by fluorescence microscopy. The pattern in 3T3-L1 with caveolin-2 is to observed caveolins-1 and not P.E. Okamoto T. Chun M. Nishimoto I. Lodish H.F. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar, Full Text PDF PubMed Scopus Google Scholar, T. P. M. J. Cell Biol. PubMed Scopus Google Scholar, P.E. Tang Z.-L. Chun Sargiacomo M. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Z.-L. Scherer P.E. Okamoto T. C. Nishimoto I. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, M. PubMed Scopus Google Scholar, M. M. Tang Z.-L. Lisanti M.P. J. Cell Biol. PubMed Scopus Google Scholar). small are the cell and the cell In experiments employing 3T3-L1 that caveolin-1 and caveolin-2 of these two distinct The the of the cell as caveolae are to be in this of the cell Full Text PDF PubMed Scopus Google Scholar). experiments using fluorescence of caveolins 1 and 2, we confocal laser scanning to A a of from the to the of a 3T3-L1 A of these is in that in the caveolins-1 and the pattern of that these two caveolins within the of a we the localization of caveolin-2 by immunoelectron microscopy. the distribution of caveolin-2 in a cell line and endothelial cells from a In cells, is with caveolae In endothelial cells, caveolae and of the cell by with In the the and by this of caveolae within endothelial cells is with that caveolin-2 is abundantly expressed in endothelial cells by of caveolin-1 expression appears to be a of the caveolin-1 was identified as a in cells J. Biol. Full Text PDF PubMed Google Scholar). this it has been that caveolin-1 a during cell transformation J. Biol. Full Text PDF PubMed Google Scholar, Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). In of this caveolin-1 and protein expression are or in NIH 3T3 cells by a variety of as and caveolae are from these cells Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). it caveolin-2 is down-regulated in response to oncogenic A that while caveolin-1 expression is dramatically down-regulated in and NIH 3T3 cells, caveolin-2 expression in cells and is induced in we have that these cells not caveolae Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google it appears that expression of caveolin-2 is not to caveolae caveolin-2 can be expressed within cells that caveolin-1 a complex M. Scherer P.E. Tang Z.-L. E. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar, S. J. T. Biol. PubMed Scopus Google we levels of caveolin-1 expression the of caveolin-2. we the of caveolin-2 in and NIH 3T3 cells Our results indicate that in cells that levels of caveolin-1 a of caveolin-2 was in the or This is with results that of caveolin-2 in cells and caveolin-2 P.E. Okamoto T. Chun M. Nishimoto I. Lodish H.F. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). in NIH 3T3 cells that of the caveolin-2 was within These results suggest that caveolin-1 the of that caveolins 1 and The distribution of caveolin-2 expression in cells is caveolin-2 was using that recognizes the In to caveolin-2, caveolin-2 as a in these P.E. Okamoto T. Chun M. Nishimoto I. Lodish H.F. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). the of the we that are levels of caveolin-2 in generated with in generated with caveolin-2 that the not with caveolin-2, we found this A this is in caveolin-1 to caveolin-2 to the by the this we of a cell line that a of the caveolin-1 the of the S. Okamoto T. Lisanti M.P. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). these cells levels of caveolin-1 to caveolin-1 expression levels can be dramatically induced in the of that in the of levels of small of caveolin-2 can be with of levels of caveolin-2 can be with in with of caveolin-2 caveolin-1 of caveolin-1 the of caveolin-2 signal that can be with and This is in line with that caveolin-1 to caveolin-2 the by the caveolin-2 In experiments that caveolin-2 levels and of caveolin-1 we that caveolin-2 molecules are within the caveolin-1 C2C12 cells a to skeletal These cells can be induced to from myoblasts in a of 2 S. M. J. Biol. Full Text PDF PubMed Google Scholar, C. 1983; Full Text PDF PubMed Scopus Google Scholar). and have that caveolin-3 and protein are in myoblasts and are induced during differentiation Scherer P.E. Tang Z.-L. Okamoto T. Li S. M. C. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Z.-L. Scherer P.E. Okamoto T. C. Nishimoto I. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, M. PubMed Scopus Google Scholar). In caveolin-1 expression was in either myoblasts or differentiated Scherer P.E. Tang Z.-L. Okamoto T. Li S. M. C. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Z.-L. Scherer P.E. Okamoto T. C. Nishimoto I. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). These results are with the expression of caveolin-3 in skeletal muscle and other muscle Scherer P.E. Tang Z.-L. Okamoto T. Li S. M. C. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Z.-L. Scherer P.E. Okamoto T. C. Nishimoto I. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, M. PubMed Scopus Google and suggest that caveolin-3 in muscle from the of caveolin-2 was expressed in and skeletal myoblasts we caveolin-2 is induced during differentiation of C2C12 cells from myoblasts to that caveolin-2 levels during this of a the differentiation we the of caveolin-3 within the In caveolin-3 was dramatically induced during the from myoblasts to These results suggest that the expression of caveolins 2 and 3 are independently within skeletal muscle that caveolin-2 was expressed in distinct cell (L6, BC3H1, and and within differentiated C2C12 myotubes, we the localization of caveolin-2 within skeletal muscle that caveolin-2 is expressed within the endothelial cells that line the that the muscle but not within the The distribution of caveolin-3 is that caveolin-3 is to the of the and is not within other cell of and in myoblasts and not the of expression within skeletal muscle and are a family of that to caveolae membranes from the plasma membrane and in the of molecules within 2Couet J. Li S. Okamoto T. Scherer P.S. Lisanti M.P. Trends Cardiovasc. Med. 1997; 7: 103-110Crossref PubMed Scopus (111) Google Scholar). Although caveolins-1 and are the of caveolin-2 has been by a of antibody the distribution of caveolin-2 was and a form of the protein has been expressed in cells P.E. Okamoto T. Chun M. Nishimoto I. Lodish H.F. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). Here, we have generated and a novel probe that recognizes the caveolin-2 protein but not other of the caveolin This novel probe the of caveolae in endothelial cells, and smooth and muscle cells as caveolin-2 is the most expressed caveolin family observed to is expressed in cell that to that caveolin-2 not caveolin-1 of caveolin-2 in 3T3-L1 that caveolin-2 is to the plasma membrane and internal this pattern strictly with the distribution of caveolin-1 within the In line with these observations, co-immunoprecipitation experiments that caveolins 1 and 2 form a stable hetero-oligomeric complex in vivo. This is with that the caveolins 1 and 2 are within the cell types and are during differentiation P.E. Okamoto T. Chun M. Nishimoto I. Lodish H.F. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). have the of caveolin-1 M. Scherer P.E. Tang Z.-L. E. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). This was a we the of caveolin A of experiments to that caveolin-1 as a complex. These studies in cells are in that caveolin-1 but caveolin-2 are we that caveolins-1 and are in most other cell systems. this that caveolin-1 a complex in cells M. Scherer P.E. Tang Z.-L. E. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). In we have that caveolin-1 expressed in E. and cells is to form caveolin-1 of the as caveolin-1 M. Scherer P.E. Tang Z.-L. E. Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar, S. S. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, S. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). we that the of caveolins 1 and 2 is by cellular transformation by as and caveolin-1 and protein levels are down-regulated in response to cellular transformation Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google caveolin-2 protein levels remain unchanged. these cells to caveolin-2 protein to as we have Lisanti M.P. Proc. Natl. Acad. Sci. S. PubMed Scopus Google Scholar). These suggest that caveolin-2 expression is not to the of the of that are not as by microscopy. These suggest that microdomains be with In of this we have expressed caveolin-2 in cells using expression in these cells to the of P. while expression of caveolin-1 within the cell is to the of of in S. S. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). These results are with the that caveolin-2 as in with caveolin-1. In experiments we observed a abundant and form of caveolin-2 2, and This a of caveolin-2 or be a a caveolin-1 to and P.E. Tang Z.-L. Chun Sargiacomo M. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google we the that the form of caveolin-2 is generated as a of In of this further and of the of the caveolin-2 of the The can be found are the of this is that this of caveolin-2 as is a In these two as to two distinct of caveolin-2 and this is the only the of caveolin-2 be to is a caveolin-related protein that is expressed in muscle cell types and Scherer P.E. Tang Z.-L. Okamoto T. Li S. M. C. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Z.-L. Scherer P.E. Okamoto T. C. Nishimoto I. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, M. PubMed Scopus Google Scholar). caveolin-1 is not expressed in muscle to caveolin-2 expression in skeletal cell (L6, BC3H1, and and in differentiated C2C12 caveolins-1 and are most closely and caveolin-2 is most Z.-L. Scherer P.E. Okamoto T. C. Nishimoto I. Lodish H.F. Lisanti M.P. J. Biol. Full Text Full Text PDF PubMed Scopus Google caveolin-2 in muscle as a complex with we have been to a stable caveolins 2 and 3 by co-immunoprecipitation not as caveolin-2 is not expressed within skeletal muscle 1 and 3 have from a as we have identified only two caveolins within C. and Okamoto T. P. T. Lisanti M. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). is most closely to caveolins-1 and is most closely to caveolin-2 Okamoto T. P. T. Lisanti M. J. Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). caveolin-2 appears to be and from to caveolin-2 in the regulation of caveolae membranes. of the Scherer and Lisanti laboratories and with laser scanning confocal of muscle the of of and and