The Stomatin/Prohibitin/Flotillin/HflK/C Domain of Flotillin-1 Contains Distinct Sequences That Direct Plasma Membrane Localization and Protein Interactions in 3T3-L1 Adipocytes

Abstract

Flotillin-1 is a lipid raft-associated protein that has been implicated in various cellular processes. We examined the subcellular distribution of flotillin-1 in different cell types and found that localization is cell type-specific. Flotillin-1 relocates from a cytoplasmic compartment to the plasma membrane upon the differentiation of 3T3-L1 adipocytes. To delineate the structural determinants necessary for its localization, we generated a series of truncation mutants of flotillin-1. Wild type flotillin-1 has two putative hydrophobic domains and is localized to lipid raft microdomains at the plasma membrane. Flotillin-1 fragments lacking the N-terminal hydrophobic stretch are excluded from the lipid raft compartments but remain at the plasma membrane. On the other hand, mutants with the second hydrophobic region deleted fail to traffic to the plasma membrane but are instead found in intracellular granule-like structures. Flotillin-1 specifically interacts with the adaptor protein CAP, the Src family kinase Fyn, and cortical F-actin in lipid raft microdomains in adipocytes. Furthermore, CAP and Fyn associate with different regions in the N-terminal sequences of flotillin-1. These results furthered our understanding for how flotillin-1 can function as a molecular link between lipid rafts of the plasma membrane and a multimeric signaling complex at the actin cytoskeleton. Flotillin-1 is a lipid raft-associated protein that has been implicated in various cellular processes. We examined the subcellular distribution of flotillin-1 in different cell types and found that localization is cell type-specific. Flotillin-1 relocates from a cytoplasmic compartment to the plasma membrane upon the differentiation of 3T3-L1 adipocytes. To delineate the structural determinants necessary for its localization, we generated a series of truncation mutants of flotillin-1. Wild type flotillin-1 has two putative hydrophobic domains and is localized to lipid raft microdomains at the plasma membrane. Flotillin-1 fragments lacking the N-terminal hydrophobic stretch are excluded from the lipid raft compartments but remain at the plasma membrane. On the other hand, mutants with the second hydrophobic region deleted fail to traffic to the plasma membrane but are instead found in intracellular granule-like structures. Flotillin-1 specifically interacts with the adaptor protein CAP, the Src family kinase Fyn, and cortical F-actin in lipid raft microdomains in adipocytes. Furthermore, CAP and Fyn associate with different regions in the N-terminal sequences of flotillin-1. These results furthered our understanding for how flotillin-1 can function as a molecular link between lipid rafts of the plasma membrane and a multimeric signaling complex at the actin cytoskeleton. The plasma membrane of most cell types contains specialized subdomains that are highly enriched in cholesterol and sphingolipids, referred to as lipid raft microdomains (1Song K.S. Li S. Okamoto T. Quilliam L.A. Sargiacomo M. Lisanti M.P. J. Biol. Chem. 1996; 271: 9690-9697Abstract Full Text Full Text PDF PubMed Scopus (918) Google Scholar, 2Simons K. Ikonen E. Nature. 1997; 387: 569-572Crossref PubMed Scopus (8048) Google Scholar, 3Simons K. Toomre D. Nat. Rev. Mol. Cell. Biol. 2000; 1: 31-39Crossref PubMed Scopus (5133) Google Scholar, 4Anderson R.G. Annu. Rev. Biochem. 1998; 67: 199-225Crossref PubMed Scopus (1719) Google Scholar). Lipid rafts are highly organized, dynamic structures connected to the cytoskeleton and are enriched in growth factor receptors, integrins, Src family kinases, glycosylphosphatidylinositol-linked proteins, and adaptor proteins (5Brown D.A. Rose J.K. Cell. 1992; 68: 533-544Abstract Full Text PDF PubMed Scopus (2604) Google Scholar, 6Harris T.J. Siu C.H. BioEssays. 2002; 24: 996-1003Crossref PubMed Scopus (84) Google Scholar, 7Pike L.J. Biochem. J. 2004; 378: 281-292Crossref PubMed Scopus (612) Google Scholar). The selective enrichment of key signaling molecules in these regions suggests that they could function as organization centers for signaling via the formation of multicomponent complexes. Lipid raft domains are insoluble in nonionic detergents (Triton X-100) (5Brown D.A. Rose J.K. Cell. 1992; 68: 533-544Abstract Full Text PDF PubMed Scopus (2604) Google Scholar). Depending on the tissue and cell type, protein complexes found in these fractions often contain the proteins caveolin and/or flotillin (8Bickel P.E. Scherer P.E. Schnitzer J.E. Oh P. Lisanti M.P. Lodish H.F. J. Biol. Chem. 1997; 272: 13793-13802Abstract Full Text Full Text PDF PubMed Scopus (493) Google Scholar, 9Lang D.M. Lommel S. Jung M. Ankerhold R. Petrausch B. Laessing U. Wiechers M.F. Plattner H. Stuermer C.A. J. Neurobiol. 1998; 37: 502-523Crossref PubMed Scopus (202) Google Scholar, 10Stuermer C.A. Lang D.M. Kirsch F. Wiechers M. Deininger S-O. Plattner H. Mol. Biol. Cell. 2001; 12: 3031-3045Crossref PubMed Scopus (184) Google Scholar, 11Solomon S. Masilamani M. Rajendran L. Bastmeyer M. Stuermer C.A. Illges H. Immunobiology. 2002; 205: 108-119Crossref PubMed Scopus (48) Google Scholar). The insertion of caveolin-1 into lipid rafts results in the formation of caveolae, flask-shaped invaginations that are abundant in glial, epithelial, endothelial, muscle, and adipose cells (3Simons K. Toomre D. Nat. Rev. Mol. Cell. Biol. 2000; 1: 31-39Crossref PubMed Scopus (5133) Google Scholar). The flotillin/reggie proteins are ubiquitously expressed (8Bickel P.E. Scherer P.E. Schnitzer J.E. Oh P. Lisanti M.P. Lodish H.F. J. Biol. Chem. 1997; 272: 13793-13802Abstract Full Text Full Text PDF PubMed Scopus (493) Google Scholar, 12Schulte T. Paschke K.A. Laessing U. Lottspeich F. Stuermer C.A. Development (Camb.). 1997; 124: 577-587Crossref PubMed Google Scholar). Reggie-1 and -2 were originally identified in developing neurons of goldfish optic nerves (12Schulte T. Paschke K.A. Laessing U. Lottspeich F. Stuermer C.A. Development (Camb.). 1997; 124: 577-587Crossref PubMed Google Scholar). The same proteins were subsequently identified from endothelial cells in low density detergent-insoluble complexes that also contained caveolin, where they were named flotillin-2 and -1 (8Bickel P.E. Scherer P.E. Schnitzer J.E. Oh P. Lisanti M.P. Lodish H.F. J. Biol. Chem. 1997; 272: 13793-13802Abstract Full Text Full Text PDF PubMed Scopus (493) Google Scholar). Both isoforms were shown to interact and co-localize with the Src family kinase Fyn in lipid rafts derived from neurons and astrocytes, although in Jurkat lymphoma cells, flotillin proteins were found to concentrate in endolysosomal compartments (10Stuermer C.A. Lang D.M. Kirsch F. Wiechers M. Deininger S-O. Plattner H. Mol. Biol. Cell. 2001; 12: 3031-3045Crossref PubMed Scopus (184) Google Scholar). As well as its postulated role in axon regeneration in retinal ganglion cells (12Schulte T. Paschke K.A. Laessing U. Lottspeich F. Stuermer C.A. Development (Camb.). 1997; 124: 577-587Crossref PubMed Google Scholar), flotillin-1 has also been implicated in phagosome maturation (13Dermine J.F. Duclos S. Garin J. St-Louis F. Rea S. Parton R.G. Desjardins M. J. Biol. Chem. 2001; 276: 18507-18512Abstract Full Text Full Text PDF PubMed Scopus (252) Google Scholar) in macrophages and in NF-κB in Jurkat cells D. J. T. P.E. J. 2004; PubMed Scopus Google Scholar). to a family of proteins that plasma CAP, density low density plasma CAP, density low density M. Biochem. 24: Full Text Full Text PDF PubMed Scopus Google Scholar). The function of domains most family are membrane proteins with a region the flotillin-1 has two hydrophobic sequences that are in the (8Bickel P.E. Scherer P.E. Schnitzer J.E. Oh P. Lisanti M.P. Lodish H.F. J. Biol. Chem. 1997; 272: 13793-13802Abstract Full Text Full Text PDF PubMed Scopus (493) Google Scholar). has been that is membrane protein with a and a cytoplasmic B. E. D. Li K. Lottspeich F. Mol. Biol. Cell. 2001; 12: PubMed Scopus Google Scholar). a that flotillin-1 a protein but is to the plasma membrane via of the Rea S. S. R. J.F. Parton R.G. J. Biol. Chem. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). We in flotillin-1 we identified the protein as a for in 3T3-L1 C.A. M. S. S. P.E. J.E. Nature. 2000; PubMed Scopus Google Scholar). CAP is a adaptor protein with domains in its and a region of to the in its is highly expressed in and Mol. Cell. Biol. 1998; PubMed Scopus Google Scholar). We that in flotillin-1 to the complex to lipid that for the to the of C.A. J. Biol. Chem. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar). The organization of CAP is also found in other proteins, and S. T. T. K. S. J. Biol. PubMed Scopus Google Scholar, H. M. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). that these proteins a adaptor protein can function in the of cell and growth factor signaling K. T. 2002; PubMed Scopus Google Scholar). and CAP were shown to at in of protein the formation of actin and S. T. T. K. S. J. Biol. PubMed Scopus Google Scholar, R. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, K. H. K. K. H. J. Biol. PubMed Scopus Google Scholar). a the of the complex to lipid rafts to for actin in of cells K. J. 2004; PubMed Scopus Google Scholar). we domains in flotillin-1 that to its subcellular localization and protein in 3T3-L1 adipocytes. and CAP Fyn and were from The from The and were from The caveolin and the and were from were from The and were from and were from The and were from The protein were from from and for different CAP isoforms and caveolin-1 were as M. Mol. PubMed Google Scholar, S. S. J.E. J. Biol. Chem. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). flotillin-1 derived from C.A. J. Biol. Chem. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar). flotillin-1 flotillin-1 with at the in the and of mutants of flotillin-1 were generated a of and of the second hydrophobic were the to the The and were of different flotillin-1 in the is shown in and cells were in and cells were in 3T3-L1 were in with and of 3T3-L1 cells to with and as The cells were in were in with of cells to the cells in for 3T3-L1 were as cells in were as J. J. Biol. Chem. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar). of a M. of to flotillin-1 into different cell The flotillin-1 at the with into the and of the The into cells in a with the from The at and to The cells were in a and were subsequently in for and cells in 3T3-L1 in were with and were for at with and of The were with the for at from were with of protein from 3T3-L1 adipocytes. The complexes were with protein for at and were with in proteins were and to proteins were with the and with fractions plasma membrane density and low density were from 3T3-L1 and a of and as and J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). cells on were in for cells with for various were on with the cells in of and and were in a The cell were into various and the were in a protein of and to and were on in the with for cells were with for and with and for and were at in and the were on with were 3T3-L1 with the of were on The cells were to for and were for with the and on as were in for with the cells were for on in and The The insoluble in and as C.A. M. S. S. P.E. J.E. Nature. 2000; PubMed Scopus Google Scholar). of Flotillin-1 in the cellular in flotillin-1 has been we to and its intracellular localization in different cell To flotillin-1 at the with a and expressed in a series of cell via that flotillin-1 at membrane with a intracellular distribution in and cells, the protein localized at the plasma membrane with cytoplasmic in cells, flotillin-1 intracellular granule-like with a at the plasma membrane flotillin-1 can in plasma membrane and intracellular and the distribution between these two compartments to cell type-specific. The of Flotillin-1 in 3T3-L1 flotillin-1 is localized in we the distribution of flotillin-1 subcellular As shown in flotillin-1 in and fractions with a in fractions in 3T3-L1 and adipocytes. a of flotillin-1 in the to that in upon differentiation of differentiation the subcellular distribution of caveolin, a lipid raft protein enriched in the of To these we examined the localization of flotillin-1 in 3T3-L1 cells flotillin-1. As shown in flotillin-1 found in intracellular structures in with of these with the actin cytoskeleton. differentiation into flotillin-1 found to localized at the plasma where cortical F-actin also To the cellular compartments in that contain proteins of the and were As shown in the structures flotillin-1 in were but that flotillin-1 is in to cellular To differentiation also a of we expressed in and these cells to of growth in the that flotillin-1 localized in intracellular in and of flotillin-1 is also cell type-specific. To the flotillin-1 protein lipid raft localization in we 3T3-L1 and 3T3-L1 with low from and insoluble fractions were with different of flotillin-1 protein in the of the protein in the differentiation into flotillin-1 protein found in the Fyn, a Src family kinase that shown to interact with flotillin-1 in and cells, also a lipid raft As a caveolin found to localized to lipid rafts of the differentiation of the shown that lipid raft subdomains in the plasma membrane can as for actin cytoskeleton structures (3Simons K. Toomre D. Nat. Rev. Mol. Cell. Biol. 2000; 1: 31-39Crossref PubMed Scopus (5133) Google Scholar, 6Harris T.J. Siu C.H. BioEssays. 2002; 24: 996-1003Crossref PubMed Scopus (84) Google Scholar). To the role of the actin cytoskeleton in flotillin localization, we cells with the actin to the As shown in of actin cytoskeleton on the lipid raft localization of flotillin-1 caveolin in and adipocytes. The N-terminal for the Lipid of Flotillin-1 in the structural determinants for the localization of flotillin-1 to the lipid raft domains of we generated a series of truncation mutants of flotillin-1 at the with a We examined the of these on the flotillin-1 localization in 3T3-L1 As of flotillin-1 in a of the N-terminal that contain the hydrophobic stretch the the second hydrophobic stretch on of a that the N-terminal hydrophobic in a cytoplasmic localization with a of protein at the N-terminal that the second hydrophobic in intracellular The results that the second but the hydrophobic is for the of flotillin-1 to the plasma membrane of 3T3-L1 adipocytes. We examined the localization of and of flotillin-1 to the lipid raft microdomains of the We protein with various flotillin proteins in 3T3-L1 adipocytes. were with at low and the membrane were is that proteins in the are lipid the of flotillin-1 and caveolin from these structures cholesterol that is a for lipid raft localization of flotillin-1 As shown in the protein to the in a in the with its in lipid the flotillin to and in the membrane the with and from the membrane and were they also were these that the hydrophobic to the of flotillin-1 role in the protein to the lipid raft To the results from the cells were also to subcellular into and The distribution of various flotillin mutants between these two fractions examined As shown in although of the protein found in the of and of were localized in the same is with the results from as the that in the intracellular compartments as found to in the the hydrophobic is necessary for flotillin-1 to lipid raft microdomains in and intracellular membrane structures. that of is in flotillin-1 with the in cells Rea S. S. R. J.F. Parton R.G. J. Biol. Chem. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). To of also is for the localization of flotillin in we 3T3-L1 with type of flotillin-1 with As the type flotillin with the in cells and localized with in in intracellular that also were of to on the subcellular localization of flotillin and has been in cells, the of to a role in the lipid raft localization of flotillin-1 in adipocytes. of the as the of of localization of and at the cell of to that the second hydrophobic between and flotillin-1 to the plasma membrane. To delineate the for localization, we various N-terminal of flotillin to the and expressed protein in 3T3-L1 adipocytes. As flotillin and were localized to and intracellular generated of the second hydrophobic stretch to in intracellular of from the protein the same on the localization as and of region On the other hand, and that the second hydrophobic well with the from the protein of the hydrophobic from its these that the second but the hydrophobic of flotillin-1 is for the localization and for the of the protein from intracellular structures. CAP at the of 3T3-L1 is a adaptor protein highly expressed in and Mol. Cell. Biol. 1998; PubMed Scopus Google Scholar). to a protein at the in K. H. K. K. H. J. Biol. PubMed Scopus Google Scholar) and a lipid raft in C.A. M. S. S. P.E. J.E. Nature. 2000; PubMed Scopus Google Scholar), we to CAP associate with the cortical actin cytoskeleton at the of adipocytes. on 3T3-L1 a to to for F-actin the of the cells, that CAP to the cortical F-actin with intracellular the plasma membrane CAP found to well with F-actin at the cell and the structures. CAP at the and the of actin at the plasma membrane we also found that CAP of to and F-actin in in and S. M. M. L. H. and R. of Flotillin-1 with that flotillin-1 CAP to plasma membrane lipid rafts in C.A. M. S. S. P.E. J.E. Nature. 2000; PubMed Scopus Google Scholar). To the of CAP with were cell from 3T3-L1 adipocytes. CAP proteins were with the of As were and As shown in a of flotillin-1 with CAP of CAP were The same of and were to CAP a between CAP and flotillin-1 in of the results in isoforms of CAP We M. Mol. PubMed Google Scholar) that were isoforms of CAP protein expressed in adipose To the of CAP to flotillin-1 is we cells with and a of the CAP with As shown in specifically with but with the other and the same the of flotillin with CAP is of with Flotillin-1 and that flotillin-1 and actin to these are in To we and in well that with actin and at at the of the cells, where found to at the of the to well with in the We with in 3T3-L1 Both CAP proteins to in cells were with we that the of with in the of cells with to cortical F-actin from the as well as the membrane On the other hand, the of cortical actin on the localization of flotillin in the lipid These results that is with flotillin-1 in the lipid raft is on the of the cortical F-actin of and Fyn in to the region of flotillin-1 for to and with with the same as the of the that the hydrophobic from to a protein that to a that a of the protein in the various These that the hydrophobic of flotillin-1 is for its with shown that flotillin-1 and flotillin-2 are with the Src family kinase Fyn in fractions of that flotillin role in the formation of centers (10Stuermer C.A. Lang D.M. Kirsch F. Wiechers M. Deininger S-O. Plattner H. Mol. Biol. Cell. 2001; 12: 3031-3045Crossref PubMed Scopus (184) Google Scholar). To we cells with type kinase mutants of Fyn with flotillin-1 with of the that of Fyn with flotillin-1. Fyn in the lacking flotillin-1. that the of Fyn the Fyn kinase a complex with flotillin-1 of its kinase To the region in we Fyn and various truncation mutants of flotillin-1. that of the N-terminal the of the second hydrophobic Fyn that these regions are for the N-terminal to the of the second hydrophobic in flotillin Fyn These results that the region between the two hydrophobic domains in flotillin the of the protein to To Fyn the of to cells were also with and in the of were with that the of with type kinase Fyn of on the between Fyn and flotillin in a These results that the regions in flotillin-1 for and Fyn with these proteins of in a multimeric and of and -2 are ubiquitously expressed lipid raft proteins that been with cellular from Stuermer and D.M. Lommel S. Jung M. Ankerhold R. Petrausch B. Laessing U. Wiechers M.F. Plattner H. Stuermer C.A. J. Neurobiol. 1998; 37: 502-523Crossref PubMed Scopus (202) Google Scholar, 10Stuermer C.A. Lang D.M. Kirsch F. Wiechers M. Deininger S-O. Plattner H. Mol. Biol. Cell. 2001; 12: 3031-3045Crossref PubMed Scopus (184) Google Scholar) that flotillin proteins in at the of and also shown that flotillin-1 localized to the cell of the cell and Rea S. S. R. J.F. Parton R.G. J. Biol. Chem. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). Jurkat lymphoma cells, were with and Fyn in intracellular that (10Stuermer C.A. Lang D.M. Kirsch F. Wiechers M. Deininger S-O. Plattner H. Mol. Biol. Cell. 2001; 12: 3031-3045Crossref PubMed Scopus (184) Google Scholar). flotillin-1 found to on J. R. S. J.F. Duclos S. E. R. Desjardins M. J. Biol. 2001; PubMed Scopus Google Scholar). the subcellular localization of flotillin proteins to cell type-specific. we that although flotillin-1 in the intracellular granule-like compartments in cell and the protein is localized at the plasma membrane in other cells as and Furthermore, we found that flotillin-1 from intracellular compartments to the the of cellular The intracellular in were identified as flotillin-1 found to to the complex in cells B. E. D. Li K. Lottspeich F. Mol. Biol. Cell. 2001; 12: PubMed Scopus Google Scholar). growth localized to the cell D.M. Lommel S. Jung M. Ankerhold R. Petrausch B. Laessing U. Wiechers M.F. Plattner H. Stuermer C.A. J. Neurobiol. 1998; 37: 502-523Crossref PubMed Scopus (202) Google Scholar), although differentiation of cells in a of flotillin-1. is well that lipid rafts in as well as the B. E. D. Li K. Lottspeich F. Mol. Biol. Cell. 2001; 12: PubMed Scopus Google Scholar, D. S. K. Biochem. J. PubMed Scopus Google Scholar, S. S. P. Ikonen E. U. S. 2000; PubMed Scopus Google Scholar). results a in differentiation can the of flotillin-1 and other raft-associated proteins, in the membrane of intracellular into the lipid raft microdomains of the the flotillin-1 can in as as lipid and/or protein and and lipid raft with we found that flotillin-1 to interact with the adaptor protein CAP at the of adipocytes. of its membrane has been and flotillin-1 is a membrane protein is the membrane of the from to domains from the in the N-terminal region M. Biochem. 24: Full Text Full Text PDF PubMed Scopus Google Scholar). function is a membrane protein found in the of is membrane protein that as a in the of of complexes. and a membrane of the two hydrophobic and the of flotillin-1. with the in the of at that flotillin-1 membrane protein (8Bickel P.E. Scherer P.E. Schnitzer J.E. Oh P. Lisanti M.P. Lodish H.F. J. Biol. Chem. 1997; 272: 13793-13802Abstract Full Text Full Text PDF PubMed Scopus (493) Google Scholar). from of membrane that flotillin-1 a protein with the second hydrophobic stretch as its B. E. D. Li K. Lottspeich F. Mol. Biol. Cell. 2001; 12: PubMed Scopus Google Scholar). Rea S. S. R. J.F. Parton R.G. J. Biol. Chem. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar) that the the of flotillin-1 in a the of the hydrophobic identified as the of cells that flotillin-1 a protein at the Rea S. S. R. J.F. Parton R.G. J. Biol. Chem. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). the membrane of flotillin-1 to the flotillin-1 is to the lipid rafts of and the two hydrophobic of flotillin-1 in to its subcellular We the that the hydrophobic the postulated for the localization of flotillin-1 in adipocytes. found to in of the protein to the lipid raft the that the protein lacking to associate with fractions in and subcellular of on the lipid raft of flotillin-1. The of the between our results and the Rea S. S. R. J.F. Parton R.G. J. Biol. Chem. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar) with cells is is that the of the of in the localization also cell type-specific. role for the second hydrophobic in the subcellular distribution of flotillin-1 the truncation of hydrophobic the the proteins were in the intracellular These results that the second hydrophobic region as a localization as well as a to flotillin-1 from the membrane to the second hydrophobic stretch of flotillin-1 is in the a hydrophobic has been to to membrane for most proteins in family M. Biochem. 24: Full Text Full Text PDF PubMed Scopus Google Scholar). we the that a in flotillin-1 for membrane the with a a flotillin-1 between the two hydrophobic to associate with the membrane the of a in On the other hand, flotillin-2 contain hydrophobic but membrane localization to that flotillin-1 in a of cells D.M. Lommel S. Jung M. Ankerhold R. Petrausch B. Laessing U. Wiechers M.F. Plattner H. Stuermer C.A. J. Neurobiol. 1998; 37: 502-523Crossref PubMed Scopus (202) Google Scholar, 10Stuermer C.A. Lang D.M. Kirsch F. Wiechers M. Deininger S-O. Plattner H. Mol. Biol. Cell. 2001; 12: 3031-3045Crossref PubMed Scopus (184) Google Scholar). The in flotillin-2 to the second hydrophobic stretch of flotillin-1 contains two (8Bickel P.E. Scherer P.E. Schnitzer J.E. Oh P. Lisanti M.P. Lodish H.F. J. Biol. Chem. 1997; 272: 13793-13802Abstract Full Text Full Text PDF PubMed Scopus (493) Google Scholar). a that of with of N-terminal are necessary for the localization of flotillin-2 B. T. S. Stuermer C.A. R. Biochem. J. 2004; 378: PubMed Scopus Google Scholar), to sequences the membrane of flotillin-2 in intracellular compartments and and with CAP and CAP has been shown to in signaling via to Mol. Cell. Biol. 1998; PubMed Scopus Google Scholar, C.A. J. Biol. Chem. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar) and in organization via to K. H. K. K. H. J. Biol. PubMed Scopus Google Scholar). The and the two domains of CAP interact with the regions of and from our C.A. M. S. S. P.E. J.E. Nature. 2000; PubMed Scopus Google Scholar) a between CAP and flotillin-1 in and The in CAP identified to the and for CAP to in the lipid raft microdomains of C.A. U. S. 2001; PubMed Scopus Google Scholar). of of CAP in domains the region were deleted the of in 3T3-L1 C.A. M. S. S. P.E. J.E. Nature. 2000; PubMed Scopus Google Scholar, C.A. U. S. 2001; PubMed Scopus Google Scholar). These results to that CAP in that the lipid raft localization of we that CAP and flotillin-1 proteins interact with other in where CAP also is with cortical F-actin and structures at the the CAP isoforms in the of to flotillin-1 in a also is the a that is to the formation of a These results that the on is in the of CAP with flotillin-1 in the function as a is that the lipid and protein of rafts with the actin cytoskeleton cellular J. S. D. L. M.P. M. U. S. PubMed Scopus Google Scholar). of the complex to lipid rafts to role in growth K. J. 2004; PubMed Scopus Google Scholar). we that function as a between the actin cytoskeleton and lipid rafts at the with flotillin-1 and F-actin at the the actin cytoskeleton to of the cells, found to in derived from with flotillin-1. CAP proteins and with actin of CAP actin and formation of structures. of F-actin of cells the of in the and its lipid raft of cells with as flotillin-1 and from the detergent-insoluble we to that flotillin-1 with F-actin to lipid although we the that other also to actin and CAP proteins to the the of CAP and F-actin in of is to that the actin the of CAP and a structural for signaling in adipocytes. between and (10Stuermer C.A. Lang D.M. Kirsch F. Wiechers M. Deininger S-O. Plattner H. Mol. Biol. Cell. 2001; 12: 3031-3045Crossref PubMed Scopus (184) Google Scholar) shown that flotillin-1 and -2 associate and with Fyn in microdomains of neurons and also that Fyn in detergent-insoluble rafts in J. Biol. Chem. 1997; 272: Full Text Full Text PDF PubMed Scopus Google Scholar, Jung S. S. H. Mol. Cell. Biol. 2001; PubMed Scopus Google Scholar). We the between flotillin-1 and Fyn and and we also that and Fyn to different regions in the of flotillin-1. of Fyn on the and that these proteins to in the same Fyn and other Src family are well of signaling and the actin cytoskeleton 2004; PubMed Scopus Google Scholar). the role of Src in is well J. Biol. Chem. 1997; 272: Full Text Full Text PDF PubMed Scopus Google Scholar, S. T. E. M.F. J. Biol. Chem. 1996; 271: Full Text Full Text PDF PubMed Scopus Google Scholar, E. Mol. Biol. Cell. 2002; PubMed Scopus Google Scholar). of Fyn in the complex in the F-actin and also in the lipid rafts of adipocytes.