Caveolin-1 Contributes to Assembly of Store-operated Ca2+ Influx Channels by Regulating Plasma Membrane Localization of TRPC1

Abstract

TRPC1, a component of store-operated Ca2+ entry (SOCE) channels, is assembled in a complex with caveolin-1 (Cav1) and key Ca2+ signaling proteins. This study examines the role of Cav1 in the function of TRPC1. TRPC1 and Cav1 were colocalized in the plasma membrane region of human submandibular gland and Madin-Darby canine kidney cells. Full-length Cav1 bound to both the N and C termini of TRPC1. Amino acids 271–349, which includes a Cav1 binding motif (amino acids 322–349), was identified as the Cav1 binding domain in the TRPC1 N terminus. Deletion of amino acids 271–349 or 322–349 prevented plasma membrane localization of TRPC1. Importantly, TRPC1Δ271–349 induced a dominant suppression of SOCE and was associated with wild-type TRPC1. Although the role of the C-terminal Cav1 binding domain is not known, its deletion did not affect localization of TRPC1 (Singh, B. B., Liu, X., and Ambudkar, I. S. (2000) J. Biol. Chem. 275, 36483–36486). Further, expression of a truncated Cav1 (Cav1Δ51-169), but not full-length Cav1, similarly disrupted plasma membrane localization of endogenously and exogenously expressed TRPC1 in human submandibular gland and Madin-Darby canine kidney cells. Cav1Δ51–169 also suppressed thapsigarginand carbachol-stimulated Ca2+ influx and increased the detergent solubility of TRPC1, although plasma membrane lipid raft domains were not disrupted. These data demonstrate that plasma membrane localization of TRPC1 depends on an interaction between its N terminus and Cav1. Thus, our data suggest that Cav1 has an important role in the assembly of SOCE channel(s). TRPC1, a component of store-operated Ca2+ entry (SOCE) channels, is assembled in a complex with caveolin-1 (Cav1) and key Ca2+ signaling proteins. This study examines the role of Cav1 in the function of TRPC1. TRPC1 and Cav1 were colocalized in the plasma membrane region of human submandibular gland and Madin-Darby canine kidney cells. Full-length Cav1 bound to both the N and C termini of TRPC1. Amino acids 271–349, which includes a Cav1 binding motif (amino acids 322–349), was identified as the Cav1 binding domain in the TRPC1 N terminus. Deletion of amino acids 271–349 or 322–349 prevented plasma membrane localization of TRPC1. Importantly, TRPC1Δ271–349 induced a dominant suppression of SOCE and was associated with wild-type TRPC1. Although the role of the C-terminal Cav1 binding domain is not known, its deletion did not affect localization of TRPC1 (Singh, B. B., Liu, X., and Ambudkar, I. S. (2000) J. Biol. Chem. 275, 36483–36486). Further, expression of a truncated Cav1 (Cav1Δ51-169), but not full-length Cav1, similarly disrupted plasma membrane localization of endogenously and exogenously expressed TRPC1 in human submandibular gland and Madin-Darby canine kidney cells. Cav1Δ51–169 also suppressed thapsigarginand carbachol-stimulated Ca2+ influx and increased the detergent solubility of TRPC1, although plasma membrane lipid raft domains were not disrupted. These data demonstrate that plasma membrane localization of TRPC1 depends on an interaction between its N terminus and Cav1. Thus, our data suggest that Cav1 has an important role in the assembly of SOCE channel(s). SOCE 1The abbreviations used are: SOCE, store-operated Ca2+ entry; aa, amino acid(s); Ad, adenovirus; AEBSF, 4-(2-aminoethyl)-benzenesulfonyl fluoride; Cav, caveolin-1; CCh, carbachol; GFP, green fluorescent protein; GST, glutathione S-transferase; HA, hemagglutinin; HSG cells, human submandibular gland cells; MDCK, Madin-Darby canine kidney; Tg, thapsigargin; YFP, yellow fluorescent protein; TRPC, transient receptor potential canonical; INAD, inactivation-no-after potential D; OG, n-octyl-β-d-glycopyranoside. is activated in response to stimulation of plasma membrane receptors that are coupled to the mobilization of intracellular Ca2+. Although there is considerable evidence to suggest that the signal for the activation of SOCE is the depletion of Ca2+ within the endoplasmic reticulum (1Putney Jr., J.W. Broad L.M. Braun F.J. Lievremont J.P. Bird G.S. J. Cell Sci. 2001; 114: 2223-2229Crossref PubMed Google Scholar), the mechanism involved in activation or inactivation of SOCE is not yet known. A major drawback in understanding the mechanism of SOCE has been the lack of information regarding the identity and regulation of the SOCE channel. Members of the TRPC protein family have been suggested as molecular components of the SOCE channel (2Minke B. Cook B. Physiol. Rev. 2002; 82: 429-472Crossref PubMed Scopus (534) Google Scholar, 3Zitt C. Halaszovich C.R. Luckhoff A. Prog. Neurobiol. 2002; 66: 243-264Crossref PubMed Scopus (125) Google Scholar, 4Montell C. Science's STKE. 2001; (http://www.stke.org/cgi/content/full/OC_sigtrans;2000/90/re1)PubMed Google Scholar). TRPC1 has been reported to be required for SOCE in several cell types (5Antoniotti S. Lovisolo D. Fiorio Pla A. Munaron L. FEBS Lett. 2002; 510: 189-195Crossref PubMed Scopus (69) Google Scholar, 6Brough G.H. Wu S. Cioffi D. Moore T.M. Li M. Dean N. Stevens T. FASEB J. 2001; 15: 1727-1738Crossref PubMed Scopus (154) Google Scholar, 7Xu S.Z. Beech D.J. Circ. Res. 2001; 88: 84-87Crossref PubMed Scopus (294) Google Scholar, 8Mori Y. Wakamori M. Miyakawa T. Hermosura M. Hara Y. Nishida M. Hirose K. Mizushima A. Kurosaki M. Mori E. Gotoh K. Okada T. Fleig A. Penner R. Iino M. Kurosaki T. J. Exp. Med. 2002; 195: 673-681Crossref PubMed Scopus (177) Google Scholar). Our previous studies showed that TRPC1 is a critical component of SOCE in salivary epithelial cells (9Liu X. Wang W. Singh B.B. Lockwich T. Jadlowiec J. O'Connell B. Weller R. Zhu M.X. Ambudkar I.S. J. Biol. Chem. 2000; 275: 3403-3411Abstract Full Full PubMed Scopus Google Scholar, B.B. C. X. Lockwich T. D. Zhu M.X. L. Ambudkar I.S. FASEB J. 2001; 15: PubMed Scopus Google Scholar, B.B. X. J. Zhu M.X. Ambudkar I.S. 2002; Full Full PubMed Scopus (125) Google Scholar). Further, reported the C. J. Cell Biol. 2000; PubMed Scopus Google Scholar), TRPC1 and are assembled in signaling that are associated with Cav1 and key Ca2+ signaling as membrane Ca2+ reticulum Ca2+ and X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar, T. Singh B.B. X. Ambudkar I.S. J. Biol. Chem. 2001; Full Full PubMed Scopus Google Scholar, B.B. X. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). is assembled INAD, a to a of in the complex and its localization in the C. Science's STKE. 2001; (http://www.stke.org/cgi/content/full/OC_sigtrans;2000/90/re1)PubMed Google Scholar, C. J. Cell Biol. 2000; PubMed Scopus Google Scholar). the components of to be to the plasma and interaction with is required for that Although several have been to as for signaling in the plasma membrane M. Res. 2001; PubMed Scopus Google Scholar), is the of TRPC in cells K. D. Cell Biol. 2002; Scopus Google Scholar). Y. J. C. Li M. Zhu M.X. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google have reported that a protein that with the with of also with and and be involved in with C the C-terminal domain binding motif in is in TRPC1. Thus, the molecular involved in the assembly of the protein complex is not yet known. evidence has which that key involved in Ca2+ signaling are associated with lipid the of in Ca2+ signaling X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar, M. Cell PubMed Scopus Google Scholar, 2001; PubMed Scopus Google Scholar, M. T. J. Biol. Chem. 2002; Full Full PubMed Scopus Google Scholar, R. J. Biol. Chem. 2002; Full Full PubMed Scopus Google Scholar). are membrane domains the of and which have been suggested to function as for protein and signaling Full PubMed Scopus Google Scholar, K. E. PubMed Scopus Google Scholar, Biol. PubMed Scopus Google Scholar, K. D. Rev. Biol. 2000; PubMed Scopus Google Scholar). A of lipid the protein which a which to signaling in the plasma This membrane of and K. D. Rev. Biol. 2000; PubMed Scopus Google Scholar, Y. Full PubMed Scopus Google Scholar, Sci. S. A. PubMed Scopus Google Scholar, M. M. J. Cell Biol. PubMed Scopus Google Scholar). Our that TRPC1 and with Ca2+ signaling that are associated with domains that regulation of SOCE within with our several studies that TRPC1 C. R. A. FEBS Lett. 2001; PubMed Scopus Google Scholar, C. J. J. Biol. Chem. 2002; Full Full PubMed Scopus Google and S. T. C. S. J. Biol. Chem. 2002; Full Full PubMed Scopus Google are associated with lipid raft of the lipid domain is critical for SOCE and TRPC1 function X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar, C. J. J. Biol. Chem. 2002; Full Full PubMed Scopus Google Scholar). study have the role of Cav1 in Our data demonstrate that Cav1 the plasma membrane localization of TRPC1 binding to a on its N terminus. Deletion of the Cav1 binding in TRPC1 of TRPC1 to the plasma membrane and also with our previous studies that TRPC1 is a component of SOCE (9Liu X. Wang W. Singh B.B. Lockwich T. Jadlowiec J. O'Connell B. Weller R. Zhu M.X. Ambudkar I.S. J. Biol. Chem. 2000; 275: 3403-3411Abstract Full Full PubMed Scopus Google Scholar, X. Singh B.B. Ambudkar I.S. J. Biol. Chem. Full Full PubMed Scopus Google Scholar), the data a important role for Cav1 in the plasma membrane assembly of SOCE and A were was and was the used for and the used for were and and were was was and were was a was the full-length and were used to the to an truncated of Cav1 of of the were and a and were used to were and the was both to of cells. was the the and was with and and the was used to E. were and deletion TRPC1 TRPC1Δ271–349 and regarding B.B. X. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google the TRPC1 is to the the N were as were of and as as and a of as in the were used as for of with and This a TRPC1 of with an deletion to was with and was and or B.B. X. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google to the TRPC1Δ271–349 and was both to of cells. deletion TRPC1 was similarly TRPC1 and and and were as to the TRPC1 deletion Cell and for and the human submandibular gland cells have been (9Liu X. Wang W. Singh B.B. Lockwich T. Jadlowiec J. O'Connell B. Weller R. Zhu M.X. Ambudkar I.S. J. Biol. Chem. 2000; 275: 3403-3411Abstract Full Full PubMed Scopus Google Scholar). Madin-Darby canine kidney cells were in with and cells with Cav1 of was with in were with for and with or HSG cells with or were with TRPC1 of for or and were and as X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). cells were and with a in AEBSF, and for to the cell was for to the and the membrane were and the was for to the the membrane was the protein were as X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). were on and X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar, B.B. X. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). were used a of for the and which were used of HSG Cell and of membrane was on for with and in of and was for and the was in of the as of and were on for was with of and were used or were used a of N and C terminus of TRPC1 were of E. and were induced with and as B.B. X. J. Zhu M.X. Ambudkar I.S. 2002; Full Full PubMed Scopus (125) Google Scholar). HSG cells or with or were as cells were and with a and of was to the cell were on for and for of and of were for with of cell were with of and with were in and identified and of the TRPC1 N terminus were binding deletion of of was activation were used to the which was on and to for were on and that on amino acids were to be for A was to and the as the or cells were on for were and for as W. O'Connell B. R. T. C. W. Zhu M.X. L. Ambudkar I.S. J. Physiol. PubMed Google Scholar). lipid raft the was to cells a of and for were with and as W. O'Connell B. R. T. C. W. Zhu M.X. L. Ambudkar I.S. J. Physiol. PubMed Google Scholar). were (9Liu X. Wang W. Singh B.B. Lockwich T. Jadlowiec J. O'Connell B. Weller R. Zhu M.X. Ambudkar I.S. J. Biol. Chem. 2000; 275: 3403-3411Abstract Full Full PubMed Scopus Google Scholar). in cells was a and to an with a were an and the of the are of TRPC1 with expressed in HSG cells a localization in the plasma membrane signal in was expressed was the not the localization of did not was with the C terminus of Cav1 of the N terminus not of TRPC1 in HSG cells was X. Singh B.B. Ambudkar I.S. J. Biol. Chem. Full Full PubMed Scopus Google Scholar). TRPC1 was in the plasma membrane and membrane of and TRPC1 was in the plasma membrane as a yellow signal yellow with our TRPC1 has been to with Cav1 in the plasma membrane of C. R. A. FEBS Lett. 2001; PubMed Scopus Google Scholar). showed that there was of the to the signal not the of exogenously expressed in HSG cells was used to in cells with the localization of green was also in the plasma membrane and region of the and a plasma membrane of the yellow This was on a of TRPC1 and Cav1 was also in epithelial cell in HSG cells, expressed and expressed were colocalized in the plasma membrane region Thus, plasma membrane of TRPC1 and Cav1 was not to HSG cells. of Cav1 and TRPC1 was of with were in the of cells and were also in the with or that are not in cells, data not with our previous that TRPC1 or exogenously expressed TRPC1 is with Cav1 in HSG cells X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar, B.B. X. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar), data suggest that TRPC1 and Cav1 with interaction in of the N or C terminus of TRPC1 were HSG cells were or with both the N and C terminus of TRPC1, although there was binding with the C terminus and that protein not and of the Cav1 in the N of data in are with our previous that TRPC1 has binding domains in both the N and C terminus X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). Although studies be required to the of the binding of the C terminus of TRPC1 to Cav1, have reported that C-terminal deletion of TRPC1 not affect its plasma membrane localization or SOCE B.B. X. J. Zhu M.X. Ambudkar I.S. 2002; Full Full PubMed Scopus (125) Google Scholar, B.B. X. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). the Cav1 binding on the TRPC1 N terminus. A of Cav1 was which the membrane and the and be used in a between Cav1 and the N and C terminus of TRPC1 were with the TRPC1 N terminus but not the C terminus with a to Cav1 with the TRPC1 N terminus. the Cav1 binding domain in the TRPC1 N of TRPC1, in were the and interaction was between Cav1 and 271–349 the role of Cav1 binding domain in TRPC1 271–349 were in and the protein was expressed in or HSG cells cell plasma membrane localization of the protein was and an intracellular localization was deletion was in the N terminus of which the C terminus and the protein was expressed in Although was in the plasma membrane region B.B. X. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar), deletion of 271–349 in protein disrupted its plasma membrane localization the expression of and with that of full-length Further, SOCE was in cells Ca2+ was not the expression of in HSG cells. was HSG cells showed an in Importantly, SOCE, was in HSG cells TRPC1Δ271–349 with that in HSG cells for also Thus, in to expression of full-length which an in SOCE, induced a dominant suppression of suggested that the TRPC1 322–349 includes the binding motif X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). Importantly, motif to be in a of TRPC Thus, 322–349 in TRPC1 and expressed protein in HSG cells. with the in deletion of domain TRPC1 the localization of the TRPC1 was to be in the plasma membrane with and Further, SOCE was also suppressed in cells not TRPC1 have been suggested to X. Singh B.B. Ambudkar I.S. J. Biol. Chem. Full Full PubMed Scopus Google Scholar, A. L. C. 2000; Full Full PubMed Scopus Google Scholar, M. C. C. E. Luckhoff A. J. FEBS Lett. 2002; PubMed Scopus Google Scholar). on previous suggest that and with TRPC1 and This a in plasma membrane SOCE and for the in This is in which that was with the were that the to with wild-type TRPC1. These data for the suppression of SOCE in cells the TRPC1 proteins. the suggest that the Cav1 binding of TRPC1 is involved in the plasma membrane localization of the protein and to of on the role of Cav1 in TRPC1 the of a Cav1 that the protein and membrane domains the N that is but not its protein not to is that domains of or with are involved in expressed in HSG cells, an intracellular localization that was the and the and green Importantly, in cells there was a intracellular localization of TRPC1 or exogenously expressed there was of TRPC1 and in the plasma membrane region of cells, but of and green was the cells in and yellow with localization of yellow signal in of on and Ca2+ was also HSG cells, the SOCE was and in and with in and and data and was expressed in cells or in HSG cells, and were not or SOCE was in HSG cells with were and in cells with and in cells with and Tg, TRPC1 was in cells, SOCE was with the HSG cells data as in and and of and HSG cells and cells the full-length or was in the and membrane and the of the in the also the of in expressed was in the membrane in HSG cells as as cells the or TRPC1 associated with the membrane in cells in Cav1 cells in and of has been used as a for with lipid Full PubMed Scopus Google Scholar, M. M. J. Cell Biol. PubMed Scopus Google Scholar). showed that a major of the TRPC1 in HSG cells is X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). the detergent solubility of the full-length and as as that of in HSG cell was in the the of which was associated with was the HSG cells, was in the although was also in the and in cells was in the in the and Importantly, in cells was in and with the of TRPC1, data suggest that the localization of in raft domains is disrupted expression of was not a of plasma membrane lipid raft as the binding of to HSG cells J. Cell Biol. PubMed Scopus Google Scholar). Full-length Cav1 is to the plasma the truncated Cav1 is in intracellular region in HSG cells similarly the plasma membrane in HSG cells and in cells the full-length or truncated Cav1 signal was also the of a of the A of studies have that SOCE within a plasma membrane domain in cells. has been that the of domain a or a between the molecular components which to or of plasma membrane SOCE (2Minke B. Cook B. Physiol. Rev. 2002; 82: 429-472Crossref PubMed Scopus (534) Google Scholar, X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar, K. D. Cell Biol. 2002; Scopus Google Scholar, K. Zhu M.X. S. Full Full PubMed Scopus Google Scholar). evidence has been for the localization of a Ca2+ signaling within lipid raft domains in the plasma membrane M. Cell PubMed Scopus Google Scholar, R. J. Biol. Chem. 2002; Full Full PubMed Scopus Google Scholar). SOCE has been reported to lipid X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar, M. Cell PubMed Scopus Google Scholar). have reported that TRPC1 and are associated with the Cav1, and are assembled in a protein complex with key Ca2+ signaling X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar, T. Singh B.B. X. Ambudkar I.S. J. Biol. Chem. 2001; Full Full PubMed Scopus Google Scholar, B.B. X. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). have that TRPC1 is a critical component of SOCE in HSG cells (9Liu X. Wang W. Singh B.B. Lockwich T. Jadlowiec J. O'Connell B. Weller R. Zhu M.X. Ambudkar I.S. J. Biol. Chem. 2000; 275: 3403-3411Abstract Full Full PubMed Scopus Google Scholar, X. Singh B.B. Ambudkar I.S. J. Biol. Chem. Full Full PubMed Scopus Google Scholar). Thus, suggested that regulation of the SOCE channel is within the signaling complex of the complex X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). the involved in the regulation of SOCE are not known, and the role of Cav1 in is also not yet is assembled in a signaling complex C. Halaszovich C.R. Luckhoff A. Prog. Neurobiol. 2002; 66: 243-264Crossref PubMed Scopus (125) Google Scholar, 4Montell C. Science's STKE. 2001; (http://www.stke.org/cgi/content/full/OC_sigtrans;2000/90/re1)PubMed Google Scholar). of are assembled in the interaction with the protein INAD, which several domains and also C. J. Cell Biol. 2000; PubMed Scopus Google Scholar). in or in the domain of in of the and of was to as a of TRPC function expressed in cells C. A. R. FASEB J. 2002; PubMed Scopus Google Scholar). Thus, information regarding the assembly of the signaling complex is key to understanding the mechanism involved in data demonstrate that Cav1 is a critical protein in the mechanism of with our previous X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar), the data demonstrate that there are binding in TRPC1. deletion of the Cav1 binding domain in full-length or C-terminal truncated TRPC1 prevented plasma membrane localization of the have reported that of the C terminus which includes the C-terminal Cav1 binding not localization of TRPC1 B.B. X. J. Zhu M.X. Ambudkar I.S. 2002; Full Full PubMed Scopus (125) Google Scholar, B.B. X. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). These data suggest that plasma membrane localization of TRPC1 depends on the interaction of its N but not the C with Cav1. have that plasma membrane localization of both and exogenously expressed TRPC1 was disrupted a Cav1, its protein and membrane was expressed in the cells. Our data that was not of a of plasma membrane lipid raft have also that Cav1 with wild-type TRPC1, although not yet with TRPC1. the membrane that the on TRPC1 localization is the of Cav1 to to the plasma role of Cav1 in the plasma membrane localization of TRPC1 is our data that TRPC1 the Cav1 binding domain is not in the plasma membrane and to a dominant on the SOCE and Ca2+ TRPC1 induced a in with our data that TRPC1 with wild-type TRPC1, data suggest that an important role in the of SOCE in the plasma reported studies suggest that TRPC1 with and with TRPC to SOCE A. L. C. 2000; Full Full PubMed Scopus Google Scholar, M. C. C. E. Luckhoff A. J. FEBS Lett. 2002; PubMed Scopus Google Scholar, B. M. T. C. Zhu M.X. K. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). with have also that exogenously expressed TRPC1 with and with the TRPC1 protein in HSG cells X. Singh B.B. Ambudkar I.S. J. Biol. Chem. Full Full PubMed Scopus Google Scholar). on data suggest that TRPC1 the Cav1 domain with the TRPC1 protein in HSG cells and to the plasma in SOCE on the cell for the of important of data is that of the TRPC to plasma membrane of our data is that interaction is required for the of TRPC1 in the plasma studies be to Cav1 is the that of TRPC1 in the plasma membrane or is involved in of the protein to the cell is assembled SOCE of our data demonstrate that Cav1 has an important role in plasma membrane of SOCE Our data also suggest that not components in the TRPC1 signaling complex are have that Ca2+ is not expression of which that the signaling to TRPC1 are A of signaling that are as and of not Cav1 for to the plasma membrane are to the plasma membrane and are to the TRPC1, not to have for lipid This is with our that TRPC1 is to the plasma membrane a interaction of its N terminus with Cav1. Our data demonstrate that Cav1 is required for the localization of TRPC1 in plasma membrane lipid raft Further, have that the of TRPC1 are in cells TRPC1 cells was in detergent cells full-length Cav1. with the of were with of full-length was in the in the membrane and the of protein that was to be in data demonstrate that interaction of TRPC1 with Cav1 a critical role in the of TRPC1 to plasma membrane lipid raft domains is assembled a signaling complex with key Ca2+ signaling proteins. Our study not the that Cav1 on TRPC1 its binding to the C terminus. as a for the assembly of signaling Cav1 also as a signaling as protein and in a B. A. J. Cell Sci. 2000; PubMed Google Scholar, B. 2001; Full Full PubMed Scopus Google and is involved in M. S. J. FASEB J. 2002; PubMed Scopus Google Scholar). although SOCE was a the involved in its regulation are not yet known. of studies suggest that SOCE is associated with a plasma membrane signaling complex that includes key Ca2+ signaling proteins. with a of TRPC channels, TRPC1, and have been reported to be associated with or of studies our and have that TRPC1 is a molecular component of SOCE in several cell types (5Antoniotti S. Lovisolo D. Fiorio Pla A. Munaron L. FEBS Lett. 2002; 510: 189-195Crossref PubMed Scopus (69) Google Scholar, 6Brough G.H. Wu S. Cioffi D. Moore T.M. Li M. Dean N. Stevens T. FASEB J. 2001; 15: 1727-1738Crossref PubMed Scopus (154) Google Scholar, 7Xu S.Z. Beech D.J. Circ. Res. 2001; 88: 84-87Crossref PubMed Scopus (294) Google Scholar, 8Mori Y. Wakamori M. Miyakawa T. Hermosura M. Hara Y. Nishida M. Hirose K. Mizushima A. Kurosaki M. Mori E. Gotoh K. Okada T. Fleig A. Penner R. Iino M. Kurosaki T. J. Exp. Med. 2002; 195: 673-681Crossref PubMed Scopus (177) Google Scholar, X. Wang W. Singh B.B. Lockwich T. Jadlowiec J. O'Connell B. Weller R. Zhu M.X. Ambudkar I.S. J. Biol. Chem. 2000; 275: 3403-3411Abstract Full Full PubMed Scopus Google Scholar, B.B. C. X. Lockwich T. D. Zhu M.X. L. Ambudkar I.S. FASEB J. 2001; 15: PubMed Scopus Google Scholar, B.B. X. J. Zhu M.X. Ambudkar I.S. 2002; Full Full PubMed Scopus (125) Google Scholar, B.B. X. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar, X. Singh B.B. Ambudkar I.S. J. Biol. Chem. Full Full PubMed Scopus Google Scholar). Further, reported that TRPC1 is assembled in a signaling complex with Cav1 X. Singh B.B. Jadlowiec J. S. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar, T. Singh B.B. X. Ambudkar I.S. J. Biol. Chem. 2001; Full Full PubMed Scopus Google Scholar, B.B. X. Ambudkar I.S. J. Biol. Chem. 2000; 275: Full Full PubMed Scopus Google Scholar). have that plasma membrane localization of TRPC1 depends on an Cav1 binding Importantly, of plasma membrane localization of TRPC1 suppressed on our and previous suggest that Cav1 to the assembly of SOCE in plasma membrane lipid raft studies be required to stimulation of the Ca2+ signaling in activation of SOCE for the and for the also for