title: Interaction between TRPC channel subunits in endothelial cells.
abstract: Transient Receptor Potential Canonical (TRPC) proteins have been identified in mammals as a family of plasma membrane calcium-permeable channels activated by different kinds of stimuli in several cell types. We have studied TRPC subunit expression in bovine aortic endothelial (BAE-1) cells, where stimulation with basic fibroblast growth factor (bFGF), a potent angiogenetic factor, induces calcium entry carried at least partially by TRPC1 channels. By means of a RT-PCR approach, we have found that, in addition to TRPC1, only TRPC4 is expressed, both at the mRNA and protein level, as confirmed by immunoblotting and immunocytochemical analysis. Because functional TRPC channels are formed by assembly of four subunits in either homo- or heterotetrameric structures, we have carried out immunoprecipitation experiments and showed that TRPC1 and TRPC4 interact to form heteromers in these cells, independently from culture conditions (high or low percent of fetal calf serum, stimulation with bFGF). Moreover, the data show that TRPC subunits are not tyrosine-phosphorylated after bFGF stimulation and they do not co-immunoprecipitate with the type 1 FGF receptor. These results suggest that BAE-1 cells are a suitable model to study function and regulation of endogenous TRPC1/TRPC4 heteromers.
authors.affiliation: Department of Animal and Human Biology, University of Torino, Torino, Italy. susanna.antoniotti@unito.it
authors.forename: Susanna
authors.initials: S
authors.lastname: Antoniotti
authors.forename: Alessandra
authors.initials: A
authors.lastname: Fiorio Pla
authors.forename: Serena
authors.initials: S
authors.lastname: Barral
authors.forename: Orietta
authors.initials: O
authors.lastname: Scalabrino
authors.forename: Luca
authors.initials: L
authors.lastname: Munaron
authors.forename: Davide
authors.initials: D
authors.lastname: Lovisolo
mesh_terms: D000818:Animals; D001011:Aorta / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D018919:Neovascularization, Physiologic; D010455:Peptides / Q000737:chemistry; D012333:RNA, Messenger / Q000378:metabolism; D051496:Receptor, Fibroblast Growth Factor, Type 1 / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050052:TRPC Cation Channels / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism*
chemical_list: D010455:Peptides; D012333:RNA, Messenger; D050052:TRPC Cation Channels; C489571:TRPC4 ion channel; C096351:transient receptor potential cation channel, subfamily C, member 1; D016222:Fibroblast Growth Factor 2; D051496:Receptor, Fibroblast Growth Factor, Type 1