title: Overexpression of transient receptor potential canonical type 1 (TRPC1) alters both store operated calcium entry and depolarization-evoked calcium signals in C2C12 cells.
abstract: When the intracellular calcium stores are depleted, a Ca(2+) influx is activated to refill these stores. This store-operated Ca(2+) entry (SOCE) depends on the cooperation of several proteins as STIM1, Orai1, and, possibly, TRPC1. To elucidate this role of TRPC1 in skeletal muscle, TRPC1 was overexpressed in C2C12 cells and SOCE was studied by measuring the changes in intracellular Ca(2+) concentration ([Ca(2+)](i)). TRPC1 overexpression significantly increased both the amplitude and the maximal rate-of-rise of SOCE. When YM-58483, an inhibitor of TRPC1 was used, these differences were eliminated, moreover, SOCE was slightly suppressed. A decrease in the expression of STIM1 together with the downregulation of SERCA was confirmed by Western-blot. As a consequence, a reduction in maximal Ca(2+) uptake rate and a higher resting [Ca(2+)](i) following the Ca(2+) transients evoked by 120mM KCl were detected. Morphological changes also accompanied the overexpression of TRPC1. Differentiation of the myoblasts started later, and the myotubes were thinner in TRPC1-overexpressing cultures. For these changes the observed decrease in the nuclear expression of NFAT1 could be responsible. Our results suggest that enhanced expression of TRPC1 increases SOCE and has a negative effect on the STIM1-Orai1 system, indicating an interaction between these proteins.
authors.affiliation: Department of Physiology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Oláh
authors.forename: János
authors.initials: J
authors.lastname: Fodor
authors.forename: Olga
authors.initials: O
authors.lastname: Ruzsnavszky
authors.forename: János
authors.initials: J
authors.lastname: Vincze
authors.forename: Celine
authors.initials: C
authors.lastname: Berbey
authors.forename: Bruno
authors.initials: B
authors.lastname: Allard
authors.forename: László
authors.initials: L
authors.lastname: Csernoch
mesh_terms: D000813:Anilides / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling; D002460:Cell Line; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D000071740:ORAI1 Protein; D011189:Potassium Chloride / Q000494:pharmacology; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism; D000071737:Stromal Interaction Molecule 1; D050052:TRPC Cation Channels / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D013830:Thiadiazoles / Q000494:pharmacology
chemical_list: C476308:4-methyl-4'-(3,5-bis(trifluoromethyl)-1H-pyrazol-1-yl)-1,2,3-thiadiazole-5-carboxanilide; D000813:Anilides; D015220:Calcium Channels; D008562:Membrane Glycoproteins; D000071740:ORAI1 Protein; C520430:Orai1 protein, mouse; C100757:Stim1 protein, mouse; D000071737:Stromal Interaction Molecule 1; D050052:TRPC Cation Channels; D013830:Thiadiazoles; C096351:transient receptor potential cation channel, subfamily C, member 1; D011189:Potassium Chloride; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D002118:Calcium