TRPC3-like protein and vitamin D receptor mediate 1alpha,25(OH)2D3-induced SOC influx in muscle cells.
1alpha,25-Dihydroxy-Vitamin-D3 (1alpha,25(OH)2-Vitamin D3) stimulates in skeletal muscle cells Ca2+ release from inner stores and influx through both voltage-dependent and store-operated Ca2+ (SOC, CCE) channels. We investigated the involvement of TRPC proteins and Vitamin D receptor (VDR) in CCE induced by 1alpha,25(OH)2D3 in chick muscle cells. Two fragments were amplified by RT-PCR, exhibiting approximately 80% sequence homology with mammalian TRPC3/6/7. Northern and Western blots employing a TRPC3-probe and anti-TRPC3 antibodies, respectively, confirmed endogenous expression of a TRPC3-like protein of 140 kDa. Spectrofluorimetric measurements in Fura-2 loaded cells showed reduced CCE and Mn2+ entry in response to either thapsigargin or 1alpha,25(OH)2D3 upon transfection with anti-TRPC3/6/7 antisense oligodeoxynucleotides (ODNs). Transfection with anti-VDR antisense ODNs diminished 1alpha,25(OH)2D3-dependent Ca2+ and Mn2+ influx. Co-immunoprecipitation of TRPC3-like protein and VDR under non-denaturating conditions was observed. We propose that endogenous TRPC3-like proteins and the VDR participate in the modulation of CCE by 1alpha,25(OH)2D3 in muscle cells, which could be mediated by an interaction between these proteins.
Santillán
Graciela
G
Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur. (8000) Bahía Blanca, Argentina.
Katz
Sebastián
S
Vazquez
Guillermo
G
Boland
Ricardo L
RL
D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D002478:Cells, Cultured; D002645:Chickens; D047468:Immunoprecipitation; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism*; D032342:Muscle Cells / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010446:Peptide Fragments / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000378:metabolism*; D050052:TRPC Cation Channels; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000494:pharmacology*
D015220:Calcium Channels; D007473:Ion Channels; D010446:Peptide Fragments; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D050052:TRPC Cation Channels; C104603:TRPC3 cation channel; C118756:dihydroxy-vitamin D3; D014807:Vitamin D; D002118:Calcium