Ca(2+)-dependent interaction between FKBP12 and calcineurin regulates activity of the Ca(2+) release channel in skeletal muscle.
Calcineurin is a Ca(2+) and calmodulin-dependent protein phosphatase with diverse cellular functions. Here we examined the physical and functional interactions between calcineurin and ryanodine receptor (RyR) in a C2C12 cell line derived from mouse skeletal muscle. Coimmunoprecipitation experiments revealed that the association between RyR and calcineurin exhibits a strong Ca(2+) dependence. This association involves a Ca(2+) dependent interaction between calcineurin and FK506-binding protein (FKBP12), an accessory subunit of RyR. Pretreatment with cyclosporin A, an inhibitor of calcineurin, enhanced the caffeine-induced Ca(2+) release (CICR) in C2C12 cells. This effect was similar to those of FK506 and rapamycin, two drugs known to cause dissociation of FKBP12 from RyR. Overexpression of a constitutively active form of calcineurin in C2C12 cells, DeltaCnA(391-521) (deletion of the last 131 amino acids from calcineurin), resulted in a decrease in CICR. This decrease in CICR activity was partially recovered by pretreatment with cyclosporin A. Furthermore, overexpression of an endogenous calcineurin inhibitor (cain) or an inactive form of calcineurin (DeltaCnA(H101Q)) in C2C12 cells resulted in up-regulation of CICR. Taken together, our data suggest that a trimeric-interaction among calcineurin, FKBP12, and RyR is important for the regulation of the RyR channel activity and may play an important role in the Ca(2+) signaling of muscle contraction and relaxation.
Shin
Dong Wook
DW
Department of Physiology and Biophysics, UMDNJ-Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA.
Pan
Zui
Z
Bandyopadhyay
Arun
A
Bhat
Manjunatha B
MB
Kim
Do Han
DH
Ma
Jianjie
J
D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D015153:Blotting, Western; D016466:CHO Cells; D002110:Caffeine / Q000494:pharmacology; D019703:Calcineurin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002411:Cation Exchange Resins / Q000494:pharmacology; D002460:Cell Line; D003001:Cloning, Molecular; D006224:Cricetinae; D016572:Cyclosporine / Q000494:pharmacology; D018076:DNA, Complementary / Q000378:metabolism; D019281:Dimerization; D015536:Down-Regulation; D017353:Gene Deletion; D049452:Green Fluorescent Proteins; D008055:Lipids / Q000494:pharmacology; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D018482:Muscle, Skeletal / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism*; D015398:Signal Transduction; D020123:Sirolimus / Q000494:pharmacology; D022061:Tacrolimus Binding Protein 1A / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D000596:Amino Acids; D002411:Cation Exchange Resins; D018076:DNA, Complementary; D008055:Lipids; C086724:Lipofectamine; D008164:Luminescent Proteins; D019837:Ryanodine Receptor Calcium Release Channel; D049452:Green Fluorescent Proteins; D002110:Caffeine; D016572:Cyclosporine; D019703:Calcineurin; D022061:Tacrolimus Binding Protein 1A; D002118:Calcium; D020123:Sirolimus