Temperature-dependent modulation of CaV3 T-type calcium channels by protein kinases C and A in mammalian cells.
Modulation of low voltage-activated Ca(V)3 T-type calcium channels remains poorly characterized compared with high voltage-activated Ca(V)1 and Ca(V)2 calcium channels. Notably, it is yet unresolved whether Ca(V)3 channels are modulated by protein kinases in mammalian cells. In this study, we demonstrate that protein kinase A (PKA) and PKC (but not PKG) activation induces a potent increase in Ca(V)3.1, Ca(V)3.2, and Ca(V)3.3 currents in various mammalian cell lines. Notably, we show that protein kinase effects occur at physiological temperature ( approximately 30-37 degrees C) but not at room temperature ( approximately 22-27 degrees C). This temperature dependence could involve kinase translocation, which is impaired at room temperature. A similar temperature dependence was observed for PKC-mediated increase in high voltage-activated Ca(V)2.3 currents. We also report that neither Ca(V)3 surface expression nor T-current macroscopic properties are modified upon kinase activation. In addition, we provide evidence for the direct phosphorylation of Ca(V)3.2 channels by PKA in in vitro assays. Overall, our results clearly establish the role of PKA and PKC in the modulation of Ca(V)3 T-channels and further highlight the key role of the physiological temperature in the effects described.
Chemin
Jean
J
Département de Physiologie, Institut de Génomique Fonctionnelle, CNRS UMR 5203, INSERM U661, Universités de Montpellier 1 et 2, Institut Fédératif de Recherche 3, 141 Rue de la Cardonille, Montpellier, France. jean.chemin@igf.cnrs.fr
Mezghrani
Alexandre
A
Bidaud
Isabelle
I
Dupasquier
Sebastien
S
Marger
Fabrice
F
Barrère
Christian
C
Nargeot
Joël
J
Lory
Philippe
P
D000818:Animals; D020747:Calcium Channels, T-Type / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D006224:Cricetinae; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004594:Electrophysiology; D018408:Patch-Clamp Techniques; D011493:Protein Kinase C / Q000378:metabolism*; D021381:Protein Transport; D013696:Temperature; D013755:Tetradecanoylphorbol Acetate / Q000031:analogs & derivatives / Q000494:pharmacology
D020747:Calcium Channels, T-Type; C016658:phorbolol myristate acetate; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate