Modulation of Cav3.2 T‐type Ca2+ channels by protein kinase C

Abstract
Although T‐type Ca2+ channels have been implicated in numerous physiological functions, their regulations by protein kinases have been obscured by conflicting reports. We investigated the effects of protein kinase C (PKC) on Cav3.2 T‐type channels reconstituted in Xenopus oocytes. Phorbol‐12‐myristate‐13‐acetate (PMA) strongly enhanced the amplitude of Cav3.2 channel currents (∼3‐fold). The augmentation effects were not mimicked by 4α‐PMA, an inactive stereoisomer of PMA, and abolished by preincubation with PKC inhibitors. Our findings suggest that PMA upregulates Cav3.2 channel activity via activation of oocyte PKC.