Modulation of Ca v 3.2 T‐type Ca 2+ channels by protein kinase C

Although T‐type Ca 2+ 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 Ca v 3.2 T‐type channels reconstituted in Xenopus oocytes. Phorbol‐12‐myristate‐13‐acetate (PMA) strongly enhanced the amplitude of Ca v 3.2 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 Ca v 3.2 channel activity via activation of oocyte PKC.