Determinants of PKC-dependent modulation of a family of neuronal calcium channels

AbstractThe modulation of Ca2+ channel activity by protein kinases contributes to the dynamic regulation of neuronal physiology. Using the transient expression of a family of neuronal Ca2+ channels, we have identified several factors that contribute to the PKC-dependent modulation of Ca2+ channels. First, the nature of the Ca2+ channel α1 subunit protein is critical. Both α1Bα1E channels exhibit a 30%–40% increase in peak currents after exposure to phorbol esters, whereas neither α1A nor α1C channels are significantly affected. This up-regulation can be mimicked for α1E channels by stimulation of a coexpressed metabotropic glutamate receptor (type 1α) through a PKC-dependent pathway. Second, PKC-stimulated up-regulation is dependent upon coexpression with a Ca2+ channel β subunit. Third, substitution of the cytoplasmic domain I–II linker from α1B confers PKC sensitivity to α1A channels. The results provide direct evidence for the modulation of a subset of neuronal Ca2+ channels by PKC and implicate α1 and β subunit interactions in regulating channel activity via second messenger pathways