Phosphorylation of protein kinase C by casein kinase‐1

Abstract

Because phosphorylation of protein kinase C (PKC) may provide a mechanism for regulation of this enzyme, we have examined the ability of two other kinases to phosphorylate PKC. Our results show that casein kinase 1 (CK‐1), but not casein kinase 2 (CK‐2), can phosphorylate PKC in the absence of Ca2+ and phospholipids. The 32P incorporation into PKC in the presence of Ca2+ and phospholipids is also enhanced by CK‐1.

The mechanism of protein kinase C regulation

“…Other known protein kinases which phosphorylate PKC isoforms include casein kinase-1 (CK1) and casein kinase-2 (CK2). Rat brain PKC was shown to be phosphorylated by CK1 (Vila et al, 1989). Another report demonstrated that PKCβ was phosphorylated by rat lung CK2 and that neither PKCγ nor PKCα was significantly phosphorylated by the same kinase (Tominaga et al, 1991).…”