Proteolytic activation of protein kinase C‐ɛ

Abstract

Proteolysis of native protein kinase C-.epsilon. (PKC-.epsilon.) is shown to occur through tryptic attack at multiple sites within the PCK-.epsilon. V2/V3 domain. Following initial cleavage of PCK-.epsilon. with trypsin, the kinase activity using a synthetic peptide substrate was found to be lipid/phorbol-ester independent, as observed for other members of this kinase family. Interestingly, there is also an increase in the histone kinase activity, indicating that there is an influence of the regulatory domain of the enzyme on substrate specificity. This is discussed in the context of alternatively spliced PKC-.epsilon. mRNAs that are shown to be present in brain and lung tissues.