Identification of a rat liver cAMP-dependent protein kinase, type II, which binds DNA.

A novel protein kinase which specifically binds single strand DNA was identified in rat liver by chromatography on double strand- and single strand- DNA cellulose. This protein kinase activity was stimulated by cAMP and was inhibited by the heat stable inhibitor, suggesting it was a cAMP-dependent protein kinase. Isoelectric focusing studies confirmed that the single strand DNA-binding protein kinase was indeed a cAMP-dependent protein kinase and had the same pI as cAMP-dependent protein kinase, Type II. The DNA binding capacity of this kinase was primarily localized in the regulatory subunit. These results support the recent hypothesis that in addition to regulating enzymatic activity by phosphorylating proteins, cAMP-dependent protein kinase, Type II, may regulate mammalian gene expression through a mechanism similar to that in prokaryotes.