Inactivation of DNA polymerase beta by in vitro phosphorylation with protein kinase C

• Published in: The Journal of biological chemistry 1991-06, Vol.266 (17), p.10820-10824
• Main Authors: TOKUI, T, INAGAKI, M, NISHIZAWA, K, YATANI, R, KUSAGAWA, M, AJIRO, K, NISHIMOTO, Y, DATE, T, MATSUKAGE, A
• Format: Article
• Language: English
• Subjects: Alkaline Phosphatase - metabolism; Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Binding Sites; Biological and medical sciences; Brain - enzymology; Chromatography, Affinity; DNA Polymerase I - antagonists & inhibitors; DNA Polymerase I - isolation & purification; DNA Polymerase I - metabolism; DNA, Single-Stranded - metabolism; Enzymes and enzyme inhibitors; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; Kinetics; Macromolecular Substances; Molecular Sequence Data; Myocardium - enzymology; Phosphorylation; Protein Kinase C - metabolism; Rats; Recombinant Proteins - antagonists & inhibitors; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Substrate Specificity; Transferases
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)99092-7

The Mr = 38,300 polypeptide of the purified recombinant rat DNA polymerase beta served as an excellent substrate for protein kinase C (PKC) in vitro but not for the catalytic subunit of cAMP-dependent protein kinase. The phosphorylation by PKC resulted in inactivation of DNA polymerase beta activity, and recovery was achieved by dephosphorylation with alkaline phosphatase. Since the phosphorylated DNA polymerase beta was retained with use of a single-stranded DNA-cellulose column, inactivation might occur at a site different from that for the DNA binding. Amino acid sequence analysis of the phosphopeptides revealed that the phosphorylated sites were 2 serine residues at positions 44 and 55 from the NH2 terminus, either or both of which might be involved in the catalytic activity of DNA polymerase beta. Thus, the inactivation of the DNA repair enzyme, DNA polymerase beta, by PKC may be an important process in the modification of DNA metabolism in the nucleus through signal transduction processes.