Ornithine decarboxylase activity is inhibited by epidermal polyamine-dependent protein kinase-mediated phosphorylation.
Polyamine-dependent protein kinase in cytosol of pig epidermal cells was extracted. The fraction containing this enzyme exhibited multiple polypeptide bands on polyacrylamide gel electrophoresis, including 4 major polypeptide bands and several minor polypeptide bands. A 80 kilodalton (KD) polypeptide, one of the minor polypeptide bands, was phosphorylated by polyamine-dependent protein kinase. Authentic ornithine decarboxylase (ODC) exogenously added was separated into 2 subunits (80 KD and 40 KD) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a 80 KD polypeptide was also phosphorylated by polyamine-dependent protein kinase. A 80 KD polypeptide of ODC comigrated with the polypeptide of cytosol which was phosphorylated by polyamine-dependent protein kinase. Kinetic study revealed that the ODC activity decreased as ODC was phosphorylated. Therefore, ODC activity was inhibited by epidermal polyamine-dependent protein kinase-mediated phosphorylation. The overall results indicate that the rapid turnover of ODC might be regulated by a phosphorylation-dephosphorylation reaction without new protein synthesis.
D000818:Animals; D002848:Chromatography, DEAE-Cellulose; D003600:Cytosol / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D010766:Phosphorylation; D011073:Polyamines / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D012867:Skin / Q000201:enzymology*; D013552:Swine
D011073:Polyamines; D011494:Protein Kinases; D009955:Ornithine Decarboxylase