Phosphorylation of a low Mr high mobility group protein in Chinese hamster ovary cells.
Phosphorylation of high mobility group (HMG) chromatin proteins was studied both in intact Chinese hamster ovary cells (strain CHO-P22) and in vitro conditions using isolated HMG proteins from the same cells and purified protein kinases. Prominent phosphorylation of serine in a low Mr HMG protein designated as HMG P was observed in unsynchronized cells. Of the three protein kinases tested, only nuclear type II protein kinase phosphorylated HMG P in vitro. The phosphorylated amino acid was phosphoserine. Cyclic nucleotide dependent protein kinases did not phosphorylate HMG P but phosphorylated HMG 14 with a preference for cGMP-dependent protein kinase. 32P-labeling of HMG 17 was not observed in intact cells or in vitro.
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D006609:High Mobility Group Proteins / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D008970:Molecular Weight; D010053:Ovary; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism
D006609:High Mobility Group Proteins; D006657:Histones; D010750:Phosphoproteins; D010768:Phosphoserine; D011494:Protein Kinases