Identification of p34cdc2 kinase from sea urchin Hemicentrotus pulcherrimus and its involvement in the phosphorylation of myosin II regulatory light chain in the metaphase extract

We present here the nucleotide sequence for a cDNA clone encoding p34cdc2 from sea urchin, Hemicentrotus pulcherrimus. The obtained cDNA comprised 301 amino acid residues that contained the PSTAIRE domain to be important for binding to cyclins. Amino acid sequence similarity between this clone and other eukaryotic cdc2 sequences averaged approximately 72%. Using p13suc1-conjugated Sepharose 4B and a selective inhibitor of p34cdc2 kinase, butyrolactone I, it was first suggested that p34cdc2 kinase is involved in the phosphorylation of MRLC at both MLCK site and two PKC sites.