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Echinobase
ECB-ART-31193
Biochem J 1992 May 01;283 ( Pt 3):829-37. doi: 10.1042/bj2830829.
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Purification and characterization of echinoderm casein kinase II. Regulation by protein kinase C.

Sanghera JS , Charlton LA , Paddon HB , Pelech SL .


Abstract
Casein kinase II (CKII) is one of several protein kinases that become activated before germinal-vesicle breakdown in maturing sea-star oocytes. Echinoderm CKII was purified over 11,000-fold with a recovery of approximately 10% by sequential fractionation of the oocyte cytosol on tyrosine-agarose, heparin-agarose, casein-agarose and MonoQ. The purified enzyme contained 45, 38 and 28 kDa polypeptides, which corresponded to its alpha, alpha'' and beta subunits respectively. The beta-subunit was autophosphorylated on one major tryptic peptide on serine residues, whereas the alpha''-subunit incorporated phosphate into at least two tryptic peptides primarily on threonine residues. Western-blotting analysis of sea-star oocyte extracts with two different anti-peptide antibodies that recognized conserved regions of the alpha-subunit indicated that the protein levels of the alpha- and alpha''-subunits of CKII were unchanged during oocyte maturation. The purified CKII was partly inactivated (by 25%) by preincubation with protein-serine/threonine phosphatase 2A, but protein-tyrosine phosphatases had no effect. The beta-subunit of CKII was phosphorylated on a serine residue(s) up to 0.54 mol of P/mol of beta-subunit by purified protein kinase C, and this correlated with a 1.5-fold enhancement of its phosphotransferase activity with phosvitin as a substrate. CKII was not a substrate for the maturation-activated myelin basic protein kinase p44mpk from sea-star oocytes, nor for cyclic-AMP-dependent protein kinase. These studies point to possible regulation of CKII by protein phosphorylation.

PubMed ID: 1590772
PMC ID: PMC1130961
Article link: Biochem J


Genes referenced: LOC100887844 LOC586799 pkcl2

References [+] :
Ackerman, Regulation of casein kinase II activity by epidermal growth factor in human A-431 carcinoma cells. 1989, Pubmed