Open Accessp21Waf1 inhibits the activity of cyclin dependent Kinase 2 by preventing its activating phosphorylation
Author(s) -
Masahiro Hitomi,
Junyan Shu,
Munna L. Agarwal,
Archana Agarwal,
Dennis W. Stacey
Publication year - 1998
Publication title -
oncogene
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.395
H-Index - 342
eISSN - 1476-5594
pISSN - 0950-9232
DOI - 10.1038/sj.onc.1202005
Subject(s) - cyclin dependent kinase , cyclin dependent kinase 2 , biology , phosphorylation , kinase , microbiology and biotechnology , cyclin e , cyclin a , cancer research , cell cycle , biochemistry , protein kinase a , cell
Prostaglandin A2 (PGA2), a potent inhibitor of the growth of many cell types, inhibits G1 phase cyclin dependent kinases (cdk). Although PGA2 suppresses cyclin D1 and elevates p21Waf1 levels, it was the failure of cdk2 to become activated by phosphorylation which correlated best with growth inhibition. In kinetic studies, cdk2 activation was inhibited efficiently only if p21Waf1 levels increased prior to the activating phosphorylation; suggesting that p21Waf1 had blocked this phosphorylation. This model was confirmed in cells from p21Waf1 knockout mice where PGA2 was completely unable to block the activating phosphorylation of cdk2, or inhibit cdk2 activity. As expected, growth inhibition of p21Waf1(-/-) cells was not observed at PGA2 concentrations which inhibited cdk2 activity and growth of p21Waf1(+/+) cells.