p27, a novel inhibitor of G1 cyclin-Cdk protein kinase activity, is related to p21

H Toyoshima, T Hunter - Cell, 1994 - cell.com
H Toyoshima, T Hunter
Cell, 1994cell.com
Using a yeast interaction screen to search for proteins that interact with cyclin Dl-Cdk4, we
identified a 27 kDa mouse protein related to the p21 cyclin-Cdk inhibitor. p27 interacts
strongly with D-type cyclins and Cdk4 in vitro and more weakly with cyclin E and Cdk2. In
mouse fibroblasts, p27 is associated predominantly with cyclin Dl-Cdk4. Recombinant p27 is
a potent inhibitor of cyclin Dl-Cdk4 and cyclin A-Cdk2 protein kinase activity and a weaker
inhibitor of cyclin Bl-Cdc2. Overexpression of p27 in Saos-2 cells causes Gl arrest. p27 …
Summary
Using a yeast interaction screen to search for proteins that interact with cyclin Dl-Cdk4, we identified a 27 kDa mouse protein related to the p21 cyclin-Cdk inhibitor. p27 interacts strongly with D-type cyclins and Cdk4 in vitro and more weakly with cyclin E and Cdk2. In mouse fibroblasts, p27 is associated predominantly with cyclin Dl-Cdk4. Recombinant p27 is a potent inhibitor of cyclin Dl-Cdk4 and cyclin A-Cdk2 protein kinase activity and a weaker inhibitor of cyclin Bl-Cdc2. Overexpression of p27 in Saos-2 cells causes Gl arrest. p27 protein levels do not change as serumstimulated quiescent mouse fibroblasts progress through the cell cycle. p27 is identical to~ 27~‘p’, a cyclin-Cdk inhibitor present in TGFP-treated cells. p27 has the hallmarks of a negative regulator of Gl progression and may mediate TGFfi-induced Gl arrest.
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