IndraLab
Statements
"Phosphorylated by cdk6 and cdk4, and subsequently by cdk2 at ser-567 in g1, thereby releasing e2f1 which is then able to activate cell growth. Here we show that although these cdks phosphorylate multiple residues in prb, they do so with different residue selectivities in vitro;thr821 and thr826 are preferentially phosphorylated by cdk6 and cdk4, respectively."
"Phosphorylated by cdk6 and cdk4, and subsequently by cdk2 at ser-567 in g1, thereby releasing e2f1 which is then able to activate cell growth. Here we show that although these cdks phosphorylate multiple residues in prb, they do so with different residue selectivities in vitro;thr821 and thr826 are preferentially phosphorylated by cdk6 and cdk4, respectively."
"Phosphorylation was observed 6 hours after p25 induction and was abolished in the presence of a cdk5 inhibitor, roscovitine, which does not inhibit the usual rb cyclin-d kinases cdk4 and cdk6. Furthermore, analyses of levels and subcellular localization of cdk-related cyclins did not reveal any change following cdk5 activation, arguing for a direct effect of cdk5 activity on rb protein. Rb phosphorylation was visualized using phosphorylation-dependent antibodies (p-rbser795 and p-rbser807/811)."
"The retinoblastoma gene product (prb) is a nuclear phosphoprotein that is thought to play a key role in the negative regulation of cellular proliferation. The active form of prb is underphosphorylated. Using synthetic peptides corresponding to potential cdc2 phosphorylation sites, we have developed a strategy which has allowed the identification of five sites. S249, t252, t373, s807 and s811 are phosphorylated in vivo, and in each case these sites correspond closely to the consensus sequence for phosphorylation by p34cdc2."