Invitrogen™ Phospho-p27 Kip1 (Thr157) Polyclonal Antibody

p27 Kip1 functions as a negative regulator of G1 mouse expression and has been proposed to function as a possible mediator of TGFb induced G1 arrest. p27 Kip1 is an important regulator of cell cycle progression, a potent inhibitor of cyclin E- and cyclin A-CDK2 complexes. p27 Kip1 forms a complex with cyclin type D-CDK4 complexes and is involved in the assembly, stability, and modulation of CCND1-CDK4 complex activation. p27 Kip1 acts either as an inhibitor or an activator of cyclin type D-CDK4 complexes depending on its phosphorylation state and/or stoichometry. p27 Kip1 has a molecular weight of approximately 27kDa and the degradation of this protein, which is triggered by its CDK dependent phosphorylation and subsequent ubiquitination by SCF complexes, is required for the cellular transition from quiescence to the proliferative state.