PP2ACdc55regulates G1cyclin stability

摘要: Maintaining accurate progression through the cell cycle requires proper temporal expression and regulation of cyclins. The mammalian D-type cyclins promote G1-S transition. D1 cyclin protein stability is regulated its ubiquitylation resulting proteolysis catalyzed by SCF E3 ubiquitin ligase complex containing F-box protein, Fbx4. E3-ligase-dependent trigged an increase in phosphorylation status cyclin. As inhibition ubiquitin-dependent degradation seen many human cancers, we set out to uncover how regulated. Here show that S. cerevisiae, a heterotrimeric phosphatase 2A (PP2A(Cdc55)) PPP2R2/PR55 B subunit ortholog Cdc55 regulates G1 Cln2 directly regulating state. Cells lacking contain drastically reduced levels caused due cdk-dependent hyperphosphorylation, as mutant unable be phosphorylated yeast cdk Cdc28 highly stable cdc55-null cells. Moreover, cells become inviable when SCF(Grr1) activity known regulate eliminated or overexpressed, indicating critical relationship between PP2A functions modulation degradation/stability. In sum, our results indicate absolutely required maintain modulating their status, event necessary properly transit cycle.