TORC1 coordinates the conversion of Sic1 from a target to an inhibitor of cyclin-CDK-Cks1.

ABSTRACT: Eukaryotic cell cycle progression through G₁-S is driven by hormonal and growth-related signals that are transmitted by the target of rapamycin complex 1 (TORC1) pathway. In yeast, inactivation of TORC1 restricts G₁-S transition due to the rapid clearance of G₁ cyclins (Cln) and the stabilization of the B-type cyclin (Clb) cyclin-dependent kinase (CDK) inhibitor Sic1. The latter mechanism remains mysterious but requires the phosphorylation of Sic1-Thr¹⁷³ by Mpk1 and inactivation of the Sic1-pThr¹⁷³-targeting phosphatase (PP2A^Cdc55) through greatwall kinase-activated endosulfines. Here we show that the Sic1-pThr¹⁷³ residue serves as a specific docking site for the CDK phospho-acceptor subunit Cks1 that sequesters,

SUBMITTER: Moreno-Torres M 

PROVIDER: S-EPMC5412858 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature