Ubiquitination of the G1 cyclin Cln2p by a Cdc34p-dependent pathway.

AUTOR(ES)

Deshaies, R J

RESUMO

Recombinant G1 cyclin Cln2p can bind to and stimulate the protein kinase activity of p34CDC28 (Cdc28p) in an extract derived from cyclin-depleted and G1-arrested Saccharomyces cerevisiae cells. Upon activating Cdc28p, Cln2p is extensively phosphorylated and conjugated with multiubiquitin chains. Ubiquitination of Cln2p in vitro requires the Cdc34p ubiquitin-conjugating enzyme, Cdc28p, protein phosphorylation and unidentified factors in yeast extract. Ubiquitination of Cln2p by Cdc34p contributes to the instability of Cln2p in vivo, as the rate of Cln2p degradation is reduced in cdc34ts cells. These results provide a molecular framework for G1 cyclin instability and suggest that a multicomponent, regulated pathway specifies the selective ubiquitination of G1 cyclins.

Documentos Relacionados

• G1 cyclin-dependent activation of p34CDC28 (Cdc28p) in vitro.
• Mechanisms Controlling Subcellular Localization of the G1 Cyclins Cln2p and Cln3p in Budding Yeast
• Activation of CLN1 and CLN2 G1 cyclin gene expression by BCK2.
• The cyclin-dependent kinase inhibitor p40SIC1 imposes the requirement for Cln G1 cyclin function at Start.
• Structure-function analysis of the Saccharomyces cerevisiae G1 cyclin Cln2.