The Cln3-Cdc28 kinase complex of S. cerevisiae is regulated by proteolysis and phosphorylation.

In Saccharomyces cerevisiae, several of the proteins involved in the Start decision have been identified; these include the Cdc28 protein kinase and three cyclin-like proteins, Cln1, Cln2 and Cln3. We find that Cln3 is a very unstable, low abundance protein. In contrast, the truncated Cln3-1 protein is stable, suggesting that ...
the PEST-rich C-terminal third of Cln3 is necessary for rapid turnover. Cln3 associates with Cdc28 to form an active kinase complex that phosphorylates Cln3 itself and a co-precipitated substrate of 45 kDa. The cdc34-2 allele, which encodes a defective ubiquitin conjugating enzyme, dramatically increases the kinase activity associated with Cln3, but does not affect the half-life of Cln3. The Cln--Cdc28 complex is inactivated by treatment with non-specific phosphatases; prolonged incubation with ATP restores kinase activity to the dephosphorylated kinase complex. It is thus possible that phosphate residues essential for Cln-Cdc28 kinase activity are added autocatalytically. The multiple post-translational controls on Cln3 activity may help Cln3 tether division to growth.
Mesh Terms:
Base Sequence, Blotting, Northern, Blotting, Western, CDC2 Protein Kinase, CDC28 Protein Kinase, S cerevisiae, Cell Cycle, Enzyme Stability, Hydrolysis, Molecular Sequence Data, Phosphorylation, Precipitin Tests, Protein Kinases, Protein Processing, Post-Translational, RNA, Messenger, Saccharomyces cerevisiae, Ubiquitins
EMBO J.
Date: May. 01, 1992
Download Curated Data For This Publication
14859
Switch View:
  • Interactions 2