Cdc37 engages in stable, S14A mutation-reinforced association with the most atypical member of the yeast kinome, Cdk-activating kinase (Cak1).
In most eukaryotes, Cdc37 is an essential chaperone, transiently associating with newly synthesised protein kinases in order to promote their stabilisation and activation. To determine whether the yeast Cdc37 participates in any stable protein interactions in vivo, genomic two-hybrid screens were conducted using baits that are functional as they preserve the integrity of the conserved N-terminal region of Cdc37, namely a Cdc37-Gal4 DNA binding domain (BD) fusion in both its wild type and its S14 nonphosphorylatable (Cdc37(S14A)) mutant forms. While this failed to identify the protein kinases previously identified as Cdc37 interactors in pull-down experiments, it did reveal Cdc37 engaging in a stable association with the most atypical member of the yeast kinome, cyclin-dependent kinase (Cdk1)-activating kinase (Cak1). Phosphorylation of the conserved S14 of Cdc37 is normally crucial for the interaction with, and stabilisation of, those protein kinase targets of Cdc37, Cak1 is unusual in that the lack of this Cdc37 S14 phosphorylation both reinforces Cak1:Cdc37 interaction and does not compromise Cak1 expression in vivo. Thus, this is the first Cdc37 client kinase found to be excluded from S14 phosphorylation-dependent interaction. The unusual stability of this Cak1:Cdc37 association may partly reflect unique structural features of the fungal Cak1.
Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK.
Stefan
S
Millson
Patricija
P
van Oosten-Hawle
Mohammed A
MA
Alkuriji
Andrew
A
Truman
Marco
M
Siderius
Peter W
PW
Piper
D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism*; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D005838:Genotype; D018832:Molecular Chaperones / Q000235:genetics* / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D000095043:Cyclin-Dependent Kinase-Activating Kinase
C513270:CDC37 protein, S cerevisiae; D018797:Cell Cycle Proteins; D018832:Molecular Chaperones; D029701:Saccharomyces cerevisiae Proteins; D017346:Protein Serine-Threonine Kinases; D018844:Cyclin-Dependent Kinases; D000095043:Cyclin-Dependent Kinase-Activating Kinase