RRC ID 33951
Author Caspari T, Hilditch V.
Title Two Distinct Cdc2 Pools Regulate Cell Cycle Progression and the DNA Damage Response in the Fission Yeast S.pombe.
Journal PLoS ONE
Abstract The activity of Cdc2 (CDK1) kinase, which coordinates cell cycle progression and DNA break repair, is blocked upon its phosphorylation at tyrosine 15 (Y15) by Wee1 kinase in the presence of DNA damage. How Cdc2 can support DNA repair whilst being inactivated by the DNA damage checkpoint remains to be explained. Human CDK1 is phosphorylated by Myt1 kinase at threonine 14 (T14) close to its ATP binding site before being modified at threonine 161 (T167Sp) in its T-loop by the CDK-activating kinase (CAK). While modification of T161 promotes association with the cyclin partner, phosphorylation of T14 inhibits the CDK1-cyclin complex. This inhibition is further enforced by the modification of Y15 by Wee1 in the presence of DNA lesions. In S.pombe, the dominant inhibition of Cdc2 is provided by the phosphorylation of Y15 and only a small amount of Cdc2 is modified at T14 when cells are in S phase. Unlike human cells, both inhibitory modifications are executed by Wee1. Using the novel IEFPT technology, which combines isoelectric focusing (IEF) with Phos-tag SDS electrophoresis (PT), we report here that S.pombe Cdc2 kinase exists in seven forms. While five forms are phosphorylated, two species are not. Four phospho-forms associate with cyclin B (Cdc13) of which only two are modified at Y15 by Wee1. Interestingly, only one Y15-modified species carries also the T14 modification. The fifth phospho-form has a low affinity for cyclin B and is neither Y15 nor T14 modified. The two unphosphorylated forms may contribute directly to the DNA damage response as only they associate with the DNA damage checkpoint kinase Chk1. Interestingly, cyclin B is also present in the unphosphorylated pool. We also show that the G146D mutation in Cdc2.1w, which renders Cdc2 insensitive to Wee1 inhibition, is aberrantly modified in a Wee1-dependent manner. In conclusion, our work adds support to the idea that two distinct Cdc2 pools regulate cell cycle progression and the response to DNA damage.
Volume 10(7)
Pages e0130748
Published 2015
DOI 10.1371/journal.pone.0130748
PII PONE-D-14-58392
PMID 26131711
PMC PMC4488491
MeSH Amino Acid Sequence CDC2 Protein Kinase / chemistry CDC2 Protein Kinase / genetics CDC2 Protein Kinase / metabolism* Cell Cycle* Cell Cycle Proteins / genetics Cell Cycle Proteins / metabolism Checkpoint Kinase 1 Cyclin B / genetics Cyclin B / metabolism DNA Damage* Molecular Sequence Data Nuclear Proteins / genetics Nuclear Proteins / metabolism Phosphorylation Protein Binding Protein Isoforms / chemistry Protein Isoforms / genetics Protein Isoforms / metabolism Protein Kinases / genetics Protein Kinases / metabolism Protein Processing, Post-Translational* Protein-Tyrosine Kinases / genetics Protein-Tyrosine Kinases / metabolism Schizosaccharomyces / genetics* Schizosaccharomyces / metabolism Schizosaccharomyces pombe Proteins / chemistry Schizosaccharomyces pombe Proteins / genetics Schizosaccharomyces pombe Proteins / metabolism*
IF 2.766
Times Cited 1
WOS Category CELL BIOLOGY
Resource
Yeast S. pombe strains