Title: Vertebrate p34<i>cdc2</i> phosphorylation site mutants: effects upon cell cycle progression in the fission yeast <i>Schizosaccharomyces pombe</i>
Abstract: ABSTRACT We have used the fission yeast Schizosaccharomyces pombe to analyse the effects of in vitro mutagenesis of the four known phosphorylation sites in the chicken p34cdc2 protein, Thr14, Tyr15, Thr161 and Ser277, upon cell cycle progression. We have studied both the effect of overexpression of mutant proteins in a cdc2+ background and assayed their ability to rescue null and temperature-sensitive alleles of cdc2. Mutations of Thrl4 and Tyrl5 within the ATP binding domain of p34cdc2 that mimic constitutive phosphorylation cause dominant negative cell cycle arrest when overexpressed. In contrast, some substitutions that simulate permanent dephosphorylation of the corresponding sites advance mitosis. These data confirm the model that p34cdc2 function is negatively regulated by phosphorylation of residues in the ATP binding site. Mutagenesis of the conserved residue Thr161 functionally inactivates p34cdc2, and our data suggest that both phosphorylation and dephosphorylation events at Thr161 are required for progression through the cell cycle. Mutations at the fourth site of phosphorylation, Ser277, lead to coldsensitive cell cycle arrest, in minimal but not rich growth medium, suggesting that this site is involved in monitoring the nutritional status of the cell.
Publication Year: 1992
Publication Date: 1992-05-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
Access and Citation
Cited By Count: 41
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot