Open AccessIdentification of phosphoproteins correlated with proliferation and cell cycle arrest in Saccharomyces cerevisiae: positive and negative regulation by cAMP-dependent protein kinase.
Author(s) -
Matthew L. Tripp,
R. Piñón,
Jill Meisenhelder,
Tony Hunter
Publication year - 1986
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.83.16.5973
Subject(s) - phosphoprotein , protein kinase a , phosphorylation , biology , protein phosphorylation , adenylate kinase , microbiology and biotechnology , biochemistry , threonine , kinase , serine , cell cycle , cdc25 , cell growth , phosphorylation cascade , cyclin dependent kinase 1 , cell , enzyme
Recent genetic and biochemical studies of two mutants of the cAMP pathway in yeast, cyr1 and bcy1, have demonstrated that cAMP-dependent protein phosphorylation plays a major regulatory role in the control of proliferation and differentiation. As a first step in examining this regulatory system in more detail and in identifying the protein substrates of cAMP-dependent protein kinase, we have analyzed phosphoprotein patterns in the mutants cyr1-2(ts) and bcy1 by two-dimensional polyacrylamide gel electrophoresis. Our analysis has revealed several proteins whose phosphorylation is controlled positively or negatively by the cAMP pathway in yeast. The presence of some of these phosphoproteins was directly associated with proliferation (positive regulation), while that of others was correlated with cell cycle arrest (negative regulation). The phosphoprotein patterns of cyr1-2(ts) temperature-arrested cells, and nitrogen (NH+4)-starved cells, were strikingly similar, suggesting that response to NH+4 is mediated in part by adenylate cyclase. Phosphoproteins whose presence correlated with cell cycle arrest were found to be phosphorylated on serine and threonine residues, while the major phosphoproteins present predominantly in proliferating cells were phosphorylated only on serine residues. None of the greater than 20 phosphoproteins we examined contained phosphotyrosine under either growth condition.