CDK-dependent nuclear localization of B-cyclin Clb1 promotes FEAR activation during meiosis I in budding yeast.
Cyclin-dependent kinases (CDK) are master regulators of the cell cycle in eukaryotes. CDK activity is regulated by the presence, post-translational modification and spatial localization of its regulatory subunit cyclin. In budding yeast, the B-cyclin Clb1 is phosphorylated and localizes to the nucleus during meiosis I. However the functional significance of Clb1's phosphorylation and nuclear localization and their mutual dependency is unknown. In this paper, we demonstrate that meiosis-specific phosphorylation of Clb1 requires its import to the nucleus but not vice versa. While Clb1 phosphorylation is dependent on activity of both CDK and polo-like kinase Cdc5, its nuclear localization requires CDK but not Cdc5 activity. Furthermore we show that increased nuclear localization of Clb1 during meiosis enhances activation of FEAR (Cdc Fourteen Early Anaphase Release) pathway. We discuss the significance of our results in relation to regulation of exit from meiosis I.
University of Warwick, Coventry, United Kingdom.
Katherine Louise
KL
Tibbles
Sourav
S
Sarkar
Bela
B
Novak
Prakash
P
Arumugam
D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D019926:Cyclin B / Q000235:genetics / Q000378:metabolism*; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008540:Meiosis; D008677:Metaphase; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
C074860:CDC14 protein, S cerevisiae; C068264:CLB1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D019926:Cyclin B; D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; C064979:IME2 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; C081927:CDC5 protein, S cerevisiae; D018844:Cyclin-Dependent Kinases; D017027:Protein Tyrosine Phosphatases