1. Regulation of MBK-2/DYRK by CDK-1 and the Pseudophosphatases EGG-4 and EGG-5 during the Oocyte-to-Embryo Transition
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Cheng, Ken Chih-Chien, Klancer, Richard, Singson, Andrew, and Seydoux, Geraldine
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Tyrosine ,Proteins ,Phosphotransferases ,Phosphatases ,Biological sciences - Abstract
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cell.2009.08.047 Byline: Ken Chih-Chien Cheng (1), Richard Klancer (2), Andrew Singson (2), Geraldine Seydoux (1) Keywords: DEVBIO; SIGNALING Abstract: DYRKs are kinases that self-activate in vitro by autophosphorylation of a YTY motif in the kinase domain, but their regulation in vivo is not well understood. In C. elegans zygotes, MBK-2/DYRK phosphorylates oocyte proteins at the end of the meiotic divisions to promote the oocyte-to-embryo transition. Here we demonstrate that MBK-2 is under both positive and negative regulation during the transition. MBK-2 is activated during oocyte maturation by CDK-1-dependent phosphorylation of serine 68, a residue outside of the kinase domain required for full activity in vivo. The pseudotyrosine phosphatases EGG-4 and EGG-5 sequester activated MBK-2 until the meiotic divisions by binding to the YTY motif and inhibiting MBK-2's kinase activity directly, using a mixed-inhibition mechanism that does not involve tyrosine dephosphorylation. Our findings link cell-cycle progression to MBK-2/DYRK activation and the oocyte-to-embryo transition. Author Affiliation: (1) Department of Molecular Biology and Genetics and Howard Hughes Medical Institute, Center for Cell Dynamics, Johns Hopkins School of Medicine, 725 N. Wolfe Street, PCTB 706, Baltimore, MD 21205, USA (2) Waksman Institute and Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA Article History: Received 10 December 2008; Revised 4 June 2009; Accepted 26 August 2009 Article Note: (miscellaneous) Published: October 29, 2009
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- 2009