Send to

Choose Destination
Mol Cell. 2008 Oct 24;32(2):210-20. doi: 10.1016/j.molcel.2008.08.029.

Meiotic inactivation of Xenopus Myt1 by CDK/XRINGO, but not CDK/cyclin, via site-specific phosphorylation.

Author information

CNIO (Spanish National Cancer Center), Melchor Fernández Almagro 3, 28029 Madrid, Spain.


Cell-cycle progression is regulated by cyclin-dependent kinases (CDKs). CDK1 and CDK2 can be also activated by noncyclin proteins named RINGO/Speedy, which were identified as inducers of the G2/M transition in Xenopus oocytes. However, it is unclear how XRINGO triggers M phase entry in oocytes. We show here that XRINGO-activated CDKs can phosphorylate specific residues in the regulatory domain of Myt1, a Wee1 family kinase that plays a key role in the G2 arrest of oocytes. We have identified three Ser that are major phosphoacceptor sites for CDK/XRINGO but are poorly phosphorylated by CDK/cyclin. Phosphorylation of these Ser inhibits Myt1 activity, whereas their mutation makes Myt1 resistant to inhibition by CDK/XRINGO. Our results demonstrate that XRINGO-activated CDKs have different substrate specificity than the CDK/cyclin complexes. We also describe a mechanism of Myt1 regulation based on site-specific phosphorylation, which is likely to mediate the induction of G2/M transition in oocytes by XRINGO.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center