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XB-ART-4115
Genes Dev. January 1, 2004; 18 (1): 48-61.

Progesterone and insulin stimulation of CPEB-dependent polyadenylation is regulated by Aurora A and glycogen synthase kinase-3.

Sarkissian M , Mendez R , Richter JD .


Abstract
Progesterone stimulation of Xenopus oocyte maturation requires the cytoplasmic polyadenylation-induced translation of mos and cyclin B mRNAs. One cis element that drives polyadenylation is the CPE, which is bound by the protein CPEB. Polyadenylation is stimulated by Aurora A (Eg2)-catalyzed CPEB serine 174 phosphorylation, which occurs soon after oocytes are exposed to progesterone. Here, we show that insulin also stimulates Aurora A-catalyzed CPEB S174 phosphorylation, cytoplasmic polyadenylation, translation, and oocyte maturation. However, these insulin-induced events are uniquely controlled by PI3 kinase and PKC-zeta, which act upstream of Aurora A. The intersection of the progesterone and insulin signaling pathways occurs at glycogen synthase kinase 3 (GSK-3), which regulates the activity of Aurora A. GSK-3 and Aurora A interact in vivo, and overexpressed GSK-3 inhibits Aurora A-catalyzed CPEB phosphorylation. In vitro, GSK-3 phosphorylates Aurora A on S290/291, the result of which is an autophosphorylation of serine 349. GSK-3 phosphorylated Aurora A, or Aurora A proteins with S290/291D or S349D mutations, have reduced or no capacity to phosphorylate CPEB. Conversely, Aurora A proteins with S290/291A or S349A mutations are constitutively active. These results suggest that the progesterone and insulin stimulate maturation by inhibiting GSK-3, which allows Aurora A activation and CPEB-mediated translation.

PubMed ID: 14724178
PMC ID: PMC314275
Article link: Genes Dev.
Grant support: DK32520 NIDDK NIH HHS , GM46779 NIGMS NIH HHS

Genes referenced: aurka ccnb1.2 cpeb1 gsk3b gys1 ins mos prkcz
Antibodies referenced:
Morpholinos referenced:

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