Translational Medicine Branch (TMB), National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
Cell Cycle. 2010 Dec 1;9(23):4720-34. doi: 10.4161/cc.9.23.14090.
Mechanisms of cAMP/PKA-induced meiotic arrest in oocytes are not completely identified. In cultured, G2/M-arrested PDE3A(-/-) murine oocytes, elevated PKA activity was associated with inactivation of Cdc2 and Plk1, and inhibition of phosphorylation of histone H3 (S10) and of dephosphorylation of Cdc25B (S323) and Cdc2 (Thr14/Tyr15). In cultured WT oocytes, PKA activity was transiently reduced and then increased to that observed in PDE3A(-/-) oocytes; Cdc2 and Plk1 were activated, phosphorylation of histone H3 (S10) and dephosphorylation of Cdc25B (S323) and Cdc2 (Thr14/Tyr15) were observed. In WT oocytes, PKAc were rapidly translocated into nucleus, and then to the spindle apparatus, but in PDE3A(-/-) oocytes, PKAc remained in the cytosol. Plk1 was reactivated by incubation of PDE3A(-/-) oocytes with PKA inhibitor, Rp-cAMPS. PDE3A was co-localized with Plk1 in WT oocytes, and co-immunoprecipitated with Plk1 in WT ovary and Hela cells. PKAc phosphorylated rPlk1 and Hela cell Plk1 and inhibited Plk1 activity in vitro. Our results suggest that PKA-induced inhibition of Plk1 may be critical in oocyte meiotic arrest and female infertility in PDE3A(-/-) mice.
cAMP/PKA 诱导卵母细胞减数分裂阻滞的机制尚未完全确定。在培养的 G2/M 期阻滞的 PDE3A(-/-) 小鼠卵母细胞中，升高的 PKA 活性与 Cdc2 和 Plk1 的失活以及组蛋白 H3（S10）磷酸化和 Cdc25B（S323）和 Cdc2（Thr14/Tyr15）去磷酸化的抑制有关。在培养的 WT 卵母细胞中，PKA 活性短暂降低，然后增加到 PDE3A(-/-)卵母细胞中观察到的水平；Cdc2 和 Plk1 被激活，观察到组蛋白 H3（S10）磷酸化和 Cdc25B（S323）和 Cdc2（Thr14/Tyr15）去磷酸化。在 WT 卵母细胞中，PKAc 迅速易位到核内，然后到纺锤体装置，但在 PDE3A(-/-)卵母细胞中，PKAc 仍留在细胞质中。Plk1 通过用 PKA 抑制剂 Rp-cAMPS 孵育 PDE3A(-/-)卵母细胞而被重新激活。PDE3A 在 WT 卵母细胞中与 Plk1 共定位，并在 WT 卵巢和 Hela 细胞中与 Plk1 共免疫沉淀。PKAc 磷酸化 rPlk1 和 Hela 细胞 Plk1，并在体外抑制 Plk1 活性。我们的结果表明，PKA 诱导的 Plk1 抑制可能在 PDE3A(-/-) 小鼠卵母细胞减数分裂阻滞和女性不育中起关键作用。
