In vivo actions of protein phosphatase inhibitor-2 in Xenopus oocytes.
Meiotic maturation of amphibian oocytes induced by progesterone is known to be regulated by protein phosphorylation. To investigate a possible role for protein phosphatase-1 in this process, the effect of phosphatase inhibitor-2 was determined on the in vivo rate of dephosphorylation of phosphorylase a and on the rate of oocyte maturation. Dephosphorylation of microinjected phosphorylase a was inhibited up to 40% in the presence of inhibitor-2, with half-maximal inhibition at an intracellular concentration of 0.6 microM. Inhibitor-2 also caused over a 3-fold increase in the half-time for maturation, suggesting a possible role for protein phosphatase-1 in the regulation of meiosis.
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000378:metabolism*; D005260:Female; D008345:Manganese / Q000494:pharmacology; D009865:Oocytes / Q000254:growth & development / Q000378:metabolism*; D010063:Ovum / Q000378:metabolism*; D010762:Phosphorylase a / Q000378:metabolism; D011506:Proteins; D014982:Xenopus laevis; D000097847:Protein Phosphatase Inhibitory Proteins
D004791:Enzyme Inhibitors; D008345:Manganese; D010762:Phosphorylase a; D011506:Proteins; C024833:protein phosphatase inhibitor-2; D000097847:Protein Phosphatase Inhibitory Proteins