Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.16 (calcineurin)
 17,112 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The puromycin analog N6,N6-dimethyladenine (6-dimethylaminopurine or 6-DMAP) was found to inhibit meiosis reinitiation in starfish oocytes stimulated by the natural hormone 1-methyladenine. Increasing concentrations of this agent delayed and eventually blocked germinal vesicle breakdown. They were found to be effective even when applied during the hormone-independent period, after the oocytes had been already committed to reinitiate meiosis. 6-DMAP mimics most of the effects of emetine since it induces protein dephosphorylation, inhibits polar body formation, and promotes the precocious appearance of resting nuclei. However, unlike emetine, 6-DMAP does not affect protein synthesis. The effect of this agent cannot be accounted for by a stimulation of the protease or phosphoprotein phosphatase activities since the rate and extent of protein dephosphorylation do not increase in its presence. Data from in vivo and in vitro endogenous protein phosphorylation experiments suggest rather that 6-DMAP may directly or indirectly affect the activity of a relevant c-AMP and Ca2+-independent protein kinase which is stimulated after hormone addition and seems to support starfish oocyte maturation.
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PMID:6-Dimethylaminopurine blocks starfish oocyte maturation by inhibiting a relevant protein kinase activity. 283 30

The transition from metaphase to interphase involves protein dephosphorylation. Genetic and immunologic evidence suggest that protein phosphatase (PP) 1 and PP 2A may be required for this transition. Okadaic acid, a specific inhibitor of PP 1 and 2A, prevents the exit from metaphase in mammalian cells, but also disrupts the mitotic apparatus. Since disruption of the spindle itself causes cell cycle arrest, the present study was carried out to determine whether okadaic acid-treated cells fail to exit from metaphase because PP 1 and/or 2A activity is required, or because of spindle disruption. It was possible to distinguish between these two alternatives by including the protein kinase inhibitor, 6-dimethylaminopurine (6-DMAP), in the culture medium, since cells treated with 6-DMAP exit from metaphase despite disruption of the spindle. Mouse eggs, physiologically arrested at metaphase of the second meiotic division, complete meiosis and enter interphase when exposed to the calcium ionophore A23187. When eggs were exposed to 80 or 100 nM okadaic acid for 8 h, the meiotic spindle disappeared and the chromosomes disjoined. Nuclei did not form in eggs treated with okadaic acid and A23187, but did form in eggs treated with okadaic acid, A23187, and 6-DMAP. Therefore, eggs treated with okadaic acid have the capacity to exit from metaphase and enter interphase.
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PMID:Inhibition of mouse egg chromosome decondensation due to meiotic apparatus derangement induced by the protein phosphatase inhibitor, okadaic acid. 897 85