Okadaic Acid Category

Predominant localization of PP2A in the ooplasm suggests that PP2A might be associated with cytoskeletal components. The possible role of PP2A in the regulation of microtubule assembly in oocytes, similar to its role in somatic and neuronal cells, is intriguing. Unfortunately, there are presently no pharmacological PP2A inhibitors available that do not also inhibit PP1, […]

The presence of PP1 in the nucleus of GVI oocytes may suggest a direct regulatory role in GVB and/or chromatin condensation. Nuclear envelope breakdown, entailing disassembly of the nuclear lamina, requires phosphorylation of the lamins, which is believed to be regulated by p34cdc2 kinase activity. Nuclear PP1 activity may be as important as p34cdc2 kinase […]

In this report we have demonstrated that macaque oocytes from preantral and antral follicles contain both PP1 and PP2A. The anti-PPl antibody utilized in this experiment was prepared against a portion of the catalytic domain of PP1, isotype a. At present, there are five known isoforms of the catalytic subunit of PP1, termed PP1„, PPlp, […]

GVB rates for rhesus monkey oocytes have been reported to range from 13% to 48%, with the majority of this meiotic resumption occurring during the first 24 h. In this study, GVB rates for the control groups in the two separate experiments were 23% and 47%. This difference in GVB rates between controls in separate […]

Because 1 |xM OA completely prevents serine/threonine dephosphorylation of most proteins, and in view of the central role of phosphorylation/dephosphorylation in cellular regulation, it is not surprising that multiple secondary effects are observed following extended culture with this PP inhibitor. Short-term (15 min) incubation of hepatocytes with 1 |xM OA did not cause morphological changes […]

CL-A, originally derived from the marine sponge Dis-codermia calyx, is similar to OA in its potent inhibition of PP1 and PP2A. However, CL-A differs from О A in that PP1 and PP2A display greater sensitivity to CL-A, therefore requiring less pharmacological inhibitor to yield a comparable decrease in PP1/PP2A activity. This has been demonstrated in […]

The intracellular mechanisms governing regulation of mammalian oocyte meiosis have been extensively investigated, with significant progress in the identification of critical components such as cAMP, PKA, mitogen-activated protein kinase, and MPF. However, it is becoming increasingly apparent that significant gaps in our knowledge exist with respect to regulation of these intracellular enzymes. In addition, the […]