| First Author | Cau J | Year | 2000 |
| Journal | J Biol Chem | Volume | 275 |
| Issue | 4 | Pages | 2367-75 |
| PubMed ID | 10644687 | Mgi Jnum | J:60205 |
| Mgi Id | MGI:1352970 | Doi | 10.1074/jbc.275.4.2367 |
| Citation | Cau J, et al. (2000) Regulation of Xenopus p21-activated kinase (X-PAK2) by Cdc42 and maturation-promoting factor controls Xenopus oocyte maturation. J Biol Chem 275(4):2367-75 |
| abstractText | Signal transduction cascades involved in regulation of the cell cycle machinery are poorly understood. In the Xenopus oocyte model, meiotic maturation is triggered by MPF, a complex of p34(cdc2)-cyclin B, which is activated in response to a progesterone signal by largely unknown mechanisms. We have previously shown that the p21-activated kinase (PAK) family negatively regulates the MPF amplification loop. In this study, we identify the endogenous PAK2 as a key enzyme in this regulation and describe the pathways by which PAK2 is regulated. We show that the small GTPase Cdc42 is required for maintenance of active endogenous X-PAK2 in resting stage VI oocytes, whereas Rac1 is not involved in this regulation. During the process of maturation, X-PAK2 phosphorylation results in its inactivation and allows maturation to proceed to completion. Activation of mitogen-activated protein kinase and cyclin B-p34(cdc2) is coincident with X-PAK2 inactivation, and purified active MPF inhibits X-PAK2, demonstrating the existence of a new positive feedback loop. Our results confirm and extend the importance of p21-activated kinases in the control of the G(2)/M transition. We hypothesize that the X-PAK2/Cdc42 pathway could link p34(cdc2) activity to the major cytoskeleton rearrangements leading to spindle migration and anchorage to the animal pole cortex. |
