Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.


Sci. STKE, 27 March 2001
Vol. 2001, Issue 75, p. tw7
[DOI: 10.1126/stke.2001.75.tw7]

EDITORS' CHOICE

Cell Biology Oocyte Maturation and G Beta and Gamma Subunits

The molecular details of progesterone-dependent Xenopus oocyte maturation are not well defined, but adenylyl cyclase activity is inhibited and cyclic AMP (cAMP) concentrations decrease. Maturation does not appear to involve Gαi activity; however, Sheng et al. found that Gβ{gamma} subunits are involved in arresting oocyte meiosis. maturation was induced by overexpressing in oocytes Gβ{gamma} scavengers, such as the α subunit of bovine transducin (Gαt) or a membrane-localized COOH-terminal bovine β-adrenergic receptor kinase (βARK-CCAAX) fragment, both of which sequester Gβ{gamma} subunits. βARK-CCAAX coprecipitated with Gβ in oocyte lysates, suggesting that Gβ-dependent inhibition was perturbed by direct association. Xenopus mitogen-activated protein kinase (xMAPK) was activated, an essential step in maturation, as a consequence of Gβ sequestration. Finally, overexpression of Gβ{gamma} in oocytes expressing βARK-CCAAX inhibited maturation and resulted in increased production of cAMP. These data suggest that Gβ{gamma} may influence oocyte maturation arrest and that progesterone may prevent the activation of a heterotrimeric G protein and the consequent release of Gβ{gamma}.

Y. Sheng, M. Tiberi, R. A. Booth, C. Ma, X. J. Liu, Regulation of Xenopus oocyte meiosis arrest by G protein β{gamma} subunits. Curr. Biol. 11, 405-416 (2001). [Online Journal]

Citation: Oocyte Maturation and G Beta and Gamma Subunits. Sci. STKE 2001, tw7 (2001).



To Advertise     Find Products


Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882