La. Jaffe et al., OOCYTE MATURATION IN STARFISH IS MEDIATED BY THE BETA-GAMMA-SUBUNIT COMPLEX OF A G-PROTEIN, The Journal of cell biology, 121(4), 1993, pp. 775-783
The stimulation of meiotic maturation of starfish oocytes by the hormo
ne 1-methyladenine is mimicked by injection of betagamma subunits of G
-proteins from either retina or brain. Conversely, the hormone respons
e is inhibited by injection of the GDP-bound forms of alpha(i1) or alp
ha(t) subunits, or by injection of phosducin; all of these proteins sh
ould bind free betagamma. alpha-subunit forms with reduced affinity fo
r betagamma (alpha(i1) or alpha(t) bound to hydrolysis-resistant GTP a
nalogs, or alpha(i1)-GMPPCP treated with trypsin to remove the amino t
erminus of the protein) are less effective inhibitors of 1-methyladeni
ne action. These results indicate that the betagamma subunit of a G-pr
otein mediates 1-methyladenine stimulation of oocyte maturation.