The stimulation of meiotic maturation of starfish oocytes by the hormone 1-methyladenine is mimicked by injection of beta gamma subunits of G-proteins from either retina or brain. Conversely, the hormone response is inhibited by injection of the GDP-bound forms of alpha i1 or alpha t subunits, or by injection of phosducin; all of these proteins should bind free beta gamma. alpha-subunit forms with reduced affinity for beta gamma (alpha i1 or alpha t bound to hydrolysis-resistant GTP analogs, or alpha i1-GMPPCP treated with trypsin to remove the amino terminus of the protein) are less effective inhibitors of 1-methyladenine action. These results indicate that the beta gamma subunit of a G-protein mediates 1-methyladenine stimulation of oocyte maturation.
Oocyte maturation in starfish is mediated by the beta gamma-subunit complex of a G-protein.
L A Jaffe, C J Gallo, R H Lee, Y K Ho, T L Jones; Oocyte maturation in starfish is mediated by the beta gamma-subunit complex of a G-protein.. J Cell Biol 15 May 1993; 121 (4): 775–783. doi: https://doi.org/10.1083/jcb.121.4.775
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