Grb2 promotes reinitiation of meiosis in Xenopus oocytes.
The adaptor protein Grb2 plays a central role in cell proliferation and/or cell cycle progression. In this study, we investigate the role of Grb2 in signalling pathways involved in meiotic reinitiation. For that purpose, Xenopus Grb2 cRNA and its mutated forms or human Grb2 protein was microinjected into immature Xenopus oocytes. Reinitiation of meiosis was seen in unstimulated oocytes. Induction of the meiosis was time dependent and Ras dependent, and the presence in Grb2 of SH2 and SH3 domains was required. Several tyrosine phosphorylated proteins were solely detected in oocytes responsive to Grb2 injection. Our results are in favour of an unusual recruitment and initiation of the Grb2 transduction cascade independent of a receptor tyrosine kinase (RTK) stimulation.
Laboratoire de Biologie du Développement, Université des Sciences et Technologies de Lille, UE 1033, Bâtiment SN3, 59655 Villeneuve D'Ascq Cedex, France.
K
K
Cailliau
E
E
Browaeys-Poly
I
I
Broutin-L'Hermite
P
P
Nioche
C
C
Garbay
A
A
Ducruix
J P
JP
Vilain
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D005260:Female; D051380:GRB2 Adaptor Protein; D006801:Humans; D008540:Meiosis; D009865:Oocytes / Q000166:cytology*; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D011506:Proteins / Q000819:agonists* / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D014982:Xenopus laevis
D048868:Adaptor Proteins, Signal Transducing; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D011506:Proteins; D011505:Protein-Tyrosine Kinases