Requirement of phospholipase C-catalyzed hydrolysis of phosphatidylcholine for maturation of Xenopus laevis oocytes in response to insulin and ras p21.
Recent studies have demonstrated the activation of phospholipase C-mediated hydrolysis of phosphatidylcholine both by growth factors and by the product of ras oncogene, ras p21. Also, evidence has been presented indicating that the stimulation of this phospholipid-degradative pathway is sufficient to activate mitogenesis in fibroblasts. In Xenopus laevis oocytes, microinjection of transforming ras p21 is a potent inducer of maturation, whereas microinjection of a neutralizing anti-ras p21 antibody specifically inhibits maturation induced by insulin but not by progesterone. The results presented here demonstrated that microinjection of phosphatidylcholine-hydrolyzing phospholipase C is sufficient to induce maturation of Xenopus laevis oocytes. Furthermore, microinjection of a neutralizing anti-phosphatidylcholine-hydrolyzing phospholipase C specifically blocks the maturation program induced by ras p21/insulin but not by progesterone.
García de Herreros
A
A
Medicina y Cirugía Experimental, Hospital General Gregorio Marañón, Madrid, Spain.
Dominguez
I
I
Diaz-Meco
M T
MT
Graziani
G
G
Cornett
M E
ME
Guddal
P H
PH
Johansen
T
T
Moscat
J
J
D000818:Animals; D004075:Diglycerides / Q000378:metabolism; D005260:Female; D011905:Genes, ras; D006868:Hydrolysis; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D010712:Phosphatidic Acids / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism*; D011374:Progesterone / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics / Q000502:physiology*; D010738:Type C Phospholipases / Q000378:metabolism*; D014982:Xenopus laevis
D004075:Diglycerides; D007328:Insulin; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D011374:Progesterone; D011433:Propranolol; D010738:Type C Phospholipases; D016283:Proto-Oncogene Proteins p21(ras)