Inhibition of ras-induced germinal vesicle breakdown in Xenopus oocytes by rap-1B.


Journal Article

A cDNA clone (Krev-1) has recently been identified that possesses the ability to reverse the transformed phenotype when introduced into a K-ras-transformed NIH/3T3 cell line. The Krev-1 protein, also known as rap-1A, was found to share 50% homology with the ras proteins. The rap-1A protein has also been shown to block the interaction of ras with its GTPase activating protein in vitro, leading to speculation regarding its role in vivo. A closely related protein, rap-1B, has also been identified in platelets, human erythroleukemia cells, neutrophils, and aortic smooth muscle cells. Unlike rap-1A, rap-1B has been shown to be phosphorylated in platelets. Given the high degree of similarity between the amino acid sequences of rap-1A and rap-1B, we sought to investigate the effect of microinjected rap-1B on H-ras(Val12)-induced germinal vesicle breakdown in Xenopus laevis oocytes. In this assay system, equimolar concentrations of rap-1B were found to block germinal vesicle breakdown triggered by the oncogenic ras protein. However, in the presence of IGF-1, this inhibition was not observed. Moreover, rap-1B is readily phosphorylated in the oocytes.

Full Text

Duke Authors

Cited Authors

  • Campa, MJ; Chang, KJ; Molina y Vedia, L; Reep, BR; Lapetina, EG

Published Date

  • January 15, 1991

Published In

Volume / Issue

  • 174 / 1

Start / End Page

  • 1 - 5

PubMed ID

  • 1899188

Pubmed Central ID

  • 1899188

International Standard Serial Number (ISSN)

  • 0006-291X

Digital Object Identifier (DOI)

  • 10.1016/0006-291x(91)90475-m


  • eng

Conference Location

  • United States