Open AccessRaf-MEK-Erk Cascade in Anoikis Is Controlled by Rac1 and Cdc42 via Akt
Author(s) -
Olivier Zugasti,
Wilfrid Rul,
Pierre Roux,
Carole Peyssonnaux,
Alain Eychène,
Thomas Franke,
Philippe Fort,
Urszula Hibner
Publication year - 2001
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.21.19.6706-6717.2001
Subject(s) - anoikis , protein kinase b , cdc42 , mapk/erk pathway , biology , rac1 , microbiology and biotechnology , kinase , rhoa , signal transduction , pak1 , programmed cell death , apoptosis , biochemistry
Signals from the extracellular matrix are essential for the survival of many cell types. Dominant-negative mutants of two members of Rho family GTPases, Rac1 and Cdc42, mimic the loss of anchorage in primary mouse fibroblasts and are potent inducers of apoptosis. This pathway of cell death requires the activation of both the p53 tumor suppressor and the extracellular signal-regulated mitogen-activated protein kinases (Erks). Here we characterize the proapoptotic Erk signal and show that it differs from the classically observed survival-promoting one by the intensity of the kinase activation. The disappearance of the GTP-bound forms of Rac1 and Cdc42 gives rise to proapoptotic, moderate activation of the Raf-MEK-Erk cascade via a signaling pathway involving the kinases phosphatidlyinositol 3-kinase and Akt. Moreover, concomitant activation of p53 and inhibition of Akt are both necessary and sufficient to signal anoikis in primary fibroblasts. Our data demonstrate that the GTPases of the Rho family control three major components of cellular signal transduction, namely, p53, Akt, and Erks, which collaborate in the induction of apoptosis due to the loss of anchorage.