The regulator of G protein signaling domain of axin selectively interacts with Galpha12 but not Galpha13.


Journal Article

Axin, a negative regulator of the Wnt signaling pathway, contains a canonical regulator of G protein signaling (RGS) core domain. Herein, we demonstrate both in vitro and in cells that this domain interacts with the alpha subunit of the heterotrimeric G protein G12 but not with the closely related Galpha13 or with several other heterotrimeric G proteins. Axin preferentially binds the activated form of Galpha12, a behavior consistent with other RGS proteins. However, unlike other RGS proteins, that of axin (axinRGS) does not affect intrinsic GTP hydrolysis by Galpha12. Despite its inability to act as a GTPase-activating protein, we demonstrate that in cells, axinRGS can compete for Galpha12 binding with the RGS domain of p115RhoGEF, a known G12-interacting protein that links G12 signaling to activation of the small G protein Rho. Moreover, ectopic expression of axinRGS specifically inhibits Galpha12-directed activation of the Rho pathway in MDA-MB 231 breast cancer cells. These findings establish that the RGS domain of axin is able to directly interact with the alpha subunit of heterotrimeric G protein G12 and provide a unique tool to interdict Galpha12-mediated signaling processes.

Full Text

Duke Authors

Cited Authors

  • Stemmle, LN; Fields, TA; Casey, PJ

Published Date

  • October 2006

Published In

Volume / Issue

  • 70 / 4

Start / End Page

  • 1461 - 1468

PubMed ID

  • 16868183

Pubmed Central ID

  • 16868183

International Standard Serial Number (ISSN)

  • 0026-895X

Digital Object Identifier (DOI)

  • 10.1124/mol.106.023705


  • eng

Conference Location

  • United States