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A more recent version of this article appeared on January 1, 2008
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Submitted on November 27, 2006
Revised on October 5, 2007
Accepted on October 10, 2007
12/13 to Cell Polarity and Microtubule Dynamics
*Institute of Pharmacology, University of Heidelberg, 69120, Heidelberg, Germany;
Nikon Imaging Center at the University of Heidelberg, Bioquant, 69120, Heidelberg, Germany
Monitoring Editor: Martin A. Schwartz
Regulation of cell polarity is a process observed in all cells. During directed migration, cells orientate their microtubule cytoskeleton and the microtubule-organizing-center (MTOC), which involves integrins and downstream Cdc42 and GSK-3
activity. However, the contribution of G protein-coupled receptor signal transduction for MTOC polarity is less well understood. Here we report that the heterotrimeric G
12 and G
13 proteins are necessary for MTOC polarity as well as microtubule dynamics based on studies using G
12/13-deficient mouse embryonic fibroblasts. Cell polarization involves the G
12/13-interacting leukemia-associated Rho-GEF (LARG) and the actin nucleating diaphanous formin mDia1. Interestingly, LARG associates with pericentrin and localizes to the MTOC and along microtubule tracks. We propose that G
12/13 proteins exert essential functions linking extracellular signals to microtubule dynamics and cell polarity via RhoGEF and formin activity.