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beta 3 Integrin-EGF receptor cross-talk activates p190RhoGAP in mouse mammary gland epithelial cells
Journal article   Open access   Peer reviewed

beta 3 Integrin-EGF receptor cross-talk activates p190RhoGAP in mouse mammary gland epithelial cells

Nikolas Balanis, Masaaki Yoshigi, Michael K. Wendt, William P. Schiemann and Cathleen R. Carlin
Molecular biology of the cell, Vol.22(22), pp.4288-4301
11/15/2011
DOI: 10.1091/mbc.E10-08-0700
PMCID: PMC3216655
PMID: 21937717
url
https://doi.org/10.1091/mbc.E10-08-0700View
Published (Version of record) Open Access

Abstract

Active RhoA localizes to plasma membrane, where it stimulates formation of focal adhesions and stress fibers. RhoA activity is inhibited by p190RhoGAP following integrin-mediated cell attachment to allow sampling of new adhesive environments. p190RhoGAP is itself activated by Src-dependent tyrosine phosphorylation, which facilitates complex formation with p120RasGAP. This complex then translocates to the cell surface, where p190RhoGAP down-regulates RhoA. Here we demonstrate that the epidermal growth factor receptor (EGFR) cooperates with beta 3 integrin to regulate p190RhoGAP activity in mouse mammary gland epithelial cells. Adhesion to fibronectin stimulates tyrosine phosphorylation of the EGFR in the absence of receptor ligands. Use of a dominant inhibitory EGFR mutant demonstrates that fibronectin-activated EGFR recruits p120RasGAP to the cell periphery. Expression of an inactive beta 3 integrin subunit abolishes p190RhoGAP tyrosine phosphorylation, demonstrating a mechanistic link between beta 3 integrin-activated Src and EGFR regulation of the RhoA inhibitor. The beta 3 integrin/EGFR pathway also has a positive role in formation of filopodia. Together our data suggest that EGFR constitutes an important intrinsic migratory cue since fibronectin is a key component of the microenvironment in normal mammary gland development and breast cancer. Our data also suggest that EGFR expressed at high levels has a role in eliciting cell shape changes associated with epithelial-to-mesenchymal transition.
Cell Biology Life Sciences & Biomedicine Science & Technology

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