NHERF Links the N-Cadherin/Catenin Complex to the Platelet-derived Growth Factor Receptor to Modulate the Actin Cytoskeleton and Regulate Cell Motility<sup><a href="#FN1" rid="FN1" class=" fn"><img alt="An external file that holds a picture, illustration, etc. Object name is dbox.jpg" src="/pmc/articles/PMC1838972/bin/dbox.jpg"><img alt="An external file that holds a picture, illustration, etc. Object name is vbox.jpg" src="/pmc/articles/PMC1838972/bin/vbox.jpg"></a></sup>
Abstract
Using phage display, we identified Na/H exchanger regulatory factor (NHERF)-2 as a novel binding partner for the cadherin-associated protein, β-catenin. We showed that the second of two PSD-95/Dlg/ZO-1 (PDZ) domains of NHERF interacts with a PDZ-binding motif at the very carboxy terminus of β-catenin. N-cadherin expression has been shown to induce motility in a number of cell types. The first PDZ domain of NHERF is known to bind platelet-derived growth factor-receptor β (PDGF-Rβ), and the interaction of PDGF-Rβ with NHERF leads to enhanced cell spreading and motility. Here we show that β-catenin and N-cadherin are in a complex with NHERF and PDGF-Rβ at membrane ruffles in the highly invasive fibrosarcoma cell line HT1080. Using a stable short hairpin RNA system, we showed that HT1080 cells knocked down for either N-cadherin or NHERF had impaired ability to migrate into the wounded area in a scratch assay, similar to cells treated with a PDGF-R kinase inhibitor. Cells expressing a mutant NHERF that is unable to associate with β-catenin had increased stress fibers, reduced lamellipodia, and impaired cell migration. Using HeLa cells, which express little to no PDGF-R, we introduced PDGF-Rβ and showed that it coimmunoprecipitates with N-cadherin and that PDGF-dependent cell migration was reduced in these cells when we knocked-down expression of N-cadherin or NHERF. These studies implicate N-cadherin and β-catenin in cell migration via PDGF-R–mediated signaling through the scaffolding molecule NHERF.
ACKNOWLEDGMENTS
We thank Jill Nieset and Jennifer Oiler for excellent technical assistance. This work was supported by grants DE-12308 and GM-51188 from the National Institutes of Health (to K.R.J. and M.J.W., respectively). C.T. was supported by the Ruth C. Kirschstein National Research Service Award T32CA09476-14.
Abbreviations used:
NHERF | Na/H exchanger regulatory factor |
PDZ | PSD-95/Dlg/ZO-1 |
PDGF-R | platelet-derived growth factor receptor. |
Footnotes
This article was published online ahead of print in MBC in Press (http://www.molbiolcell.org/cgi/doi/10.1091/mbc.E06-10-0960) on January 17, 2007.
The online version of this article contains supplemental material at MBC Online (http://www.molbiolcell.org).