Non-Smad transforming growth factor-β signaling regulated by focal adhesion kinase binding the p85 subunit of phosphatidylinositol 3-kinase

Min Hong, Mark C. Wilkes, Sumedha G. Penheiter, Shiv K. Gupta, Maryanne Edens, Edward B Leof

Research output: Contribution to journalArticle

35 Scopus citations


TGF-β modulates numerous diverse cellular phenotypes including growth arrest in epithelial cells and proliferation in fibroblasts. Although the Smad pathway is fundamental for the majority of these responses, recent evidence indicates that non-Smad pathways may also have a critical role. Here we report a novel mechanism whereby the nonreceptor tyrosine focal adhesion kinase (FAK) functions as an adaptor necessary for cell type-specific responses to TGF-β. We show that in contrast to Smad actions, non-Smad pathways, including c-Abl, PAK2, and Akt, display an obligate requirement for FAK. Interestingly, this occurs in Src null SYF cells and is independent of FAK tyrosine phosphorylation, kinase activity, and/or proline-rich sequences in the C-terminal FAT domain. FAK binds the phosphatidylinositol 3-kinase (PI3K) p85 regulatory subunit following TGF-β treatment in a subset of fibroblasts but not epithelial cells and has an obligate role in TGF-β-stimulated anchorage-independent growth and migration. Together, these results uncover a new scaffolding role for FAK as the most upstream component regulating the profibrogenic action of TGF-β and suggest that inhibiting this interaction may be useful in treating a number of fibrotic diseases.

Original languageEnglish (US)
Pages (from-to)17841-17850
Number of pages10
JournalJournal of Biological Chemistry
Issue number20
StatePublished - May 20 2011


ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

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