{alpha}v{beta}6 Integrin Is Required for TGF{beta}1-Mediated Matrix Metalloproteinase2 Expression

TGFβ activity depends on a complex signaling cascade that controls expression of several genes. Among others, TGFβ1 regulates expression of matrix metalloproteinases (MMPs) through activation of Smads. Here, we demonstrate for the first time that the αvβ6 integrin interacts with TGFβ receptor II (TβRII) through the β6 cytoplasmic domain and promotes Smad3 activation in prostate cancer cells. Another related αv integrin, αvβ5, as well as the αvβ6/3 integrin,which contains a chimeric form of β6 with a β3 cytoplasmic domain, do not associate with TβRII and fail to show similar responses. We provide evidence that αvβ6 is required for upregulation of MMP2 by TGFβ1 through a Smad3-mediated transcriptional program in prostate cancer cells. The functional relevance of these results is underscored by the finding that αvβ6 modulates cell migration in a MMP2-dependent manner on an αvβ6 specific ligand, latency associated peptide (LAP)-TGFβ. Overall, these mechanistic studies establish that expression of a single integrin, αvβ6, is sufficient to promote activation of Smad3, regulation of MMP2 levels, and consequent catalytic activity, as well as cell migration. Our study describes a new TGFβ1\αvβ6\MMP2 signaling pathway that, given TGFβ1 pro-metastatic activity, may have profound implicat...

Source: BJ Disease - January 6, 2015 Category: Biochemistry Authors: A Dutta, J Li, C Fedele, A Sayeed, A Singh, S M. Violette, T D. Manes, L R Languino Tags: BJ Signal Source Type: research