GIV-Kindlin interaction is required for Kindlin-Mediated Integrin Recognition and Activation

Abstract

Cells perceive and respond to the extracellular matrix (ECM) via integrin receptors; their dysregulation has been implicated in inflammation and cancer metastasis. Here we show that a guanine nucleotide exchange modulator of trimeric-GTPase Gi, GIV (a.k.a Girdin), directly binds the integrin adaptor Kindlin-2. A non-canonical short linear motif within GIVs C-terminus binds Kindlin-2-FERM3 domain at a site that is distinct from the binding site for the canonical NPxY motif on the -integrin tail. Binding of GIV to Kindlin-2 allosterically enhances Kindlin-2s affinity for {beta}1-integrin. Consequently, integrin activation and clustering are maximized, which augments cell adhesion, spreading and invasion. Findings elucidate how the GIV*Kindlin-2 complex has a two-fold impact: it allosterically synergizes integrin activation and enables {beta}1-integrins to indirectly access and modulate trimeric GTPases via the complex. Furthermore, Cox proportional-hazard models on tumor transcriptomics provide trans-scale evidence of synergistic interactions between GIV*Kindlin-2*{beta}1-integrin on time to progression to metastasis. The eTOC blurbIntegrins mediate cell adhesion to the extracellular matrix; their dysregulation fuels inflammation, cancer cell invasion and metastasis. Authors show how two pro-metastatic scaffold proteins, Kindlin and GIV/Girdin bind and cooperatively enhance their allosteric coupling to integrins, and their subsequent activation. Findings reveal novel interfaces in integrin signaling for pharmacologic manipulation. HIGHLIGHTSO_LIGIV and Kindlin(K2), two integrin adaptors that promote metastasis, bind each other C_LIO_LIBinding of GIV or integrin to K2 allosterically enhances GIV*K2*integrin complexes C_LIO_LIBinding is required for the maximal recruitment of GIV and K2 to active integrins C_LIO_LIBinding facilitates integrin clustering, activation, tumor cell adhesion, invasion. C_LI