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Updated: Jul 12, 2026

Methods to Study Mrp4-containing Macromolecular Complexes in the Regulation of Fibroblast Migration
Published on: May 19, 2016
Focal adhesion kinase controls actin assembly via a FERM-mediated interaction with the Arp2/3 complex
Bryan Serrels1, Alan Serrels, Valerie G Brunton
1The Beatson Institute for Cancer Research, Cancer Research UK Beatson Laboratories, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK.
Abstract:
Networks of actin filaments, controlled by the Arp2/3 complex, drive membrane protrusion during cell migration. How integrins signal to the Arp2/3 complex is not well understood. Here, we show that focal adhesion kinase (FAK) and the Arp2/3 complex associate and colocalize at transient structures formed early after adhesion. Nascent lamellipodia, which originate at these structures, do not form in FAK-deficient cells, or in cells in which FAK mutants cannot be autophosphorylated after integrin engagement. The FERM domain of FAK binds directly to Arp3 and can enhance Arp2/3-dependent actin polymerization. Critically, Arp2/3 is not bound when FAK is phosphorylated on Tyr 397. Interfering peptides and FERM-domain point mutants show that FAK binding to Arp2/3 controls protrusive lamellipodia formation and cell spreading. This establishes a new function for the FAK FERM domain in forming a phosphorylation-regulated complex with Arp2/3, linking integrin signalling directly with the actin polymerization machinery.
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