title: FAK, talin and PIPKIγ regulate endocytosed integrin activation to polarize focal adhesion assembly.
abstract: Integrin endocytic recycling is critical for cell migration, yet how recycled integrins assemble into new adhesions is unclear. By synchronizing endocytic disassembly of focal adhesions (FAs), we find that recycled integrins reassemble FAs coincident with their return to the cell surface and dependent on Rab5 and Rab11. Unexpectedly, endocytosed integrins remained in an active but unliganded state in endosomes. FAK and Src kinases co-localized with endocytosed integrin and were critical for FA reassembly by regulating integrin activation and recycling, respectively. FAK sustained the active integrin conformation by maintaining talin association with Rab11 endosomes in a type I phosphatidylinositol phosphate kinase (PIPKIγ)-dependent manner. In migrating cells, endocytosed integrins reassembled FAs polarized towards the leading edge, and this polarization required FAK. These studies identify unanticipated roles for FA proteins in maintaining endocytosed integrin in an active conformation. We propose that the conformational memory of endocytosed integrin enhances polarized reassembly of FAs to enable directional cell migration.
authors.affiliation: Department of Pathology &Cell Biology, Columbia University, P&S 15-420, 630 West 168th Street, New York, New York 10032, USA.
authors.forename: Guilherme P F
authors.initials: GP
authors.lastname: Nader
authors.affiliation: Department of Pathology &Cell Biology, Columbia University, P&S 15-420, 630 West 168th Street, New York, New York 10032, USA.
authors.forename: Ellen J
authors.initials: EJ
authors.lastname: Ezratty
authors.affiliation: Department of Pathology &Cell Biology, Columbia University, P&S 15-420, 630 West 168th Street, New York, New York 10032, USA.
authors.forename: Gregg G
authors.initials: GG
authors.lastname: Gundersen
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D016764:Cell Polarity; D004705:Endocytosis; D005353:Fibronectins / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism*; D022001:Focal Adhesions / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D039482:Integrin alpha5 / Q000378:metabolism*; D019012:Integrin beta1 / Q000378:metabolism*; D051379:Mice; D008870:Microtubules / Q000378:metabolism; D041681:NIH 3T3 Cells; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D015398:Signal Transduction; D016608:Talin / Q000378:metabolism*; D016596:Vinculin / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D005353:Fibronectins; D039482:Integrin alpha5; D019012:Integrin beta1; D016608:Talin; D016596:Vinculin; D017853:Phosphotransferases (Alcohol Group Acceptor); C020077:1-phosphatidylinositol-4-phosphate 5-kinase; D051417:Focal Adhesion Kinase 1; D019061:src-Family Kinases