title: Interactions of the protein-tyrosine phosphatase-α with the focal adhesion targeting domain of focal adhesion kinase are involved in interleukin-1 signaling in fibroblasts.
abstract: Interleukin-1 (IL-1) signaling in fibroblasts is mediated through focal adhesions, organelles that are enriched with adaptor and cytoskeletal proteins that regulate signal transduction. We examined interactions of the focal adhesion kinase (FAK) with protein-tyrosine phosphatase-α (PTP-α) in IL-1 signaling. In wild type and FAK knock-out mouse embryonic fibroblasts, we found by immunoblotting, immunoprecipitation, immunostaining, and gene silencing that FAK is required for IL-1-mediated sequestration of PTPα to focal adhesions. Immunoprecipitation and pulldown assays of purified proteins demonstrated a direct interaction between FAK and PTPα, which was dependent on the FAT domain of FAK and by an intact membrane-proximal phosphatase domain of PTPα. Recruitment of PTPα to focal adhesions, IL-1-induced Ca(2+) release from the endoplasmic reticulum, ERK activation, and IL-6, MMP-3, and MMP-9 expression were all blocked in FAK knock-out fibroblasts. These processes were restored in FAK knock-out cells transfected with wild type FAK, FAT domain, and FRNK. Our data indicate that IL-1-induced signaling through focal adhesions involves interactions between the FAT domain of FAK and PTPα.
authors.affiliation: From the Matrix Dynamics Group, University of Toronto, Toronto, Ontario M5S 3E2, Canada.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.affiliation: From the Matrix Dynamics Group, University of Toronto, Toronto, Ontario M5S 3E2, Canada.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: From the Matrix Dynamics Group, University of Toronto, Toronto, Ontario M5S 3E2, Canada.
authors.forename: Dominik
authors.initials: D
authors.lastname: Fritz
authors.affiliation: From the Matrix Dynamics Group, University of Toronto, Toronto, Ontario M5S 3E2, Canada.
authors.forename: Dhaarmini
authors.initials: D
authors.lastname: Rajshankar
authors.affiliation: the Division of Pulmonary, Sleep, and Critical Care Medicine, Department of Medicine, National Jewish Health, Denver, Colorado 80206, and the Division of Pulmonary Sciences and Critical Care Medicine, Departments of Medicine and Integrated Department of Immunology, University of Colorado, Aurora, Colorado 80045.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Downey
authors.affiliation: From the Matrix Dynamics Group, University of Toronto, Toronto, Ontario M5S 3E2, Canada, christopher.mcculloch@utoronto.ca.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: McCulloch
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005347:Fibroblasts / Q000201:enzymology* / Q000378:metabolism; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D022001:Focal Adhesions / Q000201:enzymology* / Q000378:metabolism; D007375:Interleukin-1 / Q000235:genetics / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D041681:NIH 3T3 Cells; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D007375:Interleukin-1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4; D020780:Matrix Metalloproteinase 9; D002118:Calcium
keywords: Cell Adhesion; Fibroblast; Matrix Metalloproteinase (MMP); Phosphatase; Signaling; Tyrosine-protein Kinase (Tyrosine Kinase)