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Association Of The Tensin N-Terminal Protein-Tyrosine Phosphatase Domain With The Alpha Isoform Of Protein Phosphatase-1 In Focal Adhesions, Masumi Eto, Jason Kirkbride, Elizabeth Elliott, Su Hao Lo, David L. Brautigan

Department of Molecular Physiology and Biophysics Faculty Papers

Focal adhesions attach cultured cells to the extracellular matrix, and we found endogenous protein phosphatase-1alpha isoform (PP1alpha) localized in adhesions across the entire area of adherent fibroblasts. However, in fibroblasts migrating into a scrape wound or spreading after replating PP1alpha did not appear in adhesions near the leading edge but was recruited into other adhesions coincident in time and space with incorporation of tensin. Endogenous tensin and PP1alpha co-precipitated from cell lysates with isoform-specific PP1 antibodies. Chemical cross-linking of focal adhesion preparations with Lomant's reagent demonstrated molecular proximity of endogenous PP1alpha and tensin, whereas neither focal adhesion kinase nor vinculin …