title: D120 and K152 within the PH Domain of T Cell Adapter SKAP55 Regulate Plasma Membrane Targeting of SKAP55 and LFA-1 Affinity Modulation in Human T Lymphocytes.
abstract: The β2-integrin lymphocyte function-associated antigen 1 (LFA-1) is needed for the T cell receptor (TCR)-induced activation of LFA-1 to promote T cell adhesion and interaction with antigen-presenting cells (APCs). LFA-1-mediated cell-cell interactions are critical for proper T cell differentiation and proliferation. The Src kinase-associated phosphoprotein of 55 kDa (SKAP55) is a key regulator of TCR-mediated LFA-1 signaling (inside-out/outside-in signaling). To gain an understanding of how SKAP55 controls TCR-mediated LFA-1 activation, we assessed the functional role of its pleckstrin homology (PH) domain. We identified two critical amino acid residues within the PH domain of SKAP55, aspartic acid 120 (D120) and lysine 152 (K152). D120 facilitates the retention of SKAP55 in the cytoplasm of nonstimulated T cells, while K152 promotes SKAP55 membrane recruitment via actin binding upon TCR triggering. Importantly, the K152-dependent interaction of the PH domain with actin promotes the binding of talin to LFA-1, thus facilitating LFA-1 activation. These data suggest that K152 and D120 within the PH domain of SKAP55 regulate plasma membrane targeting and TCR-mediated activation of LFA-1.
authors.affiliation: Otto von Guericke University, Institute of Molecular and Clinical Immunology, Health Campus Immunology, Infectiology and Inflammation, Magdeburg, Germany.
authors.forename: Amelie
authors.initials: A
authors.lastname: Witte
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Protein Biochemistry Group, Berlin, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Meineke
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Protein Biochemistry Group, Berlin, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Sticht
authors.affiliation: Otto von Guericke University, Institute of Molecular and Clinical Immunology, Health Campus Immunology, Infectiology and Inflammation, Magdeburg, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Philipsen
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Protein Biochemistry Group, Berlin, Germany.
authors.forename: Benno
authors.initials: B
authors.lastname: Kuropka
authors.affiliation: Otto von Guericke University, Institute of Molecular and Clinical Immunology, Health Campus Immunology, Infectiology and Inflammation, Magdeburg, Germany.|Helmholtz Center for Infection Research (HZI), Department of Immune Control, Braunschweig, Germany.
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Müller
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Protein Biochemistry Group, Berlin, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Freund
authors.affiliation: Otto von Guericke University, Institute of Molecular and Clinical Immunology, Health Campus Immunology, Infectiology and Inflammation, Magdeburg, Germany burkhart.schraven@med.ovgu.de stefanie.kliche@med.ovgu.de.|Helmholtz Center for Infection Research (HZI), Department of Immune Control, Braunschweig, Germany.
authors.forename: Burkhart
authors.initials: B
authors.lastname: Schraven
authors.affiliation: Otto von Guericke University, Institute of Molecular and Clinical Immunology, Health Campus Immunology, Infectiology and Inflammation, Magdeburg, Germany burkhart.schraven@med.ovgu.de stefanie.kliche@med.ovgu.de.
authors.forename: Stefanie
authors.identifier: http://orcid.org/0000-0001-5786-3462
authors.initials: S
authors.lastname: Kliche
mesh_terms: D000199:Actins / Q000378:metabolism; D001224:Aspartic Acid / Q000378:metabolism*; D002448:Cell Adhesion; D002462:Cell Membrane / Q000378:metabolism*; D006801:Humans; D019169:Jurkat Cells; D008055:Lipids / Q000737:chemistry; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism*; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism*; D000072417:Protein Domains; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D013329:Structure-Activity Relationship; D013601:T-Lymphocytes / Q000378:metabolism*; D016608:Talin / Q000378:metabolism; D020668:rap GTP-Binding Proteins / Q000378:metabolism
chemical_list: D000199:Actins; D008055:Lipids; D016169:Lymphocyte Function-Associated Antigen-1; D050505:Mutant Proteins; D018129:Phosphatidylinositol Phosphates; D010750:Phosphoproteins; D011948:Receptors, Antigen, T-Cell; C108336:SKAP1 protein, human; D016608:Talin; C060974:phosphatidylinositol 3,4,5-triphosphate; D001224:Aspartic Acid; D020668:rap GTP-Binding Proteins; D008239:Lysine
keywords: LFA-1; SKAP55; adhesion