title: TCR engagement induces proline-rich tyrosine kinase-2 (Pyk2) translocation to the T cell-APC interface independently of Pyk2 activity and in an immunoreceptor tyrosine-based activation motif-mediated fashion.
abstract: The relocation of kinases in T lymphocytes during their cognate interaction with APCs is essential for lymphocyte activation. We found that the proline-rich tyrosine kinase-2 (Pyk2) is rapidly translocated to the T cell-APC contact area upon T cell-specific recognition of superantigen-pulsed APCs. Stimulation with anti-CD3-coated latex microspheres was sufficient for Pyk2 reorientation, and the coengagement of CD28 boosted Pyk2 redistribution. Nevertheless, Pyk2 translocation did not result in its recruitment to lipid rafts. Two results support that Pyk2 translocation was independent of its kinase activity. First, Lck activity was required for TCR-induced Pyk2 translocation, but not for TCR-induced Pyk2 activation. Second, a kinase-dead Pyk2 mutant was equally translocated upon TCR triggering. In addition, Lck activity alone was insufficient to induce Pyk2 reorientation and activation, requiring the presence of at least one intact immunoreceptor tyrosine-based activation motif (ITAM). Despite the dependence on functional Lck and on phosphorylated ITAM for Pyk2 translocation, the ITAM-binding tyrosine kinase zeta-associated protein 70 (ZAP-70) was not essential. All these data suggest that, by translocating to the vicinity of the immune synapse, Pyk2 could play an essential role in T cell activation and polarized secretion of cytokines.
authors.affiliation: Servicio de Inmunología, Hospital de la Princesa, Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Sancho
authors.forename: María C
authors.initials: MC
authors.lastname: Montoya
authors.forename: Alicia
authors.initials: A
authors.lastname: Monjas
authors.forename: Mónica
authors.initials: M
authors.lastname: Gordón-Alonso
authors.forename: Takuya
authors.initials: T
authors.lastname: Katagiri
authors.forename: Diana
authors.initials: D
authors.lastname: Gil
authors.forename: Reyes
authors.initials: R
authors.lastname: Tejedor
authors.forename: Balbino
authors.initials: B
authors.lastname: Alarcón
authors.forename: Francisco
authors.initials: F
authors.lastname: Sánchez-Madrid
mesh_terms: D020816:Amino Acid Motifs / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000201:enzymology* / Q000378:metabolism; D002450:Cell Communication / Q000276:immunology; D002461:Cell Line, Transformed; D004789:Enzyme Activation / Q000276:immunology; D051418:Focal Adhesion Kinase 2; D006801:Humans; D007365:Intercellular Junctions / Q000276:immunology*; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000276:immunology*; D021962:Membrane Microdomains / Q000378:metabolism; D011392:Proline / Q000378:metabolism; D021381:Protein Transport / Q000276:immunology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D011971:Receptors, Immunologic / Q000502:physiology*; D013601:T-Lymphocytes / Q000201:enzymology* / Q000276:immunology* / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
chemical_list: D011948:Receptors, Antigen, T-Cell; D011971:Receptors, Immunologic; D014443:Tyrosine; D011392:Proline; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2