title: Positive and negative regulation by SLP-76/ADAP and Pyk2 of chemokine-stimulated T-lymphocyte adhesion mediated by integrin α4β1.
abstract: Stimulation by chemokines of integrin α4β1-dependent T-lymphocyte adhesion is a crucial step for lymphocyte trafficking. The adaptor Vav1 is required for chemokine-activated T-cell adhesion mediated by α4β1. Conceivably, proteins associating with Vav1 could potentially modulate this adhesion. Correlating with activation by the chemokine CXCL12 of T-lymphocyte attachment to α4β1 ligands, a transient stimulation in the association of Vav1 with SLP-76, Pyk2, and ADAP was observed. Using T-cells depleted for SLP-76, ADAP, or Pyk2, or expressing Pyk2 kinase-inactive forms, we show that SLP-76 and ADAP stimulate chemokine-activated, α4β1-mediated adhesion, whereas Pyk2 opposes T-cell attachment. While CXCL12-promoted generation of high-affinity α4β1 is independent of SLP-76, ADAP, and Pyk2, the strength of α4β1-VCAM-1 interaction and cell spreading on VCAM-1 are targets of regulation by these three proteins. GTPase assays, expression of activated or dominant-negative Rac1, or combined ADAP and Pyk2 silencing indicated that Rac1 activation by CXCL12 is a common mediator response in SLP-76-, ADAP-, and Pyk2-regulated cell adhesion involving α4β1. Our data strongly suggest that chemokine-stimulated associations between Vav1, SLP-76, and ADAP facilitate Rac1 activation and α4β1-mediated adhesion, whereas Pyk2 opposes this adhesion by limiting Rac1 activation.
authors.affiliation: Centro de Investigaciones Biológicas (CSIC), Department of Cellular and Molecular Medicine, 28040 Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Dios-Esponera
authors.affiliation: Centro de Investigaciones Biológicas (CSIC), Department of Cellular and Molecular Medicine, 28040 Madrid, Spain.
authors.forename: Soledad
authors.initials: S
authors.lastname: Isern de Val
authors.affiliation: Centro de Investigaciones Biológicas (CSIC), Department of Cellular and Molecular Medicine, 28040 Madrid, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Sevilla-Movilla
authors.affiliation: Centro de Investigaciones Biológicas (CSIC), Department of Cellular and Molecular Medicine, 28040 Madrid, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: García-Verdugo
authors.affiliation: Centro de Investigaciones Biológicas (CSIC), Department of Cellular and Molecular Medicine, 28040 Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: García-Bernal
authors.affiliation: Centro de Investigaciones Biológicas (CSIC), Department of Cellular and Molecular Medicine, 28040 Madrid, Spain.
authors.forename: Nohemí
authors.initials: N
authors.lastname: Arellano-Sánchez
authors.affiliation: Centro de Biología Molecular (CSIC), Department of Cell Biology and Immunology, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Cabañas
authors.affiliation: Centro de Investigaciones Biológicas (CSIC), Department of Cellular and Molecular Medicine, 28040 Madrid, Spain joaquint@cib.csic.es.
authors.forename: Joaquin
authors.initials: J
authors.lastname: Teixidó
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D002448:Cell Adhesion / Q000502:physiology; D002460:Cell Line; D054377:Chemokine CXCL12 / Q000378:metabolism; D051418:Focal Adhesion Kinase 2 / Q000378:metabolism*; D006801:Humans; D039041:Integrin alpha4beta1 / Q000378:metabolism*; D019169:Jurkat Cells; D008024:Ligands; D010750:Phosphoproteins / Q000378:metabolism*; D021381:Protein Transport; D051567:Proto-Oncogene Proteins c-vav / Q000378:metabolism; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; C106957:FYB1 protein, human; D039041:Integrin alpha4beta1; D008024:Ligands; D010750:Phosphoproteins; D051567:Proto-Oncogene Proteins c-vav; C107953:RAC1 protein, human; C092947:SLP-76 signal Transducing adaptor proteins; C496618:VAV1 protein, human; D019010:Vascular Cell Adhesion Molecule-1; D051418:Focal Adhesion Kinase 2; D020830:rac1 GTP-Binding Protein