title: Lateral Mobility and Nanoscale Spatial Arrangement of Chemokine-activated α4β1 Integrins on T Cells.
abstract: Chemokine stimulation of integrin α4β1-dependent T lymphocyte adhesion is a key step during lymphocyte trafficking. A central question regarding α4β1 function is how its lateral mobility and organization influence its affinity and avidity following cell stimulation with chemokines and/or ligands. Using single particle tracking and superresolution imaging approaches, we explored the lateral mobility and spatial arrangement of individual α4β1integrins on T cells exposed to different activating stimuli. We show that CXCL12 stimulation leads to rapid and transient α4β1activation, measured by induction of the activation epitope recognized by the HUTS-21 anti-β1antibody and by increased talin-β1 association. CXCL12-dependent α4β1 activation directly correlated with restricted lateral diffusion and integrin immobilization. Moreover, co-stimulation by CXCL12 together with soluble VCAM-1 potentiated integrin immobilization with a 5-fold increase in immobile integrins compared with unstimulated conditions. Our data indicate that docking by talin of the chemokine-activated α4β1 to the actin cytoskeleton favors integrin immobilization, which likely facilitates ligand interaction and increased adhesiveness. Superresolution imaging showed that the nanoscale organization of high-affinity α4β1 remains unaffected following chemokine and/or ligand addition. Instead, newly activated α4β1 integrins organize on the cell membrane as independent units without joining pre-established integrin sites to contribute to cluster formation. Altogether, our results provide a rationale to understand how the spatiotemporal organization of activated α4β1 integrins regulates T lymphocyte adhesion.
authors.affiliation: From the Institut de Ciencies Fotoniques, Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Sosa-Costa
authors.affiliation: the Centro de Investigaciones Biológicas, Department of Cellular and Molecular Medicine, 28040 Madrid, Spain, and.
authors.forename: Sol
authors.initials: S
authors.lastname: Isern de Val
authors.affiliation: the Centro de Investigaciones Biológicas, Department of Cellular and Molecular Medicine, 28040 Madrid, Spain, and.
authors.forename: Silvia
authors.initials: S
authors.lastname: Sevilla-Movilla
authors.affiliation: From the Institut de Ciencies Fotoniques, Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.
authors.forename: Kyra J E
authors.identifier: http://orcid.org/0000-0001-7898-2911
authors.initials: KJ
authors.lastname: Borgman
authors.affiliation: From the Institut de Ciencies Fotoniques, Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.
authors.forename: Carlo
authors.identifier: http://orcid.org/0000-0002-8625-0996
authors.initials: C
authors.lastname: Manzo
authors.affiliation: the Centro de Investigaciones Biológicas, Department of Cellular and Molecular Medicine, 28040 Madrid, Spain, and.
authors.forename: Joaquin
authors.initials: J
authors.lastname: Teixidó
authors.affiliation: From the Institut de Ciencies Fotoniques, Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain, the ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain maria.garcia-parajo@icfo.es.
authors.forename: Maria F
authors.identifier: http://orcid.org/0000-0001-6618-3944
authors.initials: MF
authors.lastname: Garcia-Parajo
mesh_terms: D002448:Cell Adhesion / Q000502:physiology; D002460:Cell Line; D054377:Chemokine CXCL12 / Q000378:metabolism*; D039041:Integrin alpha4beta1 / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D013601:T-Lymphocytes / Q000378:metabolism*; D016608:Talin / Q000235:genetics / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism*
chemical_list: C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D039041:Integrin alpha4beta1; D016608:Talin; D019010:Vascular Cell Adhesion Molecule-1
keywords: cell adhesion; cell migration; integrin; membrane biophysics; microscopy; single particle analysis