Integrin and CD3/TCR activation are regulated by the scaffold protein AKAP450.
During antigen recognition by T cells, membrane receptors and cytoskeletal molecules form a specialized structure at the T cell-antigen-presenting cell junction called the immune synapse (IS). We report a role for the scaffolding protein A-kinase anchoring protein-450 (AKAP450), a member of the A-kinase anchoring protein family, in IS formation and T-cell signaling in antigen- and superantigen-dependent T-cell activation. Suppression of AKAP450 by overexpression of a dominant-negative form or siRNA knockdown disrupted the positioning and conformational activation of lymphocyte function-associated antigen 1 at the IS and impaired associated signaling events, including phosphorylation of phospholipase C-gamma1 and protein kinase C-. AKAP450 was also required for correct activation and phosphorylation of CD3, LAT, and Vav1, key T-cell receptor-activated intracellular signaling molecules. Consistently, antigen-triggered reorientation of the microtubule-organizing center at the IS and interleukin-2 secretion were diminished in AKAP450-disrupted T cells. These results indicate key roles for AKAP450 in the organization and activation of receptor molecules at the IS during T-cell signaling events.
Servicio de Inmunología, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Madrid, Spain.
Javier
J
Robles-Valero
Noa B
NB
Martín-Cófreces
Amalia
A
Lamana
Stephen
S
Macdonald
Yuri
Y
Volkov
Francisco
F
Sánchez-Madrid
D054758:A Kinase Anchor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D017951:Antigen Presentation; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D001483:Base Sequence; D017252:CD3 Complex / Q000378:metabolism*; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D054992:Immunological Synapses / Q000276:immunology / Q000378:metabolism; D016023:Integrins / Q000378:metabolism*; D019169:Jurkat Cells; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism; D022101:Microtubule-Organizing Center / Q000276:immunology / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism
D054758:A Kinase Anchor Proteins; C119719:AKAP9 protein, human; D017252:CD3 Complex; D003598:Cytoskeletal Proteins; D016023:Integrins; D016169:Lymphocyte Function-Associated Antigen-1; D034741:RNA, Small Interfering; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins