Abstract
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.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
A Kinase Anchor Proteins / antagonists & inhibitors
-
A Kinase Anchor Proteins / genetics
-
A Kinase Anchor Proteins / metabolism*
-
Antigen Presentation
-
B-Lymphocytes / immunology
-
B-Lymphocytes / metabolism
-
Base Sequence
-
CD3 Complex / metabolism*
-
Cell Line
-
Cytoskeletal Proteins / antagonists & inhibitors
-
Cytoskeletal Proteins / genetics
-
Cytoskeletal Proteins / metabolism*
-
Humans
-
Immunological Synapses / immunology
-
Immunological Synapses / metabolism
-
Integrins / metabolism*
-
Jurkat Cells
-
Lymphocyte Function-Associated Antigen-1 / metabolism
-
Microtubule-Organizing Center / immunology
-
Microtubule-Organizing Center / metabolism
-
RNA, Small Interfering / genetics
-
Receptor-CD3 Complex, Antigen, T-Cell / metabolism
-
Receptors, Antigen, T-Cell / metabolism*
-
Recombinant Fusion Proteins / genetics
-
Recombinant Fusion Proteins / metabolism
-
Signal Transduction
-
T-Lymphocytes / immunology
-
T-Lymphocytes / metabolism
Substances
-
A Kinase Anchor Proteins
-
AKAP9 protein, human
-
CD3 Complex
-
Cytoskeletal Proteins
-
Integrins
-
Lymphocyte Function-Associated Antigen-1
-
RNA, Small Interfering
-
Receptor-CD3 Complex, Antigen, T-Cell
-
Receptors, Antigen, T-Cell
-
Recombinant Fusion Proteins