Surface Adhesion Molecule Promotes Immune Signaling

They stabilize interaction between antigen receptors and cellular structures

THURSDAY, June 19 (HealthDay News) -- Surface adhesion molecules can affect normal immune responses by stabilizing the interaction between antigen receptors and cellular structures, favoring the transmission of stimulatory signals, researchers report in the June 13 issue of Immunity.

Ken Nguyen, and colleagues from Tufts University School of Medicine in Boston, investigated how the integrin VLA-4, a cell adhesion molecule, and T-cell receptors, which bind antigen, communicate in generating immune responses. Both proteins signal through the SLP-76 protein, which is present in cellular structures known as microclusters.

The researchers found that when VLA-4 was bound, the microclusters had reduced mobility and remained bound to the antigen receptor, favoring the transmission of stimulatory signals. Engagement of VLA-4 also reduced the ability of the cytoskeletal protein actin to separate the antigen receptor from the microclusters, prolonging the survival of the complex, the report indicates.

"In conclusion, we have shown that T cell costimulation through VLA-4 is associated with dramatic reductions in the mobility of cytoskeletal and signaling structures," Nguyen and colleagues write. "We predict that comparable effects on the movement of cytoskeletal and signaling structures govern the outcome of the diverse processes involving antigen receptors and integrins."

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