Association of CD2 with tubulin. Evidence for a role of the cytoskeleton in T cell activation.

In addition to the antigen-specific T cell receptor, a number of other T cell surface molecules contribute to T cell adhesion and activation. CD2 is a 50-kDa glycoprotein found on the surface of human T lymphocytes which plays a role in T cell adhesion and stimulation. The intracellular mechanisms by which CD2 functions are, however, not fully defined. Here we show that the T cell surface molecule CD2 physically interacts with tubulin. This interaction appears to involve the membrane-proximal part of the cytoplasmic domain of the CD2 molecule, suggesting that CD2 binds to the tubulin fraction previously shown to be present in membranes. Stimulation of T cells with activating pairs of anti-CD2 antibodies, capable of initiating lymphokine production and T cell proliferation, disrupts the CD2-tubulin complexes, suggesting that the dynamic interaction of CD2 with tubulin may play a role in T cell activation.