Tunicamycin inhibits the expression of functional thrombin receptors on human T-lymphoblastoid cells

N-linked glycosylation plays an important role in intracellular trafficking and the surface expression of many membrane-associated proteins. In the present report we investigated the effect of tunicamycin, a specific inhibitor of N-linked glycosylation, on the expression and function of the thrombin receptor on human T-lymphoblastoid cells. We found that tunicamycin selectively inhibited thrombin-induced Ca2+ mobilization in a dose-dependent manner while the same response triggered by anti-CD3 antibody was unchanged in these cells. Surface expression of the thrombin receptor, as assessed by immunofluorescence staining using two different antibodies, was strongly decreased in the presence of tunicamycin. These findings indicate a role for N-linked glycosylation in the surface expression of the thrombin receptor in T lymphoid cells.