The Journal of Immunology, Vol 140, Issue 8 2702-2707, Copyright © 1988 by American Association of Immunologists

ARTICLES

Phosphorylation of a 15- to 17-kDa protein correlated with lytic function in cytotoxic T lymphocytes

MC Filiaggi, DE McCulley and JH Russell
Department of Pharmacology, Washington University Medical School, St. Louis, MO 63110.

CTL are activated to lyse their targets through the interaction of the CTL-R and the appropriate Ag on the surface of the target cell. Experiments with tumor-promoting phorbol esters have suggested that the activation and translocation of protein kinase C (PKC) to the CTL membrane may be important in the activation process. We have studied the functional role of PKC in lytic signal transduction by correlating the phosphorylation of a set of CTL membrane proteins bound by the lectin Con A with lytic function in CTL clones. The data obtained indicate that the phosphorylation of a 15- to 17-kDa polypeptide in this subset is associated with the translocation of PKC to the membrane and the stimulation of lytic function. This suggests that the 15- to 17- kDa protein may be a physiologically relevant substrate for PKC translocated to the membrane as a result of Ag-specific perturbation of the CTL-R.