ASSOCIATION OF MURINE SPLENOCYTE CD3 COMPLEX TO THE CYTOSKELETON - ABSENCE OF MODULATION BY EXOGENOUS FATTY-ACIDS

The cytoplasmic regions of the CD3 complex are presumably involved in signal transduction following ligand-receptor binding. We investigated the effects of incubating either stearic or oleic acid on the associa tion of murine lymphocyte CD3 complex with the cytoskeleton. Both cyto chalasin D, an inhibitor of microfilament formation, and W7, an inhibi tor of calmodulin, inhibited capping of CD3. The association of CD3 wi th the cytoskeleton was confirmed by confocal laser scanning microscop y studies, which showed co-localization of the cross-linked CD3 recept ors and the membrane attachment proteins ankyrin and fodrin. Although exogenous oleic acid increased plasma membrane fluidity, neither expre ssion nor capping of CD3 receptors was increased. Nonetheless, oleic a cid did increase uptake of tritiated thymidine after binding of anti-C D3 antibodies. Lymphoproliferation was progressively inhibited by both cytochalasin D and W7, confirming the importance of intact cytoskelet on for cellular activation. (C) 1996 Academic Press Limited