Recent studies suggest that trimerization of Fas is insufficient for apoptosis induction and
indicate that super-aggregation of trimerized Fas might be prerequisite. For many cell
surface receptors, cross-linking by multivalent ligands or antibodies induces their lateral
segregation within the plasma membrane and co-localization into" caps" on one pole of the
cell. In this study, we show that capping of Fas is essential for optimal function and that
capping is ceramide-dependent. In Jurkat T lymphocytes and in primary cultures of …