Ligand-induced capping of surface proteins on trifluoperazine-treated macrophages

Abstract

Peritoneal exudate macrophages directly endocytose cross-linked membrane proteins such as conA receptors and histocompatibility proteins. Under identical conditions lymphocytes and transformed macrophages cap these proteins. We hypothesized that macrophages are programmed for endocytosis after membrane protein cross-linking, as opposed to lymphocytes which cap their cross-linked membrane proteins. In the presence of trifluoperazine, a calmodulin antagonist which inhibits endocytosis, a proportion of macrophages capped their membrane proteins.