Metabolic and cytoskeletal modulation of transferrin receptor mobility in mitogen-activated human lymphocytes.
The transferrin receptors which appear on mitogen-activated human peripheral blood lymphocytes were found by the use of immunofluorescence techniques to display temperature-dependent patching and capping reactions upon binding of transferrin. Lateral mobility of ligand-occupied membrane sites was accompanied by both shedding and endocytosis of receptor-transferrin complexes. In the presence of sodium azide or the microfilament inhibitor cytochalasin B, cap formation and shedding were markedly inhibited. In contrast, endocytosis of patched receptor-ligand complexes was inhibited by azide and microtubule inhibitors, including colchicine, vinblastine and vincristine. Co-capping experiments performed to elucidate further the alterations in membrane configuration involved in these reactions failed to reveal any topographical relationship between transferrin receptors and lectin-binding sites in these cells. These studied indicate that temperature-dependent mobility of transferrin receptors upon mitogen-activated peripheral blood lymphocytes is dependent upon the integrity of the cytoskeletal system and metabolic function of the cell.
D001665:Binding Sites; D005455:Fluorescent Antibody Technique; D006801:Humans; D007152:Immunologic Capping / Q000187:drug effects; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000276:immunology / Q000378:metabolism*; D011952:Receptors, Concanavalin A; D011990:Receptors, Transferrin; D013696:Temperature; D014168:Transferrin / Q000378:metabolism
D010835:Phytohemagglutinins; D011956:Receptors, Cell Surface; D011952:Receptors, Concanavalin A; D011990:Receptors, Transferrin; D014168:Transferrin