title: Patching and capping of LFA-1 molecules on human lymphocytes.
abstract: The distribution and dynamics of LFA-1 molecules over the surface of human lymphocytes were analysed using immunogold label-fracture and fracture-flip methods. Patching and capping were induced by incubation at 37 degrees C with antibodies directed against the alpha and beta chains respectively of the heterodimeric LFA-1 molecule, and were followed by immunofluorescence. Treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) to link LFA-1 molecules to the cytoskeleton increased the percentage of capped cells, implying a faster and more efficient process of capping. At all times of clustering or upon phorbol ester treatment, the concentration of LFA-1 in patches and then in caps was not accompanied by a parallel concentration of membrane particles on the freeze-fractured plasma membranes. Our results support the role of the cytoskeleton in regulating the capping phenomenon and in controlling the structural organization of the plasma membranes.
authors.affiliation: Dipartimento di Medicina Sperimentale, Università di Roma La Sapienza, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Pavan
authors.forename: G
authors.initials: G
authors.lastname: Lucania
authors.forename: T
authors.initials: T
authors.lastname: Sansolini
authors.forename: L
authors.initials: L
authors.lastname: Frati
authors.forename: M R
authors.initials: MR
authors.lastname: Torrisi
mesh_terms: D000906:Antibodies; D002462:Cell Membrane / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D005614:Freeze Fracturing; D006801:Humans; D007150:Immunohistochemistry; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism*; D008214:Lymphocytes / Q000378:metabolism* / Q000648:ultrastructure; D010703:Phorbol Esters; D011940:Receptor Aggregation
chemical_list: D000906:Antibodies; D016169:Lymphocyte Function-Associated Antigen-1; D010703:Phorbol Esters