title: The association of alpha-actinin and clathrin with the plasma membrane.
abstract: The role of alpha-actinin in the attachment of actin to plasma membranes has been investigated. Double-label indirect immunofluorescence has been used to show that in lymphocytes alpha-actinin will concentrate beneath caps of aggregated surface Ig, confirming the recent report by Geiger and Singer [23]. Specific antibody-staining of SDS gels has indicated that alpha-actinin is a major component in isolated plasma membranes prepared from three different cell types by two different procedures. A fraction of this alpha-actinin is readily dissociated from these membranes wit relatively little parallel release of actin. The remaining alpha-actinin is more resistant to extraction but can be removed by prolonged dialysis against low ionic-strength buffers which also dissociate most of the actin. The dissociation characteristics of alpha-actinin from the plasma membrane lead us to suggest that alpha-actinin does not form a direct link between actin and the membrane, although it may promote and stabilize actin attachment by cross-linking adjacent actin filaments close to the membrane. During the course of our work with isolated plasma membranes we have tentatively identified a prominent component of these membranes as clathrin, the major protein of coated vesicles [8].
mesh_terms: D000185:Actinin / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D002966:Clathrin; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D007152:Immunologic Capping; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism*; D009124:Muscle Proteins / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D002966:Clathrin; D008565:Membrane Proteins; D009124:Muscle Proteins; D000185:Actinin