A lymphoma plasma membrane-associated protein with ankyrin-like properties.
In this study we have used several complementary techniques to isolate and characterize a 72-kD polypeptide that is tightly associated with a major mouse T-lymphoma membrane glycoprotein, gp 85 (a wheat germ agglutinin-binding protein), in a 16 S complex. These two proteins do not separate in the presence of high salt but can be dissociated by treatment with 2 M urea. Further analysis indicates that the 72-kD protein has ankyrin-like properties based on the following criteria: (a) it cross-reacts with specific antibodies raised against erythrocyte and brain ankyrin; (b) it displays a peptide mapping pattern and a pI (between 6.5 and 6.8) similar to that of the 72-kD proteolytic fragment of erythrocyte ankyrin; (c) it competes with erythrocyte ghost membranes (spectrin-depleted preparations) for spectrin binding; and (d) it binds to purified spectrin and fodrin molecules. Most importantly, in intact lymphoma cells this ankyrin-like protein is localized directly underneath the plasma membrane and is found to be preferentially accumulated beneath receptor cap structures as well as associated with a membrane-cytoskeleton complex preparation. It is proposed that the ankyrin-like 72-kD protein may play an important role in linking certain surface glycoprotein(s) to fodrin which, in turn, binds to actin filaments required for lymphocyte cap formation.
D000818:Animals; D017487:Ankyrins; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D003599:Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D007152:Immunologic Capping; D008223:Lymphoma / Q000032:analysis* / Q000378:metabolism / Q000648:ultrastructure; D008565:Membrane Proteins / Q000302:isolation & purification* / Q000378:metabolism / Q000502:physiology; D051379:Mice; D008840:Microfilament Proteins / Q000378:metabolism; D008970:Molecular Weight; D011948:Receptors, Antigen, T-Cell / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D013049:Spectrin / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism / Q000648:ultrastructure
D017487:Ankyrins; D002352:Carrier Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D011948:Receptors, Antigen, T-Cell; D013049:Spectrin