Identification of transmembrane bridging proteins in the plasma membrane of cultured mouse L cells.
Studies were carried out to identify transmembrane bridging proteins in the plasma membrane of mouse L-929 cells. Cells grown in suspension culture were 125I-labeled by lactoperoxidase and allowed to ingest latex particles to produce inside-out membrane phagosome preparations. Phagosomes were isolated and the inner membrane surface was labeled with N-(5'-aminopentyl)-5-dimethylamino-1-naphthalenesulfonamide (dansylcadavarine) by a transglutaminase-catalyzed reaction. The phagosome membrane proteins were solubilized and dansylcadavarine-labeled proteins were isolated by anti-dansyl immunoadsorbent affinity chromatography. Dansylcadavarine-labeled proteins were analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and autoradiography for the presence of 125I-labeled material. By this technique, two iodinated proteins with molecular weights of approximately 50,000 and 80,000 appear to be selectively retained by the anti-dansyl immunoadsorbent, suggesting that these proteins span the plasma membrane.
D002103:Cadaverine / Q000378:metabolism; D002462:Cell Membrane / Q000648:ultrastructure*; D007739:L Cells / Q000648:ultrastructure; D008565:Membrane Proteins / Q000032:analysis*; D008970:Molecular Weight; D010587:Phagocytosis; D005723:gamma-Glutamyltransferase / Q000378:metabolism
D008565:Membrane Proteins; D005723:gamma-Glutamyltransferase; D002103:Cadaverine