Abstract
Sendai virus envelopes and human erythrocyte band 3 membrane polypeptides were isolated in detergent solutions and coreconstituted into detergent-free vesicle structurally resembling viral envelopes. Formation of hybrid viral envelope-band 3 vesicles (VB3) was demonstrated by immunoprecipitation of VB3 containing 4,4'-diisothiocyano-2,2'-ditritostilbenedisulfonic acid-labeled band 3 in the presence of antiviral antiserum. The hybrid VB3 vesicles displayed agglutination, fusion, and hemolytic properties similar to those of reconstituted viral envelopes. Incubation of VB3 with Friend erythroleukemic cells resulted in fusion-mediated insertion of viral antigens and of band 3 into the plasma membranes of the recipient cells. The presence of band 3 incorporated into Friend erythroleukemic cells was revealed structurally by electron microscopy after staining with ferritin-conjugated anti-human erythrocyte membrane antiserum. Incorporation of band 3, the putative erythrocyte antion channel, led to a marked and specific stimulation of anion exchange in Friend erythroleukemic cells. The viral-mediated insertion of an isolated membrane protein into viable Friend erythroleukemic cells provides a method for studying membrane protein turnover and for assaying reconstituted membrane components such as carriers or channels.