BOUND SIMIAN-VIRUS-40 TRANSLOCATES TO CAVEOLIN-ENRICHED MEMBRANE DOMAINS, AND ITS ENTRY IS INHIBITED BY DRUGS THAT SELECTIVELY DISRUPT CAVEOLAE

Simian virus 40 (SV40) entry leading to infection occurred only after the virus was at the cell surface for 1.5 to 2 h. SV40 infectious entr y was not sensitive to cytosol acidification, a treatment that blocks endocytosis via clathrin-coated vesicles. Instead, SV40 infectious ent ry was blocked by treating cells with the phorbol ester PMA or nystati n, which selectively disrupts caveolae. In control experiments, transf errin internalization was sensitive to cytosol acidification but was n ot sensitive to PMA or nystatin. Also, absorbed transferrin entered ce lls within minutes. Finally, bound SV40 translocated to caveolin-enric hed membrane complexes isolated by a Triton X-100 insolubility protoco l. Treatment with nystatin did not impair SV40 binding but did block t he partitioning of virus into the caveolin-enriched complexes.