Adenovirus-dependent release of choline from plasma membrane vesicles at an acidic pH is mediated by the penton base protein.
It has been suggested that during receptor-mediated endocytosis of human adenovirus (Ad) type 2 into cells, Ad disrupts the membrane of endocytic vesicles to enter the cytosol. To understand the mechanism of Ad-mediated disruption of the endocytic vesicles, I exposed Ad to plasma membrane vesicles derived from KB cells. Ad caused release of choline from the plasma membrane vesicles preloaded with [3H]choline. The efflux of choline was dependent on (i) the concentration of Ad, with a half-maximal effect at 0.5 microgram/ml; (ii) the pH of the buffer, with the optimum pH of the reaction ranging from 5.5 to 6.0; (iii) the length of the incubation, with a half-maximal release at 2 min; and (iv) the temperature of the incubation, with the optimum temperature being 37 degrees C. The Ad-dependent release of choline was inhibited by anti-penton base, while antihexon did not block the effect. These results suggest roles for a low-pH environment and the penton base protein in the Ad-dependent efflux of choline from plasma membrane vesicles.
Seth
P
P
Laboratory of Molecular Biology, National Cancer Institute, Bethesda, Maryland 20892.
D000143:Acids; D000260:Adenoviruses, Human / Q000378:metabolism*; D002213:Capsid / Q000378:metabolism*; D036022:Capsid Proteins; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D002794:Choline / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration
D000143:Acids; D036022:Capsid Proteins; C043322:penton protein, adenovirus; D002794:Choline