FIG. 7.

Effect of increased ionic strength on cellular membranes and poliovirus-induced vesicles. Following infection with wild-type poliovirus for 4 h, the plasma membranes of COS-1 cells were disrupted in homogenization buffer and the cellular organelles were separated on a 12% stock isotonic Percoll density gradient that did not (A and C) or did (B and D) contain 60 mM KCl; lightest fractions are at the left. (A and B) Distributions of ER membranes and poliovirus-induced vesicles identified by immunoblotting as indicated. (C and D) Distributions of Golgi, mitochondrial, and lysosomal (Lyso) membranes identified by immunoblotting against p115, immunoblotting against mtHSP70 [HSP70m(mito), and β-hexosaminidase (β-Hex) assays as indicated.