The glycoprotein of VSV accumulates in a distal Golgi compartment in the presence of CCCP.

The post-translational modifications of the G protein of vesicular stomatitis virus, described in the preceding paper, indicate that its transport is arrested by carbonylcyanide m-chlorophenylhydrazone (CCCP) in or near the trans-Golgi. Immunofluorescence microscopy of BHK-21 cells infected with vesicular stomatitis virus and treated with CCCP shows an accumulation of G protein in the Golgi area. In the same cells, the morphology of wheat germ agglutinin (WGA)-staining structures in the perinuclear region is aberrant. Using anti-BiP antibody, there is no obvious change in the structure of the endoplasmic reticulum. Electron microscopy reveals that the aberrant structures in the perinuclear region result from dilation of Golgi cisternae and accumulation of large vacuoles near the Golgi stack. The appearance of these aberrant structures is dose-dependent and they disappear after the protonophore is removed. The vast majority of the vacuoles accumulate on the trans side of the Golgi stack. A small fraction of them contain the marker enzyme thiamine pyrophosphatase (TPPase). By immunoelectron microscopy, most of the vacuoles contain G protein. We conclude that most of the Golgi-associated vacuoles are derived from a distal Golgi transport compartment, possibly the trans-Golgi reticulum, and that CCCP reversibly inhibits the transport of newly synthesized G protein through this distal compartment.