COS-7 cells were transiently transfected with a plasmid expressing wild type valosin-containing protein (VCP) fused to green fluorescent protein (GFP) and were exposed the following day to the Hsp90 inhibitor geldanamycin and the proteasome inhibitor Velcade. Twenty-four hours later, cells were examined for the presence of endoplasmic reticulum-derived vacuoles. Fluorescent images layered over phase-contrast photographs show that cells expressing exogenous VCP (green) failed to form vacuoles in response to combined Hsp90 and proteasome inhibition. Conversely, cell containing drug-induced vacuoles expressed little or no exogenous VCP. For details, see the article by Mimnaugh et al. 667.