p97/VCP (valosin containing protein) belongs to the AAA ATPase family, predicted molecular weight 97 kD. VCP is associated with a variety of cellular activities, including cell cycle control, membrane fusion after mitosis, regulates spindle disassembly at the end of mitosis, nuclear trafficking and the ubiquitin-proteasome degradation pathway. In many instances, specific adaptor proteins with which VCP forms multiprotein complexes direct its role in a given process. This protein is required for the fusion of ER and Golgi membranes. Clone 4G9 has been shown to be useful for western blotting, immunoprecipitation, and immunofluorescence staining of human p97/VCP protein.