Valosin containing protein (VCP), also designated TERA (for transitional endoplasmic reticulum ATPase) or p97, is a member of the AAA family of ATPases, which are involved in a variety of cellular activities. VCP is the mammalian homolog of Saccharomyces cerevisiae Cdc48, a protein essential for the completion of mitiosis in yeast. VCP is thought to be involved in a variety of membrane functions and in the regulation of the cell cycle. It associates with ubiquitinated IκB-α as well as with the 26S Proteosome, indicating a potential role for VCP in the proteosome-mediated degradation of IκB-α.