A simple model for the function of p97. A substrate protein (S) is ubiquitylated by a cascade of E1, E2 and the E3 ubiquitin ligase. If the substrate is tightly attached to a binding partner (B) or subcellular structure, p97 binds the substrate via a ubiquitin adapter containing a ubiquitin-binding domain (UBD) and a p97-binding UBX (ubiquitin regulatory X) or UBX-like (UBX-L) domain. Upon ATP hydrolysis, p97 extracts the substrate and delivers it to the proteasome (Pr) for degradation.
Meyer BMC Biology 2012 10:48 doi:10.1186/1741-7007-10-48