New ATPase regulators—p97 goes to the PUB

The conserved eukaryotic AAA-type ATPase complex, known as p97 or VCP in mammals and Cdc48 in yeast, is involved in a number of cellular pathways, including fusion of homotypic membranes, protein degradation, and activation of membrane-bound transcription factors. Most likely, p97 is directed to this broad spectrum of cellular functions through its binding to specific cofactors. More than 20 different p97 cofactors have been described to date and our understanding of their cellular functions is rapidly expanding. Common to these proteins is their intimate connection with the ubiquitin system. Recently, a small, conserved family of proteins, containing PUB domains, was found to function as p97 adaptors. Intriguingly, their association with p97 is regulated by tyrosine phosphorylation, suggesting that they act as a relay between signalling pathways and p97 functions. Here we give an overview of the currently known PUB-domain proteins and other p97-interacting proteins.