Figure 2

Domain structure of p97 and UBX/UBX-L domain cofactors. p97 cofactors are defined by p97-binding domains or motifs that directly interact with p97, and of which the UBX/UBX-like domain is the one that is found in the largest subset. Adapters are those cofactors that also contain a ubiquitin-binding domain (UBD), such as UBA, that links p97 to ubiquitylated substrates. (a) p97 contains two ATPase domains and an amino-terminal regulatory domain that binds cofactors and substrates. (b) Human UBD-UBX/UBX-L adapters comprise the Ufd1-Npl4 heterodimer and the five listed UBA-UBX proteins. (c) Other UBX and UBX-L cofactors are depicted. Not shown is a growing number of other cofactors that bind p97 directly through other domains. aa, amino acid; BS1, binding site-1; M, membrane anchor; NZF, Npl4 zinc finger; OTU, ovarian tumor deubiquitylatiing domain; PUB, peptide N-glysosidase/ubiquitin-associated) domain; SEP, Shp1-eyc-p47 domain; UAS, ubiquitin-associating domain; UBA, ubiquitin-associated domain; UBL, ubiquitin-like domain; UIM, ubiquitin-interaction motif; UT3, Ufd1 truncation 3 domain; VIM, VCP/p97 interaction motif.