UBA domain found in plant PNGase/UBA or UBX (PUB) domain-containing proteins
This family includes some uncharacterized hypothetical proteins found in plants. Although their biological function remain unclear, all family members contain an N-terminal ubiquitin-associated (UBA) domain and a C-terminal PUB domain. UBA domain, along with UBL (ubiquitin-like) domain, has been implicated in proteasomal degradation by associating with substrates destined for degradation as well as with subunits of the proteasome, thus regulating protein turnover. PUB domain functions as a p97 (also known as valosin-containing protein or VCP) adaptor by interacting with the D1 and/or D2 ATPase domains. The type II AAA+ ATPase p97 is involved in a variety of cellular processes such as the deglycosylation of ERAD substrates, membrane fusion, transcription factor activation and cell cycle regulation through differential binding to specific adaptor proteins.