26S proteasome complex ubiquitin receptor, subunit Rpn13 (IPR006773)

Short name: 26S_Psome_Ubiquitin-recp_Rpn13

Family relationships



This family was thought originally to be involved in cell-adhesion [PMID: 10610020, PMID: 10919708], but the members are now known to be proteasome subunit Rpn13, a novel ubiquitin receptor. The 26S proteasome is a huge macromolecular protein-degradation machine consisting of a proteolytically active 20S core, in the form of four disc-like proteins, and one or two 19S regulatory particles. The regulatory particle(s) sit on the top and or bottom of the core, de-ubiquitinate the substrate peptides, unfold them and guide them into the narrow channel through the centre of the core. Rpn13 and its homologues dock onto the regulatory particle through the N-terminal region which binds Rpn2. The C-terminal part of the domain binds de-ubiquitinating enzyme Uch37/UCHL5 and enhances its isopeptidase activity. Rpn13 binds ubiquitin via a conserved amino-terminal region called the pleckstrin-like receptor for ubiquitin, termed Pru, domain [PMID: 18497817]. The domain forms two contiguous anti-parallel beta-sheets with a configuration similar to the pleckstrin-homology domain (PHD) fold [PMID: 18497827]. Rpn13's ability to bind ubiquitin and the proteasome subunit Rpn2/S1 simultaneously supports evidence of its role as a ubiquitin receptor. Finally, when complexed to di-ubiquitin, via the Pru, and Uch37 via the C-terminal part, it frees up the distal ubiquitin for de-ubiquitination by the Uch37 [PMID: 18497827].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0005737 cytoplasm
GO:0005634 nucleus

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.