This is the C-terminal domain found in RPN1 proteins (26S proteasome non-ATPase regulatory subunit 2). The 26S proteasome holocomplex consists of a 28-subunit barrel-shaped core particle (CP) in the center capped at the top and bottom by 19-subunit ...
This is the C-terminal domain found in RPN1 proteins (26S proteasome non-ATPase regulatory subunit 2). The 26S proteasome holocomplex consists of a 28-subunit barrel-shaped core particle (CP) in the center capped at the top and bottom by 19-subunit regulatory particles (RPs). The CP forms the catalytic chamber and the RP is formed from two subcomplexes known as the lid and the base [1]. The lid comprises nine Rpn subunits in yeast (Rpn3/5/6/7/8/9/11/12/15) and the base comprises three Rpn subunits (Rpn1/2/13) and six ATPases (Rpt1-6) [2].
This family was thought originally to be involved in cell-adhesion [1,2], 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 ...
This family was thought originally to be involved in cell-adhesion [1,2], 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 [4]. The domain forms two contiguous anti-parallel beta-sheets with a configuration similar to the pleckstrin-homology domain (PHD) fold [5]. 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 [5].
This is the C-terminal domain found in S. cerevisiae Rpn2 (26S proteasome regulatory subunit RPN2) as well as other eukaryotic species. A study revealed that the C-terminal 52 residues of the Rpn2 C-terminal domain are responsible for mediating inter ...
This is the C-terminal domain found in S. cerevisiae Rpn2 (26S proteasome regulatory subunit RPN2) as well as other eukaryotic species. A study revealed that the C-terminal 52 residues of the Rpn2 C-terminal domain are responsible for mediating interactions with the ubiquitin-binding subunit Rpn13. Futhermore, the extreme C-terminal 20 or 21 residues of Rpn2 (926-945 or 925-945) of S. cerevisiae, were shown to be equally effective at binding Rpn13. Multiple sequence alignments indicate that Rpn2 orthologs are highly conserved in this C-terminal region and share characteristic acidic, aromatic, and proline residues, suggesting a common function. In the structure of Rpn2 from S. cerevisiae , this region is exposed and disordered, and is thus accessible for associating with Rpn13. The Rpn2 binding surface of human Rpn13 has been mapped by nuclear magnetic resonance titration to one surface of its Pru domain [1].
