Ha SW, et al. (2012)
The N-terminal domain of Rpn4 serves as a portable ubiquitin-independent degron and is recognized by specific 19S RP subunits. Biochem Biophys Res Commun
Abstract: The number of proteasomal substrates that are degraded without prior ubiquitylation continues to grow. However, it remains poorly understood how the proteasome recognizes substrates lacking a ubiquitin (Ub) signal. Here we demonstrated that the Ub-independent degradation of Rpn4 requires the 19S regulatory particle (RP). The Ub-independent degron of Rpn4 was mapped to an N-terminal region including the first 80 residues. Inspection of its amino acid sequence revealed that the Ub-independent degron of Rpn4 consists of an intrinsically disordered domain followed by a folded segment. Using a photo-crosslinking-label transfer method, we captured three 19S RP subunits (Rpt1, Rpn2 and Rpn5) that bind the Ub-independent degron of Rpn4. This is the first time that specific 19S RP subunits have been identified interacting with a Ub-independent degron. This study provides insight into the mechanism by which Ub-independent substrates are recruited to the 26S proteasome.CI - Copyright (c) 2012 Elsevier Inc. All rights reserved.
||Type: Journal Article | Research Support, Non-U.S. Gov't | Research Support, U.S. Gov't, Non-P.H.S. ||PubMed ID: 22349505 |