1. Academic Validation
  2. Proteasome subunit Rpn13 is a novel ubiquitin receptor

Proteasome subunit Rpn13 is a novel ubiquitin receptor

  • Nature. 2008 May 22;453(7194):481-8. doi: 10.1038/nature06926.
Koraljka Husnjak 1 Suzanne Elsasser Naixia Zhang Xiang Chen Leah Randles Yuan Shi Kay Hofmann Kylie J Walters Daniel Finley Ivan Dikic
Affiliations

Affiliation

  • 1 Institute of Biochemistry II and Cluster of Excellence Macromolecular Complexes, Goethe University, Theodor-Stern-Kai 7, D-60590 Frankfurt (Main), Germany.
Abstract

Proteasomal receptors that recognize ubiquitin chains attached to substrates are key mediators of selective protein degradation in eukaryotes. Here we report the identification of a new ubiquitin receptor, Rpn13/ARM1, a known component of the Proteasome. Rpn13 binds ubiquitin through a conserved amino-terminal region termed the pleckstrin-like receptor for ubiquitin (Pru) domain, which binds K48-linked diubiquitin with an affinity of approximately 90 nM. Like proteasomal ubiquitin receptor Rpn10/S5a, Rpn13 also binds ubiquitin-like (UBL) domains of UBL-ubiquitin-associated (UBA) proteins. In yeast, a synthetic phenotype results when specific mutations of the ubiquitin binding sites of Rpn10 and Rpn13 are combined, indicating functional linkage between these ubiquitin receptors. Because Rpn13 is also the proteasomal receptor for Uch37, a deubiquitinating Enzyme, our findings suggest a coupling of chain recognition and disassembly at the Proteasome.

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