Interaction of NUB1 with the proteasome subunit S5a

Biochem Biophys Res Commun. 2005 Nov 11;337(1):116-20. doi: 10.1016/j.bbrc.2005.09.014.

Abstract

NUB1 interacts with a ubiquitin-like protein NEDD8 to target the NEDD8 monomer and neddylated proteins to the proteasome for degradation. Therefore, NUB1 is thought to be a potent downregulator of NEDD8 conjugation system. Since NUB1 possesses a UBL domain, which was previously shown to be an S5a-interacting motif in RAD23/HHR23, we initially hypothesized that NUB1 interacts with the S5a subunit of the proteasome through its UBL domain. To examine this, we performed an in vitro GST pull-down assay and a yeast two-hybrid assay. Unexpectedly, our studies revealed that NUB1 directly interacts with the S5a subunit through its C-terminal region between amino acid residues 536 and 584, not through its UBL domain. Although the UBL domain was not an S5a-interacting motif in NUB1, our further studies revealed that the UBL domain is required for the function of NUB1.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Binding Sites
  • COS Cells
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Chlorocebus aethiops
  • Humans
  • Proteasome Endopeptidase Complex
  • Protein Structure, Tertiary
  • RNA-Binding Proteins
  • Saccharomyces cerevisiae Proteins
  • Sequence Deletion
  • Transcription Factors / chemistry
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Two-Hybrid System Techniques

Substances

  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • NUB1 protein, human
  • PSMD4 protein, human
  • RNA-Binding Proteins
  • RPN10 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • Proteasome Endopeptidase Complex