Cic1, an adaptor protein specifically linking the 26S proteasome to its substrate, the SCF component Cdc4

EMBO J. 2001 Aug 15;20(16):4423-31. doi: 10.1093/emboj/20.16.4423.

Abstract

In eukaryotes, the ubiquitin-proteasome system plays a major role in selective protein breakdown for cellular regulation. Here we report the discovery of a new essential component of this degradation machinery. We found the Saccharomyces cerevisiae protein Cic1 attached to 26S proteasomes playing a crucial role in substrate specificity for proteasomal destruction. Whereas degradation of short-lived test proteins is not affected, cic1 mutants stabilize the F-box proteins Cdc4 and Grr1, substrate recognition subunits of the SCF complex. Cic1 interacts in vitro and in vivo with Cdc4, suggesting a function as a new kind of substrate recruiting factor or adaptor associated with the proteasome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Cycle Proteins / metabolism*
  • F-Box Proteins*
  • F-Box-WD Repeat-Containing Protein 7
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Humans
  • Molecular Sequence Data
  • Peptide Hydrolases / metabolism*
  • Peptide Synthases / metabolism*
  • Proteasome Endopeptidase Complex*
  • SKP Cullin F-Box Protein Ligases
  • Saccharomyces cerevisiae Proteins*
  • Substrate Specificity
  • Ubiquitin-Protein Ligases*
  • Ubiquitins

Substances

  • Carrier Proteins
  • Cell Cycle Proteins
  • Cic1 protein, S cerevisiae
  • F-Box Proteins
  • F-Box-WD Repeat-Containing Protein 7
  • FBXW7 protein, human
  • Fungal Proteins
  • Saccharomyces cerevisiae Proteins
  • Ubiquitins
  • GRR1 protein, S cerevisiae
  • SKP Cullin F-Box Protein Ligases
  • Ubiquitin-Protein Ligases
  • Peptide Hydrolases
  • Proteasome Endopeptidase Complex
  • ATP dependent 26S protease
  • Peptide Synthases