The recognition component of the N-end rule pathway

EMBO J. 1990 Oct;9(10):3179-89.


The N-end rule-based degradation signal, which targets a protein for ubiquitin-dependent proteolysis, comprises a destabilizing amino-terminal residue and a specific internal lysine residue. We report the isolation and functional analysis of a gene (UBR1) for the N-end recognizing protein of the yeast Saccharomyces cerevisiae. UBR1 encodes a approximately 225 kd protein with no significant sequence similarities to other known proteins. Null ubr1 mutants are viable but are unable to degrade the substrates of the N-end rule pathway. These mutants are partially defective in sporulation and grow slightly more slowly than their wild-type counterparts. The UBR1 protein specifically binds in vitro to proteins bearing amino-terminal residues that are destabilizing according to the N-end rule, but does not bind to otherwise identical proteins bearing stabilizing amino-terminal residues.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cloning, Molecular
  • DNA, Fungal / genetics
  • DNA, Fungal / isolation & purification
  • Fungal Proteins / genetics*
  • Fungal Proteins / metabolism
  • Genes, Fungal*
  • Genotype
  • Ligases*
  • Molecular Sequence Data
  • Mutation
  • Oligonucleotide Probes
  • Phenotype
  • Plasmids
  • Restriction Mapping
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae Proteins*
  • Substrate Specificity
  • Ubiquitin-Protein Ligases*


  • DNA, Fungal
  • Fungal Proteins
  • Oligonucleotide Probes
  • Saccharomyces cerevisiae Proteins
  • UBR1 protein, S cerevisiae
  • Ubiquitin-Protein Ligases
  • Ligases

Associated data

  • GENBANK/X53747