Coatomer is essential for retrieval of dilysine-tagged proteins to the endoplasmic reticulum

Cell. 1994 Dec 30;79(7):1199-207. doi: 10.1016/0092-8674(94)90011-6.


Dilysine motifs in cytoplasmic domains of transmembrane proteins are signals for their continuous retrieval from the Golgi back to the endoplasmic reticulum (ER). We describe a system to assess retrieval to the ER in yeast cells making use of a dilysine-tagged Ste2 protein. Whereas retrieval was unaffected in most sec mutants tested (sec7, sec12, sec13, sec16, sec17, sec18, sec19, sec22, and sec23), a defect in retrieval was observed in previously characterized coatomer mutants (sec21-1, sec27-1), as well as in newly isolated retrieval mutants (sec21-2, ret1-1). RET1 was cloned by complementation and found to encode the alpha subunit of coatomer. While temperature-sensitive for growth, the newly isolated coatomer mutants exhibited a very modest defect in secretion at the nonpermissive temperature. Coatomer from beta'-COP (sec27-1) and alpha-COP (ret1-1) mutants, but not from gamma-COP (sec21) mutants, had lost the ability to bind dilysine motifs in vitro. Together, these results suggest that coatomer plays an essential role in retrograde Golgi-to-ER transport and retrieval of dilysine-tagged proteins back to the ER.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Biological Transport / physiology
  • Coatomer Protein
  • Dipeptides
  • Endoplasmic Reticulum / metabolism*
  • Fungal Proteins / metabolism
  • Hexosyltransferases*
  • Membrane Proteins / metabolism*
  • Membrane Proteins / physiology*
  • Molecular Sequence Data
  • Mutation
  • Protein Sorting Signals / physiology
  • Receptors, Mating Factor
  • Receptors, Peptide / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / metabolism
  • Transcription Factors*
  • Transferases / metabolism


  • Coatomer Protein
  • Dipeptides
  • Fungal Proteins
  • Membrane Proteins
  • Protein Sorting Signals
  • Receptors, Mating Factor
  • Receptors, Peptide
  • Recombinant Fusion Proteins
  • Transcription Factors
  • lysyllysine
  • Transferases
  • Hexosyltransferases
  • dolichyl-diphosphooligosaccharide - protein glycotransferase

Associated data

  • GENBANK/Z46617