A molecular specificity code for the three mammalian KDEL receptors

J Cell Biol. 2007 Dec 17;179(6):1193-204. doi: 10.1083/jcb.200705180.

Abstract

AC-terminal KDEL-like motif prevents secretion of soluble endoplasmic reticulum (ER)-resident proteins. This motif interacts with KDEL receptors localized in the intermediate compartment and Golgi apparatus. Such binding triggers retrieval back to the ER via a coat protein I-dependent pathway. To date, two human KDEL receptors have been reported. Here, we report the Golgi localization of a third human KDEL receptor. Using a reporter construct system from a screen of 152 variants, we identified 35 KDEL-like variants that result in efficient ER localization but do not match the current Prosite motif for ER localization ([KRHQSA]-[DENQ]-E-L). We cloned 16 human proteins with one of these motifs and all were found in the ER. A subsequent screen by bimolecular fluorescence complementation determined the specificities of the three human KDEL receptors. Each KDEL receptor has a unique pattern of motifs with which it interacts. This suggests a specificity in the retrieval of human proteins that contain different KDEL variants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Animals
  • COS Cells
  • Chlorocebus aethiops
  • Cloning, Molecular
  • Endoplasmic Reticulum / metabolism
  • Genes, Reporter
  • Golgi Apparatus / metabolism
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Protein Sorting Signals
  • Receptors, Peptide / analysis
  • Receptors, Peptide / chemistry*
  • Sequence Alignment

Substances

  • KDEL receptor
  • Protein Sorting Signals
  • Receptors, Peptide