JAGN1, tetraspanins, and Erv proteins: is common topology indicative of common function in cargo sorting?

Am J Physiol Cell Physiol. 2020 Oct 1;319(4):C667-C674. doi: 10.1152/ajpcell.00436.2019. Epub 2020 Aug 12.


The endoplasmic reticulum protein Jagunal (JAGN1) was first identified as a requirement for Drosophila melanogaster oocyte development. Subsequent studies in human patients linked mutations in JAGN1 to severe congenital neutropenia, as well as a broad range of additional symptoms, suggesting that JAGN1 function is required in many tissues. Moreover, JAGN1 orthologs are found throughout animal and plant phylogeny, suggesting that JAGN1 supports fundamental cellular processes not restricted to egg development or neutrophil function. JAGN1 lacks sequence similarity or recognizable domains other than a coatomer protein complex I-binding motif, and its cellular function is currently unknown. JAGN1 shares a tetraspanning membrane topology with two families of known cargo transporters: the tetraspanins and the endoplasmic reticulum vesicle (Erv) proteins. Herein, we discuss the similarities between JAGN1, tetraspanins, and Ervs and, based on those, suggest a role for JAGN1 in facilitating the traffic of cell-restricted and ubiquitously expressed proteins at the endoplasmic reticulum-Golgi interface.

Keywords: Erv proteins; JAGN1; cargo receptors, cargo sorting; tetraspanins.

Publication types

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

MeSH terms

  • Animals
  • Coatomer Protein / genetics
  • Drosophila Proteins / genetics*
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / growth & development
  • Endoplasmic Reticulum / genetics*
  • Gene Expression Regulation, Developmental / genetics
  • Golgi Apparatus / genetics
  • Humans
  • Membrane Proteins / genetics*
  • Multiprotein Complexes / genetics
  • Oocytes / growth & development*
  • Oocytes / metabolism
  • Phylogeny
  • Protein Domains / genetics
  • Tetraspanins / genetics


  • Coatomer Protein
  • Drosophila Proteins
  • JAGN1 protein, human
  • Membrane Proteins
  • Multiprotein Complexes
  • Tetraspanins
  • jagn protein, Drosophila