Recombinant SARS-CoV-2 envelope protein traffics to the trans-Golgi network following amphipol-mediated delivery into human cells

J Biol Chem. 2021 Aug;297(2):100940. doi: 10.1016/j.jbc.2021.100940. Epub 2021 Jul 5.

Abstract

The severe acute respiratory syndrome coronavirus 2 envelope protein (S2-E) is a conserved membrane protein that is important for coronavirus (CoV) assembly and budding. Here, we describe the recombinant expression and purification of S2-E in amphipol-class amphipathic polymer solutions, which solubilize and stabilize membrane proteins, but do not disrupt membranes. We found that amphipol delivery of S2-E to preformed planar bilayers results in spontaneous membrane integration and formation of viroporin cation channels. Amphipol delivery of the S2-E protein to human cells results in plasma membrane integration, followed by retrograde trafficking to the trans-Golgi network and accumulation in swollen perinuclear lysosomal-associated membrane protein 1-positive vesicles, likely lysosomes. CoV envelope proteins have previously been proposed to manipulate the luminal pH of the trans-Golgi network, which serves as an accumulation station for progeny CoV particles prior to cellular egress via lysosomes. Delivery of S2-E to cells will enable chemical biological approaches for future studies of severe acute respiratory syndrome coronavirus 2 pathogenesis and possibly even development of "Trojan horse" antiviral therapies. Finally, this work also establishes a paradigm for amphipol-mediated delivery of membrane proteins to cells.

Keywords: E protein; SARS; amphipol; coronavirus; envelope; insertion; ion channel; lysosomes; membrane; trans-Golgi network.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Cell Membrane / drug effects*
  • Cell Membrane / metabolism
  • Coronavirus Envelope Proteins / genetics
  • Coronavirus Envelope Proteins / metabolism*
  • HeLa Cells
  • Humans
  • Lipid Bilayers / chemistry
  • Lipid Bilayers / metabolism
  • Lysosomes / metabolism
  • Polymers / chemistry
  • Polymers / pharmacology*
  • Propylamines / chemistry
  • Propylamines / pharmacology*
  • Protein Transport
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Surface-Active Agents / chemistry
  • Surface-Active Agents / pharmacology*
  • trans-Golgi Network / metabolism*

Substances

  • Coronavirus Envelope Proteins
  • Lipid Bilayers
  • Polymers
  • Propylamines
  • Recombinant Proteins
  • Surface-Active Agents
  • amphipol A8-35
  • envelope protein, SARS-CoV-2