Negative charge and membrane-tethered viral 3B cooperate to recruit viral RNA dependent RNA polymerase 3D pol

Sci Rep. 2017 Dec 11;7(1):17309. doi: 10.1038/s41598-017-17621-6.

Abstract

Most single stranded plus RNA viruses hijack phosphatidylinositol 4-kinases (PI4Ks) to generate membranes highly enriched in phosphatidylinositol 4-phosphate (PI4P). These membranous compartments known as webs, replication factories or replication organelles are essential for viral replication because they provide protection from the innate intracellular immune response while serving as platforms for viral replication. Using purified recombinant proteins and biomimetic model membranes we show that the nonstructural viral 3A protein is sufficient to promote membrane hyper-phosphorylation given the proper intracellular cofactors (PI4KB and ACBD3). However, our bio-mimetic in vitro reconstitution assay revealed that rather than the presence of PI4P specifically, negative charge alone is sufficient for the recruitment of 3Dpol enzymes to the surface of the lipid bilayer. Additionally, we show that membrane tethered viral 3B protein (also known as Vpg) works in combination with the negative charge to increase the efficiency of membrane recruitment of 3Dpol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Cell Membrane / metabolism*
  • Humans
  • Kobuvirus / enzymology*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Phosphatidylinositol Phosphates / metabolism*
  • Phosphotransferases (Alcohol Group Acceptor) / genetics
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism*
  • Picornaviridae Infections / metabolism*
  • Picornaviridae Infections / virology
  • Viral Nonstructural Proteins / genetics
  • Viral Nonstructural Proteins / metabolism*

Substances

  • ACBD3 protein, human
  • Adaptor Proteins, Signal Transducing
  • Membrane Proteins
  • Phosphatidylinositol Phosphates
  • Viral Nonstructural Proteins
  • phosphatidylinositol 4-phosphate
  • Phosphotransferases (Alcohol Group Acceptor)
  • phosphatidylinositol 4-kinase IIIbeta, human