Lyn kinase regulates egress of flaviviruses in autophagosome-derived organelles

Nat Commun. 2020 Oct 15;11(1):5189. doi: 10.1038/s41467-020-19028-w.

Abstract

Among the various host cellular processes that are hijacked by flaviviruses, few mechanisms have been described with regard to viral egress. Here we investigate how flaviviruses exploit Src family kinases (SFKs) for exit from infected cells. We identify Lyn as a critical component for secretion of Dengue and Zika infectious particles and their corresponding virus like particles (VLPs). Pharmacological inhibition or genetic depletion of the SFKs, Lyn in particular, block virus secretion. Lyn-/- cells are impaired in virus release and are rescued when reconstituted with wild-type Lyn, but not a kinase- or palmitoylation-deficient Lyn mutant. We establish that virus particles are secreted in two distinct populations - one as free virions and the other enclosed within membranes. Lyn is critical for the latter, which consists of proteolytically processed, infectious virus progenies within autophagosome-derived vesicles. This process depends on Ulk1, Rab GTPases and SNARE complexes implicated in secretory but not degradative autophagy and occur with significantly faster kinetics than the conventional secretory pathway. Our study reveals a previously undiscovered Lyn-dependent exit route of flaviviruses in LC3+ secretory organelles that enables them to evade circulating antibodies and might affect tissue tropism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagosomes / metabolism*
  • Autophagosomes / virology*
  • Autophagy
  • Autophagy-Related Protein-1 Homolog / metabolism
  • Cell Line
  • Chlorocebus aethiops
  • Dengue
  • Dengue Virus / metabolism
  • Flavivirus / metabolism*
  • Host Microbial Interactions / physiology
  • Humans
  • Intracellular Signaling Peptides and Proteins / metabolism
  • SNARE Proteins / metabolism
  • Secretory Pathway
  • Vero Cells
  • Virion / metabolism
  • Virus Release
  • Zika Virus / metabolism
  • Zika Virus Infection
  • rab GTP-Binding Proteins / metabolism
  • src-Family Kinases / genetics
  • src-Family Kinases / metabolism*

Substances

  • Intracellular Signaling Peptides and Proteins
  • SNARE Proteins
  • lyn protein-tyrosine kinase
  • src-Family Kinases
  • Autophagy-Related Protein-1 Homolog
  • ULK1 protein, human
  • rab GTP-Binding Proteins