5 years ago

Protein composition of the hepatitis A virus quasi-envelope [Microbiology]

Protein composition of the hepatitis A virus quasi-envelope [Microbiology]
Olga Gonzalez–Lopez, Efrain E. Rivera–Serrano, Kevin L. McKnight, Ling Xie, Xian Chen, Stanley M. Lemon

The Picornaviridae are a diverse family of RNA viruses including many pathogens of medical and veterinary importance. Classically considered “nonenveloped,” recent studies show that some picornaviruses, notably hepatitis A virus (HAV; genus Hepatovirus) and some members of the Enterovirus genus, are released from cells nonlytically in membranous vesicles. To better understand the biogenesis of quasi-enveloped HAV (eHAV) virions, we conducted a quantitative proteomics analysis of eHAV purified from cell-culture supernatant fluids by isopycnic ultracentrifugation. Amino acid-coded mass tagging (AACT) with stable isotopes followed by tandem mass spectrometry sequencing and AACT quantitation of peptides provided unambiguous identification of proteins associated with eHAV versus unrelated extracellular vesicles with similar buoyant density. Multiple peptides were identified from HAV capsid proteins (53.7% coverage), but none from nonstructural proteins, indicating capsids are packaged as cargo into eHAV vesicles via a highly specific sorting process. Other eHAV-associated proteins (n = 105) were significantly enriched for components of the endolysosomal system (>60%, P < 0.001) and included many common exosome-associated proteins such as the tetraspanin CD9 and dipeptidyl peptidase 4 (DPP4) along with multiple endosomal sorting complex required for transport III (ESCRT-III)-associated proteins. Immunoprecipitation confirmed that DPP4 is displayed on the surface of eHAV produced in cell culture or present in sera from humans with acute hepatitis A. No LC3-related peptides were identified by mass spectrometry. RNAi depletion studies confirmed that ESCRT-III proteins, particularly CHMP2A, function in eHAV biogenesis. In addition to identifying surface markers of eHAV vesicles, the results support an exosome-like mechanism of eHAV egress involving endosomal budding of HAV capsids into multivesicular bodies.

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.