Site-Specific Photo-Crosslinking Proteomics Reveal Regulation of IFITM3 Trafficking and Turnover by VCP/p97 ATPase

Cell Chem Biol. 2020 May 21;27(5):571-585.e6. doi: 10.1016/j.chembiol.2020.03.004. Epub 2020 Apr 2.

Abstract

Interferon-induced transmembrane protein 3 (IFITM3) is a key interferon effector that broadly prevents infection by diverse viruses. However, the cellular factors that control IFITM3 homeostasis and antiviral activity have not been fully elucidated. Using site-specific photo-crosslinking and quantitative proteomic analysis, here we present the identification and functional characterization of VCP/p97 AAA-ATPase as a primary interaction partner of IFITM3. We show that IFITM3 ubiquitination at lysine 24 is crucial for VCP binding, trafficking, turnover, and engagement with incoming virus particles. Consistently, pharmacological inhibition of VCP/p97 ATPase activity leads to defective IFITM3 lysosomal sorting, turnover, and co-trafficking with virus particles. Our results showcase the utility of site-specific protein photo-crosslinking in mammalian cells and reveal VCP/p97 as a key cellular factor involved in IFITM3 trafficking and homeostasis.

Keywords: IFITM3; VCP/p97; chemical proteomics; photo-crosslinking; protein-protein interaction; unnatural amino acid.

Publication types

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

MeSH terms

  • HEK293 Cells
  • Humans
  • Membrane Proteins / metabolism*
  • Protein Interaction Maps
  • Protein Transport
  • Proteomics
  • RNA-Binding Proteins / metabolism*
  • Ubiquitination
  • Valosin Containing Protein / metabolism*

Substances

  • IFITM3 protein, human
  • Membrane Proteins
  • RNA-Binding Proteins
  • VCP protein, human
  • Valosin Containing Protein