The Yount laboratory aims to identify and characterize post-translational modifications on innate immune system proteins, with the goal of exploiting these enzymatic modifications to control immune functions. Using chemical tools, mass spectrometry, and biochemical techniques, we have identified lipid modifications that control the activity of Toll-like receptors and the interferon-induced transmembrane protein (IFITM) family of antiviral proteins. Our ongoing studies of IFITM3 have also uncovered its regulation by additional post-translational modifications including phosphorylation and ubiquitination. This work has revealed mechanisms that govern IFITM3 cellular trafficking and turnover, and provides insight into the deleterious effects of an IFITM3 polymorphism present in the human population that increases susceptibility to severe influenza virus infections. Our most recent efforts have identified the primary E3 ubiquitin ligase responsible for promoting IFITM3 degradation. Targeting this enzyme leads to increased IFITM3 levels in cells and provides broad cellular resistance to multiple influenza virus strains. We are continuing to explore how ubiquitination and other post-translational modifications can be manipulated for prevention or treatment of infections.
Compton A, Roy N, Porrot F, Billet A, Casartelli N, Yount JS, Liang C, and Schwartz O. Natural mutations in IFITM3 modulate post-translational regulation and toggle antiviral specificity. EMBO Reports. 2016.
Antonucci J, St. Gelais C, de Silva S, Yount JS, Tang C, Ji X, Xiong Y, Kim B, and Wu L. RNase activity of SAMHD1 is not essential for HIV-1 restriction in cells. Nature Medicine. 2016.
Percher A, Ramakrishnan S, Yuan X, Thinon E, Yount JS#, and Hang HC#. Mass-tag labeling reveals site-specific and quantitative levels of protein S-fatty acylation. PNAS. 2016.
Wang F, St. Gelais C, de Silva S, Zhang H, Geng Y, Shepard C, Kim B, Yount JS, Wu L. Phosphorylation of mouse SAMHD1 regulates its restriction of human immunodeficiency virus type 1 infection, but not murine leukemia virus infection. Virology. 2016.
Chesarino NC, McMichael, and Yount JS. E3 ubiquitin ligase NEDD4 promotes infection by influenza virus by decreasing levels of the antiviral protein IFITM3. PLOS Pathogens. 2015.
Chesarino NC, McMichael TM, Hach HC, and Yount JS. IFITMs from mycobacteria confer resistance to influenza virus when expressed in human cells. Viruses. 2015.
Chesarino NC, McMichael TM, and Yount JS. Regulation of the trafficking and antiviral activity of IFITM3 by post-translational modifications. Future Microbiology. 2014.
Chesarino NM, Hach JC, Chen JL, Zaro BW, Rajaram M, Turner J, Schlesinger LS, PrattM, Hang HC, and Yount JS. Chemoproteomics reveals Toll-like receptor fatty acylation. BMC Biology. 2014.
Chesarino NC, McMichael TM, Hach JC, and Yount JS. Phosphorylation of the antiviral protein IFITM3 dually regulates its endocytosis and ubiquitination. Journal of Biological Chemistry. 2014.
St. Gelais C, Hach JC, DeSilva S, Yount JS, and Wu L. Identification of cell cycle proteins interacting with human and mouse anti-retroviral protein SAMHD1. Journal of Virology. 2014.
Hach JC, McMichael T, Chesarino N, and Yount JS. Palmitoylation on conserved and non-conserved cysteines of murine IFITM1 regulates its stability and anti-influenza A virus activity. Journal of Virology. 2013.