In this R21 application, we aim to determine how the newly identified cellular restriction factors, known as interferon-inducible transmembrane (IFITM) proteins, modulate viral membrane fusion and entry, and in doing so, aid the development of novel antiviral therapeutics.
The specific aims of this proposal are as follows.
Aim 1 : Test the hypothesis that IFITM proteins inhibit membrane fusion by preventing hemifusion. We will perform cell-cell and virion-cell fusion assays, including the use of single viral particle imaging technique, to determine the stages of the viral membrane fusion process blocked by IFITM proteins. Lipid analogs that modulate distinct stages of the membrane fusion process will be applied. We will explore the possibility that IFITM proteins restrict membrane fusion induced by cellular and developmental fusogens.
Aim 2 : Test the hypothesis that expression of IFITM proteins changes the lipid order of cell membranes and confers positive spontaneous curvature. We will perform fluorescence membrane labeling experiments to test the hypothesis that IFITM proteins cause the cell membrane to be more ordered, resulting in reduced fluidity and therefore less competency for fusion. We will also determine the effect of IFITM proteins on membrane curvature by reconstituting artificial liposomes with synthetic peptides corresponding to the functional domains in IFITM proteins. Cryo-EM tomography will be applied to directly visualize the curvature changes upon insertion of IFITM peptides into the artificial liposome vesicles. IFITM proteins are the first and so far only cellular restriction fators that are known to restrict viral membrane fusion and entry. Results from the proposed studies will provide novel insight as to how IFITM proteins restrict viral membrane fusion. These results will guide future comprehensive investigations into the biology of IFITM proteins, as well as their critical roles in restricting viral entry and infection.

Public Health Relevance

Viruses must enter host cells to initiate infection, and hosts have evolved many strategies to restrict the viral infection. We study how some cellular restriction factors intrinsically block viral fusion with cell membranes and thus infectio. Our study may lead to new strategies for antiviral therapy.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AI105584-02
Application #
8605170
Study Section
Virology - B Study Section (VIRB)
Program Officer
Cassetti, Cristina
Project Start
2013-01-15
Project End
2014-12-31
Budget Start
2014-01-01
Budget End
2014-12-31
Support Year
2
Fiscal Year
2014
Total Cost
$172,688
Indirect Cost
$60,188
Name
University of Missouri-Columbia
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
153890272
City
Columbia
State
MO
Country
United States
Zip Code
65211
Li, Minghua; Ablan, Sherimay D; Miao, Chunhui et al. (2014) TIM-family proteins inhibit HIV-1 release. Proc Natl Acad Sci U S A 111:E3699-707
Jia, Rui; Xu, Fengwen; Qian, Jin et al. (2014) Identification of an endocytic signal essential for the antiviral action of IFITM3. Cell Microbiol 16:1080-93
Ding, Shilei; Pan, Qinghua; Liu, Shan-Lu et al. (2014) HIV-1 mutates to evade IFITM1 restriction. Virology 454-455:11-24
Li, Kun; Markosyan, Ruben M; Zheng, Yi-Min et al. (2013) IFITM proteins restrict viral membrane hemifusion. PLoS Pathog 9:e1003124