The fusion and poration of membranes underlies many fundamental processes in biology, including interaction of viruses with their hosts, neurotransmission and vesicle trafficking. This project aims to determine the mechanism of membrane fusion at the molecular level. The PI will use the prototypic influenza hemagglutinin fusion protein to understand membrane fusion during viral infection and cellular entry. The results of this project will reveal how proteins mediate membrane fusion and answer important questions on viral infection. These results will lead to important insights into a variety of viral infection mechanisms, as well as enhance our knowledge of fundamental processes in biological membranes. The educational aspects of the project integrates graduate students, undergraduates and research experiments in the classroom with molecular techniques in modern biophysics.
Membrane fusion will be studied by investigating the vital fusion peptide (HAfp) and transmembrane (HAtmd) domains of the influenza hemagglutinin. These domains are highly conserved and necessary for influenza membrane fusion and cellular entry. Yet, their molecular structures, impact on membranes, and intermolecular interactions remain poorly understood. The PI has made important advances in producing full-length, fully functional HAfp proteins as well as developed new techniques in NMR to determine how proteins impact membranes. With these advances, the PI will investigate 1) features in the HAfp structure that enhance early fusion activity, 2) changes in membrane structure and lipid dynamics by HAfp peptides, and 3) the protein-protein interactions necessary for pore formation late in the membrane fusion process. A multi-pronged biophysical approach will be used, including molecular structure determination by NMR, calorimetry of membranes, fluorescence spectroscopy, mass spectrometry, analytic ultracentrifugation and size-exclusion chromatography.
