Credit: Cell
How the flu virus resets its trap: Advanced smFRET imaging of individual molecules of the influenza surface protein hemagglutinin (HA) reveals a new model of HA function. According to this proposed model, HA, anchored in the viral membrane, reaches out away from the surface of the virus looking for a target cell membrane with which it can fuse before hijacking the cell. If no target cell is found, HA can reverse configurations and return to its starting state, ready to try again. The virus is able to repeat this process 5 to 10 times a second. The Tufts University School of Medicine discovery, which appears in the journal Cell, can help advance efforts to make more effective vaccines and improve understanding of other viruses, including Ebola, HIV and SARS. HA1 is the part of HA that makes initial contact with the cell; HA2 is the part responsible for fusing the virus to the cell.