Structural Biology/Biophysics Research Track

The ESCRT pathway directs cargo into multivesicular bodies within the cell but is hijacked by HIV to assist with particle budding from the cell surface. CHMP-like proteins form the third stage of ESCRT function, working to pinch off the budding membrane. CHMP3 and IST1 are representative structures from this family and these serve as working models to study protein-protein complexes and structural activation of the pathway.

The Mechanism of Membrane Deformation by F-BAR Domains Cells expressing GFP-tagged F-BAR proteins observed by A) fluorescence and B) transmission EM. In vitro reconstitutions visualized by C) cryo-EM and analyzed via D) helical reconstruction. The F-BAR coat is blue-gray and the membrane is green. E) Fitting F-BAR structures into EM reconstructions revealed four contact points between clusters of cationic residues on the concave surface of the F-BAR domain. Adapted from (9). Bars: A) 5 μm; B) 50 nm; C) 50 nm.

Tetherin is a molecule involved in the innate immune response to protect against HIV infection. Tetherin works by forming a dimeric protein bridge between the cell and a budding virion using a transmembrane helix and GPI anchor on either end of a long coiled-coil stabilized with disulfide bonds (orange). By holding on to newly released particle tetherin restricts diffusion of the virus, but is unfortunately downregulated by the HIV protein vpu.

Artistic rendering of Vesicular Stomatitis Virus during RNA capture at the plasma membrane. For simplicity only the N molecule is shown. The illustrated packing within the virion is consistent with Cryo EM studies of VSV. The extended spiral outside the formed virion is an artistic expression. It is not clear for how long the RNA would retain its spiral twist in the cytoplasm.