SpeakerSeminar: Prof. Christoph Haselwandter from USC, Hosted by: Frank Brown
Date and LocationWednesday February 03, 2016 11:00am to 12:00pm
Experiments have revealed that membrane proteins can form two-dimensional lattices with regular translational and orientational protein arrangements, which may allow cells to modulate protein function. However, the physical mechanisms yielding supramolecular organization and collective function of membrane proteins remain largely unknown. Here we show that lipid bilayer-mediated interactions between membrane proteins can yield regular and distinctive lattice architectures of protein clusters, and may also provide a general link between lattice architecture and lattice function. We develop general theoretical concepts of membrane protein organization and collective function based on three model systems: (1) We show how the interplay between protein-induced lipid bilayer curvature deformations, topological defects in protein packing, and thermal effects can explain the observed symmetry and size of membrane protein polyhedral nanoparticles; (2) We predict that the observed tetrameric and pentameric oligomeric states of mechanosensitive ion channels yield characteristic ground-state lattice architectures of channel clusters in the form of face-on square lattices and distorted hexagonal lattices, respectively, with distinctive collective gating properties; (3) We show that lipid bilayer-mediated interactions between chemoreceptor trimers provide a mechanism for the observed self-assembly of face-on honeycomb lattices of chemoreceptor trimers and the localization of large chemoreceptor lattices to the cell poles, and may contribute to the cooperative signaling response of the chemotaxis system.