Polar chemoreceptor clustering by coupled trimers of dimers.
Receptors of bacterial chemotaxis form clusters at the cell poles, where clusters act as "antennas" to amplify small changes in ligand concentration. It is worthy of note that chemoreceptors cluster at multiple length scales. At the smallest scale, receptors form dimers, which assemble into stable timers of dimers. At a large scale, trimers form large polar clusters composed of thousands of receptors. Although much is known about the signaling properties emerging from receptor clusters, it is unknown how receptors localize at the cell poles and what the determining factors are for cluster size. Here, we present a model of polar receptor clustering based on coupled trimers of dimers, where cluster size is determined as a minimum of the cluster-membrane free energy. This energy has contributions from the cluster-membrane elastic energy, penalizing large clusters due to their high intrinsic curvature, and receptor-receptor coupling that favors large clusters. We find that the reduced cluster-membrane curvature mismatch at the curved cell poles leads to large and robust polar clusters, in line with experimental observation, whereas lateral clusters are efficiently suppressed.
Endres
Robert G
RG
Division of Molecular Biosciences and Centre for Integrated Systems Biology at Imperial College, Imperial College London, London, United Kingdom. r.endres@imperial.ac.uk
D018407:Bacterial Physiological Phenomena; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D016764:Cell Polarity; D002633:Chemotaxis; D003198:Computer Simulation; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008954:Models, Biological; D055503:Protein Multimerization
D001426:Bacterial Proteins; D008565:Membrane Proteins