Molecular architecture of the bacterial actin cytoskeleton. (360G-Wellcome-095514_Z_11_Z)

Bacteria are now known to contain proteins that form fibrous structures on the inside and these proteins are related to similar ones in all other organisms. The functions of these fibres in bacteria, however, are different: the two most important functions are facilitating growth by dividing cells into two daughter cells and giving bacteria their distinctive shapes, since they would otherwise be round and spherical. We propose to investigate the second function, cell shape, which is mediated by the MreB protein. MreB is related to another fibrous protein, present in all non-bacterial cells, called actin. We will investigate what fibres MreB forms inside cells by using a microscopy method (electron cryotomography) that allows imaging whole bacterial cells in three dimensions at a magnification that makes molecules visible. We will combine this new knowledge with an investigation of the interactions that MreB forms in cells. Taking all data together, we will be able to determine how the fibres of MreB give bacteria shape. In the future, our knowledge might make it possible to disrupt this process using drugs, killing bacteria.