Cellular targeting and segregation of bacterial chemosensory systems

The bacterial cytoplasm is not a homogeneous solution of macromolecules, but rather a highly organized and compartmentalized space where the clustering and segregation of macromolecular complexes in certain cell regions confers functional efficiency. Bacterial chemoreceptors represent a versatile model system to study the subcellular localization of macromolecules, as they are present in almost all motile bacterial and archaeal species, where they tend to form highly ordered arrays that occupy distinct positions in cells. The positioning of chemoreceptor clusters, as well as their segregation mechanism on cell division, varies from species to species and probably depends on cells size, environment and speed of movement. In this review, we summarize the current understanding of the architecture and the segregation mechanisms of chemoreceptors in a limited number of bacterial model systems and suggest that the pattern of chemoreceptor distribution is coupled to behavioral life-style of that species.