Department of Biology, University of Michigan, Ann Arbor, Michigan 48109-1048, USA.
The Escherichia coli chemoreceptors and their associated cytoplasmic proteins, CheA and CheW, cluster predominantly at the cell poles. The nature of the clustering remains a mystery. Recent studies suggest that CheR binding to and/or methylation of the chemoreceptors may play a role in chemoreceptor complex aggregation. In this study, we examined the intracellular distribution of the chemoreceptors by immunoelectron microscopy in strains lacking either the methyltransferase CheR or the methylesterase CheB. The localization data revealed that, in vivo, aggregation of the chemoreceptor complex was independent of either CheR or CheB.