Clustering of the chemoreceptor complex in Escherichia coli is independent of the methyltransferase CheR and the methylesterase CheB

Abstract

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.

FIG. 1

Immunolocalization of chemoreceptors. Immunoelectron micrographs depicting the intracellular position of MCPs in strains lacking either CheR (strain RP1254) (A) or CheB (strain RP4792) (B) are shown. Antibody reactions were performed as described in the text. Sections were poststained with 1% uranyl acetate and examined on a Philips CM10 electron microscope at 60 kV.