FIGURE 3.

Catecholamine sensing and signal transduction in enterohemorrhagic and enteropathogenic E. coli (EHEC/EPEC). QseC is an adrenergic sensor kinase that autophosphorylates on detection of NE, Epi and AI-3 and transfers the phosphate moiety to its cognate response regulator QseB, thereby activating transcription of the flagellar regulon (Clarke et al., 2006). Transcription of genes encoding a second two-component system (QseEF) is sensitive to NE and Epi and is implicated in small RNAs expression (Reading et al., 2009). Kinase activity in QseC is promiscuous and can activate two additional non-cognate response regulators, KdpE and QseF. QseC also activates the locus of enterocyte effacement (LEE), through KdpE, which is inhibited through sRNAs (glmY) that are modulated by QseF. (Adapted from Ellermann and Sperandio, 2020). KdpD, a transmembrane protein showing partial homology with QseC may also act as a catecholamine receptor (Borrel et al., 2019).