The interplay of EIIA^Ntr with C‐source regulation of the Pu promoter of Pseudomonas putida mt‐2

Abstract

The presence of some sugars (e.g. glucose) downregulates the activity of the Pu promoter of plasmid pWW0 of Pseudomonas putida mt-2, which drives the upper TOL operon for biodegradation of m-xylene. Genetic evidence produced 20 years ago documented an effect of the EIIA (PtsN) protein of the nitrogen-related phosphoenolpyruvate-dependent phosphotransferase system (PTS ) in such a C-source control of Pu activity. In this study, we have exploited the wealth of recent information on the PTS of P. putida as well as transcriptomic data available in the last few years on this bacterium to revisit this question - and the role of EIIA as such. To this end, we examined Pu output under physiological conditions known to either phosphorylate PTS proteins to saturation or to deplete them altogether from high-energy phosphate. The results showed that Pu activity is checked by EIIA regardless of its phosphorylation state. However, such inhibition is intensified during growth on glucose (which correlates with more phosphate-free EIIA ) and partially relieved in fructose, which triggers phosphorylation of PTS proteins. These data explain former inconsistencies on the Pu-PTS interplay and provides a better understanding of the metabolic and regulatory retroactivity between the TOL plasmid and its host metabolism.

Multiple regulatory inputs including cell envelope stress orchestrate expression of the Escherichia coli rpoN operon

“…Mutation of the −10 sequence strongly decreased promoter strength but did not abolish regulation by ethanol (Figure 1). A promoter in the rpoN 3′ end was also identified in the non‐related species Pseudomonas aeruginosa , which shares synteny of the rpoN operon with E. coli (Akiyama et al., 2018; Perez‐Pantoja et al., 2018). Interestingly, the −10 sequences of these promoters are not conserved, and their positions are shifted by 18 bp with regard to the encoded amino acid sequence in the two species (Supplementary Figure S9).…”

“…For instance, the activity or expression of several K + transport systems is controlled by non‐phosphorylated PtsN in E. coli (Lee et al., 2007; Mörk‐Mörkenstein et al., 2017; Schulte & Goulian, 2018; Sharma et al., 2016). However, recent data suggest a more extensive interaction network for both forms of PtsN and propose that PtsN exerts additional regulatory roles independent of its phosphorylation state (Choi & Ryu, 2019; Gravina et al., 2021; Jahn et al., 2013; Perez‐Pantoja et al., 2018; Steingard & Helmann, 2023).…”

What are the signals that control catabolite repression in Pseudomonas?

“…In addition, in the presence of glucose, the PTS Ntr system inhibits the induction of some peripheral catabolic pathways, including the assimilation of toluene specified in the P. putida pWW0 plasmid (Aranda‐Olmedo et al., 2005 , 2006 ; Cases et al., 1999 ). The non‐phosphorylated form of PtsN was found to be the PTS Ntr component that exerts the repressive effect (Pérez‐Pantoja et al., 2018 ).…”