Think globally, act locally: how bacteria integrate local decisions with their global cellular programme

Abstract

EMBO J 32 14, 2001–2014 doi:; DOI: 10.1038/emboj.2013.120; published online May 24 2013

It has long been speculated that the bacterial second messenger c-di-GMP, a key molecular switch of bacterial community behaviour and persistence, can trigger specific cellular processes both on a global level as well as through some local action that prevents crosstalk originating from rapid diffusion of the signalling molecule. In this issue, Lindenberg et al (2013) report on a mechanism that not only helps to explain how spatial sequestration of c-di-GMP signalling components could be organized within bacterial cells, but also demonstrates how global and local command levels are interconnected.

Figure 1

Model for the regulation of the motile-sessile switch by hierarchical modules of c-di-GMP-metabolizing enzymes in E. coli. In the motile single-cell state, the global cellular programme set by module I is dominated by the PDE YhjH, which licences cell motility and keeps module II inactive. Under these conditions, csgD expression is OFF as a result of the inhibitory action of YciR on YdaM and MlrA (left). Upon induction of the DGC YegE by the stationary phase sigma factor sigma S, module I induces a global increase of c-di-GMP levels (right). High levels of c-di-GMP activate YcgR to interfere with cell motility and, through the inactivation of YciR, stimulate the transcription of csgD and curli formation.