A nutrient-dependent division antagonist is regulated post-translationally by the Clp proteases in Bacillus subtilis

Abstract

BackgroundChanges in nutrient availability have dramatic and well-defined impacts on both transcription and translation in bacterial cells. At the same time, the role of post-translational control in adaptation to nutrient-poor environments is poorly understood. Previous studies demonstrate the ability of the glucosyltransferase UgtP to influence cell size in response to nutrient availability. Under nutrient-rich medium, interactions with its substrate UDP-glucose promote interactions between UgtP and the tubulin-like cell division protein FtsZ in Bacillus subtilis, inhibiting maturation of the cytokinetic ring and increasing cell size. In nutrient-poor medium, reductions in UDP-glucose availability favor UgtP oligomerization, sequestering it from FtsZ and allowing division to occur at a smaller cell mass.ResultsIntriguingly, in nutrient-poor conditions UgtP levels are reduced ~ 3-fold independent of UDP-glucose. B. subtilis cells cultured under different nutrient conditions indicate that UgtP accumulation is controlled through a nutrient-dependent post-translational mechanism dependent on the Clp proteases. Notably, all three B. subtilis Clp chaperones appeared able to target UgtP for degradation during growth in nutrient-poor conditions.ConclusionsTogether these findings highlight conditional proteolysis as a mechanism for bacterial adaptation to a rapidly changing nutritional landscape.Electronic supplementary materialThe online version of this article (10.1186/s12866-018-1155-2) contains supplementary material, which is available to authorized users.

Cellular resource allocation strategies for cell size and shape control in bacteria

“…Recently, Ojkic and Banerjee [62] developed a model for cell size control in B . subtilis by FtsZ inhibitors, predicting that UgtP synthesis rate increases nonlinearly with cellular growth rate, in line with recent experimental findings [65]. This nonlinear dependence of UgtP production rate on growth rate leads to an increase in cell length and aspect ratio with nutrient concentrations, as observed experimentally [7,66].…”

Cellular resource allocation strategies for cell size and shape control in bacteria

“…While in nutrient-rich conditions UgtP strongly inhibits FtsZ accumulation in the ring, delays cell division resulting in elongated cells [66]. Recently, Ojkic and Banerjee [64] developed a molecular model for cell size control in B. subtilis by FtsZ inhibitors, predicting that UgtP synthesis rate increases non-linearly with cellular growth rate, in line with recent experimental findings [67]. This nonlinear dependence of UgtP production rate on growth rate leads to an increase in cell length and aspect ratio with nutrient concentrations, as observed experimentally [7,68].…”

Role and Regulation of Clp Proteases: A Target against Gram-Positive Bacteria

“…These proteases were recently shown to be involved in nutrient-dependent cell growth. Nutrients can affect both bacterial growth and morphology [50]. Moreover, it has been disclosed that Clp proteases are responsible for the degradation of UgtP in low carbon conditions, becoming this molecule in an antagonist responsible for the size coordination of cells in response to the availability of nutrients [50].…”