Nε−Lysine Acetylation of a Bacterial Transcription Factor Inhibits Its DNA-Binding Activity

Abstract

Evidence suggesting that eukaryotes and archaea use reversible N ε-lysine (N ε-Lys) acetylation to modulate gene expression has been reported, but evidence for bacterial use of N ε-Lys acetylation for this purpose is lacking. Here, we report data in support of the notion that bacteria can control gene expression by modulating the acetylation state of transcription factors (TFs). We screened the E. coli proteome for substrates of the bacterial Gcn5-like protein acetyltransferase (Pat). Pat acetylated four TFs, including the RcsB global regulatory protein, which controls cell division, and capsule and flagellum biosynthesis in many bacteria. Pat acetylated residue Lys180 of RcsB, and the NAD+-dependent Sir2 (sirtuin)-like protein deacetylase (CobB) deacetylated acetylated RcsB (RcsBAc), demonstrating that N ε-Lys acetylation of RcsB is reversible. Analysis of RcsBAc and variant RcsB proteins carrying substitutions at Lys180 provided biochemical and physiological evidence implicating Lys180 as a critical residue for RcsB DNA-binding activity. These findings further the likelihood that reversible N ε-Lys acetylation of transcription factors is a mode of regulation of gene expression used by all cells.

Post-translational regulation of a Porphyromonas gingivalis regulator

“…This notion was validated in the cases of the CheY and RcsB response regulators of E. coli [6] and [13], respectively). In the case of CheY, it was revealed by co-crystallization that certain lysine residues were directly involved in binding to DNA targets [27,28].…”

“…Furthermore, it appears that phosphorylated, that is, activated RprY is the preferred substrate for acetylation suggesting cross-talk between the protein modification activities. Finally, we show that acetylated RprY had diminished ability to bind to promoter DNA; thus, modification of regulator proteins by acetylation appears to be another mechanism to modulate their function [6], including derepression.…”

Identification of sirtuin and its target as the ribosomal protein S4 in <i>Lactobacillus paracasei</i>

“…One such candidate is the transcription factor RcsB, which was reported to be deacetylated by CobB in E. coli and S. enterica. In this case, deacetylation of the RcsB protein was reported to lead to augmentation of its DNA-binding activity (Thao et al, 2010). Ma and Wood (2011) reported that protein deacetylation by CobB leads to a decreased resistance of E. coli against oxidative stress.…”

“…In order to elicit such effects as probiotics, the bacteria need to survive gastric fluid and bile acid in the digestive canal of the host, and preferably to settle on appropriate sites. Regarding the application of LAB as a probiotic, it would be intriguing to find out which target proteins of LAB play a role in the survival against stress in host intestines (van de Guchte et al, 2002).…”

“…It is not clear whether bacterial sirtuin has a similar function in the chromatin remodeling system in eukaryotes. However, as an example of an individual transcription factor, it was reported that, when the acetylated Lysine 180 of RcsB protein (two-component response regulator) was deacetylated by CobB protein, the DNA binding activity of RcsB is increased to activate the transcription of the target gene, flhDC in E. coli (Thao et al, 2010). In addition, the importance of protein acetylation as a posttranslational modification has been documented (Bernal et al, 2014).…”