Open AccessDeciphering the Regulatory Circuitry That Controls Reversible Lysine Acetylation in Salmonella enterica
Author(s) -
Kristy L. Hentchel,
Sandy Thao,
Peter J. Intile,
Jorge C. EscalanteSemerena
Publication year - 2015
Publication title -
mbio
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.562
H-Index - 121
eISSN - 2161-2129
pISSN - 2150-7511
DOI - 10.1128/mbio.00891-15
Subject(s) - acetylation , acetyltransferase , lysine , repressor , salmonella enterica , biochemistry , biology , gene expression , mutant , catabolism , chemistry , gene , enzyme , amino acid , escherichia coli
InSalmonella enterica , the reversible lysine acetylation (RLA) system is comprised of the protein acetyltransferase (Pat) and sirtuin deacetylase (CobB). RLA controls the activities of many proteins, including the acetyl coenzyme A (acetyl-CoA) synthetase (Acs), by modulating the degree of Acs acetylation. We report that IolR, amyo -inositol catabolism repressor, activates the expression of genes encoding components of the RLA system.In vitro evidence shows that the IolR protein directly regulatespat expression. AniolR mutant strain displayed a growth defect in minimal medium containing 10 mM acetate, a condition under which RLA function is critical to control Acs activity. Increased levels of Pat, CobB, or Acs activity reversed the growth defect, suggesting the Pat/CobB ratio in aniolR strain is altered and that such a change affects the level of acetylated, inactive Acs. Results of quantitative reverse transcription-PCR (qRT-PCR) analyses ofpat ,cobB , andacs expression indicated that expression of the genes alluded to in the IolR-deficient strain was reduced 5-, 3-, and 2.6-fold, respectively, relative to the levels present in the strain carrying theiolR+ allele. Acs activity in cell-free extracts from aniolR mutant strain was reduced ~25% relative to that of theiolR + strain. Glucose differentially regulated expression ofpat ,cobB , andacs . The catabolite repressor protein (Crp) positively regulated expression ofpat while having no effect oncobB .IMPORTANCE Reversible lysine acylation is used by cells of all domains of life to modulate the function of proteins involved in diverse cellular processes. Work reported herein begins to outline the regulatory circuitry that integrates the expression of genes encoding enzymes that control the activity of a central metabolic enzyme in C2 metabolism. Genetic analyses revealed effects on reversible lysine acylation that greatly impacted the growth behavior of the cell. This work provides the first insights into the complexities of the system responsible for controlling reversible lysine acylation at the transcriptional level in the enteropathogenic bacteriumSalmonella enterica .