Protein lysine acetylation is a regulatory mechanism for Bacillus subtilis multicellularity

Abstract

Lysine acetylation is a post‐translational modification that alters the charge, conformation, and stability of proteins. Published lists of acetylated proteins, or acetylomes, in bacteria have demonstrated that lysine acetylation occurs on proteins with a wide diversity of function, including central metabolism, DNA transcription and binding, chemotaxis, and cell size. Bacillus subtilis is a non‐pathogenic soil bacterium, and model organism for sporulation, motility, biofilm formation, and general multicellular development. The genetic regulation of these processes has been extensively studied, thus, we aimed to investigate the role of lysine acetylation in multicellular development (or biofilm formation) in B. subtilis. To further investigate acetylation, we generated an acetylome under biofilm‐inducing conditions and identified acetylated proteins involved in multicellularity; specifically, swarming and biofilm formation. Upon deletion of known genes for acetylation, cells had significantly slower swarming kinetics and a significantly smaller final swarming radius compared to wildtype. This suggests that acetylation impacts bacterial swarming. Biofilm is a mixture of cells and secreted matrix consisting of exopolysaccharides, proteins, and nucleotides that assists bacterial communities in colonization and survival. Genetic analysis of acetylation in biofilm formation demonstrated that lack of acetylation impacts biofilm development as shown by a decrease in matrix production. Targeting the acetylated biofilm proteins, we performed site‐directed mutagenesis of known acetylated lysine residues and assayed for biofilm formation. Two biofilm proteins, YmcA, a biofilm regulatory protein, and GtaB, an enzyme for biosynthesis of a precursor sugar for exopolysaccharides, demonstrated severe biofilm defects upon mutation of lysine residues. This suggests the importance of YmcA Lys64 and GtaB Lys89 and Lys191 for function in biofilm formation. In summary, we believe that protein lysine acetylation is a novel regulatory mechanism linking cell metabolism to bacterial multicellular development.Support or Funding InformationNational Science Foundation and Northeastern UniversityThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.