cAMP-regulated Protein Lysine Acetylases in Mycobacteria

Abstract

Cyclic AMP synthesized by Mycobacterium tuberculosis has been shown to play a role in pathogenesis. However, the high levels of intracellular cAMP found in both pathogenic and nonpathogenic mycobacteria suggest that additional and important biological processes are regulated by cAMP in these organisms. We describe here the biochemical characterization of novel cAMP-binding proteins in M. smegmatis and M. tuberculosis (MSMEG_5458 and Rv0998, respectively) that contain a cyclic nucleotide binding domain fused to a domain that shows similarity to the GNAT family of acetyltransferases. We detect protein lysine acetylation in mycobacteria and identify a universal stress protein (USP) as a substrate of MSMEG_5458. Acetylation of a lysine residue in USP is regulated by cAMP, and using a strain deleted for MSMEG_5458, we show that USP is indeed an in vivo substrate for MSMEG_5458. The Rv0998 protein shows a strict cAMP-dependent acetylation of USP, despite a lower affinity for cAMP than MSMEG_5458. Thus, this report not only represents the first demonstration of protein lysine acetylation in mycobacteria but also describes a unique functional interplay between a cyclic nucleotide binding domain and a protein acetyltransferase.

Acylation of Biomolecules in Prokaryotes: a Widespread Strategy for the Control of Biological Function and Metabolic Stress

“…M. tuberculosis and M. smegmatis encode unique protein lysine acetyltransferases (MtPatA and MsPatA, respectively). In these organisms, the GNAT domain is attached to a cyclic AMP (cAMP) binding domain (type III) (178,191). cAMP allosterically activates MtPatA and MsPatA, enhancing their activity Ͼ2-fold (178,(191)(192)(193)(194).…”

“…MsPatA acetylates a universal stress protein (USP) (MSMEG_ 4207) at a single lysine residue, and acetylation increases in the presence of cAMP (191). The in vivo significance of USP acetylation was not tested, likely because the function of most USPs is unclear, but there is evidence suggesting that USPs provide resistance to various stressors (reviewed in reference 195).…”

Allosteric Regulation of a Protein Acetyltransferase in Micromonospora aurantiaca by the Amino Acids Cysteine and Arginine

“…The activity of protein acetyltransferases is also controlled by allosteric effects. In M. tuberculosis and Mycobacterium smegmatis, cAMP directly activates the protein acetyltransferases MtKat (Rv0998) and MsKat (MSMEG_5458) by binding to a cyclic nucleotide-binding domain that is fused to the N terminus of the catalytic GNAT domain (5,6).…”

Sirtuin-dependent reversible lysine acetylation of glutamine synthetases reveals an autofeedback loop in nitrogen metabolism

“…Allosteric effects also control the activity of protein acetyltransferases. In Mycobacterium tuberculosis and Mycobacterium smegmatis, cAMP directly activates the protein acetyltransferases MtKat (Rv0998) and MsKat (MSMEG_5458) by binding to a cyclic nucleotide-binding domain that is fused to the N terminus of the catalytic GNAT domain (20). Recently, we found that an amino acid-binding domain (ACT domain) fused to the GNAT acetyltransferase of Micromonospora aurantica is used to exert amino acid-induced allosteric regulation of the enzyme (21).…”