The regulatory functions of ESX-1 substrates, EspE and EspF, are separable from secretion.

Pathogenic mycobacteria are a significant global health burden. The ESX-1 secretion system is essential for mycobacterial pathogenesis. The secretion of ESX-1 substrates is required for phagosomal lysis, which allows the bacteria to enter the macrophage cytoplasm, induce a Type I IFN response, and spread to new host cells.

N acetyl-transferases required for iron uptake and aminoglycoside resistance promote virulence lipid production in .

Unlabelled: Phagosomal lysis is a key aspect of mycobacterial infection of host macrophages. Acetylation is a protein modification mediated enzymatically by N-acetyltransferases (NATs) that impacts bacterial pathogenesis and physiology. To identify NATs required for lytic activity, we leveraged a nontubercular pathogen and an established model for hemolysis is a proxy for phagolytic activity.

The loss of the PDIM/PGL virulence lipids causes differential secretion of ESX-1 substrates in .

The mycobacterial cell envelope is a major virulence determinant in pathogenic mycobacteria. Specific outer lipids play roles in pathogenesis, modulating the immune system and promoting the secretion of virulence factors. ESX-1 (ESAT-6 system-1) is a conserved protein secretion system required for mycobacterial pathogenesis.

N-terminal proteomics of using bottom-up label-free quantitative analysis in data-dependent acquisition mode on a timsTOF Pro mass spectrometer.

N-terminal acetylation in is correlated with pathogenic activity. We used genomics and bottom-up proteomics to identify protein Emp1 as the sole acetyltransferase responsible for acetylation of EsxA, a known virulence factor. Using custom data analysis, we screened the proteome to identify 22 additional putative substrates of Emp1.

The antagonistic transcription factors, EspM and EspN, regulate the ESX-1 secretion system in .

Bacterial pathogens use protein secretion systems to transport virulence factors and regulate gene expression. Among pathogenic mycobacteria, including and , the ESAT-6 system 1 (ESX-1) secretion is crucial for host interaction. Secretion of protein substrates by the ESX-1 secretion system disrupts phagosomes, allowing mycobacteria cytoplasmic access during macrophage infections.