Project description:Tuberculosis is a leading cause of worldwide infectious mortality. The prevalence of multidrug-resistant Mycobacterium tuberculosis (Mtb) infections drives an urgent need to exploit new drug targets. One such target is the ATP-dependent protease ClpC1P1P2, which is strictly essential for viability. However, few proteolytic substrates of mycobacterial ClpC1P1P2 have been identified to date. Recent studies in Bacillus subtilis have shown that the orthologous ClpCP protease recognizes proteolytic substrates bearing post-translational arginine phosphorylation. While several lines of evidence suggest that ClpC1P1P2 is similarly capable of recognizing phosphoarginine-bearing proteins, the existence of phosphoarginine modifications in mycobacteria has remained in question. Here, we confirm the presence of post-translational phosphoarginine modifications in Mycolicibacterium smegmatis (Msm), a nonpathogenic surrogate of Mtb. Using a phosphopeptide enrichment workflow coupled with shotgun phosphoproteomics, we identify arginine phosphosites on several functionally diverse targets within the Msm proteome. Interestingly, phosphoarginine modifications are not upregulated by heat stress, suggesting divergent roles in mycobacteria and Bacillus. Our findings provide new evidence supporting the existence of phosphoarginine-mediated proteolysis by ClpC1P1P2 in mycobacteria and other actinobacterial species.
Project description:During our efforts to isolate potantial binding partners of Esat6, we isolated few peptides rich in phenylalanine residues that strongly interacted with Esat6. All peptides were less than fifty amino acids in length, One of them, Hcl1, when expressed in mycobacteria showed significant retardation in growth and survival within macrophages. Microarray analysis showed that Hcl1 affects a host of genes and cellular pathways. RNA was isolated from exponentially growing mycobacteria containing either plasmid vector pVV16 encoding peptide or vector pVV16 alone. Comparisons were made between Experimental (Mtb/Hcl1) and control (Mtb/pVV16) samples by extracting raw intensity values from multiple arrays.
Project description:RNA-seq of Mycobacteriophage Island3 infection of Mycolicibacterium smegmatis mc2155, Mycolicibacterium smegmatis mc2155(Butters), and Mycolicibacterium smegmatis mc2155(Buttersgp57r) to assess the impact of Butters lysogen and specifically Buttersgp57r on transcript levels of island3 during infection.
Project description:Feature reduction of microarray data from mycobacteria treated with a variety of various clinical and investigational drugs We are using feature reduction to demonstrate that subsets of biomarker genes representative of the whole genome are sufficient for MOA classification and deconvolution in a medium-throughput microfluidic format ultimately leading to a cost effective and rapid tool for routine antibacterial drug-discovery programs.
Project description:How lipids travel between membranes of diderm bacteria is a challenging mechanistic question because lipids, which are hydrophobic molecules, must traverse a hydrophilic periplasm. This question is even more complex for mycobacteria, which have a unique cell envelope that is highly impermeable to molecules. A growing body of knowledge identifies Mce transporters as lipids importers for mycobacteria. Here, using protein stability experiments and immunoprecipitation-mass spectrometry to identify protein interactions among components of the mycobacterial Mce4 transporter we provide evidence for Mce transporters existing as multiprotein complexes.
