title: The two-domain LysX protein of Mycobacterium tuberculosis is required for production of lysinylated phosphatidylglycerol and resistance to cationic antimicrobial peptides.
abstract: The well-recognized phospholipids (PLs) of Mycobacterium tuberculosis (Mtb) include several acidic species such as phosphatidylglycerol (PG), cardiolipin, phosphatidylinositol and its mannoside derivatives, in addition to a single basic species, phosphatidylethanolamine. Here we demonstrate that an additional basic PL, lysinylated PG (L-PG), is a component of the PLs of Mtb H37Rv and that the lysX gene encoding the two-domain lysyl-transferase (mprF)-lysyl-tRNA synthetase (lysU) protein is responsible for L-PG production. The Mtb lysX mutant is sensitive to cationic antibiotics and peptides, shows increased association with lysosome-associated membrane protein-positive vesicles, and it exhibits altered membrane potential compared to wild type. A lysX complementing strain expressing the intact lysX gene, but not one expressing mprF alone, restored the production of L-PG and rescued the lysX mutant phenotypes, indicating that the expression of both proteins is required for LysX function. The lysX mutant also showed defective growth in mouse and guinea pig lungs and showed reduced pathology relative to wild type, indicating that LysX activity is required for full virulence. Together, our results suggest that LysX-mediated production of L-PG is necessary for the maintenance of optimal membrane integrity and for survival of the pathogen upon infection.
authors: Department of Biochemistry, The University of Texas Health Center at Tyler, Tyler, TX, USA.
authors: Erin
authors: E
authors: Maloney
authors: Dorota
authors: D
authors: Stankowska
authors: Jian
authors: J
authors: Zhang
authors: Marek
authors: M
authors: Fol
authors: Qi-Jian
authors: QJ
authors: Cheng
authors: Shichun
authors: S
authors: Lun
authors: William R
authors: WR
authors: Bishai
authors: Malini
authors: M
authors: Rajagopalan
authors: Delphi
authors: D
authors: Chatterjee
authors: Murty V
authors: MV
authors: Madiraju
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008239:Lysine / Q000235:genetics / Q000378:metabolism*; D008246:Lysophospholipids / Q000096:biosynthesis*; D051907:Lysosomal Membrane Proteins / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D008564:Membrane Potentials; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D010588:Phagosomes / Q000378:metabolism; D010641:Phenotype; D010715:Phosphatidylglycerols / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D017434:Protein Structure, Tertiary; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D052118:Lysosomal-Associated Membrane Protein 1
chemical_list: D023181:Antimicrobial Cationic Peptides; D001426:Bacterial Proteins; D016207:Cytokines; D008239:Lysine; D008246:Lysophospholipids; D051907:Lysosomal Membrane Proteins; D010715:Phosphatidylglycerols; D010743:Phospholipids; C489116:LAMP1 protein, human; D052118:Lysosomal-Associated Membrane Protein 1