family includes lipoproteins LppX, LprA, LprF and LprG from Mycobacterium tuberculosis
This family includes the homologous lipoproteins LppX, LprA, LprF and LprG from Mycobacterium tuberculosis (Mtb), all of which share a core fold with lipoprotein transporter proteins LolA and LolB. Mtb contains components such as glycolipids, lipoglycans and lipoproteins that play critical roles in regulating host responses and promoting survival of the pathogen. Mtb LprA is a lipoprotein agonist of Toll-like receptor 2 (TLR2) that regulates innate immunity and APC function. LprF, which is also found in Mycobacterium bovis but not in the nonpathogenic Mycobacterium smegmatis, has a central hydrophobic cavity that binds a diacylated glycolipid that it transfers from the plasma membrane to the cell wall, which might be related to the pathogenesis of the bacteria. Similarly, LprG functions as a carrier of glycolipids and lipoglycans, such as lipoarabinomannan (LAM), during their trafficking and delivery to the mycobacterial cell wall, contributing to virulence; LAM inhibits fusion of phagosomes with lysosomes as a means for mycobacteria to evade host defense. In addition, LprG has potent TLR2 agonist activity that modulates antigen processing of dendritic cells and macrophages. LppX is required for the translocation of the key virulence factors, the phthiocerol dimycocerosates (PDIMs), to the surface of Mtb.