Probably helps membrane protein Rv1410c (P55) transport triacylglycerides (TAG) across the inner cell membrane into the periplasm; TAG probably regulates lipid metabolism and growth regulation (PubMed:26751071). Binds TAG and transfers it between lipid bilayers, probably to the outer membrane in vivo (PubMed:26751071). Binds di- and triacylated phosphatidyl-myo-inositol mannosides (PIMs), and glycolipid lipoglycan modulins lipoarabinomannan (LAM) and lipomannan (LM), facilitating their recognition by TLR2 (PubMed:20694006, PubMed:25356793). Binds LM > PIM6 > ManLAM > PI-LAM > PIM2 (mannose-capped LAM and phospho-myo-inositol-capped LAM, E.coli expressed without acyl-groups); deacylated LM and LAM also bind to this protein via their mannose moieties, showing LprG has at least 2 different ways to bind glycolipids (PubMed:25356793). Binds triacylglycerides (TAG) in the same cavity, is able to transfer TAG between lipid bilayers (PubMed:26751071). Overexpression of LprG and Rv1410c leads to increased levels of TAG in the culture medium (PubMed:26751071). Required for Rv1410c-mediated export of drugs (PubMed:18156250, PubMed:21762531). Required, probably with Rv1410c, for normal surface localization of LAM (PubMed:25232742). A host TLR2 agonist (toll-like receptor), shown experimentally for human and mouse (PubMed:19362712). Inhibits primary human macrophage MHC-II Ag processing via TLR2 (PubMed:15294983). Both lipidated and nonlipidated protein act as TLR2 agonists in antigen-presenting cells, although lipidated protein is more efficient (PubMed:20694006). In resting human CD4+ T-cells lipidated but not nonlipidated protein is a costimulatory ligand (with anti-CD3 and anti-CD28) for T-cell proliferation and IFN-gamma and IL-2 production, leading to increased expression of early T-cell activation markers, TLR2 and NFKB3 phosphorylation (PubMed:21078852). Human CD4+ T-cells use TLR1/TLR2 heterodimers to respond to this and probably other mycobacterial lipoproteins (PubMed:21078852). Able to stimulate proliferation of CD4+ T-cells derived from a human leprosy patient following protein processing/presentation by MHC class II molecules in peripheral blood mononuclear cells (PubMed:18424702). Requires both host TLR1 and TLR2 as coreceptors to elicit host response in mouse, although TLR6 may play a redundant role, has a partial requirement for CD14 as an accessory receptor (PubMed:19362712). Present in extracytoplasmic vesicles (PubMed:21364279). Immunoelectron microscopy indicates this protein is close to the cell surface (PubMed:25041568). Forms a U-shaped beta-half-barrel with a small hydrophobic cavity (1500 Angstroms (3)) which holds a triacylated PIM in 1 crystal structure; the 3 acyl chains are within the cavity while the sugar moieties bind to the protein surface (PubMed:20694006). In the structure bound to triacylglycerides (TAG) 2 of the 3 acyl chains are buried in the cavity, the third is solvent exposed (PubMed:26751071). A flexible lid region may move to accommodate different TAG molecules (PubMed:26751071). Fragments of the mature protein (residues 81-100, 141-160 and 218-236) prevent uptake of M.tuberculosis by a human macrophage-like cell line; lesser effects are seen on bacterial uptake by a human lung epithelial cell line (PubMed:25041568). Modified by Lgt on Cys-27 with an S-linked diacylglyceral, signal peptide is removed by LspA, Cys-27 is further modifed with a fatty acid on its amino group by Lnt yielding a triacylated protein (Probable). Probably glycosylated, which is required for T-cell activation (PubMed:18424702). A single deletion mutant leads to loss of expression of efflux pump Rv1410c due to polar effects; in infected BALB/c mice 1.5 and 2.5 log decrease in bacterial load 15 and 35 days after infection (PubMed:14998516). The single mutant increases sensitivity to malachite green, sodium dodecyl sulfate (SDS), isoniazid, ethambutal and ethidium bromide, alters the permeability of the cell wall; both genes of the operon are required to fully restore the phenotypes (PubMed:21762531). Single deletion mutant (probably without Rv1410c) has decreased surface-exposed glycolipid lipoarabinomannan (LAM), although cellular LAM, LM and PIM content is normal (PubMed:25232742, PubMed:25356793). Disruption of either Rv1410c or the lrpG-Rv1410c operon leads to increased levels of many triacylglyceride (TAG) alkylforms; up to 100-fold increase depending on the exact TAG form (PubMed:26751071). It also forms smaller colonies on agar (PubMed:25232742). Loss of surface LAM has several consequences; bacteria enter mouse macrophages with reduced efficiency and block mouse macrophage phagosome-lysosome fusion less efficiently than wild-type (PubMed:25232742). Reduced efficiency of mouse macrophage phagosome-lysosome fusion was seen in another study (PubMed:25356793). C57BL/6 mice infected with mutant bacteria have 10-fold less bacterial burden after 10 days and about 2700-fold less burden after 70 days; attenuation of mutant is not rescued in macrophages impaired for reactive oxygen or nitrogen generation (disruption of Ncf1 or iNOS) (PubMed:25232742). Bacterial LAM blocks host cell phagosome-lysosome fusion and is one way in which M.tuberculosis evades the host immune system. Triacylglycerides accumulate in lipid droplets in the cytoplasm of M.tuberculosis stationary phase and dormant bacteria, and are used as an energy source during starvation (PubMed:26751071). Belongs to the LppX/LprAFG lipoprotein family.