Probably helps membrane protein BCG_1471c (P55) transport triacylglycerides (TAG) across the inner cell membrane into the periplasm and probably ultimately to the outer membrane. TAG probably regulates lipid metabolism and growth regulation. Binds di- and triacylated phosphatidyl-myo-inositol mannosides (PIMs), and glycolipid lipoglycan modulins lipoarabinomannan (LAM) and lipomannan (LM), facilitating their recognition by TLR2. Required for activity of drug efflux transporter BCG_1471c. Required, probably with BCG_1471c, for normal surface localization of LAM. Constitutes a host TLR2 agonist (toll-like receptor) (By similarity). In vitro binds to human CD209 (DC-SIGN) and CD209-like antigen (CLEC4M) and may help mediate adherence to host cells (PubMed:21203928). In vitro able to bind to host (human) CD209, may also bind CD209-like antigen (CLEC4M) (PubMed:21203928). Present in extracytoplasmic vesicles (PubMed:21364279). Forms a U-shaped beta-half-barrel with a small hydrophobic cavity able to hold a triacylated lipid or triacylglyceride. 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 (By similarity). Bacterial LAM blocks host cell phagosome-lysosome fusion and is one way in which Mycobacteria evade 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. Belongs to the LppX/LprAFG lipoprotein family.