A putative lipoprotein that seems to be specialized for the initial steps of macrophage infection (PubMed:27220037). A non-acylated fragment (residues 26-185) binds phosphatidyl-myo-inositol mannosides (PIMs) (PubMed:27568926). Limits, in a TLR2-dependent fashion, bacterial uptake by host (mouse); this effect may be mediated by nonacylated fragment 26-185 (PubMed:27220037). Plays a TLR2-dependent role in host phagosome maturation arrest (PubMed:20844580, PubMed:27220037). Plays a TLR2-independent role in chemokine production during the first 24 hours of mouse infection (PubMed:27220037). Mature form (about 28 kDa) is associated with the cell wall and membrane fraction, secreted form is seen after 1 week axenic culture in Sauton's medium without detergent, this form is about 20 kDa (PubMed:27568926). May not be acylated, cell wall association is unchanged by mutation of the putatively acylated residue, and the mutant's migration does not change (PubMed:27568926). Constitutively expressed in culture (at protein level) (PubMed:27220037). An extracytoplasmic domain (residues 26-185, without the lipid-anchor, either periplasmic or extracellular) decreases phagocystosis by macrophages; when added exogenously to the deletion mutant initial bacteria uptake by host (mouse) decreases to wild-type levels. When added exogenously however this region is not sufficient to restore phagosome maturation arrest (PubMed:27220037). A shorter form (about 20 kDa) is secreted; upon overexpression of the whole protein in M.smegmatis the C-terminus of the short form is about residue 187, suggesting it is generated by cleavage of the protein before its C-terminal transmembrane domain (PubMed:27568926). Grows normally in liquid culture. Traffics into host (human and mouse) acidified compartments early after phagocytosis, suggesting it no longer arrests phagosome maturation as well as wild-type (PubMed:20844580, PubMed:27220037). Grows normally in mouse macrophages at 7 days post-infection (PubMed:20844580). Initial uptake (2 hours post-infection) by host (mouse) macrophages is higher than wild-type, but decreased growth in host (mouse) macrophages from 1 to 3 days post-infection, wild-type growth at 4 days (PubMed:27220037). Initial uptake of bacteria is the same in TLR2-/TLR2- mice (PubMed:27220037). Decreased host (mouse) induction of pro-inflammatory chemokines gamma IP-10 (Cxcl10), MCP-1 (Ccl2) and MIP-1-alpha (Ccl3); decreased induction is not TLR2-dependent (PubMed:27220037).