This is a family of lipoproteins found only in pathogenic mycobacteria. These pathogenic lipoproteins may play a role in host-pathogen interactions. Lipoproteins localized to the cell-envelope of pathogenic bacteria are major determinants of virulence. The proteins are localized to the cell-surface via an N-terminal lipidation carried out by a transferase - pro-lipoprotein diacylglyceryl transferase Lgt - which attaches a diacylglyceride molecule to a sulfur atom from a crucial cysteine, and a consecutively acting lipoprotein signal peptidase LspA that cleaves the signal peptide just before the modified cysteine. When the peptidase is inactivated the pathogen has difficulty in replicating inside macrophages.