Required for export of phthiocerol dimycocerosate (PDIM) to the cell wall (PubMed:10573420, PubMed:11279114). Essential for normal replication during the active-growth phase of the murine tuberculosis model (PubMed:15908378). Confers a high level of resistance to isoniazid (INH) when overexpressed in M.smegmatis. Interacts with PpsE. Phosphorylated by PknD in vitro. Phosphorylation could regulate the formation of the cell wall. Disruption causes altered colony morphology (PubMed:10573420). Inactivation increases mouse survival (PubMed:15908378). Mutants are unable to liberate PDIM into the culture medium and are compromised for growth in mouse lungs, but not in the liver or spleen (PubMed:10573420). DIM are found mostly in the cytosol and plasma membrane, and mutants exhibit higher cell wall permeability and are more sensitive to detergent (PubMed:11279114). Belongs to the resistance-nodulation-cell division (RND) (TC 2.A.6) family. MmpL subfamily.