Contributes to cell wall biosynthesis and biofilm formation. Transports the mycolic acid-containing lipids monomeromycolyl diacylglycerol (MMDAG) and mycolate ester wax (WE) to the bacterial surface. Mutant has altered cell wall lipid composition, reduced membrane permeability and altered biofilm formation. It accumulates the mycolic acid-containing precursor mycolyl phospholipid (MycPL) and fails to export MMDAG and mycolate ester wax to the bacterial surface. Does not affect trehalose monomycolate (TMM) transport.