May contribute to resistance to some drugs, such as deoxycholate, sodium dodecyl sulfate and nalidixic acid, in the absence of BepD and BepE. Probably part of a tripartite efflux pump, which is composed of an outer membrane efflux protein, an inner membrane protein and a protein that expands the periplasmic space. Could form a tripartite pump with BepC and BepG. Induced in the absence of BepD and BepE. Belongs to the membrane fusion protein (MFP) (TC 8.A.1) family.