May be a membrane transporter required for proton motive force (PMF)-dependent drug efflux. Required, with YghB, for the proper export of certain periplasmic amidases and, possibly, other Tat substrates. May play a role in determining membrane lipid composition. Regulated by the CpxA/CpxR two-component system. Double mutants lacking both yghB and yqjA show incomplete cell division, temperature sensitivity and altered phospholipid levels. They are also hypersensitive to several compounds known to be exported by other drug efflux proteins, including ethidium bromide, methyl viologen, acriflavine and beta-lactam antibiotics. Expression of either yghB or yqjA can restore the wild-type phenotype, suggesting that these proteins have redundant functions. Both individual null mutant strains grow normally at all temperatures. Belongs to the DedA family.