AcrA-AcrB-AcrZ-TolC is a drug efflux protein complex with a broad substrate specificity. This protein binds to AcrB and is required for efflux of some but not all substrates, suggesting it may influence the specificity of drug export. Part of the AcrA-AcrB-AcrZ-TolC efflux pump, interacts directly with AcrB. Belongs to the AcrZ family.