AcrA-AcrB-AcrZ-TolC is a drug efflux protein complex with broad substrate specificity that uses the proton motive force to export substrates. (Microbial infection) Involved in contact-dependent growth inhibition (CDI), acts downstream of BamA, the receptor for CDI. Its role in CDI is independent of the AcrA-AcrB-TolC efflux pump complex. Homotrimer, with large domains that extend into the periplasm, interacts with AcrA and TolC. AcrA may be required to stably link this protein and TolC. Interacts with AcrZ. Part of the AcrA-AcrB-AcrZ-TolC efflux pump. Positively regulated by MarA, Rob and SoxS transcriptional regulators (at protein level). Loss of susceptibility to contact-dependent growth inhibition (CDI); inhibiting cells still contact the target. Belongs to the resistance-nodulation-cell division (RND) (TC 2.A.6) family.