AcrAD-TolC multidrug efflux transport complex

cellstructuremech:acrad_tolc_multidrug_efflux_transport_complex · Other · Multiprotein complex · Proposed

An Escherichia coli RND-family cell-envelope efflux pump complex composed of AcrA, AcrD, and TolC subunits that exports aminoglycosides and other xenobiotic substrates across the cell envelope. [ComplexPortal:CPX-4264]

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
Multidrug efflux pump subunit AcrA	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	acrA	6 copies in the E. coli K-12 Complex Portal CPX-4264 entry	ESSENTIAL	Periplasmic adaptor subunit that couples AcrD to TolC in the AcrAD-TolC envelope-spanning efflux pump. `ComplexPortal:CPX-4264` Complex Portal CPX-4264 curates P0AE06/AcrA as six copies in the E. coli K-12 AcrAD-TolC multidrug efflux transport complex. `UniProtKB:P0AE06` UniProtKB P0AE06 is the reviewed E. coli K-12 entry for Multidrug efflux pump subunit AcrA.
Probable aminoglycoside efflux pump AcrD	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	acrD	3 copies in the E. coli K-12 Complex Portal CPX-4264 entry	ESSENTIAL	Inner-membrane RND transporter subunit that forms the trimeric core and captures aminoglycoside substrates for export through the AcrA/TolC conduit. `ComplexPortal:CPX-4264` Complex Portal CPX-4264 curates P24177/AcrD as three copies in the E. coli K-12 AcrAD-TolC multidrug efflux transport complex. `UniProtKB:P24177` UniProtKB P24177 is the reviewed E. coli K-12 entry for Probable aminoglycoside efflux pump AcrD. `PMID:15743938` Murakami et al. 2005 experimentally studied AcrD aminoglycoside capture from the periplasm and cytoplasm.
Outer membrane channel protein TolC	Protein	part of	`InterPro:IPR058622`	tolC	3 copies in the E. coli K-12 Complex Portal CPX-4264 entry	ESSENTIAL	Outer-membrane channel subunit that closes the periplasmic AcrA bridge and conducts exported substrates out of the cell envelope. `ComplexPortal:CPX-4264` Complex Portal CPX-4264 curates P02930/TolC as three copies in the E. coli K-12 AcrAD-TolC multidrug efflux transport complex. `UniProtKB:P02930` UniProtKB P02930 is the reviewed E. coli K-12 entry for Outer membrane protein TolC. `InterPro:IPR058622` InterPro IPR058622 is the Outer membrane channel protein TolC family entry.

Organism-specific protein examples

Named proteins in which each component's role was established, with the organism the evidence comes from. The component above is the taxon-agnostic family; these are the specific entries behind it.

Multidrug efflux pump subunit AcrA

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P0AE06`	Multidrug efflux pump subunit AcrA	acrA	Escherichia coli K-12 (`NCBITaxon:83333`)	REVIEWED
Role and evidence (1 reference) `UniProtKB:P0AE06` Reviewed Swiss-Prot entry ACRA_ECOLI is the E. coli K-12 AcrA accession and cross-references ComplexPortal:CPX-4264.

Probable aminoglycoside efflux pump AcrD

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P24177`	Probable aminoglycoside efflux pump	acrD	Escherichia coli K-12 (`NCBITaxon:83333`)	REVIEWED
Role and evidence (1 reference) `UniProtKB:P24177` Reviewed Swiss-Prot entry ACRD_ECOLI is the E. coli K-12 AcrD accession and cross-references ComplexPortal:CPX-4264.

Outer membrane channel protein TolC

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P02930`	Outer membrane protein TolC	tolC	Escherichia coli K-12 (`NCBITaxon:83333`)	REVIEWED
Role and evidence (1 reference) `UniProtKB:P02930` Reviewed Swiss-Prot entry TOLC_ECOLI is the E. coli K-12 TolC accession and cross-references ComplexPortal:CPX-4264.

Source composition assertions

AcrAD-TolC multidrug efflux transport complex (ComplexPortal:CPX-4264)

Escherichia coli (strain K12) (NCBITaxon:83333) · Heterododecamer · ECO:0005547 · retrieved 2026-10-02

Participant	Source type	Source name	Stoichiometry
`UniProtKB:P24177` — Probable aminoglycoside efflux pump	protein	acrD	3
`UniProtKB:P0AE06` — Multidrug efflux pump subunit AcrA	protein	acrA	6
`UniProtKB:P02930` — Outer membrane protein TolC	protein	tolC	3

Curator-scoped import: E. coli K-12 AcrAD-TolC source composition for this record. Source evidence: inferred by curator. The accession was resolved through the Complex Portal accession endpoint; no equivalence xref was inferred.

Canonical examples

NCBITaxon:83333 Escherichia coli K-12 — Source strain for Complex Portal CPX-4264, which curates the heterododecameric AcrAD-TolC pump with six AcrA, three AcrD, and three TolC subunits. [ComplexPortal:CPX-4264]

Functions

xenobiotic transmembrane transporter activity GO:0042910 — The AcrAD-TolC complex exports aminoglycosides and other xenobiotic substrates across the E. coli cell envelope through the coupled AcrD transporter, AcrA adaptor, and TolC outer-membrane channel.
- GO:0042910 GO:0042910 is the molecular-function term for xenobiotic transmembrane transporter activity.
- ComplexPortal:CPX-4264 Complex Portal cross-references GO:0042910 for the E. coli K-12 AcrAD-TolC multidrug efflux transport complex.

Physical properties

SUBUNIT_COUNT: 12 (E. coli K-12 6xAcrA:3xAcrD:3xTolC heterododecamer in ComplexPortal:CPX-4264) [ComplexPortal:CPX-4264]

Mechanism graphs

AcrAD-TolC exports aminoglycosides across the cell envelope (FUNCTION)

AcrD, AcrA, and TolC form an envelope-spanning efflux pump that exports aminoglycosides and other xenobiotic substrates from E. coli.

Subject	Predicate	Object	Evidence
Probable aminoglycoside efflux pump AcrD	couples to	Multidrug efflux pump subunit AcrA	`ComplexPortal:CPX-4264` CPX-4264 curates AcrD and AcrA as participants in the E. coli AcrAD-TolC pump.
Multidrug efflux pump subunit AcrA	couples to	Outer membrane channel protein TolC	`ComplexPortal:CPX-4264` CPX-4264 curates AcrA and TolC as participants in the E. coli AcrAD-TolC pump.
AcrAD-TolC multidrug efflux transport complex	enables	xenobiotic transmembrane transporter activity	`ComplexPortal:CPX-4264` Complex Portal cross-references GO:0042910 for the AcrAD-TolC complex.
xenobiotic transmembrane transporter activity	transports	aminoglycoside substrate	`PMID:15743938` Murakami et al. 2005 report aminoglycoside capture by the AcrD multidrug efflux transporter of E. coli.
xenobiotic detoxification by transmembrane export across the cell outer membrane	targets	cell exterior	`GO:0140330` GO:0140330 describes reducing xenobiotic toxicity by export through the outer membrane.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral protein families for AcrA and AcrD before replacing their reviewed-label-only component rows. ComplexPortal:CPX-4264 and the reviewed E. coli K-12 UniProt records exactly identify AcrA and AcrD, but no InterPro, Pfam, NCBIfam, or GO accession was verified as an exact source-neutral family for either named pump constituent; TolC is grounded to InterPro:IPR058622.

Evidence

ComplexPortal:CPX-4264 Complex Portal entry for the E. coli K-12 AcrAD-TolC multidrug efflux transport complex.
GO:1990281 Gene Ontology cellular-component parent term for efflux pump complexes.
GO:0042910 Gene Ontology molecular-function term for xenobiotic transmembrane transporter activity.
GO:0140330 Gene Ontology biological-process term for xenobiotic detoxification by transmembrane export across the cell outer membrane.
InterPro:IPR058622 InterPro family entry for Outer membrane channel protein TolC.
UniProtKB:P0AE06 Reviewed E. coli K-12 AcrA UniProtKB entry.
UniProtKB:P24177 Reviewed E. coli K-12 AcrD UniProtKB entry.
UniProtKB:P02930 Reviewed E. coli K-12 TolC UniProtKB entry.
PMID:15743938 PubMed identifier for Murakami et al. 2005, Aminoglycosides are captured from both periplasm and cytoplasm by the AcrD multidrug efflux transporter of Escherichia coli.
DOI:10.1128/JB.187.6.1923-1929.2005 DOI for Murakami et al. 2005, Aminoglycosides are captured from both periplasm and cytoplasm by the AcrD multidrug efflux transporter of Escherichia coli.
PMID:26113845 PubMed identifier for Zwama and Pos 2015, The ins and outs of RND efflux pumps in Escherichia coli.
DOI:10.3389/fmicb.2015.00587 DOI for Zwama and Pos 2015, The ins and outs of RND efflux pumps in Escherichia coli.

Curation history

2026-10-02T09:37:12Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-02T09:38:51Z codex · EXPANDED_RECORD — Added GO efflux-pump parentage, AcrA, AcrD, and TolC component rows with E. coli K-12 reviewed UniProt examples, the exact Complex Portal CPX-4264 source composition, xenobiotic transporter activity, Complex Portal/PubMed evidence, a compact function graph, and a component-family grounding TODO.

Source: data/structures/other/acrad_tolc_multidrug_efflux_transport_complex.yaml