EmrKY-TolC multidrug efflux transport complex

cellstructuremech:emrky_tolc_multidrug_efflux_transport_complex · Other · Multiprotein complex · Proposed

An Escherichia coli MFS-family cell-envelope efflux pump complex composed of EmrK, EmrY, and TolC subunits that exports xenobiotics, including antimicrobial compounds, from the cell. [ComplexPortal:CPX-4273]

Synonyms: EmrKY-TolC multidrug efflux transport system

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
Probable multidrug resistance protein EmrK	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	emrK		ESSENTIAL	Periplasmic membrane-fusion adaptor constituent of the EmrKY-TolC tripartite efflux system. `ComplexPortal:CPX-4273` Complex Portal CPX-4273 curates P52599/EmrK as an E. coli K-12 EmrKY-TolC multidrug efflux transport system participant. `UniProtKB:P52599` UniProtKB P52599 is the reviewed E. coli K-12 entry for Probable multidrug resistance protein EmrK.
Probable multidrug resistance protein EmrY	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	emrY		ESSENTIAL	Inner-membrane MFS transporter constituent that forms the EmrKY transport core with the EmrK adaptor. `ComplexPortal:CPX-4273` Complex Portal CPX-4273 curates P52600/EmrY as an E. coli K-12 EmrKY-TolC multidrug efflux transport system participant. `UniProtKB:P52600` UniProtKB P52600 is the reviewed E. coli K-12 entry for Probable multidrug resistance protein EmrY.
Outer membrane channel protein TolC	Protein	part of	`InterPro:IPR058622`	tolC	3 copies in the E. coli K-12 Complex Portal CPX-4273 entry	ESSENTIAL	Trimeric outer-membrane channel constituent that completes the EmrKY-TolC cell-envelope efflux conduit. `ComplexPortal:CPX-4273` Complex Portal CPX-4273 curates P02930/TolC as three copies in the E. coli K-12 EmrKY-TolC multidrug efflux transport system. `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.

Probable multidrug resistance protein EmrK

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P52599`	Probable multidrug resistance protein EmrK	emrK	Escherichia coli K-12 (`NCBITaxon:83333`)	REVIEWED
Role and evidence (1 reference) `UniProtKB:P52599` Reviewed Swiss-Prot entry EMRK_ECOLI is the E. coli K-12 EmrK accession and cross-references ComplexPortal:CPX-4273.

Probable multidrug resistance protein EmrY

Accession	Protein	Gene	Organism	Entry
`UniProtKB:P52600`	Probable multidrug resistance protein EmrY	emrY	Escherichia coli K-12 (`NCBITaxon:83333`)	REVIEWED
Role and evidence (1 reference) `UniProtKB:P52600` Reviewed Swiss-Prot entry EMRY_ECOLI is the E. coli K-12 EmrY accession and cross-references ComplexPortal:CPX-4273.

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-4273.

Source composition assertions

EmrKY-TolC multidrug efflux transport system (ComplexPortal:CPX-4273)

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

Participant	Source type	Source name	Stoichiometry
`UniProtKB:P52599` — Probable multidrug resistance protein EmrK	protein	emrK	not asserted
`UniProtKB:P52600` — Probable multidrug resistance protein EmrY	protein	emrY	not asserted
`UniProtKB:P02930` — Outer membrane protein TolC	protein	tolC	3

Curator-scoped import: E. coli K-12 EmrKY-TolC source composition for this record. Source evidence: inferred by curator. CPX-4273 does not supply an assembly label, and its EmrK and EmrY participants have no source stoichiometry, so those fields are omitted here. 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-4273, which curates EmrK, EmrY, and TolC as the participants of EmrKY-TolC. [ComplexPortal:CPX-4273]

Functions

xenobiotic transmembrane transporter activity GO:0042910 — The EmrKY-TolC system exports xenobiotics such as drugs from E. coli through the coupled EmrY transporter, EmrK adaptor, and TolC channel.
- GO:0042910 GO:0042910 is the molecular-function term for xenobiotic transmembrane transporter activity.
- ComplexPortal:CPX-4273 Complex Portal cross-references GO:0042910 for the E. coli K-12 EmrKY-TolC multidrug efflux transport system.

Mechanism graphs

EmrKY-TolC exports xenobiotics across the cell envelope (FUNCTION)

EmrY, EmrK, and TolC form an envelope-spanning MFS efflux pump that exports xenobiotics from E. coli.

Subject	Predicate	Object	Evidence
Probable multidrug resistance protein EmrY	couples to	Probable multidrug resistance protein EmrK	`ComplexPortal:CPX-4273` CPX-4273 curates EmrK and EmrY as participants in the E. coli EmrKY-TolC pump.
Probable multidrug resistance protein EmrK	couples to	Outer membrane channel protein TolC	`UniProtKB:P52599` UniProtKB describes EmrK as part of the tripartite EmrYK-TolC efflux system and as the system's membrane-fusion protein.
EmrKY-TolC multidrug efflux transport complex	enables	xenobiotic transmembrane transporter activity	`ComplexPortal:CPX-4273` Complex Portal cross-references GO:0042910 for the EmrKY-TolC complex.
xenobiotic transmembrane transporter activity	transports	xenobiotic substrate	`ComplexPortal:CPX-4273` CPX-4273 summarizes the EmrKY-TolC system as responsible for transport of xenobiotics such as drugs out of the cell.
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 EmrK and EmrY protein families before replacing the reviewed-label-only component rows. ComplexPortal:CPX-4273 and the reviewed E. coli K-12 UniProt records exactly identify EmrK and EmrY, 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-4273 Complex Portal entry for the E. coli K-12 EmrKY-TolC multidrug efflux transport system.
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:P52599 Reviewed E. coli K-12 EmrK UniProtKB entry.
UniProtKB:P52600 Reviewed E. coli K-12 EmrY UniProtKB entry.
UniProtKB:P02930 Reviewed E. coli K-12 TolC UniProtKB entry.
PMID:19721076 PubMed identifier for May et al. 2009, Induction of multidrug resistance mechanism in Escherichia coli biofilms by interplay between tetracycline and ampicillin resistance genes.
DOI:10.1128/AAC.00454-09 DOI for May et al. 2009, Induction of multidrug resistance mechanism in Escherichia coli biofilms by interplay between tetracycline and ampicillin resistance genes.

Curation history

2026-10-02T12:05:36Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-02T12:07:24Z codex · EXPANDED_RECORD — Added CPX-4273/GO efflux-pump parentage, EmrK, EmrY, and TolC component rows with exact E. coli K-12 reviewed UniProt examples, an exact TolC InterPro grounding, a compact xenobiotic export graph, the Complex Portal CPX-4273 source composition, and component-family grounding TODOs for EmrK and EmrY.

Source: data/structures/other/emrky_tolc_multidrug_efflux_transport_complex.yaml