Bile acid:sodium symporter/arsenical resistance protein Acr3 (IPR002657)

Short name: BilAc:Na_symport/Acr3

Overlapping homologous superfamilies

Family relationships


This family of proteins are found both in prokaryotes and eukaryotes. They are related to the human bile acid:sodium symporters (TC 2.A.28), which are transmembrane proteins functioning in the liver in the uptake of bile acids from portal blood plasma, a process mediated by the co-transport of Na+ [PMID: 1961729].

This entry also includes members of the ACR3 family of arsenite (As(III)) permeases, which confer resistance to arsenic by extrusion from cells [PMID: 19494117]. They exist in prokaryotes and eukaryotes (lower plants and fungi) [PMID: 20530755, PMID: 24291645]. The ACR3 permeases have ten-transmembrane span topology [PMID: 18088595]. Corynebacterium glutamicum has three Acr3 proteins, CgAcr3-1, CgAcr3-2, and CgAcr3-3. CgAcr3-1 is thought to be an antiporter that catalyses arsenite-proton exchange [PMID: 22102279].

The Shewanella oneidensis Acr3 is not able to transport As(III) and confers resistance only to arsenate (As(V)) [PMID: 19039703], whereas the Acr3 orthologue from Synechocystis mediates tolerance to As(III), As(V) and antimonite (Sb(III)) [PMID: 12949088].

In budding yeast, overexpression of the Acr3 gene confers an arsenite- but not an arsenate-resistance phenotype [PMID: 9234670]. Saccharomyces cerevisiae Acr3 is a plasma membrane metalloid/H+ antiporter that transports arsenite and antimonite [PMID: 21447319].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0016020 membrane

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.