Potassium uptake protein TrkA (IPR006036)

Short name: K_uptake_TrkA

Overlapping homologous superfamilies

Family relationships


The Trk system is a low to medium affinity potassium uptake system, widely found in both in bacteria and archaea, where the uptake of K(+) is believed to be linked to H(+) symport [PMID: 10423425]. The core Trk system consists of two proteins, the integral membrane K(+)-translocating protein TrkH (or TrkG), and the NAD-binding peripheral membrane protein TrkA [PMID: 15205426, PMID: 22316140]. In Escherichia coli the activity of TrkH is dependent on the ATP-binding protein SapD (also known as TrkE) which is part of the SapABCDF ABC transporter of unkown function. Not all Trk systems are dependent on SapD however - it is thought that these may utilise ATP-binding proteins from other ABC transporters [PMID: 9720051].

Sequence analysis of TrkA reveals that the protein consists of 2 tandemly arrayed halves that are 22% identical, a situation that might have arisen through gene duplication. TrkA also exhibits similarity to other Escherichia coli proteins [PMID: 8076592], in particular KefC, a glutathione- regulated efflux protein [PMID: 2046548], and to various dehydrogenase proteins that possess NAD+ binding sites.

GO terms

Biological Process

GO:0006813 potassium ion transport

Molecular Function

GO:0015079 potassium ion transmembrane transporter activity

Cellular Component

GO:0005886 plasma membrane

Contributing signatures

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