InterPro : IPR003148

Name  Regulator of K+ conductance, N-terminal Short Name  RCK_N
Type  Domain Description  The regulator of K+ conductance (RCK) domain is found in many ligand-gated K+ channels, most often attached to the intracellular carboxy terminus. The domain is prevalent among prokaryotic K+ channels, and also found in eukaryotic, high-conductance Ca2+-activated K+ channels (BK channels) [, , ]. Largely involved in redox-linked regulation of potassium channels, the N-terminal part of the RCK domain is predicted to be an active dehydrogenase at least in some cases []. Some have a conserved sequence motif (G-x-G-x-x-G-x(n)-[DE]) for NAD+ binding [], but others do not, reflecting the diversity of ligands for RCK domains. The C-terminal part is less conserved, being absent in some channels, such as the kefC antiporter from Escherichia coli. It is predicted to bind unidentified ligands and to regulate sulphate, sodium and other transporters.The X-ray structure of several RCK domains has been solved [, , ]. It reveals an alpha-beta fold similar to dehydrogenase enzymes. The domain forms a homodimer, producing a cleft between two lobes. It has a composite structure, with an N-terminal (RCK-N), and a C-terminal (RCK-C) subdomain. The RCK-N subdomain forms a Rossmann fold with two alpha helices on one side of a six stranded parallel beta sheet and three alpha helices on the other side. The RCK-C subdomain is an all-beta-strand fold. It forms an extention of the dimer interface and further stabilises the RCK homodimer [, , ]. Ca2+ is a ligand that opens the channel in a concentration-dependent manner. Two Ca2+ ions are located at the base of a cleft between two RCK domains, coordinated by the carboxylate groups of two glutamate residues, and by an aspartate residue [, , ].RCK domains occur in at least five different contexts:As a single domain on the C terminus of some K+ channels (for example, many prokaryotic K+ channels).As two tandem RCK domains on the C terminus of some transporters that form gating rings (for example, eukaryotic BK channels). The gating ring has an arrangement of eight identical RCK domains, one from each of the four pore-forming subunits and four from the intracellular solution.As two domains, one at the N terminus and another at the C terminus of transporter (for example, the prokaryotic trk system potassium uptake protein A).As a soluble protein (not part of a K+ channel) consisting of two tandem RCK domains.As a soluble protein consisting of a single RCK domain.This entry represents the N-terminal subdomain of RCK.

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

0 Contains

3 Found In

Id Name Short Name Type
IPR016040 NAD(P)-binding domain NAD(P)-bd_dom Domain
IPR006036 Potassium uptake protein TrkA K_uptake_TrkA Family
IPR020884 Glutathione-regulated potassium-efflux system protein KefB K_H_efflux_KefB Family

0 Parent Features

5 Publications

First Author Title Year Journal Volume Pages
Schlösser A NAD+ binding to the Escherichia coli K(+)-uptake protein TrkA and sequence similarity between TrkA and domains of a family of dehydrogenases suggest a role for NAD+ in bacterial transport. 1993 Mol Microbiol 9 533-43
Anantharaman V Regulatory potential, phyletic distribution and evolution of ancient, intracellular small-molecule-binding domains. 2001 J Mol Biol 307 1271-92
Jiang Y Structure of the RCK domain from the E. coli K+ channel and demonstration of its presence in the human BK channel. 2001 Neuron 29 593-601
Jiang Y Crystal structure and mechanism of a calcium-gated potassium channel. 2002 Nature 417 515-22
Dong J Structures of the MthK RCK domain and the effect of Ca2+ on gating ring stability. 2005 J Biol Chem 280 41716-24

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)