Reactome | AKAP9:KCNQ1 tetramer:KCNE dimer transports K+ from cytosol to extracellular region

AKAP9:KCNQ1 tetramer:KCNE dimer transports K+ from cytosol to extracellular region

Stable Identifier

R-HSA-5577050

Type

Reaction [transition]

Species

Homo sapiens

Compartment

cytosol, extracellular region, plasma membrane

ReviewStatus

5/5

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AKAP9:KCNQ1 tetramer:KCNE dimer transports K+ from cytosol to extracellular region

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Two potassium currents, I_Ks and I_Kr, provide the principal repolarising currents in cardiac myocytes for the termination of action potentials. Potassium voltage-gated channel subfamily KQT member 1 (KCNQ1 aka Kv7.1) is the pore-forming alpha subunit of a complex also containing an ancillary protein from potassium voltage-gated channel subfamily E members (KCNE) that assemble as a beta subunit. The stoichiometry is believed to be 4 KCNQ1 subunits to 2 KCNE subunits (Plant et al. 2014). A-kinase anchor protein 9 (AKAP9) is an essential anchoring protein that binds to KCNQ1. Defects in KCNQ1 that disrupt this binding can result in type 1 long-QT syndrome (LQT1), a hereditary, potentially lethal arrhythmia syndrome (Chen et al. 2007). The AKAP9:KCNQ1:KCNE complex creates the slowly activating delayed rectifier cardiac potassium current I_Ks by the efflux of K+ from cardiac cells (Schroeder et al. 2000).

Literature References

PubMed ID	Title	Journal	Year
18093912	Mutation of an A-kinase-anchoring protein causes long-QT syndrome Chen, L, Marquardt, ML, Tester, DJ, Sampson, KJ, Ackerman, MJ, Kass, RS	Proc. Natl. Acad. Sci. U.S.A.	2007
24591645	Individual IKs channels at the surface of mammalian cells contain two KCNE1 accessory subunits Plant, LD, Xiong, D, Dai, H, Goldstein, SA	Proc. Natl. Acad. Sci. U.S.A.	2014
10646604	A constitutively open potassium channel formed by KCNQ1 and KCNE3 Schroeder, BC, Waldegger, S, Fehr, S, Bleich, M, Warth, R, Greger, R, Jentsch, TJ	Nature	2000