KCNE2
Description
The KCNE2 (potassium voltage-gated channel subfamily E regulatory subunit 2) is a protein-coding gene located on chromosome 21.
Potassium voltage-gated channel subfamily E member 2 (KCNE2), also known as MinK-related peptide 1 (MiRP1), is a protein that in humans is encoded by the KCNE2 gene on chromosome 21. MiRP1 is a voltage-gated potassium channel accessory subunit (beta subunit) associated with Long QT syndrome. It is ubiquitously expressed in many tissues and cell types. Because of this and its ability to regulate multiple different ion channels, KCNE2 exerts considerable influence on a number of cell types and tissues. Human KCNE2 is a member of the five-strong family of human KCNE genes. KCNE proteins contain a single membrane-spanning region, extracellular N-terminal and intracellular C-terminal. KCNE proteins have been widely studied for their roles in the heart and in genetic predisposition to inherited cardiac arrhythmias. The KCNE2 gene also contains one of 27 SNPs associated with increased risk of coronary artery disease. More recently, roles for KCNE proteins in a variety of non-cardiac tissues have also been explored.
== Discovery == Steve Goldstein (then at Yale University) used a BLAST search strategy, focusing on KCNE1 sequence stretches known to be important for function, to identify related expressed sequence tags (ESTs) in the NCBI database.
KCNE2 is an ancillary protein that assembles as a beta subunit with a voltage-gated potassium channel complex of pore-forming alpha subunits. It modulates the gating kinetics and enhances stability of the channel complex. Assembled with KCNB1, it modulates the gating characteristics of the delayed rectifier voltage-dependent potassium channel KCNB1. Associated with KCNH2/HERG, KCNE2 is proposed to form the rapidly activating component of the delayed rectifying potassium current in heart (IKr). It may associate with KCNQ2 and/or KCNQ3 and modulate the native M-type current. KCNE2 may associate with HCN1 and HCN2 and increase potassium current. It interacts with KCNQ1, forming a heterooligomer complex leading to currents with an apparently instantaneous activation, a rapid deactivation process and a linear current-voltage relationship. KCNE2 decreases the amplitude of the outward current (PubMed:11101505). The KCNQ1-KCNE2 channel associates with Na(+)-coupled myo-inositol symporter in the apical membrane of choroid plexus epithelium and regulates the myo-inositol gradient between blood and cerebrospinal fluid with an impact on neuron excitability. {ECO:0000250|UniProtKB:P63161, ECO:0000250|UniProtKB:Q9D808, ECO:0000269|PubMed:10219239, ECO:0000269|PubMed:11101505}
KCNE2 is also known as ATFB4, LQT5, LQT6, MIRP1.
