KCNE4 Protein is a potassium channel regulatory subunit encoded by the KCNE4 gene (also known as MiRP3). It belongs to the KCNE family of single transmembrane domain proteins that modulate the function of voltage-gated potassium channels. The UniProt ID is Q8WXX4 [1].
KCNE4 is a critical modulator of neuronal and cardiac potassium channel function. As part of the KCNE family (KCNE1-5), KCNE4 assembles with various potassium channel α-subunits to form functionally distinct channels with unique biophysical properties, localization patterns, and regulatory mechanisms [2]. While most extensively studied in cardiac tissue, emerging research suggests important roles for KCNE4 in neuronal excitability, neurotransmitter release, and potentially in neurodegenerative disease processes. [1]
KCNE4 is a small single-pass transmembrane protein with the following structural features: [2]
N-terminus (1-72) → Transmembrane (73-95) → C-terminus (96-170)
Pro-rich Regulatory sites
KCNE4 modulates multiple potassium channel families: [3]
KCNQ1 (Kv7.1) Channels: KCNE4 co-assembles with KCNQ1 to form slowly activating delayed rectifier potassium currents (I_Ks). Unlike KCNE1 which prolongs channel opening, KCNE4 accelerates activation and shifts the voltage dependence to more positive potentials [3].
Kv3.4 Channels: KCNE4 modulates high-voltage-activated fast-decaying A-type currents, influencing neuronal repolarization kinetics [2].
HCN Channels: Some studies suggest KCNE4 may modulate hyperpolarization-activated cyclic nucleotide-gated channels, affecting pacemaker currents [2].
KCNE4 expression is detected in: [4]
KCNE4 regulates channel function through:
Potassium channels are fundamental regulators of neuronal excitability. KCNE4's modulation of Kv channels influences:
Dysregulation of these processes contributes to excitotoxicity, a common pathological mechanism in neurodegenerative diseases [4].
Evidence suggests KCNE4 may play roles in AD pathogenesis:
KCNE4 may influence PD through:
Channelopathies involving KCNE4 may contribute to motor neuron degeneration through excitotoxic mechanisms [4].
KCNE4-associated channels represent potential drug targets for:
Roura-Ferrer M, et al. Functional implications of KCNE4 expression and assembly in neuronal cells. J Neurochem. 2010;115(2):332-342. 2010. ↩︎
McCrossan ZA, Abbott GW. The MinK-related peptides. Neuropharmacology. 2004;47(6):854-868. 2004. ↩︎
Abbott GW. KCNE4 and KCNE5: K(+) channel regulatory subunits with emerging roles in neurodegeneration. Channels (Austin). 2020;14(1):6-16. 2020. ↩︎
Sanguinetti MC, Tristani-Firouzi M. hERG potassium channels and cardiac arrhythmia. Nature. 2006;440(7083):463-469. 2006. ↩︎