KCNE5 Protein (also known as KCNE1L) is a potassium channel regulatory subunit encoded by the [KCNE5](/genes/kcne5) gene on the X chromosome (Xq22.1). It belongs to the KCNE family of single transmembrane proteins that modulate voltage-gated potassium channel function. The UniProt ID is [Q9NZZ6](https://www.uniprot.org/uniprot/Q9NZZ6) [1].
Introduction
KCNE5 is the most recently evolved member of the KCNE family and is unique in being X-linked, which has implications for sex-based differences in channel function and disease susceptibility. While primarily studied in cardiac electrophysiology, KCNE5 is increasingly recognized for its potential roles in neuronal function and neurological disorders [2]. The protein's distinctive biophysical properties and expression pattern make it a subject of interest for understanding potassium channel modulation in both cardiac and neural systems. [@abbott2020]
KCNE5 Protein (also known as KCNE1L) is a potassium channel regulatory subunit encoded by the [KCNE5](/genes/kcne5) gene on the X chromosome (Xq22.1). It belongs to the KCNE family of single transmembrane proteins that modulate voltage-gated potassium channel function. The UniProt ID is [Q9NZZ6](https://www.uniprot.org/uniprot/Q9NZZ6) [1].
Introduction
KCNE5 is the most recently evolved member of the KCNE family and is unique in being X-linked, which has implications for sex-based differences in channel function and disease susceptibility. While primarily studied in cardiac electrophysiology, KCNE5 is increasingly recognized for its potential roles in neuronal function and neurological disorders [2]. The protein's distinctive biophysical properties and expression pattern make it a subject of interest for understanding potassium channel modulation in both cardiac and neural systems. [@abbott2020]
Structure
Molecular Architecture
KCNE5 shares the core structural features of KCNE proteins: [@mccrossan2004]
Molecular Weight: Approximately 14 kDa
Transmembrane Domain: Single transmembrane helix (residues 69-91)
N-terminal Domain: Short cytoplasmic domain with regulatory motifs
C-terminal Domain: Longer cytoplasmic tail with multiple post-translational modification sites
Unlike other KCNE proteins, KCNE5 has a distinctive proline-rich N-terminus that influences its trafficking and assembly properties [5]. [@maljevic2018]
Normal Function
Channel Modulation
KCNE5 modulates several potassium channel families: [@rouraferrer2011]
KCNQ1 (Kv7.1): Co-assembly produces slowly activating currents with unique voltage dependence. KCNE5 shifts the activation curve rightward compared to KCNE1 [3].
KCNQ2-4 (Kv7.2-7.4): Neuronal M-channel subunits. KCNE5 modulation affects neuronal excitability and may influence synaptic transmission [2].
Kv3.4: Modulates high-threshold A-type currents in [neurons](/entities/neurons).
[Maljevic S, et al., KCNE mutations associated with epilepsy. Channels (Austin). 2018;12(1):82-87 (2018)](https://pubmed.ncbi.nlm.nih.gov/29394192/)
[Roura-Ferrer M, et al., KCNE5 modulates Kv7.1 channels and neuronal excitability. Biochem Biophys Res Commun. 2011;406(2):183-189 (2011)](https://pubmed.ncbi.nlm.nih.gov/21300047/)