KCNN2

Chr 5q22.3

potassium calcium-activated channel subfamily N member 2

Aliases:: KCa2.2, hSK2
MANE:: ENST00000673685.1

OMIM: 605879 ↗NCBI: 3781 ↗Ensembl ↗

Annotations refreshed 9 hours ago.

Predicted protein structure

AlphaFold predicted structure

KCNN2 · Q9H2S1

v62025-08-01

Predicted Aligned Error matrix for KCNN2 — diagonal shows residue index, colour shows pairwise prediction confidence (lower is better) — Predicted Aligned Error

Mean pLDDT

76.5/ 100

Confident

579 residues

Confidence breakdown

Very high(≥ 90)43%
Confident(70–90)30%
Low(50–70)5%
Very low(< 50)23%

Open interactive 3D viewer

AlphaFold (Jumper et al., 2021) · CC BY 4.0

Clinical relevance (Genomics England PanelApp)

Diagnostic Grade (Green)

Ataxia and cerebellar anomalies - narrow panel
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
DDG2P
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Intellectual disability
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

Disease associations (Open Targets)

neurodevelopmental disorder with or without variable movement or behavioral abnormalities
0.67
Intellectual disability
0.57
Seizure
0.56
myoclonus-dystonia syndrome
0.55
Global developmental delay
0.52
atrial fibrillation
0.51
Autistic behavior
0.50
hereditary disease
0.47
movement disorder
0.46
Mild intellectual disability
0.46

Score is the Open Targets composite evidence score (0-1). Higher = stronger gene-disease association.

Protein function (UniProt)

Small conductance calcium-activated potassium channel protein 2

Small conductance calcium-activated potassium channel that mediates the voltage-independent transmembrane transfer of potassium across the cell membrane through a constitutive interaction with calmodulin which binds the intracellular calcium allowing its opening (PubMed:10991935, PubMed:33242881, PubMed:9287325). The current is characterized by a voltage-independent activation, an intracellular calcium concentration increase-dependent activation and a single-channel conductance of about 3 picosiemens (PubMed:10991935). Also presents an inwardly rectifying current, thus reducing its already small outward conductance of potassium ions, which is particularly the case when the membrane potential displays positive values, above + 20 mV (PubMed:10991935). The inward rectification could be due to a blockade of the outward current by intracellular divalent cations such as calcium and magnesium and could also be due to an intrinsic property of the channel pore, independent of intracellular divalent ions. There are three positively charged amino acids in the S6 transmembrane domain, close to the pore, that collectively control the conductance and rectification through an electrostatic mechanism. Additionally, electrostatic contributions from these residues also play an important role in determining the intrinsic open probability of the channel in the absence of calcium, affecting the apparent calcium affinity for activation. Forms an heteromeric complex with calmodulin, which is constitutively associated in a calcium-independent manner. Channel opening is triggered when calcium binds the calmodulin resulting in a rotary movement leading to the formation of the dimeric complex to open the gate (By similarity). Plays a role in the repolarization phase of cardiac action potential (PubMed:13679367)