KCNJ12 (Kir2.2) – Inward Rectifier Potassium Channel Gene
KCNJ12 encodes the Kir2.2 potassium channel subunit, critical for cardiac and neuronal excitability; implicated in inherited arrhythmias and cancer.
Gene Information Card
| Symbol | KCNJ12 |
|---|---|
| Full Name | Potassium Voltage-Gated Channel Subfamily J Member 12 |
| Gene Type | protein-coding |
| Chromosomal Location | 17p11.2 |
| NCBI Gene ID | 3768 ncbi.nlm.nih.gov/gene/3768 |
| Ensembl ID | ENSG00000184185 |
| UniProt ID | Q14500 |
| OMIM ID | 602208 |
| HGNC ID | 6256 |
| Aliases | IRK2, Kir2.2, hIRK2, KIR2.2 |
Description
KCNJ12 encodes the inward rectifier potassium channel subunit Kir2.2. These channels help maintain resting membrane potential and regulate action potential duration in excitable cells, particularly in the heart and brain. Mutations can lead to channel dysfunction and disease.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Andersen-Tawil Syndrome (ATS) | Loss-of-function mutations reduce Kir2.2 current, prolonging QT interval and causing arrhythmias. | ClinVar, OMIM |
| Long QT Syndrome (LQTS) | Dominant-negative effects on Kir2.2 reduce repolarization reserve. | ClinVar, OMIM |
| Short QT Syndrome (SQTS) | Gain-of-function mutations increase potassium efflux, shortening QT interval. | ClinVar, OMIM |
| Cancer (various) | Altered Kir2.2 expression affects cell proliferation and migration; mutations may contribute to tumor progression. | COSMIC, NCBI |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Heart | 45.2 | High |
| Brain | 32.8 | Medium |
| Skeletal Muscle | 28.1 | Medium |
| Liver | 5.3 | Low |
| Kidney | 8.7 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 12.4 | Moderate expression |
| HeLa | 3.2 | Low expression |
| SH-SY5Y | 25.6 | High expression (neuronal) |
| H9c2 (cardiomyoblast) | 40.1 | High expression (cardiac) |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| p.Arg82Gln | Missense | Rare | Reduced channel conductance |
| p.Val302Met | Missense | Rare | Altered gating kinetics |
| p.Gly144Asp | Missense | Rare | Dominant-negative effect |
| p.Thr309Ile | Missense | Rare | Gain-of-function |
Mutation functional classification
Loss of Function (LOF)
Mutations that reduce or abolish Kir2.2 current, leading to prolonged action potentials and arrhythmias.
Gain of Function (GOF)
Mutations that increase potassium current, shortening action potential duration and causing SQTS.
Dominant Negative (DN)
Mutant subunits co-assemble with wild-type, impairing channel function in a dominant manner.
View complete mutation data：
Gene Ontology (GO)
| • inward rectifier potassium channel activity | • voltage-gated potassium channel activity |
| • protein homodimerization activity | • plasma membrane |
| • integral component of plasma membrane | • potassium ion transmembrane transport |
| • regulation of membrane potential |
Pathways
• Inward rectifier potassium channels
• Cardiac conduction
• Potassium transport
• Ion channel transport
Protein Summary
Kir2.2 is a 427-amino acid protein with two transmembrane domains and a pore-forming loop. It assembles as homo- or heterotetramers with other Kir2 subunits to form functional channels. The protein is critical for setting the resting membrane potential and shaping action potentials in cardiac and neuronal cells.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| KCNJ12 Knockout HEK293 Cell Line | EDJ-KQ1932 | Human | 3768 | Details Get a Quote |
| KCNJ12 Knockout HCT 116 Cell Line | EDJ-KQ21861 | Human | 3768 | Details Get a Quote |
| KCNJ12 Knockout HeLa Cell Line | EDJ-KQ21862 | Human | 3768 | Details Get a Quote |
| KCNJ12 Knockout Hep-G2 Cell Line | EDJ-KZ305 | Human | 3768 | Details Get a Quote |
| KCNJ12 Knockout A-549 Cell Line | EDJ-KQ62194 | Human | 3768 | Details Get a Quote |
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