KCNJ18
Potassium Inwardly Rectifying Channel Subfamily J Member 18
Gene Information Card
| Symbol | KCNJ18 |
|---|---|
| Full Name | Potassium Inwardly Rectifying Channel Subfamily J Member 18 |
| Gene Type | protein-coding |
| Chromosomal Location | 17p11.2 |
| NCBI Gene ID | 100134444 ncbi.nlm.nih.gov/gene/100134444 |
| Ensembl ID | ENSG00000205683 |
| UniProt ID | Q96L42 |
| OMIM ID | 613274 |
| HGNC ID | 37263 |
| Aliases | Kir2.6, KCNJ17, MGC138499 |
Description
KCNJ18 encodes Kir2.6, an inwardly rectifying potassium channel primarily expressed in skeletal muscle. This channel helps maintain resting membrane potential and regulates muscle excitability. Mutations in KCNJ18 are associated with thyrotoxic periodic paralysis (TPP), a condition characterized by episodic muscle weakness and hypokalemia triggered by hyperthyroidism.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Thyrotoxic Periodic Paralysis (TPP) | Loss-of-function mutations in Kir2.6 reduce potassium inward rectification, leading to membrane depolarization and muscle inexcitability during thyrotoxic states. | ClinVar, OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skeletal Muscle | 12.5 | Medium |
| Heart | 1.2 | Low |
| Brain | 0.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Skeletal muscle myotubes | 15.0 | High expression in differentiated myotubes |
| HEK293 | 0.1 | Negligible endogenous expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| p.Arg43His | Missense | Rare | Loss of function; associated with TPP |
| p.Arg205His | Missense | Rare | Loss of function; associated with TPP |
| p.Thr354Met | Missense | Rare | Loss of function; associated with TPP |
Mutation functional classification
Loss of Function (LOF)
Most TPP-associated mutations reduce channel activity or surface expression, impairing potassium influx.
Gain of Function (GOF)
Not reported for KCNJ18.
Dominant Negative (DN)
Some mutations may exert dominant-negative effects on wild-type Kir2.6 or other Kir2 channels.
View complete mutation data：
Gene Ontology (GO)
| • Inward rectifier potassium channel activity | • Voltage-gated ion channel activity |
| • Potassium ion transmembrane transport | • Plasma membrane |
Pathways
• Potassium channels
• Ion transport by P-type ATPases
• Cardiac conduction
Protein Summary
Kir2.6 is a 446-amino acid protein with two transmembrane domains and a pore loop, forming a homotetrameric channel that conducts inward rectifier potassium currents. It is regulated by phosphatidylinositol 4,5-bisphosphate (PIP2) and ATP, and its expression is thyroid hormone-responsive.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| KCNJ18 Knockout HEK293 Cell Line | EDJ-KQ13893 | Human | 100134444 | Details Get a Quote |
| KCNJ18 Knockout HeLa Cell Line | EDJ-KQ43754 | Human | 100134444 | Details Get a Quote |
| KCNJ18 Knockout A-549 Cell Line | EDJ-KQ69314 | Human | 100134444 | Details Get a Quote |
| KCNJ18 Knockout HCT 116 Cell Line | EDJ-KQ77669 | Human | 100134444 | Details Get a Quote |
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