KCNH2 — Potassium Voltage-Gated Channel Subfamily H Member 2

KCNH2 — Potassium Voltage-Gated Channel Subfamily H Member 2

Introduction

Kcnh2 — Potassium Voltage Gated Channel Subfamily H Member 2 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<div class="infobox infobogene"> [@smad]
| Field | Value | [@transcriptional]
|-------|-------| [@neuroinflammation]
| Gene Symbol | KCNH2 | [@astrocyte]
| Full Name | Potassium Voltage-Gated Channel Subfamily H Member 2 |
| Chromosomal Location | 7q36.1 |
| NCBI Gene ID | 3759 |
| OMIM ID | 607446 |
| Ensembl ID | ENSG00000196878 |
| UniProt ID | Q14721 |
| Associated Diseases | Long QT Syndrome, Short QT Syndrome, Torsades de Pointes, Sudden Cardiac Death, Alzheimer's Disease, Parkinson's Disease |
</div>

Overview

KCNH2 — Potassium Voltage-Gated Channel Subfamily H Member 2

Introduction

Kcnh2 — Potassium Voltage Gated Channel Subfamily H Member 2 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<div class="infobox infobogene"> [@smad]
| Field | Value | [@transcriptional]
|-------|-------| [@neuroinflammation]
| Gene Symbol | KCNH2 | [@astrocyte]
| Full Name | Potassium Voltage-Gated Channel Subfamily H Member 2 |
| Chromosomal Location | 7q36.1 |
| NCBI Gene ID | 3759 |
| OMIM ID | 607446 |
| Ensembl ID | ENSG00000196878 |
| UniProt ID | Q14721 |
| Associated Diseases | Long QT Syndrome, Short QT Syndrome, Torsades de Pointes, Sudden Cardiac Death, Alzheimer's Disease, Parkinson's Disease |
</div>

Overview

KCNH2 (also known as HERG1, Kv11.1, or LQT2) encodes the potassium voltage-gated channel subfamily H member 2, a crucial ion channel protein that forms the rapid component of the delayed rectifier potassium current (I_Kr) in cardiac myocytes and [neurons](/entities/neurons). This channel is essential for cardiac repolarization and neuronal excitability, with growing evidence linking dysfunction to neurodegenerative diseases.

Function

Ion Channel Structure and Mechanism

The KCNH2 channel is a voltage-gated potassium channel composed of four α-subunits, each containing six transmembrane segments (S1-S6). The S4 segment serves as the voltage sensor, while the S5-S6 pore region forms the ion conduction pathway. The channel undergoes characteristic voltage-dependent activation and inactivation, with slow deactivation kinetics that are critical for its physiological function.

In the heart, KCNH2 conducts the I_Kr current, which is essential for phase 3 repolarization of the cardiac action potential. Loss-of-function mutations cause Long QT Syndrome type 2 (LQT2), while gain-of-function mutations cause Short QT Syndrome.

Neuronal Expression and Function

In the brain, KCNH2 is expressed in various regions including the hippocampus, cortex, thalamus, and basal ganglia. Neuronal KCNH2 channels contribute to:

• Action potential repolarization
• Spike frequency adaptation
• Dendritic integration
• Regulation of neuronal excitability

Disease Associations

Cardiovascular Disorders

| Condition | Mutation Type | Mechanism |
|-----------|--------------|-----------|
| Long QT Syndrome Type 2 | Loss-of-function | Reduced I_Kr current prolongs QT interval |
| Short QT Syndrome Type 1 | Gain-of-function | Increased I_Kr current shortens QT interval |
| Torsades de Pointes | Dysfunction | Triggered by prolonged QT |
| Sudden Cardiac Death | Loss-of-function | Fatal cardiac arrhythmias |

Neurodegenerative Diseases

Alzheimer's Disease

• KCNH2 expression is altered in AD brains, particularly in the hippocampus and cortex
• [Amyloid-beta](/proteins/amyloid-beta) (Aβ) peptides directly interact with KCNH2 channels, disrupting their function
• Channel dysfunction may contribute to neuronal hyperexcitability observed in AD
• HERG channel modulators are being explored as potential therapeutic agents
• Studies show reduced KCNH2 current density in AD animal models

Parkinson's Disease

• KCNH2 is expressed in dopaminergic neurons of the substantia nigra
• Channel dysfunction may affect neuronal survival
• Some PD-associated genes (LRRK2) may interact with KCNH2 signaling pathways

Expression Pattern

Brain Regional Distribution

| Region | Expression Level | Functional Significance |
|--------|----------------|----------------------|
| [Hippocampus](/brain-regions/hippocampus) | High | Synaptic plasticity, learning |
| Cerebral [Cortex](/brain-regions/cortex) | High | Cortical processing |
| Basal Ganglia | Moderate | Motor control |
| Thalamus | Moderate | Sensory integration |
| Cerebellum | Moderate | Motor coordination |

Cell Type Specificity

KCNH2 is expressed in both excitatory pyramidal neurons and inhibitory interneurons, with particularly high expression in GABAergic neurons where it contributes to inhibitory signaling.

Therapeutic Targeting

Drug Development

| Compound | Mechanism | Development Status | Indication |
|----------|-----------|-------------------|------------|
| E-4031 | HERG blocker | Research | Antiarrhythmic |
| Dofetilide | HERG blocker | FDA approved | Atrial fibrillation |
| Dronedarone | HERG blocker | FDA approved | Arrhythmia |
| Almokalant | HERG blocker | Research | Antiarrhythmic |

Considerations for Neurodegeneration

• [Blood-brain barrier](/entities/blood-brain-barrier) penetration is critical for CNS applications
• Selective modulators needed to avoid cardiac toxicity
• Channel activators may benefit neuronal function
• Gene therapy approaches are being explored

Key Publications

See Also

• [Potassium Channels](/entities/potassium-channels)
• [Ion Channelopathies](/mechanisms/ion-channelopathies)
• [Long QT Syndrome](/diseases/long-qt-syndrome)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Neuronal Excitability](/mechanisms/neuronal-excitability)
• [HERG Channel](/entities/hERG-channel)

External Links

• [NCBI Gene: KCNH2](https://www.ncbi.nlm.nih.gov/gene/3759)
• [UniProt: Q14721](https://www.uniprot.org/uniprot/Q14721)
• [OMIM: 607446](https://www.omim.org/entry/607446)
• [KEGG Pathway: Cardiac muscle contraction](https://www.kegg.jp/kegg-bin/show_pathway?map=hsa04260)

Background

The study of Kcnh2 — Potassium Voltage Gated Channel Subfamily H Member 2 has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

Brain Atlas Resources

• [Allen Brain Atlas](https://brain-map.org/) - Brain gene expression data
• [Allen Human Brain Atlas - KCNH2 Expression](https://human.brain-map.org/microarray/search/show?search_term=KCNH2): Gene expression data

References

Pathway Diagram

The following diagram shows the key molecular relationships involving KCNH2 — Potassium Voltage-Gated Channel Subfamily H Member 2 discovered through SciDEX knowledge graph analysis: