KCNH3 — Potassium Voltage-Gated Channel Subfamily H Member 3

KCNH3 — Potassium Voltage-Gated Channel Subfamily H Member 3

Introduction

Kcnh3 — Potassium Voltage Gated Channel Subfamily H Member 3 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 | KCNH3 | [@astrocyte]
| Full Name | Potassium Voltage-Gated Channel Subfamily H Member 3 |
| Chromosomal Location | 12q13.13 |
| NCBI Gene ID | 26273 |
| OMIM ID | 604528 |
| Ensembl ID | ENSG00000135502 |
| UniProt ID | Q9UQ98 |
| Associated Diseases | Epilepsy, Intellectual Disability, Alzheimer's Disease, Cognitive Impairment |
</div>

Overview

KCNH3 (also known as ERV1, EEL-1, or Kv12.2) encodes the potassium voltage-gated channel subfamily H member 3, a neuronal voltage-gated potassium channel expressed primarily in the brain. This channel is part of the EAG (ether-à-go-go) family of potassium channels and plays important roles in neuronal excitability, synaptic transmission, and cognitive function.

Function

Channel Properties

KCNH3 is a voltage-gated potassium channel with distinctive properties:

• Slow activation and deactivation kinetics
• Depolarized activation threshold
• Inactivation via N-type mechanism
• Primarily neuronal expression

Brain Distribution

...

KCNH3 — Potassium Voltage-Gated Channel Subfamily H Member 3

Introduction

Kcnh3 — Potassium Voltage Gated Channel Subfamily H Member 3 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 | KCNH3 | [@astrocyte]
| Full Name | Potassium Voltage-Gated Channel Subfamily H Member 3 |
| Chromosomal Location | 12q13.13 |
| NCBI Gene ID | 26273 |
| OMIM ID | 604528 |
| Ensembl ID | ENSG00000135502 |
| UniProt ID | Q9UQ98 |
| Associated Diseases | Epilepsy, Intellectual Disability, Alzheimer's Disease, Cognitive Impairment |
</div>

Overview

KCNH3 (also known as ERV1, EEL-1, or Kv12.2) encodes the potassium voltage-gated channel subfamily H member 3, a neuronal voltage-gated potassium channel expressed primarily in the brain. This channel is part of the EAG (ether-à-go-go) family of potassium channels and plays important roles in neuronal excitability, synaptic transmission, and cognitive function.

Function

Channel Properties

KCNH3 is a voltage-gated potassium channel with distinctive properties:

• Slow activation and deactivation kinetics
• Depolarized activation threshold
• Inactivation via N-type mechanism
• Primarily neuronal expression

Brain Distribution

KCNH3 is expressed in:

• [Hippocampus](/brain-regions/hippocampus) (CA1-CA3 regions)
• Cerebral [cortex](/brain-regions/cortex) (layer 5 pyramidal neurons)
• Basal ganglia
• [Thalamus](/brain-regions/thalamus)
• Cerebellar Purkinje cells

Physiological Roles

| Function | Mechanism |
|----------|-----------|
| Neuronal excitability | Regulates resting membrane potential |
| Synaptic plasticity | Modulates dendritic integration |
| Learning and memory | Hippocampal-dependent processes |
| Motor coordination | Cerebellar Purkinje cell function |

Disease Associations

Epilepsy

• KCNH3 mutations have been linked to epileptic encephalopathy
• Channel dysfunction leads to neuronal hyperexcitability
• Some antiepileptic drugs target related channels

Intellectual Disability

• De novo KCNH3 mutations identified in ID patients
• Cognitive deficits associated with channel dysfunction
• Mouse models show learning impairments

Alzheimer's Disease

• Altered KCNH3 expression in AD brains
• [Amyloid-beta](/proteins/amyloid-beta) affects channel function
• May contribute to network hyperexcitability

Expression Pattern

Developmental Expression

KCNH3 expression increases during development, with:

• Low expression in embryonic brain
• Gradual increase postnatally
• Adult expression highest in hippocampus and cortex

Cell Type Specificity

• Expressed predominantly in excitatory pyramidal [neurons](/entities/neurons)
• Also present in some inhibitory interneurons
• Not detected in glial cells

Therapeutic Targeting

Drug Development

| Strategy | Rationale | Status |
|----------|-----------|--------|
| Channel activators | Enhance function in disease | Preclinical |
| Selective modulators | Avoid off-target effects | Research |
| Gene therapy | Restore function | Experimental |

Key Publications

PMID: 10842010(https://pubmed.ncbi.nlm.nih.gov/10842010/) - Neuronal KCNH3 expression and function (2000)

PMID: 14551213(https://pubmed.ncbi.nlm.nih.gov/14551213/) - KCNH3 mutations and epilepsy (2003)

PMID: 20430974(https://pubmed.ncbi.nlm.nih.gov/20430974/) - HERG/ELK channel modulation in disease (2010)

PMID: 25040671(https://pubmed.ncbi.nlm.nih.gov/25040671/) - KCNH3 in cognitive function (2014)

PMID: 29847962(https://pubmed.ncbi.nlm.nih.gov/29847962/) - Voltage-gated K+ channels in AD (2018)

See Also

• [Potassium Channels](/entities/potassium-channels)
• [Neuronal Excitability](/mechanisms/neuronal-excitability)
• [Epilepsy](/diseases/epilepsy)
• [Intellectual Disability](/diseases/intellectual-disability)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [KCNH2 Gene](/proteins/kcnh2-protein)

External Links

• [NCBI Gene: KCNH3](https://www.ncbi.nlm.nih.gov/gene/26273)
• [UniProt: Q9UQ98](https://www.uniprot.org/uniprot/Q9UQ98)
• [OMIM: 604528](https://www.omim.org/entry/604528)

Background

The study of Kcnh3 — Potassium Voltage Gated Channel Subfamily H Member 3 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.

References

[Unknown, - TGF-beta signaling in neurodegeneration (n.d.)](https://pubmed.ncbi.nlm.nih.gov/27451067/)

[Unknown, - SMAD proteins in neural development (n.d.)](https://pubmed.ncbi.nlm.nih.gov/25009184/)

[Unknown, - Transcriptional regulation in AD (n.d.)](https://pubmed.ncbi.nlm.nih.gov/24668245/)

[Unknown, - Neuroinflammation and TGF-beta (n.d.)](https://pubmed.ncbi.nlm.nih.gov/25997342/)

[Unknown, - Astrocyte function in neurodegeneration (n.d.)](https://pubmed.ncbi.nlm.nih.gov/26245252/)