ITPR1 Gene

ITPR1 - Inositol 1,4,5-Trisphosphate Receptor Type 1

Introduction

Itpr1 Gene 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 infobox-gene"> [@van2007]
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">Inositol 1,4,5-Trisphosphate Receptor Type 1</th></tr>
<tr><td><strong>Gene Symbol</strong></td><td>ITPR1</td></tr>
<tr><td><strong>Full Name</strong></td><td>Inositol 1,4,5-Trisphosphate Receptor Type 1</td></tr>
<tr><td><strong>Chromosomal Location</strong></td><td>3p26.1</td></tr>
<tr><td><strong>NCBI Gene ID</strong></td><td>[3708](https://www.ncbi.nlm.nih.gov/gene/3708)</td></tr>
<tr><td><strong>Ensembl ID</strong></td><td>ENSG00000151952</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[Q14643](https://www.uniprot.org/uniprot/Q14643)</td></tr>
<tr><td><strong>Associated Diseases</strong></td><td>Spinocerebellar Ataxia Type 15, Alzheimer's Disease, Huntington's Disease, SCA29, Autism</td></tr>
</table>
</div>

Overview

...

ITPR1 - Inositol 1,4,5-Trisphosphate Receptor Type 1

Introduction

Itpr1 Gene 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 infobox-gene"> [@van2007]
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">Inositol 1,4,5-Trisphosphate Receptor Type 1</th></tr>
<tr><td><strong>Gene Symbol</strong></td><td>ITPR1</td></tr>
<tr><td><strong>Full Name</strong></td><td>Inositol 1,4,5-Trisphosphate Receptor Type 1</td></tr>
<tr><td><strong>Chromosomal Location</strong></td><td>3p26.1</td></tr>
<tr><td><strong>NCBI Gene ID</strong></td><td>[3708](https://www.ncbi.nlm.nih.gov/gene/3708)</td></tr>
<tr><td><strong>Ensembl ID</strong></td><td>ENSG00000151952</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[Q14643](https://www.uniprot.org/uniprot/Q14643)</td></tr>
<tr><td><strong>Associated Diseases</strong></td><td>Spinocerebellar Ataxia Type 15, Alzheimer's Disease, Huntington's Disease, SCA29, Autism</td></tr>
</table>
</div>

Overview

ITPR1 is a gene that encodes a protein involved in inositol trisphosphate receptor and calcium signaling. This gene is implicated in neurodegenerative diseases and represents a potential therapeutic target.

Overview

ITPR1 encodes the inositol 1,4,5-trisphosphate receptor type 1 (IP3R1), a ligand-gated calcium release channel located on the endoplasmic reticulum (ER) membrane. IP3R1 mediates calcium signaling in response to various stimuli by releasing Ca²⁺ from intracellular stores into the cytoplasm. This receptor is particularly crucial in [neurons](/entities/neurons) where it regulates synaptic plasticity, gene expression, and cellular excitability[@berridge1993]. Mutations in ITPR1 cause spinocerebellar ataxia type 15 (SCA15), making it one of the few genes directly linked to both cerebellar degeneration and neurodegenerative diseases[@van2007].

Gene Structure

• Chromosomal location: 3p26.1
• Genomic size: ~270 kb
• Exons: 58 exons
• Alternative splicing: Multiple splice variants

Protein Structure

IP3R1 Subunit

• Length: ~2,700 amino acids per monomer
• Molecular weight: ~300 kDa per subunit
• Quaternary structure: Tetrameric assembly

Domain Organization

| Domain | Function |
|--------|----------|
| N-terminal (IP3-binding) | Binds IP3, regulatory domains |
| Suppressor domain | Modulates channel activity |
| Linker region | Couples ligand binding to gate |
| Channel domain | Forms Ca²⁺ pore (6 TMs) |
| C-terminal (gate) | Regulatory and tetramerization |

Regulatory Regions

• IP3-binding domain: N-terminal ~600 aa
• Calcium-binding sites: Multiple regulatory sites
• Phosphorylation sites: PKA, CaMKII, PKG

Molecular Function

Calcium Release Mechanism

Activation

Receptor activation generates IP3

IP3 binds to N-terminal domain

Conformational change opens channel

Ca²⁺ flows from ER to cytoplasm

Regulation

• Calcium: Biphasic regulation (activates at low, inhibits at high)
• IP3 concentration: Cooperative activation
• Phosphorylation: Modulates sensitivity
• Protein interactions: Multiple regulatory bindings

Key Interactions

• Ryanodine receptors: Cross-talk with Ca²⁺ release
• Store-operated channels: Capacitative calcium entry
• Mitochondrial calcium: Calcium uptake regulation
• ER chaperones: Quality control

Expression Pattern

Tissue Distribution

• Highest in cerebellum (Purkinje cells)
• Substantial expression in [hippocampus](/brain-regions/hippocampus)
• Present in [cortex](/brain-regions/cortex), basal ganglia

Cellular Localization

• Endoplasmic reticulum membrane
• Postsynaptic densities
• Dendritic shafts and spines

Role in Disease

Spinocerebellar Ataxia Type 15 (SCA15)

• Inheritance: Autosomal dominant
• Mechanism: Heterozygous deletions or missense mutations
• Phenotype: Progressive ataxia, cerebellar atrophy
• Pathology: Purkinje cell degeneration

Alzheimer's Disease

• Calcium dysregulation: Core feature of AD neurons
• IP3R1 alterations: Changed expression and function
• [Aβ](/proteins/amyloid-beta) effects: Impairs IP3-mediated signaling
• Therapeutic target: Restoration of calcium homeostasis

Huntington's Disease

• Transcriptional dysregulation: Altered ITPR1 expression
• Calcium signaling: Mutant [HTT](/proteins/huntingtin) affects IP3R1 function
• Excitotoxicity: Enhanced vulnerability

Autism Spectrum Disorder

• Rare variants: De novo mutations identified
• Synaptic function: Altered calcium signaling

Therapeutic Implications

Drug Development

• IP3R modulators: Channel agonists/antagonists
• Calcium stabilizers: Restore neuronal calcium homeostasis
• Neuroprotective strategies: Target excitotoxicity

Research Applications

• Calcium imaging: IP3R as biomarker
• Gene therapy: Viral vector approaches

Research Directions

Structure-function: High-resolution structures

Therapeutic targeting: Selective modulators

Genetics: Variant pathogenicity

Biomarkers: Calcium signaling dysfunction

Animal models: Knockout and transgenic

Animal Models

• ITPR1 knockout: Cerebellar dysfunction
• Conditional knockouts: Tissue-specific deletion
• Disease models: SCA15 knock-in

See Also

• [IP3R1 Protein](/proteins/itpr1-protein)
• [Calcium Signaling Pathway](/mechanisms/calcium-signaling-dysregulation)
• [Spinocerebellar Ataxia](/diseases/spinocerebellar-ataxia)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Huntington's Disease](/diseases/huntington-disease)
• [Cerebellum](/brain-regions/cerebellum)
• [Purkinje Cells](/cell-types/purkinje-cells)
• [ER Stress Pathway](/mechanisms/er-stress-pathway)

External Links

• [NCBI Gene: ITPR1](https://www.ncbi.nlm.nih.gov/gene/3708)
• [UniProt: Q14643](https://www.uniprot.org/uniprot/Q14643)
• [Ensembl: ENSG00000151952](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000151952)
• [Allen Brain Atlas: ITPR1](https://human.brain-map.org/microarray/search/show?search_term=ITPR1)

Background

The study of Itpr1 Gene 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.

External Links

• [NCBI Gene - ITPR1](https://www.ncbi.nlm.nih.gov/gene/)
• [UniProt - ITPR1](https://www.uniprot.org/uniprot/)
• [GeneCards - ITPR1](https://www.genecards.org/cgi-bin/carddisp.pl?gene=)

References

Berridge MJ, Inositol trisphosphate and calcium signalling (1993)

van de Leemput J, et al, Deletion at ITPR1 underlies ataxia in mice and humans (2007)

Pathway Diagram

The following diagram shows the key molecular relationships involving ITPR1 Gene discovered through SciDEX knowledge graph analysis: