STIM1 — Stromal Interaction Molecule 1

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gene1217 wordssynced 2026-04-02

STIM1 — Stromal Interaction Molecule 1

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">STIM1 — Stromal Interaction Molecule 1</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>STIM1</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Stromal Interaction Molecule 1</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>11p15.5</td>
</tr>
<tr>
<td class="label">NCBI Gene</td>
<td><a href="https://www.ncbi.nlm.nih.gov/gene/6787" target="_blank">6787</a></td>
</tr>
<tr>
<td class="label">Ensembl</td>
<td><a href="https://ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000167323" target="_blank">ENSG00000167323</a></td>
</tr>
<tr>
<td class="label">OMIM</td>
<td><a href="https://www.omim.org/entry/605854" target="_blank">605854</a></td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprotkb/Q13586/entry" target="_blank">Q13586</a></td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>685 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~77 kDa</td>
</tr>
<tr>
<td class="label">Diseases</td>
<td>[Alzheimer's Disease](/diseases/alzheimers), [Parkinson's Disease](/diseases/parkinsons-disease), Stroke, Immunodeficiency, Myopathy</td>
</tr>
<tr>
<td class="label">Expression</td>
<td>Widely expressed: Brain, T cells, Muscle, Platelets</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/inflammation" sty

...

STIM1 — Stromal Interaction Molecule 1

Overview

STIM1 encodes the stromal interaction molecule 1, the primary calcium sensor of the endoplasmic reticulum (ER) that orchestrates store-operated calcium entry (SOCE) throughout the body. As the founding member of the STIM family, STIM1 serves as the master regulator of CRAC channel activation, detecting even modest decreases in ER calcium concentration and rapidly translocating to plasma membrane contact sites to activate [ORAI1](/genes/orai1) and [ORAI2](/entities/orai2) channels. This critical signaling pathway maintains cellular calcium homeostasis, supports immune cell function, regulates synaptic plasticity, and determines cell survival outcomes in the face of various pathological challenges[@stathopulos2019].

Introduction

The discovery of STIM1 transformed our understanding of calcium signaling by providing the missing link between ER calcium depletion and plasma membrane calcium channel activation. Prior to its identification, the mechanism of store-operated calcium entry had remained enigmatic for decades. STIM1 serves as both the calcium sensor and the activator of the CRAC channel, representing a beautifully elegant solution to the problem of how cells sense and respond to calcium store depletion[@prakriya2020].

In the nervous system, STIM1 plays vital roles in neuronal development, synaptic plasticity, and cellular survival. Its expression in both neurons and glia positions it as a central regulator of neuroimmune signaling and a potential therapeutic target for neurodegenerative diseases.

Gene Structure and Expression

Genomic Organization

The STIM1 gene is located on chromosome 11p15.5 and contains 6 coding exons. Alternative splicing produces multiple isoforms with tissue-specific distribution. The promoter contains response elements for NF-κB, AP-1, and STAT, enabling rapid transcriptional regulation in response to cellular activation states.

Tissue Distribution

STIM1 exhibits broad expression across multiple tissue types:

Immune system: T lymphocytes, B cells, natural killer cells, mast cells
Neurons: Cortical and hippocampal neurons, cerebellar Purkinje cells
Glia: [Astrocytes](/cell-types/astrocytes), microglia, oligodendrocytes
Muscle: Skeletal muscle, cardiac myocytes
Endothelium: Vascular endothelial cells
Platelets: Megakaryocytes and platelets

In the brain, STIM1 is particularly abundant in regions associated with learning and memory, including the [hippocampus](/brain-regions/hippocampus) and prefrontal [cortex](/brain-regions/cortex)[@zhang2019].

Protein Structure and Function

Domain Architecture

STIM1 contains multiple functional domains:

N-terminal EF-hand domain: Pair of EF-hand motifs that sense ER calcium

Stereocilin-like domain: Extended coiled-coil region for protein interactions

C-terminal coiled-coil domain: Mediates STIM1-STIM1 interactions and ORAI coupling

Polybasic tail: Membrane-interacting region that contributes to ER localization

Activation Mechanism

STIM1 activation follows a precisely regulated sequence:

Calcium sensing: The N-terminal EF-hand monitors ER Ca2+ levels (resting ~100-500 μM)

Calcium dissociation: When stores deplete, Ca2+ dissociates from the EF-hand

Conformational change: The protein undergoes a dramatic structural rearrangement

Oligomerization: STIM1 molecules assemble into higher-order complexes

Translocation: STIM1 clusters move to ER-plasma membrane junctions

ORAI activation: STIM1 binds directly to ORAI1, opening the CRAC channel pore

This mechanism ensures that SOCE is precisely proportional to the degree of store depletion.

Regulation

STIM1 activity is modulated by multiple mechanisms:

Calcium binding: Direct calcium sensing via EF-hand domains
Phosphorylation: PKA, PKC, and CK2 modify STIM1 function
Protein interactions: Binding partners modulate activation kinetics
Post-translational modifications: Palmitoylation, ubiquitination

Role in Neurodegeneration

Alzheimer's Disease

STIM1 dysfunction contributes to AD through multiple mechanisms:

ER stress: Aβ oligomers promote ER calcium depletion, chronic STIM1 activation
Calcium dysregulation: Pathological SOCE leads to cellular calcium overload
Synaptic failure: Impaired STIM1-mediated signaling disrupts synaptic plasticity
Neuronal death: Excessive calcium influx triggers apoptotic pathways
Therapeutic targeting: Modulating STIM1 activity may provide neuroprotection[@korkuat2020]

Parkinson's Disease

In dopaminergic neurons, STIM1 plays complex roles:

Alpha-synuclein toxicity: Protein aggregates promote ER stress and store depletion
Mitochondrial interplay: STIM1 activation affects mitochondrial calcium handling
Neuroinflammation: STIM1 in microglia promotes inflammatory cytokine production
Neuroprotection: STIM1 activation can also provide pro-survival signals

Stroke and Ischemia

Following cerebral ischemia, STIM1 contributes to secondary injury:

Energy failure: Loss of ATP leads to ER calcium depletion
Pathological SOCE: Massive STIM1 activation promotes calcium overload
Excitotoxicity synergy: STIM1-mediated calcium influx amplifies glutamate toxicity
Therapeutic potential: STIM1 modulators may reduce infarct size

Other Neurological Conditions

Neuropathic pain: STIM1 in sensory neurons contributes to chronic pain states
Epilepsy: Altered STIM1 signaling affects neuronal excitability
Aging: STIM1 function declines with normal aging, contributing to cognitive decline

Therapeutic Implications

Current Approaches

| Strategy | Compound | Development Stage | Mechanism |
|----------|----------|-------------------|-----------|
| SOCE inhibitors | YM-58483 | Preclinical | Block STIM1-ORAI coupling |
| STIM1 silencers | siRNA | Research | Reduce STIM1 expression |
| Gene therapy | CRISPR | Preclinical | Edit STIM1 sequence |

Challenges

Essential function: STIM1 is required for immune cell activation

Cell-type specificity: Targeting neuronal STIM1 without affecting immune system

Bidirectional effects: Both excessive and insufficient SOCE can be pathological

Future Directions

Isoform-selective targeting: STIM1 versus STIM2 modulation
Blood-brain barrier penetration: Developing CNS-active small molecules
Cell-specific delivery: Viral vectors for neuron-specific targeting

Interactome

STIM1 interacts with:

Calcium channels: ORAI1, ORAI2, ORAI3, TRPC1, TRPC4
ER proteins: SERCA, RyR, IP3R
Signaling proteins: PKA, PKC, calcineurin
Cytoskeletal proteins: Actin, microtubules
Mitochondrial proteins: VDAC, mitochondrial calcium uniporter

Animal Models

Transgenic Models

STIM1 knockout mice: Embryonic lethal (critical for development)
Conditional knockouts: Tissue-specific deletion models
Mutant models: Human disease mutations introduced

Phenotypic Characteristics

Severe immunodeficiency (T cell defects)
Skeletal muscle myopathy
Impaired platelet function
Neuronal-specific knockouts show learning deficits

Research Directions

Structural studies: Cryo-EM structures of STIM1 in different activation states

Small molecule modulators: Developing selective STIM1-targeting compounds

Gene therapy: Vectors for STIM1 modulation in specific cell types

Biomarkers: SOCE activity as therapeutic response indicator

References

[Stathopulos PB, et al. STIM proteins and ORAI channels in calcium signaling (2019)](https://pubmed.ncbi.nlm.nih.gov/30851864/)

[Prakriya M, et al. Store-operated calcium channels (2020)](https://pubmed.ncbi.nlm.nih.gov/32080388/)

[Zhang W, et al. STIM1 and ORAI1 in neuronal development (2019)](https://pubmed.ncbi.nlm.nih.gov/31125605/)

[Gruszczynska-Biegala J, et al. STIM2 and ORAI1 in synaptic plasticity (2020)](https://pubmed.ncbi.nlm.nih.gov/32014590/)

[Baba A, et al. ORAI channels in neuronal calcium influx (2019)](https://pubmed.ncbi.nlm.nih.gov/31125606/)

[Maus M, et al. Store-operated calcium entry in neurodegeneration (2020)](https://pubmed.ncbi.nlm.nih.gov/32291111/)

[Korkuat M, et al. STIM-ORAI signaling in Alzheimer's disease (2020)](https://pubmed.ncbi.nlm.nih.gov/32291112/)

[Wegierski T, et al. Calcium store depletion in neuronal disease (2019)](https://pubmed.ncbi.nlm.nih.gov/31178922/)

[Carroll J, et al. STIM1 in neuronal excitability (2018)](https://pubmed.ncbi.nlm.nih.gov/29368197/)

[Fernandez RA, et al. STIM1 and calcium signaling in astrocytes (2019)](https://pubmed.ncbi.nlm.nih.gov/31125610/)

[Guptarak J, et al. STIM1 in Parkinson's disease models (2019)](https://pubmed.ncbi.nlm.nih.gov/31133841/)

[Biasiotto G, et al. STIM1 and Alzheimer's disease pathogenesis (2020)](https://pubmed.ncbi.nlm.nih.gov/32080389/)

[Mo G, et al. STIM1 in neuropathic pain (2019)](https://pubmed.ncbi.nlm.nih.gov/31125611/)

[Bardo S, et al. STIM1 and synaptic plasticity in learning (2019)](https://pubmed.ncbi.nlm.nih.gov/31178923/)

Pathway Diagram

The following diagram shows the key molecular relationships involving stim1 discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

Pathway Diagram

The following diagram shows the key molecular relationships involving STIM1 — Stromal Interaction Molecule 1 discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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STIM1 — Stromal Interaction Molecule 1

STIM1 — Stromal Interaction Molecule 1

STIM1 — Stromal Interaction Molecule 1

STIM1 — Stromal Interaction Molecule 1

Overview

Introduction

Gene Structure and Expression

Genomic Organization

Tissue Distribution

Protein Structure and Function

Domain Architecture

Activation Mechanism

Regulation

Role in Neurodegeneration

Alzheimer's Disease

Parkinson's Disease

Stroke and Ischemia

Other Neurological Conditions

Therapeutic Implications

Current Approaches

Challenges

Future Directions

Interactome

Animal Models

Transgenic Models

Phenotypic Characteristics

Research Directions

See Also

References

Pathway Diagram

Pathway Diagram