Component
STIM1
The ER calcium sensor that oligomerizes after store depletion.
4 recorded relationships. Experimental role, claim status and evidence remain attached to each record.
How nutrients influence it
Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.
Other things that act on it
Enzymes, hormones, genes, and other components with a recorded effect. These are not nutrients, so they do not count toward the arrows above. Each finding names the chapter that recorded it.
How nutrients reach it in more than one step
Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.
Tracing routes…
What it does
Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.
What it acts on
The cytosolic CRAC-activation domain of STIM1 binds ORAI1 directly and activates its calcium current.
Experimental context and source evidence
- compartment_description
- ER-plasma-membrane junctions
- experimental_model
- Human HEK293/HEK293T expression, electrophysiology and purified protein-binding assays
- limitations
- Domain-expression experiments isolate coupling; physiological amplitude depends on cellular context.
- nutrient_topic
- Calcium research collection; topical membership is not evidence of a direct dietary effect. · Calcium
- organism
- Homo sapiens
- plain_language
- STIM1 directly opens the ORAI1 calcium-entry pathway.
- primary_references
- [ca-park2009] STIM1 clusters and activates CRAC channels via direct binding of a cytosolic domain to Orai1 (2009). https://pubmed.ncbi.nlm.nih.gov/19249086/ DOI: 10.1016/j.cell.2009.02.014
- research_relationship_category
- regulation
- tissue_or_cell_type
- HEK293 expression system and purified proteins
Calcium: mechanism-first literature curation (2026-09-17) · lines 531–542
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human HEK293/HEK293T expression, electrophysiology and purified protein-binding assays · source_derived_draft · unverified_draft
### ca-stim1-direct-orai1-gating The cytosolic CRAC-activation domain of STIM1 binds ORAI1 directly and activates its calcium current. Condition category: normal nutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect. plain_language: STIM1 directly opens the ORAI1 calcium-entry pathway. organism: Homo sapiens tissue_or_cell_type: HEK293 expression system and purified proteins experimental_model: Human HEK293/HEK293T expression, electrophysiology and purified protein-binding assays limitations: Domain-expression experiments isolate coupling; physiological amplitude depends on cellular context. research_relationship_category: regulation compartment_description: ER-plasma-membrane junctions [ca-park2009] STIM1 clusters and activates CRAC channels via direct binding of a cytosolic domain to Orai1 (2009). https://pubmed.ncbi.nlm.nih.gov/19249086/ DOI: 10.1016/j.cell.2009.02.014
Complete structured claim and evidenceSTIM1 knockdown suppresses store-depletion-triggered calcium influx in HeLa cells.
Experimental context and source evidence
- availability_state
- machinery_impairment Imported condition classification; unverified.
- compartment_description
- ER-plasma-membrane signaling junction
- experimental_model
- Human HeLa cells; RNA interference screen, calcium imaging and STIM1 EF-hand mutagenesis
- limitations
- RNA interference perturbs signaling machinery; it does not model low calcium intake.
- nutrient_topic
- Calcium research collection; topical membership is not evidence of a direct dietary effect. · Calcium
- organism
- Homo sapiens
- plain_language
- Reducing STIM1 weakens calcium entry after stores empty.
- primary_references
- [ca-liou2005] STIM is a Ca2+ sensor essential for Ca2+-store-depletion-triggered Ca2+ influx (2005). https://pubmed.ncbi.nlm.nih.gov/16005298/ DOI: 10.1016/j.cub.2005.05.055
- research_relationship_category
- loss_of_function
- tissue_or_cell_type
- HeLa cells
- trigger_kind
- machinery_impairment Imported condition classification; unverified.
Calcium: mechanism-first literature curation (2026-09-17) · lines 518–529
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human HeLa cells; RNA interference screen, calcium imaging and STIM1 EF-hand mutagenesis · source_derived_draft · unverified_draft
### ca-stim1-knockdown-influx STIM1 knockdown suppresses store-depletion-triggered calcium influx in HeLa cells. Condition category: machinery_impairment nutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Reducing STIM1 weakens calcium entry after stores empty. organism: Homo sapiens tissue_or_cell_type: HeLa cells experimental_model: Human HeLa cells; RNA interference screen, calcium imaging and STIM1 EF-hand mutagenesis limitations: RNA interference perturbs signaling machinery; it does not model low calcium intake. research_relationship_category: loss_of_function compartment_description: ER-plasma-membrane signaling junction [ca-liou2005] STIM is a Ca2+ sensor essential for Ca2+-store-depletion-triggered Ca2+ influx (2005). https://pubmed.ncbi.nlm.nih.gov/16005298/ DOI: 10.1016/j.cub.2005.05.055
Complete structured claim and evidenceER-store depletion causes STIM1 to redistribute into peripheral puncta through a mechanism requiring its luminal calcium-sensing region.
Experimental context and source evidence
- compartment_description
- ER lumen and ER-plasma-membrane junctions
- experimental_model
- Human HeLa cells; RNA interference screen, calcium imaging and STIM1 EF-hand mutagenesis
- limitations
- Local store depletion is a cellular signal, not evidence of dietary calcium deficiency.
- nutrient_topic
- Calcium research collection; topical membership is not evidence of a direct dietary effect. · Calcium
- organism
- Homo sapiens
- plain_language
- STIM1 detects falling calcium inside the ER.
- primary_references
- [ca-liou2005] STIM is a Ca2+ sensor essential for Ca2+-store-depletion-triggered Ca2+ influx (2005). https://pubmed.ncbi.nlm.nih.gov/16005298/ DOI: 10.1016/j.cub.2005.05.055
- research_relationship_category
- regulation
- tissue_or_cell_type
- HeLa cells
Calcium: mechanism-first literature curation (2026-09-17) · lines 505–516
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human HeLa cells; RNA interference screen, calcium imaging and STIM1 EF-hand mutagenesis · source_derived_draft · unverified_draft
### ca-stim1-store-sensing ER-store depletion causes STIM1 to redistribute into peripheral puncta through a mechanism requiring its luminal calcium-sensing region. Condition category: normal nutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect. plain_language: STIM1 detects falling calcium inside the ER. organism: Homo sapiens tissue_or_cell_type: HeLa cells experimental_model: Human HeLa cells; RNA interference screen, calcium imaging and STIM1 EF-hand mutagenesis limitations: Local store depletion is a cellular signal, not evidence of dietary calcium deficiency. research_relationship_category: regulation compartment_description: ER lumen and ER-plasma-membrane junctions [ca-liou2005] STIM is a Ca2+ sensor essential for Ca2+-store-depletion-triggered Ca2+ influx (2005). https://pubmed.ncbi.nlm.nih.gov/16005298/ DOI: 10.1016/j.cub.2005.05.055
Complete structured claim and evidence
Where it participates (unsigned role)
ER store depletion activates STIM1 oligomerization.
Experimental context and source evidence
- cell_type
- · T cell
- evidence_scope
- Source-derived draft; primary-source verification required
- organism
- · Human
Selenium in immune cells · lines 30–38
Selenium immune-cell mechanism draft · supports · Source draft; model details require primary-source verification · source_derived_draft · unverified_draft
5. TCR → LCK → ZAP70 → LAT → PLCγ1 → PIP₂ → IP₃ + DAG 6. IP₃ → IP3R → ER Ca²⁺ release → store depletion 7. STIM1 oligomerizes → ORAI1 → CRAC channel → sustained Ca²⁺ entry 8. Ca²⁺/calmodulin → CALCINEURIN (PP2B) → dephosphorylates NFAT 9. NFAT → nucleus → partners with AP-1 → IL2, IFNG, CD25 transcription
Complete structured claim and evidence
The events it takes part in
A mechanism often involves more than two components. These are the full events, with every participant and its role.
Situations it appears in
Low-supply and faulty-machinery situations recorded in the chapters where this component plays a part.
In the sources
Preserved passages that mention this component, quoted exactly. Open one to read it in context.
Open hypotheses
Proposed ideas that involve this component. They are labeled as hypotheses and do not change any recorded statement.
This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.