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STIM2 / Stromal interaction molecule 2 · IHC design guide
Design Immunohistochemistry for STIM2
Plan chromogenic STIM2 IHC-P with the catalog antibody starting at 2.5 μg/mL (datasheet: A02345-2). Use marrow hematopoietic cells as a positive reference (HPA tissue IHC), and interpret general cytoplasmic staining (HPA tissue IHC) alongside annotated ER membrane localisation (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
STIM2 Immunohistochemistry Experimental Design Guide
Expected localisation, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before staining
| Expected localisation | General cytoplasmic tissue staining (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic staining in adipocytes and marrow cells (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Adipose tissue+4 more · see all | |
| Negative control | None in HPA (detected in all 45 tissues); use no-primary + isotype controls |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A02345-2) | |
| Caveat | ER Ca²⁺ depletion can redistribute STIM2 to ER–PM junctions (UniProt) | |
| Regulation | No expression regulator specified (UniProt) | |
| Isoform / epitope | 3 isoforms; epitope side matters, isoform coverage unknown (UniProt) |
Section 1
Recommended STIM2 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is paired with a published STIM2 method for rat and mouse mandible sections (PMC4626795).
| Sample | Tissue sections; selected-image fixative not specified (standard IHC workflow) |
| Fixation | Image fixative and duration unreported (datasheet A02345-2); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat-induced epitope retrieval in citrate buffer, pH 6.0, 20 min at 95–98 °C (standard rule: cytoplasmic / membrane antigen) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% normal serum of the secondary host, 30 min, room temperature (standard) |
| Primary antibody | Rabbit anti-STIM2, 2.5 μg/mL (datasheet A02345-2) |
| Primary incubation | Overnight at 4 °C (standard) |
| Detection | HRP-polymer secondary, DAB chromogen 5–10 min (standard) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | STIM2-positive staining in adipocytes of adipose tissue (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic expression. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 HIER at 95–98 °C for 20 min (page retrieval rule); the published mandible method also used citrate pH 6.0 for 20 min (PMC4626795).
Section 2
What Is the Expected STIM2 Staining Pattern?
STIM2 is an endoplasmic reticulum membrane protein with one transmembrane segment at residues 219–235 (UniProt Q9P246 topology). In paraffin sections, expect a cytoplasmic IHC pattern, including in adipocytes, bone marrow hematopoietic cells, and cervical glandular cells reported as High (HPA tissue IHC). HPA rates the tissue profile Supported, with medium consistency between antibody staining and RNA expression (HPA tissue IHC).
| Cytoplasmic staining in adipocytes, bone marrow hematopoietic cells, or cervical glandular cells (HPA: High). | This fits the reported tissue pattern and ER membrane location (HPA tissue IHC; UniProt Q9P246 subcellular location). Compare cells within the same section; HPA's High category does not prescribe an absolute chromogen intensity (HPA tissue IHC). |
| Predominantly nuclear staining, with little convincing cytoplasmic signal (HPA: general cytoplasmic expression). | A nuclear dominant pattern conflicts with the reported IHC profile and ER membrane location (HPA tissue IHC; UniProt Q9P246 subcellular location). Check counterstain, morphology, and staining controls before interpreting it as STIM2 (standard IHC practice). |
| Strong staining in an unexpected cell population, especially where the expected cells are unstained (HPA tissue IHC). | Consider cross-reactivity or endogenous detection activity (standard IHC practice). STIM2 is broadly expressed (UniProt Q9P246 tissue specificity), and HPA supplies no negative tissue here; an unexpected cell alone does not prove nonspecificity (HPA tissue IHC). |
| Diffuse chromogen over tissue and cell-free areas, obscuring cell boundaries (standard IHC practice). | Background can arise from detection chemistry, inadequate blocking, or washing (standard IHC practice). Such staining cannot establish the cytoplasmic cell pattern reported by HPA (HPA tissue IHC). |
| No convincing signal in adipocytes or bone marrow hematopoietic cells reported as High (HPA tissue IHC). | Review section quality, primary antibody, detection reagents, and the complete IHC workflow (standard IHC practice). A negative slide does not by itself overturn a Supported profile whose antibody and RNA data show medium consistency (HPA tissue IHC). |
💡Expected STIM2 appearanceCall a positive result when identifiable HPA High cell populations show predominantly cytoplasmic chromogen compatible with ER membrane STIM2; diffuse background or nuclear dominant staining is suspect, and High does not specify a fixed intensity threshold (HPA tissue IHC; UniProt Q9P246 subcellular location; standard IHC practice).
| Tissue and cell selection (HPA tissue IHC). | Adipocytes, bone marrow hematopoietic cells, and cervical glandular cells are reported High; parathyroid glandular cells and type I alveolar cells are Low (HPA tissue IHC). Low is a comparison category, not a validated negative control (HPA tissue IHC). |
| Epitope position and topology (UniProt Q9P246 topology). | The single membrane segment spans residues 219–235, separating residues 15–218 from the cytoplasmic region at 236–746 (UniProt Q9P246 topology). Without the antibody epitope, these boundaries cannot predict its staining performance (UniProt Q9P246 topology). |
| Antibody evidence (HPA antibody validation). | HPA lists IHC as Supported for HPA036933, HPA057511, and CAB037196 (HPA antibody validation). That status supports use of the reported IHC pattern but does not make every staining pattern from another antibody target-specific (HPA antibody validation; standard IHC practice). |
| ER redistribution (UniProt Q9P246 subcellular location). | STIM2 can move from a uniform ER distribution to punctate ER–plasma membrane junctions as ER calcium falls (UniProt Q9P246 subcellular location). A punctate appearance in a paraffin section alone cannot establish the calcium state (standard IHC interpretation). |
| IF/ICC: what pattern can be expected? (UniProt Q9P246; HPA subcellular). | ER-associated signal is biologically plausible (UniProt Q9P246 subcellular location). HPA summarizes the subcellular result as Membrane but provides no main location or ICC-IF image cell lines; it cannot establish a specific IF appearance here (HPA subcellular). |
| Situation | Likely cause | Next action |
|---|---|---|
| Known HPA High cells show no chromogen (HPA tissue IHC). | The section, primary antibody, or detection chain may have failed (standard IHC practice). | Run a reported High tissue alongside controls and verify each staining step (HPA tissue IHC; standard IHC practice). |
| Signal is predominantly nuclear (HPA: general cytoplasmic expression). | The compartment disagrees with the HPA IHC profile and ER location (HPA tissue IHC; UniProt Q9P246 subcellular location). | Inspect morphology and counterstain, then compare with primary omitted and positive controls (standard IHC practice). |
| Unexpected cells stain strongly while expected cells do not (HPA tissue IHC). | Cross-reactivity or endogenous detection activity is possible (standard IHC practice); broad STIM2 expression limits cell-type exclusion (UniProt Q9P246 tissue specificity). | Check a primary omitted control and the reported cell distribution before assigning specificity (HPA tissue IHC; standard IHC practice). |
| Diffuse background obscures cytoplasmic detail (standard IHC practice). | Blocking, washing, or detection reagents may contribute background (standard IHC practice). | Review blocking and washes; compare with a primary omitted control (standard IHC practice). |
| A Low HPA cell population is treated as a negative control (HPA tissue IHC). | Low records some staining and is not equivalent to absent expression (HPA tissue IHC). | Interpret it comparatively against reported High cells; do not require a blank result (HPA tissue IHC). |
| Puncta are read as proof of calcium depletion (UniProt Q9P246 subcellular location). | UniProt describes dynamic redistribution, but a static IHC section does not document the calcium state (UniProt Q9P246 subcellular location; standard IHC interpretation). | Report the observed distribution without assigning a stimulus or calcium state from morphology alone (standard IHC interpretation). |
Experiment evidence
IHC & IF images showing STIM2 staining
A02345-2 · IHCImmunohistochemistry of STIM2 in human spleen tissue with STIM2 antibody at 2.5 μg/mL.
A02345-2 · IFImmunofluorescence of STIM2 in Human Spleen cells with STIM2 antibody at 20 μg/mL.
A02345-4 · IFIF analysis of STIM2 using anti-STIM2 antibody (A02345-4). STIM2 was detected in an immunocytochemical section of HELA cells. Enzyme antigen
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000109689-STIM2/tissue/cerebral+cortex#imid_8991650
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000109689-STIM2/tissue/colon#imid_8991576
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000109689-STIM2/tissue/liver#imid_8991577
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000109689-STIM2/tissue/kidney#imid_8991578
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for STIM2 IHC & IF
🧪Run bone marrow first and score hematopoietic cells, which HPA rates High for STIM2 (HPA: bone marrow, hematopoietic cells, High). HPA detects STIM2 in all 45 scored tissues, so use no-primary and isotype controls instead of a negative tissue; mature erythrocytes on the positive slide should lack the expected endoplasmic reticulum staining and can provide an internal background reference (HPA: no negative tissues; UniProt Q9P246: endoplasmic reticulum membrane; standard cell biology).
Positive control tissue: Adipose tissue (Adipocytes, HPA High)
Negative control tissue: None in HPA: STIM2 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for STIM2; derive a cell-line control from the positive tissue's cell type (Adipocytes) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only slide and an irrelevant isotype control matched to the primary antibody’s host species and immunoglobulin class; use STIM2 knockout material or a validated peptide block as a biological specificity control (standard IHC practice). Quench endogenous peroxidase in bone marrow before chromogenic detection, particularly around blood cells (standard IHC practice).
⚠️Feasibility: A target-specific fixation window and the effect of fixation on STIM2 staining are unreported in the supplied evidence; the selected A02345-2 spleen IHC caption gives 2.5 μg/mL but does not report a fixative (selected-SKU tissue-IHC caption). Retrieval dependency is also unreported, so optimize antigen retrieval for paraffin sections; the supplied evidence does not establish that frozen sections or IF/ICC are easier (application evidence: IHC-P protocol only; HPA: no ICC-IF cell-line images). Bone marrow blood cells can produce endogenous peroxidase background that complicates chromogenic scoring (standard IHC practice).
HPA tissue IHC evidence for STIM2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — Medium consistency between antibody staining and RNA expression data.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | High | Protein (IHC) | HPA → |
| Appendix | Enterocytes - Microvilli | High | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Caudate | Glial cells | High | Protein (IHC) | HPA → |
| Cerebral cortex | Endothelial cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: STIM2 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced STIM2 IHC Tips
Troubleshoot STIM2 staining in paraffin sections by checking retrieval, cellular distribution, background and scoring against the stated evidence.
Which retrieval conditions should I try first for weak STIM2 staining?
Start with citrate buffer at pH 6.0 for heat induced retrieval at 95–98 °C for 20 min (page retrieval rule: cytoplasmic/membrane antigen). Let sections cool in buffer before washing, and compare staining with a section processed without retrieval to assess its contribution (general IHC practice). Keep antibody concentration, detection chemistry and exposure to chromogen constant while changing retrieval, so any improvement is interpretable (general IHC practice). If staining remains weak, test a different retrieval buffer on adjacent sections as a fallback and judge the result by specific cellular staining and preserved morphology (general IHC practice).
How should I troubleshoot fixation-related variation in STIM2 IHC?
Target-specific sensitivity of STIM2 staining to fixation is unknown from the supplied evidence; the selected spleen IHC caption does not state a fixative (selected A02345-2 caption). Record fixation duration and processing conditions for each specimen, then compare sections with similar handling before changing antibody or retrieval settings (general IHC practice). If staining varies across a batch, examine tissue preservation and staining near section edges, and run a consistently processed reference section alongside the samples (general IHC practice). Do not assign that variation to a particular STIM2 domain or modification without an experiment that isolates fixation as the variable (UniProt Q9P246 features; general IHC practice).
What staining pattern fits STIM2 biology in paraffin sections?
Expect predominantly cytoplasmic staining by tissue IHC, consistent with the reported general profile, while remembering that STIM2 resides in the endoplasmic reticulum membrane (HPA: general cytoplasmic expression; UniProt Q9P246 subcellular location). Its distribution can shift toward puncta at endoplasmic reticulum–plasma membrane junctions when endoplasmic reticulum calcium falls, but routine chromogenic sections cannot by themselves establish that dynamic event (UniProt Q9P246 subcellular location; general IHC interpretation). Assess staining within intact cell boundaries and compare neighboring cells under the same processing conditions (general IHC practice). Treat isolated nuclear staining as a reason to review specificity and counterstain, since the supplied location evidence does not place STIM2 in the nucleus (UniProt Q9P246 subcellular location).
Could epitope position or isoforms explain inconsistent STIM2 staining?
STIM2 has 3 reported isoforms, but the supplied evidence does not identify which isoforms the catalog antibody recognizes (UniProt Q9P246 isoforms; supplied antibody evidence). Check the antibody epitope specification before interpreting absent staining as absent protein, and compare results only after confirming that sections received the same retrieval and detection conditions (general IHC practice). The 219–235 transmembrane segment separates residues 15–218 from the cytoplasmic 236–746 region, so epitope position affects which domain an antibody can assess (UniProt Q9P246 topology). Glycosylation at residue 135 and reported phosphoserines are recorded features, not demonstrated causes of IHC variation here (UniProt Q9P246 features).
How can I check STIM2 localisation with complementary IF?
On the separate IF/ICC guide workflow, pair STIM2 with an endothelial marker such as CD31 when examining cerebral cortex endothelial cells, a cell population reported to stain strongly by tissue IHC (HPA: High in cerebral cortex endothelial cells; standard IF marker practice). Choose a far red fluorophore for a tissue with strong short wavelength autofluorescence, and include single stain controls to assess spectral bleed through (general IF practice). Match permeabilisation to the antibody epitope: residues 236–746 face the cytoplasm, whereas residues 15–218 lie across the endoplasmic reticulum membrane (UniProt Q9P246 topology). Confirm the epitope and IF suitability before using IF puncta to interpret chromogenic IHC patterns (general IF practice).
How do I distinguish diffuse STIM2 signal from IHC background?
First compare the stained section with a no primary control and inspect whether color follows intact cells or spreads across extracellular material and damaged areas (general IHC practice). General cytoplasmic expression makes some widespread cellular staining plausible, but it does not explain uniform color over empty spaces (HPA: general cytoplasmic expression; general IHC interpretation). Check endogenous peroxidase blocking and shorten chromogen development if the control also develops color; these are general chromogenic workflow adjustments (general IHC practice). If background persists only with primary antibody, titrate that antibody and reassess blocking and washes while retaining the same reference section for comparison (general IHC practice).
How should I score STIM2 staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and tissue area before scoring, because reported STIM2 staining varies by cell type within tissues (HPA: tissue IHC profile; general IHC practice). For cell based comparisons, record the percentage of positive cells and staining intensity, then calculate an H-score using the same thresholds for every section (general IHC practice). Where spatial distribution matters, report positive cell density per mm² of viable tissue and exclude folds, necrosis and blank space by prespecified rules (general IHC practice). Normalize comparisons to the same eligible cell population or viable tissue area, and process a reference section with each staining run (general IHC practice).
What would make a positive STIM2 IHC result convincing?
A convincing result places signal within intact cells, broadly compatible with cytoplasmic endoplasmic reticulum staining, and reproduces the pattern in a similarly processed section (HPA: general cytoplasmic expression; UniProt Q9P246 subcellular location; general IHC practice). Compare cell identity with the reported profile: adipocytes and bone marrow hematopoietic cells show high staining, whereas lung alveolar type I cells are listed as low (HPA: tissue IHC profile). Review isolated nuclear color, strong section edge staining and staining confined to necrosis as possible artefacts (UniProt Q9P246 subcellular location; general IHC practice). A no primary control helps reveal endogenous enzyme or detection background, and agreement with reported cell patterns supports interpretation without proving antibody specificity (general IHC practice; HPA: reliability Supported).
Boster reagents
Best STIM2 / Stromal interaction molecule 2 IHC Antibodies
STIM2 antibodies have IHC data from human spleen tissue and IF data from human spleen cells and HELA cells (catalog image captions).
Real IHC data
Anti-Stromal interaction molecule 2 STIM2 Antibody
Cat # A02345-2
Real IF data
Anti-STIM2 Antibody ®
Cat # A02345-4
A02345-2 has IHC-P data from human spleen tissue at 2.5 μg/mL and IF data from human spleen cells at 20 μg/mL (A02345-2 image captions). A02345-4 has IF/ICC data from HELA cells at 5 μg/mL (A02345-4 image caption).
Which to pick: Choose A02345-2 for paraffin-section IHC: IHC-P is listed, and its own image shows human spleen tissue stained at 2.5 μg/mL; the fixative is unreported (A02345-2 applications and IHC image caption). For IF/ICC, A02345-4 has a HELA-cell IF example and is listed for both IF and ICC; its datasheet describes it as polyclonal (A02345-4 image caption, applications and dilution_raw). For work across species, A02345-2 lists Human, Mouse and Rat reactivity, while A02345-4 lists Human and Rat; the supplied IHC image demonstrates human tissue only (catalog reactivity and A02345-2 IHC image caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9P246 (STIM2_HUMAN, Stromal interaction molecule 2).
- Human Protein Atlas. STIM2 tissue IHC expression (reliability: Supported).
- Human Protein Atlas. STIM2 subcellular location (ICC-IF): Membrane.
- Human Protein Atlas. STIM2 antibody validation summary (3 antibodies).
- Alternatively spliced STIM2.3 is an evolutionarily late store-operated Ca2+ entry regulator expressed in brain. Journal of cell science 2026 — PMC13143212.
- Dental enamel cells express functional SOCE channels. Scientific reports 2015 — PMC4626795.
- Modification of STIM2 by m(6)A RNA methylation inhibits metastasis of cholangiocarcinoma. Annals of translational medicine 2022 — PMC8848379.
- Impaired spatial memory and enhanced long-term potentiation in mice with forebrain-specific ablation of the Stim genes. Frontiers in behavioral neuroscience 2015 — PMC4500926.
- PubMed PMID:11463338 — UniProt-cited evidence.
- PubMed PMID:10819331 — UniProt-cited evidence.
- PubMed PMID:11230166 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for STIM2 (Stromal interaction molecule 2). Expected localisation General cytoplasmic tissue staining (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A02345-2 at 2.5 μg/mL (the product's own IHC validation image is shown). Controls (HPA): positive Adipose tissue (Adipocytes); negative None in HPA (detected in all 45 tissues); use no-primary + isotype controls. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Tissue sections; selected-image fixative not specified (standard IHC workflow); 2. Fixation: Image fixative and duration unreported (datasheet A02345-2); verify before use.; 3. Sectioning: 4–5 µm sections on charged slides (standard); 4. Deparaffinisation: Xylene, graded ethanol series to water (standard); 5. Antigen retrieval: Heat-induced epitope retrieval in citrate buffer, pH 6.0 , 20 min at 95–98 °C…; 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% normal serum of the secondary host, 30 min , room temperature (standard); 8. Primary antibody: Rabbit anti-STIM2, 2.5 μg/mL (datasheet A02345-2); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A02345-2); Caveat: ER Ca²⁺ depletion can redistribute STIM2 to ER–PM junctions (UniProt); Isoform / epitope: 3 isoforms; epitope side matters, isoform coverage unknown (UniProt); Regulation: No expression regulator specified (UniProt). Evidence: UniProt Q9P246, HPA tissue IHC · Supported, HPA ICC-IF · Membrane, Datasheet A02345-2, PMC4626795. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/STIM2/immunohistochemistry-ihc-guide.