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SRPX2 / Sushi repeat-containing protein SRPX2 · IHC design guide
Design Immunohistochemistry for SRPX2
Plan SRPX2 chromogenic IHC in paraffin sections using the mainly cytoplasmic tissue pattern as a reference (HPA tissue IHC). The catalog antibody is listed for IHC-P at 5 μg/mL (datasheet); assess staining with secreted SRPX2 in mind (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
SRPX2 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 | Mainly cytoplasmic staining across tissues (HPA tissue IHC) | |
| Staining pattern | Mainly cytoplasmic staining across tissue 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 | Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A06268) | |
| Caveat | Secreted SRPX2 may extend beyond producing cells (UniProt) | |
| Regulation | Higher in colorectal cancer than normal mucosa (UniProt) | |
| Isoform / epitope | No isoforms listed; map epitopes to the mature chain (24–465) when assessing secreted versus cytoplasmic signal (UniProt) |
Section 1
Recommended SRPX2 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is accompanied by published SRPX2 staining methods for prostate cancer, oral squamous cell carcinoma, and gastric carcinoma specimens (PMC5983007; PMC7279144; PMC6413340).
| Sample | Tissue sections; selected-image fixative not specified (standard IHC workflow) |
| Fixation | Image fixative and duration unreported (datasheet A06268); 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-SRPX2, 5 μg/mL (datasheet A06268) |
| 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 | SRPX2-positive staining in adipocytes of adipose tissue (HPA tissue IHC: High). HPA tissue profile: Mainly cytoplasmic expression in all tissues including plasma. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 retrieval at 95–98 °C for 20 min (page retrieval setting); the oral carcinoma protocol used 45 min (PMC7279144).
Section 2
What Is the Expected SRPX2 Staining Pattern?
SRPX2 is secreted and also annotated at the cytoplasm, cell surface and synapse, with no transmembrane segment (UniProt O60687 topology). In tissue IHC, expect mainly cytoplasmic staining, including in adipocytes, respiratory epithelial cells, neurons and endothelial cells (HPA tissue IHC). HPA rates its tissue evidence Approved while noting that secreted variants complicate RNA–protein comparisons and that external verification is pending (HPA tissue IHC).
| Distinct cytoplasmic stain in adipocytes, bronchial respiratory epithelium or colon endothelium. | These cell types have High reported staining (HPA tissue IHC). Judge the pattern by cell identity and compartment together; secretion means extracellular or plasma-associated signal may coexist (UniProt O60687 subcellular; HPA tissue IHC). |
| Strong, exclusively nuclear stain with little cytoplasmic signal. | This conflicts with the mainly cytoplasmic tissue profile and the reported secreted, cytoplasmic and cell-surface locations (HPA tissue IHC; UniProt O60687 subcellular). Treat it as suspect; compare the negative reagent control and a known-positive tissue section (general IHC practice). |
| Stain appears chiefly in an unexpected cell population while expected cells are faint. | The distribution warrants a specificity check against the reported High cell populations; it alone does not prove cross-reactivity because HPA describes expression across tissues (HPA tissue IHC). Check antibody omission and detection controls for endogenous activity (general IHC practice). |
| Uniform haze covers tissue and surrounding space, obscuring cell outlines. | Some extracellular or plasma-associated staining is plausible for a secreted protein (UniProt O60687 subcellular; HPA tissue IHC). Haze that also appears in reagent controls points to background; review blocking, washes and detection chemistry (general IHC practice). |
| No convincing stain in an adipose section containing adipocytes. | Adipocytes are reported High in adipose tissue (HPA tissue IHC). First verify tissue preservation and run controls, then review the validated IHC procedure and detection reagents (general IHC practice). A blank section alone cannot establish absent SRPX2 expression. |
💡Expected SRPX2 appearanceA persuasive positive is chiefly cytoplasmic, readily visible staining in a reported High cell population such as adipocytes or bronchial respiratory epithelial cells (HPA tissue IHC); isolated nuclear stain or uniform control-positive haze is suspect (HPA tissue IHC; general IHC practice).
| Secreted protein and compartment | SRPX2 has a signal peptide at residues 1–23, a mature chain at 24–465, and no transmembrane segment (UniProt O60687 processing/topology). Interpret cell-associated stain alongside possible extracellular or plasma signal; do not require a continuous membrane rim (UniProt O60687 subcellular; HPA tissue IHC). |
| Choice of tissue and cell population | High staining is reported in adipocytes, adrenal glandular cells, marrow hematopoietic cells, bronchial epithelium, caudate neurons, Purkinje cells and colon endothelium (HPA tissue IHC). Ovarian stromal and vaginal squamous epithelial cells are reported Low, so compare like cell types when judging intensity (HPA tissue IHC). |
| Evidence strength | The tissue profile is Approved, with external verification pending; one listed rabbit polyclonal antibody, HPA038786, has IHC Approved status (HPA tissue IHC; HPA antibodies). Approval supports use of the reported pattern as a reference, but does not make every unexpected stain a confirmed biological finding. |
| Retrieval and detection conditions | General IHC practice: use the IHC-validated antibody's documented paraffin-section procedure as the starting point; check retrieval, blocking, reagent concentration, washes and chromogen development when optimizing. The supplied UniProt and HPA records give no SRPX2-specific fixation or retrieval response. |
| IF/ICC evidence | Q: Does the tissue IHC pattern establish an IF/ICC protocol? A: No. HPA lists SRPX2 as secreted but provides no main ICC/IF location or cell-line images, and the listed antibody has no ICC status (HPA subcellular; HPA antibodies). Interpret IF/ICC on its own guide page. |
| Situation | Likely cause | Next action |
|---|---|---|
| A reported High population stains weakly or not at all. | Section or detection failure is possible; the reported High category is a reference, not a guarantee for every specimen (HPA tissue IHC; general IHC practice). | Check morphology and run a positive tissue plus reagent controls; then review the IHC-validated antibody's documented retrieval and detection steps (general IHC practice). |
| Nuclei dominate while cytoplasm stays pale. | An exclusively nuclear result conflicts with the mainly cytoplasmic tissue pattern (HPA tissue IHC). | Compare a known-positive section and omission control; reassess antibody concentration, blocking and chromogen development before assigning a nuclear location (general IHC practice). |
| Unexpected cells stain more than the expected population. | Cross-reactivity or endogenous detection activity is possible, though broad tissue expression prevents a conclusion from location alone (HPA tissue IHC; general IHC practice). | Confirm cell identity and compare adjacent controls; test the detection system without primary antibody (general IHC practice). |
| Diffuse staining masks cellular boundaries. | Secreted SRPX2 can contribute extracellular or plasma-associated signal; broad control staining instead suggests background (UniProt O60687 subcellular; HPA tissue IHC; general IHC practice). | Compare primary-omission controls, then review blocking, washes and detection development (general IHC practice). |
| Ovarian stroma or vaginal squamous epithelium looks faint. | Both cell populations are reported Low (HPA tissue IHC). | Score them against their own expected level and examine a reported High population in parallel before changing the assay (HPA tissue IHC; general IHC practice). |
| IF/ICC shows a pattern that differs from paraffin IHC. | HPA provides no ICC/IF images or main intracellular location, while its tissue IHC profile is mainly cytoplasmic (HPA subcellular; HPA tissue IHC). | Interpret IF/ICC with application-specific controls and its separate guide; do not infer an IF/ICC protocol from tissue IHC approval (HPA antibodies; general IF practice). |
Experiment evidence
IHC & IF images showing SRPX2 staining
A06268 · IHCImmunohistochemistry of SRPX2 in rat lung tissue with SRPX2 antibody at 5 μg/mL.
A06268 · IFImmunofluorescence of SRPX2 in human lung tissue with SRPX2 antibody at 20 μg/mL.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000102359-SRPX2/tissue/cerebral+cortex#imid_9798572
HPA · CerebellumHuman Protein Atlas IHC, Cerebellum. Source: https://www.proteinatlas.org/ENSG00000102359-SRPX2/tissue/cerebellum#imid_9798567
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000102359-SRPX2/tissue/colon#imid_9798498
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000102359-SRPX2/tissue/liver#imid_9798491
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for SRPX2 IHC & IF
🧪Run bone marrow first and assess staining in hematopoietic cells (HPA: High in hematopoietic cells). HPA detects SRPX2 in all 45 scored tissues, so there is no documented negative tissue; no-primary and isotype controls carry the negative comparison (HPA: no negative rows). Cells on the positive slide that lack specific chromogen should show counterstain alone, but should not be classified as proven SRPX2-negative.
Positive control tissue: Adipose tissue (Adipocytes, HPA High)
Negative control tissue: None in HPA: SRPX2 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 SRPX2; 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 control and an isotype control matched to the primary antibody’s host species and immunoglobulin class (and subclass if monoclonal); use SRPX2 knockout material or a validated immunizing-peptide block as a biological specificity control. Quench endogenous peroxidase in bone marrow, where hematopoietic cells can otherwise produce chromogenic background (HPA: High in hematopoietic cells).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A06268 rat-lung IHC caption does not state a fixative (caption: 5 µg/mL; fixative unreported). Antigen retrieval dependence is unreported; compare retrieved and unretrieved paraffin sections during optimization. Frozen sections and IF are not established as easier for SRPX2 from the supplied evidence (HPA: no ICC-IF cell-line images); assess bone marrow staining against its endogenous peroxidase background.
HPA tissue IHC evidence for SRPX2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — At least one protein variant secreted, tissue location of RNA and protein might differ and correlation is complex. Pending external verification.). 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 → |
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Breast | Adipocytes | High | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: SRPX2 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced SRPX2 IHC Tips
Troubleshoot SRPX2 staining in paraffin sections by checking retrieval, cell identity, and compartment before comparing chromogenic signal across samples.
Which retrieval conditions should I start with for SRPX2 in paraffin sections?
Start SRPX2 paraffin IHC with citrate buffer at pH 6.0, heated to 95–98 °C for 20 min (page retrieval setting). Cool sections consistently before blocking, and compare a positive control across runs because retrieval time and temperature affect epitope exposure (standard IHC practice). The rat lung image documents staining at 5 µg/mL, but its caption does not report fixation or retrieval conditions (catalog antibody A06268 caption). If signal is weak, adjust heating time in a small controlled series before testing an alternative retrieval buffer (standard IHC practice). Record each condition alongside staining intensity and tissue preservation so improved signal is not mistaken for improved specificity (standard IHC practice).
How should I assess whether fixation is limiting SRPX2 staining?
Target-specific fixation sensitivity is unknown from the supplied evidence; the rat lung caption gives 5 µg/mL antibody concentration but no fixative (catalog antibody A06268 caption). Record fixative, fixation duration, tissue thickness, and processing history for each paraffin sample before comparing staining (standard IHC practice). Use sections processed together when testing the prescribed pH 6.0 retrieval, so differences in handling do not masquerade as biological variation (page retrieval setting; standard IHC practice). Examine morphology and staining in a known positive tissue alongside each run, then change one preparation variable at a time (standard IHC practice). HPA tissue patterns do not establish how fixation affects this antibody (HPA tissue IHC profile).
Which staining compartments are plausible for SRPX2, and which require scrutiny?
Assess cytoplasmic, cell surface, and extracellular staining together: SRPX2 is annotated as secreted, cytoplasmic, cell surface, and synaptic, with no transmembrane segment (UniProt O60687 localisation and topology). HPA reports mainly cytoplasmic tissue staining, including plasma, while warning that secreted protein and tissue RNA may differ (HPA tissue IHC profile). Compare suspected signal with a 5 µg/mL rat lung reference only as an image-level check, since its fixation conditions are unreported (catalog antibody A06268 caption). Score epithelial, vascular, and stromal compartments separately under the same chromogenic threshold (standard IHC practice). Isolated nuclear staining warrants a control review before attribution to SRPX2 (UniProt O60687 localisation; standard IHC practice).
How do processing and domain placement affect SRPX2 epitope interpretation?
Map the antibody’s stated immunogen against the 465-aa SRPX2 precursor before interpreting absent or shifted compartment staining (UniProt O60687 sequence; standard IHC practice). The 1–23 signal peptide is cleaved, leaving a reported 24–465 chain; an epitope confined to the signal peptide would therefore need special scrutiny (UniProt O60687 processing). Three Sushi domains and one HYR domain occupy defined regions, but the supplied evidence gives no antibody epitope or alternative isoforms (UniProt O60687 domains and isoforms; catalog antibody A06268 caption). Compare staining after the prescribed pH 6.0 retrieval with a second validated epitope reagent if available (page retrieval setting; standard IHC practice). Do not attribute discordance to glycosylation without direct evidence for this specimen (UniProt O60687 glycosylation record; standard IHC practice).
How can IF help check the cell source of chromogenic SRPX2 signal?
Use IF as a separate localisation check by pairing SRPX2 with a marker for the expected cell type, such as an endothelial marker when examining colon (HPA: High in colon endothelial cells; standard IF practice). Select a far-red fluorophore when tissue autofluorescence is strong, and include single-stain controls to inspect spectral bleed-through (standard IF practice). Because SRPX2 is secreted and also annotated as cytoplasmic and cell surface, compare nonpermeabilised and gently permeabilised preparations if the antibody’s epitope location permits it (UniProt O60687 localisation; standard IF practice). Keep fixation and permeabilisation conditions documented; no IF-specific fixation or epitope validation is supplied here (supplied evidence). Do not treat an IF pattern as proof that the paraffin IHC signal has the same cellular source (standard IHC/IF practice).
What should I check when SRPX2 chromogenic staining looks diffuse?
First inspect a no-primary control and the section edges, folds, damaged areas, and necrosis under the same exposure conditions (standard IHC practice). Include a peroxidase block before DAB detection and verify that its omission is not producing endogenous enzyme signal (standard chromogenic IHC practice). Titrate the antibody around the captioned 5 µg/mL concentration rather than assuming that image condition suits every specimen (catalog antibody A06268 caption; standard IHC practice). Secreted SRPX2 can complicate assignment of diffuse staining to the producing cell, while HPA also reports plasma signal (UniProt O60687 localisation; HPA tissue IHC profile). Require reproducible cellular pattern and clean controls before scoring weak diffuse deposit as positive (standard IHC practice).
How should I score SRPX2 across tissues with mixed cell populations? ⚠ ANSWER MARKED FOR VERIFICATION
Define the scored compartment and cell population before comparing slides, since SRPX2 is secreted and HPA reports both tissue cytoplasmic and plasma staining (UniProt O60687 localisation; HPA tissue IHC profile). For cellular chromogenic signal, record the percentage of positive cells and an intensity-based H-score from 0–300 using one fixed threshold (standard IHC scoring practice). For spatial deposits, report stained area or positive-cell density per mm² within a predefined viable tissue region (standard image analysis practice). Normalise each result to the relevant cell count or viable tissue area, and exclude folds and necrosis by the same rule (standard IHC scoring practice). Compare batches with a shared reference section and identical image settings (standard IHC practice).
How can I distinguish true SRPX2 signal from staining artefacts?
Treat a reproducible cytoplasmic or plausible cell-associated pattern as more credible when it occurs in an expected population, such as colon endothelial cells (HPA: High in colon endothelial cells; UniProt O60687 localisation). Scrutinise isolated nuclear signal because nuclear localisation is absent from the supplied SRPX2 annotation (UniProt O60687 localisation). Compare suspect deposits with no-primary and peroxidase-block controls; edge staining, necrosis, and endogenous enzyme activity can mimic chromogenic positivity (standard IHC practice). A positive result at 5 µg/mL in rat lung establishes an image example, not universal specificity across samples (catalog antibody A06268 caption; standard IHC practice). Interpret extracellular signal cautiously because secreted protein may lie apart from its producing cell (UniProt O60687 localisation).
Boster reagents
Best SRPX2 / Sushi repeat-containing protein SRPX2 IHC Antibodies
A06268 has IHC data in rat lung tissue and IF data in human lung tissue (catalog image captions); its listed reactivity covers human, mouse, and rat (catalog: reactivity).
Real IHC data
Anti-SRPX2 Antibody
Cat # A06268
A06268 is listed for IHC-P and IF (catalog: applications). Its images show IHC in rat lung tissue at 5 μg/mL and IF in human lung tissue at 20 μg/mL (catalog image captions).
Which to pick: Choose A06268 for tissue IHC-P: its IHC image shows rat lung tissue at 5 μg/mL (catalog: IHC-P application; IHC image caption); the fixative is unreported (catalog: IHC image caption). For IF, A06268 has a human lung tissue image at 20 μg/mL (catalog: IF image caption); ICC is not shown (catalog: applications and image captions). For cross-species work, A06268 lists human, mouse, and rat reactivity, though the supplied images cover rat IHC and human IF only (catalog: reactivity; image captions); its host is rabbit and clonality is unreported (catalog: host; clone).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O60687 (SRPX2_HUMAN, Sushi repeat-containing protein SRPX2).
- Human Protein Atlas. SRPX2 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. SRPX2 subcellular location (ICC-IF): Secreted.
- Human Protein Atlas. SRPX2 antibody validation summary (1 antibodies).
- High SRPX2 protein expression predicts unfavorable clinical outcome in patients with prostate cancer. OncoTargets and therapy 2018 — PMC5983007.
- Sushi Repeat Containing Protein X-linked 2 Is a Downstream Signal of LEM Domain Containing 1 and Acts as a Tumor-Promoting Factor in Oral Squamous Cell Carcinoma. International journal of molecular sciences 2020 — PMC7279144.
- Systematic analysis of anoikis-related genes identifies SRPX2-FAK/AKT-IL-6 axis in the progression and peritoneal metastasis of gastric cancer. Frontiers in genetics 2025 — PMC12835628.
- O-glycans truncation modulates gastric cancer cell signaling and transcription leading to a more aggressive phenotype. EBioMedicine 2019 — PMC6413340.
- PubMed PMID:9864177 — UniProt-cited evidence.
- PubMed PMID:16303743 — UniProt-cited evidence.
- PubMed PMID:15772651 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for SRPX2 (Sushi repeat-containing protein SRPX2). Expected localisation Mainly cytoplasmic staining across tissues (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A06268 at 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 A06268); 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-SRPX2, 5 μg/mL (datasheet A06268); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A06268); Caveat: Secreted SRPX2 may extend beyond producing cells (UniProt); Isoform / epitope: No isoforms listed; map epitopes to the mature chain (24–465) when assessing secreted versus cytoplasmic signal (UniProt); Regulation: Higher in colorectal cancer than normal mucosa (UniProt). Evidence: UniProt O60687, HPA tissue IHC · Approved, HPA ICC-IF · Secreted, Datasheet A06268, PMC5983007, PMC7279144. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/SRPX2/immunohistochemistry-ihc-guide.