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EPN3 / Epsin-3 · IHC design guide
Design Immunohistochemistry for EPN3
Plan chromogenic IHC for EPN3 in formalin-fixed paraffin sections using the human-reactive IHC-P antibody (datasheet: A12667-1). Colon and gallbladder glandular cells show high staining and provide positive references for assessing the mainly cytoplasmic pattern (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
EPN3 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 in tissue sections (HPA tissue IHC) | |
| Staining pattern | Glandular-cell cytoplasmic staining in several tissues (HPA tissue IHC) | |
| Antigen retrieval | Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen) | |
| Positive control | Colon+4 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Use formalin-fixed paraffin sections (selected-SKU IHC image A12667-1); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A12667-1) | |
| Caveat | Splice/transcript discrepancy warrants caution (HPA tissue IHC) | |
| Regulation | Expressed in migrating wound keratinocytes (UniProt) | |
| Isoform / epitope | Two isoforms; N-terminal epitope coverage is unknown (UniProt; datasheet) |
Section 1
Recommended EPN3 IHC & IF Protocols
Compare the catalog antibody's IHC-P protocol with published EPN3 staining protocols for lung and breast tissue (PMC11269644; PMC8600415; PMC7296024).
| Sample | FFPE human colon carcinoma tissue (datasheet A12667-1) |
| Fixation | Image formalin-fixed; duration unreported (datasheet A12667-1); 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 Tris-EDTA buffer, pH 9.0, 20 min at 95–98 °C (standard rule: nuclear 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-EPN3, 1:10-1:50 (datasheet A12667-1) |
| 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 | EPN3-positive staining in glandular cells of colon (HPA tissue IHC: High). HPA tissue profile: Mainly cytoplasmic expression in several different tissues types. No signal in the no-primary control. |
💡Decision noteStart with Tris-EDTA pH 9.0, 95–98 °C for 20 min (page retrieval rule); compare the published citrate and EDTA conditions if staining needs optimization (PMC8600415; PMC7296024).
Section 2
What Is the Expected EPN3 Staining Pattern?
EPN3 should stain mainly cytoplasm in glandular cells of several tissues, with possible perinuclear and peripheral vesicular concentration (HPA: tissue IHC profile; UniProt Q9H201: subcellular location). Strong examples include colon, gallbladder, rectum, salivary gland and small intestine (HPA: High). EPN3 has no transmembrane segment (UniProt Q9H201: topology). HPA rates the tissue IHC evidence Approved, pending external verification, and flags a splice and/or transcript discrepancy (HPA: reliability).
| Strong cytoplasmic staining in colon or gallbladder glandular cells, possibly concentrated near nuclei or the cell periphery. | This matches high glandular-cell staining in those tissues (HPA: High) and EPN3's cytoplasmic, perinuclear and clathrin-coated-vesicle locations (UniProt Q9H201: subcellular location). Score the relevant cells and compartment, rather than treating every stained area of the section as equivalent (general IHC practice). |
| Predominant staining of a compartment outside the expected cytoplasmic pattern, especially a uniform membrane rim. | A membrane-rim-dominant pattern needs scrutiny because EPN3 has no transmembrane segment (UniProt Q9H201: topology). Nuclear signal alone is not automatically artefactual: UniProt notes possible nuclear shuttling, and HPA reports an additional nucleoplasmic IF location (UniProt Q9H201: subcellular location; HPA: ICC-IF). |
| Strong signal in adipocytes, bone-marrow hematopoietic cells or esophageal squamous epithelial cells. | HPA reports EPN3 as not detected in those cell populations by tissue IHC (HPA: Not detected). Check morphology and assay controls before interpreting such staining as EPN3; cross-reactivity or endogenous detection activity are possible explanations (general IHC practice). |
| Diffuse colour across cells and extracellular areas, without a discernible glandular-cell pattern. | This is hard to reconcile with HPA's mainly cytoplasmic tissue profile (HPA: tissue IHC profile). Assess background on a reagent control and review blocking, washing and chromogen development as general IHC checks (general IHC practice). |
| No signal in glandular cells of a colon or small-intestine section. | Both are high-staining examples in HPA, so absence calls for an assay check before concluding that EPN3 is absent (HPA: High; general IHC practice). Confirm tissue preservation and section identity, then review the antibody's specified IHC-P workflow and detection controls (general IHC practice). |
💡Expected EPN3 appearanceCall a positive result when glandular cells show clear, mainly cytoplasmic staining, potentially enriched near nuclei or peripheral vesicles, with strong staining plausible in HPA High tissues; diffuse field-wide colour or a dominant membrane rim warrants investigation (HPA: tissue IHC profile and High; UniProt Q9H201: subcellular location and topology; general IHC practice).
| Subcellular location and topology | EPN3 is cytoplasmic, perinuclear and associated with clathrin-coated vesicles near the cell periphery; it may shuttle to the nucleus and has no transmembrane segment (UniProt Q9H201: subcellular location and topology). Interpret a nuclear component in context, while questioning a dominant membrane-rim pattern. |
| Choice of tissue and cell population | Colon, gallbladder, rectum, salivary gland and small-intestine glandular cells are High; stomach glandular cells are Medium (HPA: tissue IHC). Use the annotated cell population when comparing intensity. A tissue label alone cannot establish that every cell should stain (general IHC practice). |
| Expression context and discordance | UniProt reports EPN3 in migrating keratinocytes of wounded skin, but not differentiating keratinocytes or normal skin (UniProt Q9H201: tissue specificity). HPA calls esophageal RNA tissue enhanced while reporting no protein staining in esophageal squamous epithelial cells (HPA: RNA specificity; HPA: Not detected). Do not substitute RNA abundance for the observed IHC pattern. |
| Evidence and antibody validation | The tissue IHC profile is Approved but pending external verification, with a splice and/or transcript discrepancy flagged (HPA: reliability). HPA055546 has Approved IHC status; the supplied HPA record does not rate its IHC as Enhanced (HPA: antibodies). Treat unexpected staining as a finding to check, rather than proof of a new distribution. |
| Isoforms and modifications | UniProt lists two EPN3 isoforms and phosphoserines at residues 191, 192 and 264 (UniProt Q9H201: isoforms; modified residues). The supplied sources do not identify the catalog antibody's epitope or show that these differences change IHC staining; do not assign a discrepancy to an isoform or modification without further evidence. |
| IF/ICC comparison | For the separate IF/ICC guide, HPA reports vesicles as the supported main location and nucleoplasm as an approved additional location, with images from HaCaT, MCF-7 and U2OS (HPA: ICC-IF). This supports a localisation cross-check, not a paraffin-section IHC intensity benchmark. |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected glandular-cell signal is absent in a colon or small-intestine section. | Either the assay missed its expected signal or the examined cells are not the annotated glandular population (HPA: High; general IHC practice). | Verify section identity and morphology; review the IHC-validated antibody's specified retrieval and detection steps, then check assay controls (general IHC practice). No EPN3-specific retrieval setting is supplied. |
| Staining is predominantly a crisp plasma-membrane outline. | That distribution conflicts with EPN3's lack of a transmembrane segment and its reported cytoplasmic and vesicular locations (UniProt Q9H201: topology and subcellular location). | Recheck cell boundaries and compare the stain with a control section; investigate nonspecific or endogenous detection signal before calling it EPN3 (general IHC practice). |
| Strong staining appears in adipocytes or bone-marrow hematopoietic cells. | Those populations are reported as not detected in HPA tissue IHC; cross-reactivity or endogenous activity may account for an unexpected signal (HPA: Not detected; general IHC practice). | Confirm the cell type, inspect a reagent control, and compare with a High glandular-cell tissue under the same scoring criteria (HPA: High; general IHC practice). |
| Diffuse background obscures cytoplasmic detail. | Nonspecific staining or excess detection signal can obscure localisation (general IHC practice); HPA describes a mainly cytoplasmic tissue pattern (HPA: tissue IHC profile). | Review blocking, washing, antibody concentration and chromogen development against the antibody's IHC-P instructions; assess a reagent control (general IHC practice). No dilution is supplied here. |
| Esophageal squamous cells stain despite the tissue-enhanced RNA label. | The RNA and protein observations differ: HPA reports tissue-enhanced esophageal RNA but no detected IHC signal in esophageal squamous epithelial cells (HPA: RNA specificity; HPA: Not detected). | Interpret the slide against the protein IHC observation; verify cell identity and assay controls before treating the RNA label as evidence for a positive stain (HPA: tissue IHC; general IHC practice). |
| What IF/ICC localisation can be compared with the IHC result? | HPA's IF/ICC summary gives vesicles as the supported main location and nucleoplasm as an approved additional location (HPA: ICC-IF). | Use those locations as a qualitative cross-check on compartment; follow the separate IF/ICC guide for that application. The supplied IF/ICC record does not establish an IHC-P protocol or an equivalent staining intensity (HPA: ICC-IF). |
Experiment evidence
IHC & IF images showing EPN3 staining
A12667-1 · IHCFormalin-fixed and paraffin-embedded human colon carcinoma with EPN3 Antibody (N-term), which was peroxidase-conjugated to the secondary ant
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000049283-EPN3/tissue/cerebral+cortex#imid_15828439
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000049283-EPN3/tissue/colon#imid_15828365
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000049283-EPN3/tissue/liver#imid_15828358
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000049283-EPN3/tissue/kidney#imid_15828367
HPA · ICC-IF HaCaTHuman Protein Atlas immunofluorescence, HaCaT, antibody HPA063224; green = EPN3, blue = nucleus, red = microtubules.
HPA · ICC-IF HaCaTHuman Protein Atlas immunofluorescence, HaCaT, antibody HPA063224; green = EPN3, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for EPN3 IHC & IF
🧪Run colon first: its glandular cells should stain strongly (HPA: High in colon glandular cells). Use adipose tissue adipocytes as the negative tissue (HPA: Not detected in adipocytes); on the colon slide, use non-glandular areas to assess background without assuming they are EPN3-negative (HPA: colon result specifies glandular cells only).
Positive control tissue: Colon (Glandular cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show EPN3 in HaCaT, MCF-7, U2OS, with annotated localisation: Vesicles (supported) (HPA subcellular).
Technical controls: Include no-primary (secondary-only) and host-species- and clonality-matched isotype controls, plus EPN3-knockout material as a biological negative (standard IHC practice). For colon DAB staining, quench endogenous peroxidase and check for residual background (standard IHC practice).
⚠️Feasibility: The selected A12667-1 caption explicitly describes formalin-fixed, paraffin-embedded human colon carcinoma stained with DAB, but reports no fixation duration (selected-SKU tissue-IHC caption); a target-specific fixation window and retrieval dependency are unreported in the supplied evidence. Antigen retrieval therefore needs empirical optimization for paraffin sections (standard IHC practice); the supplied evidence does not establish whether frozen sections or IF are easier. In colon, distinguish glandular cell staining from luminal stain deposit when scoring (HPA: High in colon glandular cells; standard IHC practice).
HPA tissue IHC evidence for EPN3
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Pending external verification. Caution, Splice and/or transcript discrepancy exists.). 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 |
|---|---|---|---|---|
| Colon | Glandular cells | High | Protein (IHC) | HPA → |
| Gallbladder | Glandular cells | High | Protein (IHC) | HPA → |
| Rectum | Glandular cells | High | Protein (IHC) | HPA → |
| Salivary gland | Glandular cells | High | Protein (IHC) | HPA → |
| Small intestine | Glandular cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
| Cerebellum | Cells in granular layer | Not detected | Protein (IHC) | HPA → |
| Cerebral cortex | Endothelial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced EPN3 IHC Tips
Troubleshoot EPN3 chromogenic IHC in paraffin sections by checking retrieval, cellular distribution, controls and scoring before interpreting staining.
How should I retrieve EPN3 in paraffin sections when staining is weak?
Start EPN3 paraffin IHC with Tris-EDTA pH 9.0 HIER at 95–98 °C for 20 min (page retrieval specification). Let sections cool in retrieval buffer before washing, and process positive and negative controls alongside the sample (standard IHC practice). Colon glandular cells provide a comparison for detectable staining (HPA tissue IHC: High in colon glandular cells), although tissue processing can alter the result. If signal remains weak, check antibody titration and detection chemistry before changing retrieval conditions (standard IHC practice). Record retrieval temperature and cooling time for each run so differences between sections can be traced (standard IHC practice).
Could fixation explain weak or uneven EPN3 staining?
EPN3-specific sensitivity to fixation has not been established by the supplied evidence; do not assign weak staining to a particular fixation effect. Record fixative, fixation duration, section thickness and storage history when comparing specimens, then process control and test sections together (standard IHC practice). Uneven staining can arise from inconsistent section processing, so inspect the whole slide before changing the antibody conditions (standard IHC practice). Compare intact glandular areas within the same staining run, using colon glandular cells as an expected positive reference (HPA tissue IHC: High in colon glandular cells). Treat any apparent fixation effect as a hypothesis requiring matched sections and repeated staining.
Where should convincing EPN3 chromogenic staining appear?
Prioritise cytoplasmic and perinuclear staining, including peripheral vesicular puncta, when assessing EPN3 (UniProt Q9H201: subcellular location). Vesicles are the supported main location, while nucleoplasm is an additional approved location in cell imaging (HPA subcellular). Accordingly, isolated nuclear DAB staining deserves confirmation against cytoplasmic signal, tissue morphology and controls before being called EPN3 (UniProt Q9H201; HPA subcellular). EPN3 has no annotated transmembrane segment, so a crisp membrane-only outline is unexpected from the supplied topology (UniProt Q9H201: topology). Inspect higher magnification fields to distinguish intracellular puncta from granular pigment or deposited chromogen (standard IHC practice).
How do isoforms and epitope placement affect EPN3 IHC interpretation?
EPN3 has 2 annotated isoforms, so staining cannot automatically be assigned to both without an epitope map (UniProt Q9H201: isoforms). The selected IHC image describes an N-terminal antibody, but its caption does not define the exact epitope or isoform coverage (A12667-1 tissue-IHC caption). Check the antibody immunogen against both isoform sequences before interpreting absence of staining as absence of all EPN3 (standard antibody validation practice). The ENTH domain spans residues 12–144, and two UIM regions span 209–228 and 236–255 (UniProt Q9H201: domains). Document the antibody clone or lot and epitope information with each IHC result (standard IHC practice).
How can IF help validate an ambiguous EPN3 IHC pattern?
Use IF as a separate corroborating assay, pairing EPN3 with a validated marker for the expected cell population in the sampled tissue (standard IF practice). Choose spectrally separated fluorophores and inspect an unstained section first, because tissue autofluorescence can obscure weak puncta (standard IF practice). EPN3 lacks a transmembrane segment and is associated with cytoplasmic vesicles, so include permeabilisation to expose intracellular epitopes, then optimise its strength experimentally (UniProt Q9H201: topology and subcellular location; standard IF practice). Compare vesicular and perinuclear signal with the chromogenic pattern rather than treating either assay alone as proof (UniProt Q9H201: subcellular location). Include single-label and no-primary controls when assessing multiplex signal (standard IF practice).
What should I check when EPN3 DAB background is high?
Compare the stained section with a no-primary control to locate background from the detection system or tissue (standard IHC practice). Include a peroxidase-blocking step before DAB development, and verify that its timing follows the detection reagent instructions (standard chromogenic IHC practice). If diffuse staining persists, review blocking, wash stringency, antibody titration and DAB development time together (standard IHC practice). Preserve a colon glandular positive control while adjusting conditions so lower background does not conceal expected signal (HPA tissue IHC: High in colon glandular cells; standard IHC practice). Assess extracellular deposits separately from the cytoplasmic pattern described for EPN3 (HPA tissue IHC: mainly cytoplasmic expression).
How should EPN3 staining be scored across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the scored cell population and tissue region before reviewing treatment groups, then use identical imaging and scoring settings (standard quantitative IHC practice). For glandular samples, report the percentage of positive glandular cells and an H-score based on intensity and percentage, with the scoring scale stated explicitly (standard quantitative IHC practice). Normalise counts to evaluable cells or tissue area; use positive-cell density per mm² when cell numbers differ across fields (standard quantitative IHC practice). Record cytoplasmic and nuclear staining separately because cytoplasmic expression predominates in tissue, while nuclear localisation is also annotated (HPA tissue IHC; UniProt Q9H201: subcellular location). Exclude necrotic or folded regions by a prespecified rule (standard IHC practice).
How can I separate genuine EPN3 positivity from staining artefact?
A credible positive pattern combines intracellular cytoplasmic or vesicular staining with the expected tissue cell population (UniProt Q9H201: subcellular location; HPA tissue IHC: mainly cytoplasmic). Colon glandular cells offer a positive reference, whereas adipocytes were reported as not detected in the HPA tissue survey (HPA tissue IHC). Question staining confined to section edges, folds or necrotic areas, and check no-primary and peroxidase-block controls for detection artefacts (standard IHC practice). A membrane-only outline conflicts with EPN3's lack of a transmembrane segment and warrants closer review (UniProt Q9H201: topology). Treat nuclear-only staining cautiously, since nuclear localisation is annotated but vesicles are the supported main location (UniProt Q9H201; HPA subcellular).
Boster reagents
Best EPN3 / Epsin-3 IHC Antibodies
A12667-1 has real EPN3 IHC data from formalin-fixed, paraffin-embedded human colon carcinoma (image caption); its listed reactivity is human (catalog reactivity).
Real IHC data
Anti-EPN3 Antibody (N-term)
Cat # A12667-1
A12667-1 is listed for human IHC-P and has a DAB-stained image of formalin-fixed, paraffin-embedded human colon carcinoma (catalog applications/reactivity; image caption). No IF/ICC application or IF image is listed for A12667-1 (catalog applications; IF image alts).
Which to pick: Choose A12667-1 for human paraffin-section IHC: it is a rabbit polyclonal antibody listed for IHC-P at 1:10–1:50, with an image from formalin-fixed, paraffin-embedded human colon carcinoma (catalog host/dilution; dilution raw; image caption). There is no listed IF/ICC option for A12667-1 (catalog applications; IF image alts). There is no listed cross-species option; A12667-1 lists human reactivity only (catalog reactivity).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9H201 (EPN3_HUMAN, Epsin-3).
- Human Protein Atlas. EPN3 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. EPN3 subcellular location (ICC-IF): Mainly localized to vesicles. In addition localized to the nucleoplasm..
- Human Protein Atlas. EPN3 antibody validation summary (2 antibodies).
- Lowering expression of Epsin-3 inhibits migration and invasion of lung adenocarcinoma cells by inhibiting the epithelial-mesenchymal transition. Scientific reports 2024 — PMC11269644.
- Epsin 3 potentiates the NF‑κB signaling pathway to regulate apoptosis in breast cancer. Molecular medicine reports 2022 — PMC8600415.
- A self-sustaining endocytic-based loop promotes breast cancer plasticity leading to aggressiveness and pro-metastatic behavior. Nature communications 2020 — PMC7296024.
- PubMed PMID:11359770 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for EPN3 (Epsin-3). Expected localisation Mainly cytoplasmic in tissue sections (HPA tissue IHC). Antigen retrieval: Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen). Validated IHC antibody: A12667-1 at 1:10-1:50 (the product's own IHC validation image is shown). Controls (HPA): positive Colon (Glandular cells); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: FFPE human colon carcinoma tissue (datasheet A12667-1); 2. Fixation: Image formalin-fixed; duration unreported (datasheet A12667-1); 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 Tris-EDTA buffer, pH 9.0 , 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-EPN3, 1:10-1:50 (datasheet A12667-1); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Use formalin-fixed paraffin sections (selected-SKU IHC image A12667-1); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A12667-1); Caveat: Splice/transcript discrepancy warrants caution (HPA tissue IHC); Isoform / epitope: Two isoforms; N-terminal epitope coverage is unknown (UniProt; datasheet); Regulation: Expressed in migrating wound keratinocytes (UniProt). Evidence: UniProt Q9H201, HPA tissue IHC · Approved, HPA ICC-IF · Mainly localized to vesicles. In addition localized to the…, Datasheet A12667-1, PMC11269644, PMC8600415. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/EPN3/immunohistochemistry-ihc-guide.