This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
ENPP3 / Ectonucleotide pyrophosphatase/phosphodiesterase family member 3 · IHC design guide
Design Immunohistochemistry for ENPP3
Plan chromogenic ENPP3 IHC on paraffin sections using the catalog antibody at a 1:100 starting dilution (datasheet: A05615 IHC). This guide highlights strong microvillar staining in enterocytes and proximal tubules (HPA tissue IHC) and the potential for secreted ENPP3 to contribute extracellular signal (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
ENPP3 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 | Membranous and extracellular tissue staining (HPA tissue IHC) | |
| Staining pattern | Strong microvillar staining in enterocytes and proximal tubules (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Duodenum+4 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections (standard IHC practice; not target-specific); assess staining empirically. | |
| Caveat | Secreted ENPP3 may contribute extracellular staining (UniProt) | |
| Regulation | Staining varies by tissue and cell type (HPA tissue IHC) | |
| Isoform / epitope | No isoforms listed; extracellular vs cytoplasmic epitope matters (UniProt) |
Section 1
Recommended ENPP3 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is followed by published ENPP3 staining methods for heart, renal carcinoma, and ovarian endometriosis sections (PMC12203807; PMC6731023; PMC11293237).
| Sample | Paraffin-embedded Rat Testis tissue; fixative not specified (datasheet A05615) |
| Fixation | Image fixative and duration unreported (datasheet A05615); 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-ENPP3, 1:100 (datasheet A05615) |
| 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 | ENPP3-positive staining in enterocytes - Microvilli of duodenum (HPA tissue IHC: High). HPA tissue profile: Membranous expression and extracellular positivity in several tissues. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 retrieval at 95–98 °C for 20 min (page retrieval); the renal carcinoma assay used proteinase K instead (PMC6731023).
Section 2
What Is the Expected ENPP3 Staining Pattern?
ENPP3 is a membrane protein with an extracellular domain spanning residues 31–875; it is also reported as secreted (UniProt O14638 topology; UniProt O14638 subcellular). In paraffin-section IHC, expect apical or surface staining in the specified epithelial cells, including intestinal enterocytes and kidney proximal tubules (HPA: High in enterocyte and proximal-tubule microvilli). HPA rates its tissue IHC reliability Enhanced, while noting that secreted protein can complicate the match between tissue RNA and protein location (HPA: tissue IHC reliability description).
| A crisp luminal rim on duodenal or small-intestinal enterocytes, or on kidney proximal tubules. | This matches the strongest compartment-specific examples: enterocyte and proximal-tubule microvilli are High (HPA: duodenum, small intestine, kidney). Score the relevant epithelial surface, rather than averaging its intensity with the entire section (general IHC scoring practice). |
| Membranous staining with extracellular positivity in other tissue compartments. | Both can be compatible with ENPP3: HPA describes membranous expression and extracellular positivity in several tissues, and UniProt reports membrane-bound and secreted protein (HPA: tissue IHC profile; UniProt O14638 subcellular). Confirm the local cell and compartment before calling a positive result (general IHC interpretation practice). |
| Strong nuclear staining or a predominantly intracellular pattern without the expected surface signal. | This is a compartment mismatch against the reported apical membrane, cell-surface and secreted locations (UniProt O14638 subcellular; HPA: tissue IHC profile). Treat it as questionable staining and compare it with appropriate control sections before assigning ENPP3 expression (general IHC interpretation practice). |
| Signal in cells that HPA lists as not detected, such as adipocytes in adipose tissue. | Investigate cross-reactivity or detection background before interpreting that cell population as ENPP3-positive (HPA: adipose adipocytes Not detected; general IHC troubleshooting practice). HPA's finding applies to the named cells; it does not declare every cell in that tissue negative (HPA: adipose tissue cell-level entry). |
| No visible stain in a section containing intact intestinal enterocytes or kidney proximal tubules. | An absent signal conflicts with HPA's High microvillar staining in those cells (HPA: duodenum, small intestine, kidney). Review section quality and the IHC workflow before interpreting an experimental sample as negative (general IHC troubleshooting practice). |
💡Expected ENPP3 appearanceCall a convincing positive when staining follows the apical microvilli of enterocytes or kidney proximal tubules at a clear, strong intensity (HPA: High in duodenum, small intestine and kidney; UniProt O14638 subcellular); isolated nuclear colour or colour in a listed negative cell population warrants investigation rather than an ENPP3 call (HPA: cell-level tissue IHC; general IHC interpretation practice).
| Topology and compartment | ENPP3 has one transmembrane segment at residues 12–30 and an extracellular region at 31–875 (UniProt O14638 topology). Use the epithelial surface as the main spatial reference when interpreting the reported apical staining (UniProt O14638 subcellular; HPA: microvillar IHC entries). |
| Secreted protein | UniProt reports ENPP3 in serum and epithelial lumens; HPA reports extracellular positivity (UniProt O14638 subcellular; HPA: tissue IHC profile). Extracellular colour therefore needs anatomical context, and its presence alone cannot identify the producing cell (HPA: reliability description). |
| Tissue and cell selection | Duodenal and small-intestinal enterocyte microvilli and kidney proximal-tubule microvilli are High; endometrial glandular cells are Medium (HPA: tissue IHC entries). Compare the same named cell compartment across samples when judging staining intensity (general IHC scoring practice). |
| Evidence strength | HPA calls the tissue staining Enhanced and lists antibody HPA043772 as IHC Enhanced (HPA: tissue IHC reliability; HPA: antibody validation). Its reliability description also reports medium staining–RNA consistency and warns that secretion complicates tissue-location comparisons (HPA: reliability description). |
| Antigen retrieval and epitope | The supplied UniProt topology defines extracellular orientation, but neither source identifies the catalog antibody's epitope or an ENPP3-specific retrieval response (UniProt O14638 topology; HPA: antibody entry). Record the retrieval conditions used and compare controls when optimizing IHC (general IHC practice). |
| IF/ICC? | HPA's subcellular summary says Secreted, lists no main location and provides no ICC-IF cell-line images (HPA: subcellular record). The IHC microvillar pattern can guide interpretation, but this record does not establish a validated IF/ICC pattern or an IF/ICC protocol (HPA: tissue IHC; HPA: subcellular record). |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected intestinal or kidney microvilli are unstained. | The result disagrees with High staining in those named cells (HPA: duodenum, small intestine, kidney); the failing step cannot be identified from that observation alone (general IHC troubleshooting practice). | Check that the expected cells are present, then inspect the IHC-validated antibody, retrieval, detection reagents and a known-positive control together (general IHC troubleshooting practice). |
| Chromogen coats much of the section, including unrelated structures. | Diffuse colour can arise from nonspecific binding or detection background in chromogenic IHC (general IHC practice); HPA's extracellular positivity does not make every diffuse deposit specific (HPA: tissue IHC profile). | Compare a primary-omission control, review blocking and washes, and assess whether colour tracks recognisable cells or extracellular spaces (general IHC troubleshooting practice). |
| Signal appears mainly nuclear or uniformly cytoplasmic. | That distribution differs from the reported cell-surface, apical and extracellular pattern (UniProt O14638 subcellular; HPA: tissue IHC profile). | Recheck the compartment at higher magnification and compare the same staining run with intestinal or kidney microvilli (HPA: High in those microvilli; general IHC interpretation practice). |
| Adipocytes or adrenal glandular cells show a strong signal. | Those named populations are listed as Not detected (HPA: adipose adipocytes; HPA: adrenal glandular cells); cross-reactivity or detection background is possible (general IHC troubleshooting practice). | Check primary-omission and known-positive controls, then score the stained cell type explicitly rather than assigning positivity to the whole tissue (general IHC scoring practice). |
| A glandular or luminal deposit is difficult to assign to a cell. | ENPP3 can be secreted into epithelial lumens, and HPA reports extracellular positivity (UniProt O14638 subcellular; HPA: tissue IHC profile). Its tissue RNA and protein locations need not coincide (HPA: reliability description). | Record membrane-associated and extracellular staining separately; use cell morphology and a control section when assigning a cellular source (general IHC interpretation practice). |
| An IF/ICC image shows puncta without a clear surface pattern. | HPA supplies no ICC-IF cell-line images or main subcellular location for this record (HPA: subcellular record), so that image cannot be validated against an HPA IF reference. | Treat the puncta as unresolved, assess appropriate IF controls and consult the separate IF/ICC guide for its workflow (general IF interpretation practice). |
Experiment evidence
IHC & IF images showing ENPP3 staining
A05615 · IHCImmunohistochemistry (IHC) analysis of paraffin-embedded Rat Testis, antibody was diluted at 1:100.
A05615 · IHCImmunohistochemistry (IHC) analysis of paraffin-embedded Rat Testis, antibody was diluted at 1:100.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000154269-ENPP3/tissue/cerebral+cortex#imid_12024715
HPA · Small intestineHuman Protein Atlas IHC, Small intestine. Source: https://www.proteinatlas.org/ENSG00000154269-ENPP3/tissue/small+intestine#imid_12024336
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000154269-ENPP3/tissue/colon#imid_12024369
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000154269-ENPP3/tissue/liver#imid_12024354
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for ENPP3 IHC & IF
🧪Run duodenum first: enterocyte microvilli should show apical staining (High; HPA: duodenum, enterocyte microvilli), while neighboring cells without a microvillar border should lack that distinct apical pattern (UniProt O14638 localisation). Run adipose tissue as the negative comparator: adipocytes are not detected (HPA: adipose tissue, adipocytes).
Positive control tissue: Duodenum (Enterocytes - Microvilli, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for ENPP3; derive a cell-line control from the positive tissue's cell type (Enterocytes - Microvilli) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary (secondary-only) control, a host- and immunoglobulin-class-matched isotype control for a monoclonal antibody or same-host nonimmune IgG for a polyclonal antibody, and ENPP3-knockout tissue where available (standard IHC practice). For duodenum, quench endogenous peroxidase and block endogenous biotin if using avidin–biotin detection (standard chromogenic IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A05615 paraffin-section rat testis caption does not state a fixative (caption: A05615). Antigen-retrieval dependence is unreported; the supplied evidence does not establish that frozen sections or IF are easier (HPA subcellular: no ICC-IF images). Because ENPP3 is apical and can be secreted into epithelial lumens, distinguish an intact enterocyte brush-border rim from luminal staining when scoring duodenum (UniProt O14638 localisation).
HPA tissue IHC evidence for ENPP3
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Medium consistency between antibody staining and RNA expression data. At least one protein variant secreted, tissue location of RNA and protein might differ and correlation is complex.). 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 |
|---|---|---|---|---|
| Duodenum | Enterocytes - Microvilli | High | Protein (IHC) | HPA → |
| Kidney | Proximal tubules (microvilli) | High | Protein (IHC) | HPA → |
| Nasopharynx | Ciliated cells (cilia axoneme) | High | Protein (IHC) | HPA → |
| Seminal vesicle | Glandular cells | High | Protein (IHC) | HPA → |
| Small intestine | Enterocytes - Microvilli | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Appendix | Endocrine cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced ENPP3 IHC Tips
Troubleshoot ENPP3 staining by checking apical localisation, extracellular signal, and cell-specific controls before comparing staining intensity across sections.
What retrieval conditions should I try when ENPP3 staining is weak in paraffin sections?
Start with citrate buffer at pH 6.0, heated to 95–98 °C for 20 minutes, then allow the sections to cool (page retrieval rule: membrane antigen). Keep section thickness, heating vessel, cooling time, and antibody incubation constant while comparing a high-signal control such as kidney proximal-tubule microvilli (HPA: High in kidney proximal-tubule microvilli). If staining remains weak, test a different retrieval condition on matched sections as a fallback, recording both signal and tissue damage; the supplied A05615 caption reports no retrieval condition (A05615 tissue-IHC caption). Judge improvement by sharper apical staining rather than stronger diffuse color, since ENPP3 is reported at epithelial apical surfaces (UniProt O14638 localisation).
Could fixation explain weak or uneven ENPP3 staining?
Target-specific fixation sensitivity is unknown: the A05615 image describes paraffin-embedded rat testis at 1:100 but does not state its fixative (A05615 tissue-IHC caption). Record the fixative, time before fixation, fixation duration, and processing schedule for each specimen, then compare matched sections processed together. Use the same citrate pH 6.0, 95–98 °C, 20-minute retrieval and detection conditions when assessing whether processing differences track with staining (page retrieval rule: membrane antigen). Evaluate intact morphology and the expected apical pattern alongside intensity; neither the HPA tissue pattern nor ENPP3 topology establishes a fixation-dependent effect (HPA: membranous and extracellular positivity; UniProt O14638 topology).
Where should ENPP3 staining appear, and how should extracellular color be assessed?
Expect predominantly surface-associated or apical staining in appropriate epithelium: ENPP3 has a membrane anchor at residues 12–30 and an extracellular region at 31–875 (UniProt O14638 topology). High signal in enterocyte microvilli and kidney proximal-tubule microvilli provides useful pattern references (HPA: High in small-intestine enterocyte and kidney proximal-tubule microvilli). Extracellular staining can also be compatible with ENPP3 because a secreted form and epithelial luminal localisation are reported (UniProt O14638 localisation; HPA: extracellular positivity). Compare the stained surface with the epithelial outline and luminal space, while checking whether similarly placed color appears in the negative-control section.
How can I troubleshoot discordant staining when the antibody epitope is unspecified?
The supplied record lists 0 isoforms, so an isoform-specific explanation for discordant IHC is unsupported here (UniProt O14638 isoform record). ENPP3 has an extracellular region spanning residues 31–875, with 10 listed glycosylation sites, but the A05615 caption does not identify its epitope (UniProt O14638 topology and glycosylation; A05615 tissue-IHC caption). Check the antibody documentation for its immunogen and whether the recognised sequence lies inside or outside the membrane before changing epitope-access conditions. Compare matched sections using the page’s citrate pH 6.0 retrieval and a documented fallback only if needed, judging both tissue preservation and the expected apical pattern (page retrieval rule; UniProt O14638 localisation).
How should I assess ENPP3 by multiplex IF alongside this IHC guide?
Treat IF as a separate assay requiring its own validation; the A05615 evidence supplied here is a paraffin-section chromogenic IHC image, with no IF result stated (A05615 tissue-IHC caption). Pair ENPP3 with a marker of the expected cell type, such as an enterocyte marker when examining intestinal microvilli, and compare spatial overlap with the apical pattern (HPA: High in enterocyte microvilli). Choose spectrally separated fluorophores, favoring a far-red ENPP3 channel if the tissue has strong shorter-wavelength autofluorescence, and include single-color and no-primary controls. Because residues 31–875 face outward, first establish the antibody’s epitope; compare mild or no permeabilisation for an extracellular epitope with a permeabilised condition if the epitope is cytoplasmic (UniProt O14638 topology).
How can I distinguish ENPP3 signal from diffuse chromogenic background?
Compare a no-primary control and matched sections stained with the catalog antibody, keeping retrieval, peroxidase block, detection reagent, and DAB development consistent. The catalog image uses a 1:100 antibody dilution in paraffin-embedded rat testis; that caption alone does not establish an optimal dilution for other specimens (A05615 tissue-IHC caption). Titrate the primary antibody and shorten DAB development if diffuse color obscures epithelial borders, while retaining the expected apical pattern (UniProt O14638 localisation). Check endogenous peroxidase activity and nonspecific secondary binding with appropriate controls, particularly when extracellular color is present, since ENPP3 can also be secreted (UniProt O14638 localisation; HPA: extracellular positivity).
What should I score when ENPP3 staining varies across epithelial structures? ⚠ ANSWER MARKED FOR VERIFICATION
Define the tissue compartment and scoring unit before analysis: ENPP3 can show apical membranous and extracellular positivity, so these patterns should be recorded separately (UniProt O14638 localisation; HPA: membranous and extracellular positivity). For epithelial cells, report the percentage positive and an intensity-weighted H-score from 0–300, using the same threshold and imaging settings across sections. Normalise cell-based scores to the number of evaluable cells in the specified compartment; for luminal or extracellular deposits, report stained area per mm² of evaluable tissue instead. Include a consistent positive-reference region, such as kidney proximal-tubule microvilli, and exclude folded, detached, or damaged areas before scoring (HPA: High in kidney proximal-tubule microvilli).
Which patterns support true ENPP3 staining rather than an IHC artefact?
A credible result places staining at an expected surface, such as enterocyte or kidney proximal-tubule microvilli, with appropriate morphology and little signal in the no-primary control (HPA: High in both microvillar compartments). Extracellular or luminal color can be plausible because ENPP3 is also reported as secreted, but it requires comparison with adjacent cells and controls (UniProt O14638 localisation; HPA: extracellular positivity). Treat isolated nuclear color, section-edge accentuation, necrotic areas, and widespread DAB color that persists without primary antibody as reasons to investigate artefact; ENPP3’s documented membrane topology does not predict nuclear enrichment (UniProt O14638 topology). Interpret a negative region cautiously: HPA reports several cell types as not detected, while its tissue-IHC reliability notes complex RNA–protein correspondence for a secreted variant (HPA: negative-cell profiles and Enhanced reliability description).
Boster reagents
Best ENPP3 / Ectonucleotide pyrophosphatase/phosphodiesterase family member 3 IHC Antibodies
A05615 has IHC images from paraffin-embedded rat testis and human prostate cancer (catalog image captions); IF is listed as an application, with no IF image supplied (catalog applications and images).
Real IHC data
Anti-CD203c ENPP3 Antibody
Cat # A05615
A05615 has IHC images of paraffin-embedded rat testis and human prostate cancer at 1:100 (catalog image captions). It lists IF as an application and Human, Mouse, and Rat reactivity; no IF image is supplied (catalog applications, reactivity, and images).
Which to pick: For tissue IHC, choose A05615 for paraffin sections supported by its rat testis and human prostate cancer captions; the fixative is unreported (catalog image captions). For IF, A05615 lists a 1:50 dilution, but no IF image or ICC validation is supplied (catalog dilution, applications, and images). For work across species, A05615 lists Human, Mouse, and Rat reactivity, while its IHC images show Rat and Human samples only; clone information is unreported (catalog reactivity, image captions, and clone field).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O14638 (ENPP3_HUMAN, Ectonucleotide pyrophosphatase/phosphodiesterase family member 3).
- Human Protein Atlas. ENPP3 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. ENPP3 subcellular location (ICC-IF): Secreted.
- Human Protein Atlas. ENPP3 antibody validation summary (1 antibodies).
- Divergent splicing factor SRSF1 signaling promotes inflammation post-CME: the SRSF1/ENPP3 axis acts via inhibition of BRD4 O-GlcNAcylation to enhance NF-κB activation and accelerate heart failure. Theranostics 2025 — PMC12203807.
- Phase I Trials of Anti-ENPP3 Antibody-Drug Conjugates in Advanced Refractory Renal Cell Carcinomas. Clinical cancer research : an official journal of the American Association for Cancer Research 2018 — PMC6731023.
- Hypomethylation of the ENPP3 promoter region contributes to the occurrence and development of ovarian endometriosis via the AKT/mTOR/4EBP1 signaling pathway. Biomolecules & biomedicine 2023 — PMC11293237.
- ATP metabolizing enzymes ENPP1, 2 and 3 are localized in sensory neurons of rat dorsal root ganglion. European journal of histochemistry : EJH 2018 — PMC6038112.
- PubMed PMID:9344668 — UniProt-cited evidence.
- PubMed PMID:17974005 — UniProt-cited evidence.
- PubMed PMID:14574404 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for ENPP3 (Ectonucleotide pyrophosphatase/phosphodiesterase family member 3). Expected localisation Membranous and extracellular tissue staining (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A05615 at 1:100 (the product's own IHC validation image is shown). Controls (HPA): positive Duodenum (Enterocytes - Microvilli); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded Rat Testis tissue; fixative not specified (datasheet A05615); 2. Fixation: Image fixative and duration unreported (datasheet A05615); 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-ENPP3, 1:100 (datasheet A05615); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); assess staining empirically.; Caveat: Secreted ENPP3 may contribute extracellular staining (UniProt); Isoform / epitope: No isoforms listed; extracellular vs cytoplasmic epitope matters (UniProt); Regulation: Staining varies by tissue and cell type (HPA tissue IHC). Evidence: UniProt O14638, HPA tissue IHC · Enhanced, HPA ICC-IF · Secreted, Datasheet A05615, PMC12203807, PMC6731023. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/ENPP3/immunohistochemistry-ihc-guide.