This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
PTPRJ / Receptor-type tyrosine-protein phosphatase eta · IHC design guide
Design Immunohistochemistry for PTPRJ
Plan PTPRJ staining in paraffin sections around the cytoplasmic and membranous pattern observed in glandular cells and epithelia (HPA tissue IHC). Start the catalog antibody at 2–5 μg/mL (datasheet A02319-2), using lung macrophages and adipocytes as positive and undetected-cell comparisons (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
PTPRJ 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 | Epithelial cytoplasm and membrane; immune-cell cytoplasm (HPA tissue IHC) | |
| Staining pattern | Glandular/epithelial cytoplasmic-membranous staining; immune subsets cytoplasmic (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A02319-2) | |
| Positive control | Appendix+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) | |
| Caveat | A secreted variant may complicate RNA–protein agreement (HPA tissue IHC) | |
| Regulation | Enhanced at high cell density (UniProt) | |
| Isoform / epitope | 3 isoforms; check extracellular versus cytoplasmic epitope (UniProt) |
Section 1
Recommended PTPRJ IHC & IF Protocols
The catalog antibody’s IHC-P protocol (datasheet A02319-2) is accompanied by one published chromogenic IHC protocol for human breast sections (PMC3398958).
| Sample | Paraffin-embedded human rectal cancer tissue; fixative not specified (datasheet A02319-2) |
| Fixation | Image fixative and duration unreported (datasheet A02319-2); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: EDTA pH 8.0 (datasheet A02319-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A02319-2) |
| Primary antibody | Rabbit anti-PTPRJ, 2-5 μg/ml (datasheet A02319-2) |
| Primary incubation | Overnight at 4 °C (datasheet A02319-2) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A02319-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | PTPRJ-positive staining in glandular cells of appendix (HPA tissue IHC: Medium). HPA tissue profile: Cytoplasmic expression in subsets of immune cells and cytoplasmic membranous expression in most glandular cells and epithelia. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 for the catalog antibody (datasheet A02319-2). The published breast-section protocol used acetone fixation (PMC3398958).
Section 2
What Is the Expected PTPRJ Staining Pattern?
PTPRJ is a cell membrane protein with an extracellular region and cytoplasmic tail; UniProt also lists cell junctions and extracellular space (UniProt Q12913 topology and subcellular location). In tissue IHC, expect cytoplasmic membranous staining in many glandular cells and epithelia, and cytoplasmic staining in subsets of immune cells (HPA tissue IHC profile). HPA rates its tissue staining Approved, with medium consistency against RNA data (HPA tissue IHC reliability).
| Cytoplasmic membranous staining in appendix or endometrial glandular cells. | This fits the glandular pattern; both cell populations have Medium staining in HPA tissue IHC (HPA: appendix and endometrium, glandular cells). Judge the outlined cells and cytoplasm together rather than requiring a thin, uninterrupted membrane rim (HPA tissue IHC profile). |
| Cytoplasmic staining in lung macrophages or bone marrow hematopoietic cells. | These are reported Medium positive populations (HPA: lung macrophages; bone marrow hematopoietic cells). The immune-cell pattern is cytoplasmic, so absence of a crisp membrane outline alone does not make these cells negative (HPA tissue IHC profile). |
| Predominantly nuclear or nucleolar chromogen in tissue sections. | Do not count this as the expected tissue IHC pattern: HPA describes cytoplasmic or cytoplasmic membranous tissue staining (HPA tissue IHC profile). HPA ICC-IF reports uncertain nucleoplasmic and nucleolar locations, which do not establish nuclear staining as the tissue IHC readout (HPA subcellular). |
| Strong color in HPA-negative cell populations, or a uniform haze across unrelated structures. | Staining in adipocytes or skeletal myocytes conflicts with their Not detected HPA calls (HPA: adipocytes; skeletal myocytes). Check morphology and controls before attributing it to PTPRJ; cross-reactivity or endogenous detection activity can produce misleading color (general IHC practice). |
| No signal in a section containing identifiable appendix glandular cells. | The absence conflicts with a reported Medium positive population (HPA: appendix glandular cells). First verify that those cells are present and the detection controls worked; a failed staining run or sample-specific loss remains possible (general IHC practice). HPA approval does not guarantee positivity in every section (HPA tissue IHC reliability). |
💡Expected PTPRJ appearanceCall a result consistent with PTPRJ when identifiable glandular cells show cytoplasmic membranous staining, or reported immune-cell subsets show cytoplasmic staining, at a level compatible with HPA's Medium examples (HPA tissue IHC profile and positive populations); isolated dominant nuclear color or uniform background is not the expected tissue pattern (HPA tissue IHC profile; general IHC practice).
| Cell compartment and epitope position | PTPRJ has an extracellular region at residues 36–975, a membrane span at 976–996, and a cytoplasmic region at 997–1337 (UniProt Q12913 topology). The supplied evidence gives no epitope for a particular IHC antibody, so compartment anatomy cannot predict that antibody's staining behavior. |
| Cell population within a tissue | HPA calls glandular cells Medium in appendix, endometrium, epididymis and gallbladder, but salivary gland glandular cells Not detected (HPA tissue IHC). Select and score the named cell population; a tissue name alone is an insufficient positive or negative call (HPA tissue IHC). |
| Protein distribution and variants | UniProt lists 3 isoforms and an extracellular-space location; HPA notes that at least one protein variant is secreted and that RNA–protein correlation is complex (UniProt Q12913 isoforms and subcellular location; HPA tissue IHC reliability). Do not use RNA abundance alone to adjudicate a spatially discordant stain. |
| Evidence strength | The tissue profile is Approved with medium consistency between staining and RNA expression, and antibody HPA006026 is IHC Approved (HPA tissue IHC reliability; HPA antibody validation). These ratings support comparison with the reported pattern; they do not establish that every positive-looking cell is specific. |
| IF/ICC Q&A | What should IF/ICC show? HPA reports supported cell-junction localization, with uncertain nucleoplasm, nucleoli and nuclear bodies, for its ICC-IF data (HPA subcellular). Those cell-image findings answer the IF/ICC question but do not override the tissue IHC pattern or supply an IHC protocol. |
| Antigen retrieval | No PTPRJ-specific retrieval or fixation sensitivity is established by the supplied UniProt and HPA records. If signal is weak, compare retrieval conditions using a known-positive cell population and run controls; treat this as general IHC optimization, not a predicted PTPRJ effect (general IHC practice). |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected glandular cells are blank. | The reported positive population may be absent from the section, or the staining run may have failed (HPA: appendix and endometrium glandular cells; general IHC practice). | Confirm the glandular cells by morphology, then examine the run's positive and detection controls. If controls fail, repeat the run; if they pass, compare another section containing an HPA-reported Medium population (general IHC practice; HPA tissue IHC). |
| Only nuclei appear positive. | Nuclear dominance does not match HPA's cytoplasmic or cytoplasmic membranous tissue profile; ICC-IF nucleoplasmic localization is marked uncertain (HPA tissue IHC profile; HPA subcellular). | Check a no-primary control and inspect whether cytoplasm or cell borders stain in an HPA-reported positive population. Do not score nuclear color alone as the expected tissue IHC result (general IHC practice; HPA tissue IHC profile). |
| The whole section has diffuse brown background. | Non-specific detection, inadequate blocking or excessive development can obscure cell boundaries (general IHC practice). A diffuse haze is not the described population-specific HPA tissue pattern (HPA tissue IHC profile). | Check no-primary and detection controls, review blocking and chromogen development, and reduce background before interpreting localization (general IHC practice). Reassess identifiable glandular or immune cells against the HPA profile. |
| Negative-reference cells show strong color. | Adipocytes, skeletal myocytes and soft-tissue fibroblasts are Not detected in the listed HPA observations (HPA tissue IHC negative populations). Misidentified cells, cross-reactivity or endogenous enzyme activity may explain unexpected color (general IHC practice). | Verify cell identity and compare no-primary and enzyme-block controls. Treat the listed HPA negatives as cell-population references, not proof that every cell in those tissues must be blank (HPA tissue IHC; general IHC practice). |
| Immune cells stain without a clear membrane rim. | HPA describes cytoplasmic expression in subsets of immune cells and reports Medium staining in lung macrophages and bone marrow hematopoietic cells (HPA tissue IHC profile and positive populations). | Score the identified immune-cell population and its cytoplasmic signal; do not require the glandular cytoplasmic membranous appearance in these cells (HPA tissue IHC profile). Use morphology and neighboring cells to assess whether staining is selective (general IHC practice). |
| An RNA-positive area looks IHC-negative. | HPA reports low tissue RNA specificity but only medium RNA–staining consistency; it also flags a secreted variant as a reason RNA and protein locations may differ (HPA tissue IHC reliability and RNA specificity). | Compare the same named cell population in HPA tissue IHC before calling a contradiction. Check the section and detection controls, then report the protein observation separately from the RNA result (HPA tissue IHC; general IHC practice). |
Experiment evidence
IHC & IF images showing PTPRJ staining
A02319-2 · IHCIHC analysis of DEP1/PTPRJ using anti-DEP1/PTPRJ antibody (A02319-2). DEP1/PTPRJ was detected in a paraffin-embedded section of human rectal
A02319-2 · IHCIHC analysis of DEP1/PTPRJ using anti-DEP1/PTPRJ antibody (A02319-2). DEP1/PTPRJ was detected in a paraffin-embedded section of human liver
A02319-2 · IFIF analysis of DEP1/PTPRJ using anti-DEP1/PTPRJ antibody (A02319-2). DEP1/PTPRJ was detected in a paraffin-embedded section of human liver c
A02319-1 · IHCImmunohistochemical analysis of paraffin-embedded human-liver, antibody was diluted at 1:100
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000149177-PTPRJ/tissue/cerebral+cortex#imid_19684460
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000149177-PTPRJ/tissue/colon#imid_19684394
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000149177-PTPRJ/tissue/liver#imid_19684387
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000149177-PTPRJ/tissue/kidney#imid_19684388
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA006026; green = PTPRJ, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA006026; green = PTPRJ, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for PTPRJ IHC & IF
🧪Run appendix first: its glandular cells should stain at a Medium level (HPA: Appendix, glandular cells, Medium). Use salivary gland as the tissue negative (HPA: Salivary gland, glandular cells, Not detected); on the appendix slide, treat adjacent nonglandular cells as internal background controls only where they are visibly unstained.
Positive control tissue: Appendix (Glandular cells, HPA Medium)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show PTPRJ in A-431, EFO-21, U2OS, RPTEC/TERT1, hTERT-RPE1 (serum starved), with annotated localisation: Nucleoplasm (uncertain), Cell Junctions (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only slide and a host- and immunoglobulin-matched rabbit IgG isotype control (caption: rabbit primary antibody). Confirm specificity with PTPRJ knockout material or a validated peptide-block control; quench endogenous peroxidase and check inflammatory-cell background in appendix before interpreting DAB signal (HPA: Appendix, glandular cells, Medium).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported, and the selected A02319-2 paraffin-section caption does not state the fixative (caption: fixative not stated). The documented IHC workflow uses heat retrieval in EDTA at pH 8.0, but the evidence does not establish that retrieval is required under other conditions (caption: EDTA retrieval, pH 8.0). There is no matched evidence that frozen sections or tissue IF are easier; inspect appendix inflammatory cells for peroxidase-associated DAB background (HPA: Appendix, glandular cells, Medium; caption: HRP/DAB detection).
HPA tissue IHC evidence for PTPRJ
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — 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 |
|---|---|---|---|---|
| Appendix | Glandular cells | Medium | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Medium | Protein (IHC) | HPA → |
| Endometrium | Glandular cells | Medium | Protein (IHC) | HPA → |
| Epididymis | Glandular cells | Medium | Protein (IHC) | HPA → |
| Gallbladder | Glandular cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Cerebral cortex | Endothelial cells | Not detected | Protein (IHC) | HPA → |
| Esophagus | Squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
| Oral mucosa | Squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
| Salivary gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced PTPRJ IHC Tips
Troubleshoot PTPRJ staining in paraffin sections by checking retrieval, cell identity, membrane distribution and assay controls before comparing staining intensity.
What retrieval should I try first for weak PTPRJ staining in paraffin sections?
Begin with heat-mediated antigen retrieval in EDTA at pH 8.0 (datasheet A02319-2). The selected paraffin-section example used 2 μg/ml primary antibody overnight at 4°C after retrieval, so those conditions provide a documented starting point (caption A02319-2). Run a known positive section, such as the documented human rectal cancer specimen, beside the test section to distinguish a retrieval failure from an unexpectedly low signal (caption A02319-2; standard IHC practice). If staining remains weak, adjust heating duration incrementally and inspect tissue morphology after each change; excessive heating can damage sections and complicate interpretation (standard IHC practice).
How should I assess whether fixation caused weak PTPRJ staining?
The selected PTPRJ caption identifies a paraffin-embedded section but does not state its fixative, so target-specific fixation sensitivity is unknown (caption A02319-2). Record the fixative, fixation duration and tissue processing conditions for each specimen before comparing staining between cases (standard IHC practice). Compare a weak section with a known positive section processed under the same conditions, using the documented pH 8.0 EDTA retrieval as a common starting point (datasheet A02319-2; standard IHC practice). If similarly processed positive tissue also fails, investigate processing and detection controls before attributing the result to biological absence of PTPRJ (standard IHC practice).
Where should PTPRJ staining appear, and how do I assess cytoplasmic signal?
PTPRJ has an extracellular region at residues 36–975, one transmembrane segment at 976–996 and a cytoplasmic region at 997–1337 (UniProt Q12913 topology). Membranous or junctional staining is therefore plausible, while the tissue atlas also reports cytoplasmic signal in subsets of immune cells and cytoplasmic-membranous signal in many glandular cells and epithelia (UniProt Q12913 location; HPA tissue IHC). Score membrane, junctional and cytoplasmic patterns separately rather than treating all brown signal as equivalent (standard IHC practice). If a predominantly nuclear pattern appears, seek independent confirmation: cell junctions are supported in the subcellular atlas, whereas its nucleoplasmic assignment is uncertain (HPA subcellular).
How can I interpret discordant staining when the antibody epitope is unspecified?
PTPRJ has 3 reported isoforms, but the supplied product caption does not identify which isoforms or residues its antibody recognizes (UniProt Q12913 isoforms; caption A02319-2). The extracellular region spans residues 36–975, whereas the cytoplasmic region spans 997–1337; epitope position could therefore affect what a stain detects (UniProt Q12913 topology). The extracellular region also contains numerous annotated glycosylation sites, although the supplied evidence does not place the antibody epitope at any one site (UniProt Q12913 glycosylation; caption A02319-2). For discordant cases, request epitope information and compare staining with an independently validated antibody whose recognized region is known (standard IHC validation practice).
How should I investigate PTPRJ localisation by multiplex IF?
Use a validated marker for the expected cell population, such as a macrophage marker in lung or a glandular-cell marker in an appropriate glandular section, to assign PTPRJ signal to cells (HPA tissue IHC; standard IF practice). Choose a spectrally separated, preferably far-red PTPRJ fluorophore and include single-stain and unstained controls to assess tissue autofluorescence and channel bleed-through (standard IF practice). If the antibody binds an extracellular epitope, assess staining without permeabilisation; if it binds residues 997–1337 on the cytoplasmic side, assess a permeabilised preparation (UniProt Q12913 topology; standard IF practice). The supplied IHC caption does not establish IF performance or antibody epitope location (caption A02319-2).
What controls help separate PTPRJ signal from chromogenic background?
Start with a no-primary control to assess secondary-antibody and detection-system staining, and block endogenous peroxidase before HRP and DAB development (standard IHC practice). The selected example used 10% goat serum, a peroxidase-conjugated anti-rabbit secondary for 30 minutes at 37°C, and DAB (caption A02319-2). If diffuse brown staining persists, check serum blocking, antibody concentration, wash steps and DAB development against the no-primary section (standard IHC practice). Evaluate background separately in immune-rich areas and glandular epithelium, since both can contain genuine PTPRJ-positive cells according to tissue staining evidence (HPA tissue IHC).
How should I score PTPRJ IHC across sections with different cell mixtures? ⚠ ANSWER MARKED FOR VERIFICATION
Define the scored compartment and cell population before measuring intensity, because PTPRJ tissue staining includes immune-cell cytoplasm and glandular-cell cytoplasmic-membranous patterns (HPA tissue IHC). For glandular or epithelial cells, report the percentage positive and an H-score using intensity categories 0–3; keep membrane and cytoplasmic scores separate (standard IHC scoring practice). For discrete immune-cell populations, report positive-cell density per mm² of viable tissue or the percentage positive among identified cells (standard IHC quantification practice). Normalize comparisons to the same tissue compartment and viable area, and keep retrieval, detection and image-acquisition settings consistent across sections (standard IHC practice).
How can I distinguish genuine PTPRJ staining from artefact?
A convincing result follows cell identity and distribution: the tissue atlas reports PTPRJ staining in lung macrophages and in several glandular-cell populations (HPA tissue IHC). Membrane or junctional signal also fits the reported protein topology and supported junctional localisation, while isolated nuclear staining warrants independent validation because the atlas marks nucleoplasmic localisation uncertain (UniProt Q12913 topology; HPA subcellular). Inspect section edges and necrotic regions for staining that does not follow intact cells, then compare those areas with the no-primary and peroxidase-block controls (standard IHC practice). Interpret absent staining cautiously because the tissue atlas rates antibody-to-RNA consistency as medium and notes a secreted protein variant (HPA tissue IHC).
Boster reagents
Best PTPRJ / Receptor-type tyrosine-protein phosphatase eta IHC Antibodies
Catalog antibodies A02319-2 and A02319-1 have human paraffin-section IHC images; A02319-2 also has a human liver-cancer IF image (catalog image captions). Listed reactivity spans human, mouse and rat (catalog reactivity).
Real IHC data
Anti-DEP1/PTPRJ Antibody ®
Cat # A02319-2
Real IHC data
Anti-PTPRJ/Dep1 Antibody
Cat # A02319-1
A02319-2 shows IHC on human rectal and liver cancer paraffin sections and IF on a human liver cancer paraffin section; it lists human and rat reactivity (A02319-2 image captions; catalog reactivity). A02319-1 shows IHC on a human liver paraffin section, lists IF and ICC applications, and lists human, mouse and rat reactivity (A02319-1 image caption; catalog applications and reactivity).
Which to pick: For tissue IHC, A02319-2 offers documented EDTA retrieval at pH 8.0 and a 2 μg/ml incubation on human paraffin sections; its fixative is unreported (A02319-2 image captions). For IF, A02319-2 has a human paraffin-section image at 5 μg/ml; for ICC, A02319-1 lists that application and is described as polyclonal, but has no ICC image in the payload (A02319-2 IF image caption; A02319-1 catalog applications and dilution data). For the broadest listed species coverage, choose A02319-1 for human, mouse and rat, while treating its human liver paraffin-section IHC image as the only pictured IHC evidence for that SKU; its fixative is unreported (A02319-1 catalog reactivity; A02319-1 image caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q12913 (PTPRJ_HUMAN, Receptor-type tyrosine-protein phosphatase eta).
- Human Protein Atlas. PTPRJ tissue IHC expression (reliability: Approved).
- Human Protein Atlas. PTPRJ subcellular location (ICC-IF): Mainly localized to the nucleoplasm and cell junctions. In addition localized to the nucleoli and nuclear bodies..
- Human Protein Atlas. PTPRJ antibody validation summary (1 antibodies).
- PTPRJ Inhibits Leptin Signaling, and Induction of PTPRJ in the Hypothalamus Is a Cause of the Development of Leptin Resistance. Scientific reports 2017 — PMC5599550.
- Regulated expression of PTPRJ/CD148 and an antisense long noncoding RNA in macrophages by proinflammatory stimuli. PloS one 2013 — PMC3695918.
- Expression and function of the protein tyrosine phosphatase receptor J (PTPRJ) in normal mammary epithelial cells and breast tumors. PloS one 2012 — PMC3398958.
- Comprehensive multi-omics analysis of pyroptosis for optimizing neoadjuvant immunotherapy in patients with gastric cancer. Theranostics 2024 — PMC11103507.
- PubMed PMID:7937872 — UniProt-cited evidence.
- PubMed PMID:7994032 — UniProt-cited evidence.
- PubMed PMID:16554811 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for PTPRJ (Receptor-type tyrosine-protein phosphatase eta). Expected localisation Epithelial cytoplasm and membrane; immune-cell cytoplasm (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A02319-2). Validated IHC antibody: A02319-2 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Appendix (Glandular cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human rectal cancer tissue; fixative not specified (datasheet A02319-2); 2. Fixation: Image fixative and duration unreported (datasheet A02319-2); 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 retrieval: EDTA pH 8.0 (datasheet A02319-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A02319-2); 8. Primary antibody: Rabbit anti-PTPRJ, 2-5 μg/ml (datasheet A02319-2); 9. Primary incubation: Overnight at 4 °C (datasheet A02319-2). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Caveat: A secreted variant may complicate RNA–protein agreement (HPA tissue IHC); Isoform / epitope: 3 isoforms; check extracellular versus cytoplasmic epitope (UniProt); Regulation: Enhanced at high cell density (UniProt). Evidence: UniProt Q12913, HPA tissue IHC · Approved, HPA ICC-IF · Mainly localized to the nucleoplasm and cell junctions. In addition…, Datasheet A02319-2, PMC3398958. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/PTPRJ/immunohistochemistry-ihc-guide.