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STARD3NL / STARD3 N-terminal-like protein · IHC design guide
Design Immunohistochemistry for STARD3NL
Plan paraffin-section IHC for STARD3NL using its widespread cytoplasmic tissue profile (HPA tissue IHC). Compare high-staining cell types with reported unstained cells, and interpret the pattern alongside its late-endosome membrane location (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
STARD3NL 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 | Cytoplasmic tissue staining (HPA tissue IHC) | |
| Staining pattern | Widespread cytoplasmic staining across cell types (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Breast+4 more · see all | |
| Negative control | Adipose tissue+1 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). Selected-image fixative and duration unreported (datasheet A11121); verify before use. | |
| Caveat | Adipocytes and esophageal squamous cells may be unstained (HPA tissue IHC) | |
| Regulation | No expression regulator annotated (UniProt) | |
| Isoform / epitope | Two isoforms; epitope differences are unspecified (UniProt) |
Section 1
Recommended STARD3NL IHC & IF Protocols
The catalog antibody’s IHC-P protocol (datasheet) is accompanied by a published chromogenic protocol for hepatocellular carcinoma tissue microarrays (PMC13485826).
| Sample | Paraffin-embedded Human colon carcinoma tissue; fixative not specified (datasheet A11121) |
| Fixation | Image fixative and duration unreported (datasheet A11121); 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-STARD3NL, 1:50-1:200 (datasheet A11121) |
| 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 | STARD3NL-positive staining in myoepithelial cells of breast (HPA tissue IHC: High). HPA tissue profile: Ubiquitous cytoplasmic expression. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 HIER at 95–98 °C for 20 min (page retrieval rule); the article reports HIER without its conditions (PMC13485826).
Section 2
What Is the Expected STARD3NL Staining Pattern?
STARD3NL is a four-pass late-endosome membrane protein that also contacts the endoplasmic reticulum (UniProt O95772 topology and function). In paraffin-section IHC, expect cytoplasmic staining, especially in breast myoepithelial cells, cerebellar Purkinje cells, cortical and hippocampal neurons, epididymal glandular cells, and testicular Leydig cells (HPA: High in each). HPA describes the overall tissue pattern as ubiquitous cytoplasmic expression and rates its IHC reliability Enhanced, with medium consistency between staining and RNA data (HPA tissue IHC).
| Cytoplasmic signal in the listed High cell populations, with tissue structures still discernible. | This fits the reported IHC pattern (HPA: High in those cell populations; ubiquitous cytoplasmic profile). The late-endosome membrane assignment supports an intracellular location (UniProt O95772). Score the specified cells rather than treating every cell in a positive tissue as equally positive (HPA tissue IHC). |
| A predominantly nuclear, extracellular, or continuous cell-surface pattern replaces cytoplasmic staining. | That compartment disagrees with the reported cytoplasmic IHC profile and late-endosome membrane location (HPA tissue IHC; UniProt O95772). Treat it as a possible staining artefact; review morphology, the negative control, and the validated antibody before assigning it to STARD3NL (standard IHC practice). |
| Strong staining appears in adipocytes or esophageal squamous epithelial cells. | Both cell populations are reported as Not detected (HPA tissue IHC). Check whether the signal is specific: cross-reactivity or endogenous detection activity are possibilities, not established causes (standard IHC practice). Compare the negative control and a High cell population on the same run. |
| Diffuse color covers cells or tissue regions without a discernible cellular pattern. | A uniform haze cannot establish the reported cytoplasmic localization (HPA tissue IHC). It may reflect nonspecific background or detection activity (standard IHC practice). Judge it against a reagent negative control and the morphology before scoring positive cells. |
| No staining is visible in a chosen High cell population. | An absent signal conflicts with that population's reported High staining (HPA tissue IHC), but one section does not establish biological absence. Confirm that the relevant cells are present, then examine controls and the staining workflow (standard IHC practice). |
💡Expected STARD3NL appearanceCall a section positive when the specified High cell populations show discernible cytoplasmic staining (HPA tissue IHC); predominantly nuclear or diffuse tissue-wide color is a suspect pattern (HPA tissue IHC; UniProt O95772; standard IHC practice).
| Cell population selected for scoring | HPA reports High staining in six specified populations, Medium in adrenal and appendix glandular cells, and Not detected in adipocytes and esophageal squamous cells (HPA tissue IHC). Compare like cells. |
| Membrane topology and compartment | Four transmembrane segments place STARD3NL in the late-endosome membrane (UniProt O95772 topology). HPA's tissue-level readout is cytoplasmic; it does not establish puncta resolution in paraffin sections (HPA tissue IHC). |
| Antibody evidence | The listed rabbit polyclonal HPA019204 is IHC Enhanced (HPA antibodies). That supports the reported pattern, while HPA notes only medium consistency between antibody staining and RNA expression data (HPA tissue IHC). |
| Isoforms and epitope | UniProt lists two isoforms and cytoplasmic plus extracellular segments (UniProt O95772). No epitope position is supplied, so these records cannot predict isoform coverage or an optimal permeabilisation choice. |
| What should IF/ICC show? | Vesicular staining is the supported ICC-IF location (HPA subcellular); HPA019204 is ICC Supported (HPA antibodies). Use the separate IF/ICC guide for its workflow. |
| Situation | Likely cause | Next action |
|---|---|---|
| High cell populations show no chromogenic signal. | The expected cells may be absent from the section, or the staining run may have failed; the cause is unresolved (HPA: High in the specified populations; standard IHC practice). | Locate the relevant cells morphologically and check a positive control, primary-antibody step, and detection reagents (standard IHC practice). |
| Color appears in reagent negative controls or across many unrelated structures. | Endogenous detection activity or nonspecific reagent background is possible (standard IHC practice); it does not confirm STARD3NL localization. | Use the matching negative control to identify the affected step; review blocking and detection conditions before scoring (standard IHC practice). |
| Signal is mainly nuclear or outlines the entire cell surface. | The pattern conflicts with cytoplasmic IHC and late-endosome membrane localization (HPA tissue IHC; UniProt O95772). | Inspect the negative control and a known High cell population; reassess antibody specificity and staining conditions (standard IHC practice). |
| Adipocytes or esophageal squamous cells stain strongly. | These cells are reported Not detected (HPA tissue IHC); cross-reactivity or detection background is possible (standard IHC practice). | Compare a reagent negative control and the run's positive cells; avoid calling that signal specific without supporting controls (standard IHC practice). |
| A Medium population stains less than a High population. | Different reported levels can explain the contrast: adrenal and appendix glandular cells are Medium, while the listed positive populations are High (HPA tissue IHC). | Score the same cell types and compartments separately; do not require equal intensity across tissues (HPA tissue IHC; standard IHC practice). |
| The expected cytoplasmic pattern remains weak after routine setup checks. | This record supplies no target-specific fixation sensitivity or antigen-retrieval condition; the cause cannot be assigned from HPA or UniProt. | Review the catalog antibody's validated IHC conditions and run controls, then optimize routine retrieval and dilution variables empirically (standard IHC practice). |
Experiment evidence
IHC & IF images showing STARD3NL staining
A11121 · IHCImmunohistochemistry of paraffin-embedded Human colon carcinoma using STARD3NL Rabbit pAb at dilution of 1:100 .Perform microwave antigen re
A11121 · IHCImmunohistochemistry of paraffin-embedded Rat brain using STARD3NL Rabbit pAb at dilution of 1:100 .Perform microwave antigen retrieval with
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000010270-STARD3NL/tissue/cerebral+cortex#imid_5099052
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000010270-STARD3NL/tissue/colon#imid_5098986
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000010270-STARD3NL/tissue/liver#imid_5098979
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000010270-STARD3NL/tissue/kidney#imid_5098980
HPA · ICC-IF Rh30Human Protein Atlas immunofluorescence, Rh30, antibody HPA019204; green = STARD3NL, blue = nucleus, red = microtubules.
HPA · ICC-IF Rh30Human Protein Atlas immunofluorescence, Rh30, antibody HPA019204; green = STARD3NL, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for STARD3NL IHC & IF
🧪Run breast first and score myoepithelial cells, which have high STARD3NL staining (HPA: High in breast myoepithelial cells). Use adipose tissue as the negative tissue (HPA: Not detected in adipocytes); on the breast slide, treat neighboring cells as internal negatives only if they remain unstained in the actual section, because the supplied HPA row does not establish their status.
Positive control tissue: Breast (Myoepithelial cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show STARD3NL in Rh30, U-251MG, U2OS, NIH 3T3, with annotated localisation: Vesicles (supported) (HPA subcellular).
Technical controls: Include a no-primary (secondary-only) control, concentration-matched nonimmune rabbit IgG for the rabbit polyclonal catalog antibody (selected-SKU caption: Rabbit pAb), and STARD3NL knockout tissue or a validated peptide-block control. Block endogenous peroxidase for chromogenic IHC; if using avidin–biotin detection, control for endogenous biotin (standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected-SKU paraffin-section caption does not state a fixative (selected-SKU caption: fixative not stated). The caption specifies microwave retrieval in 10 mM PBS, pH 7.2, before staining at 1:100; it does not establish that retrieval is required across specimens (selected-SKU caption). Frozen sections and IF cannot be ranked as easier from the supplied evidence; for breast IHC, resolve the thin myoepithelial layer from adjacent cells when scoring (HPA: High in breast myoepithelial cells).
HPA tissue IHC evidence for STARD3NL
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Medium consistency between antibody staining and RNA expression data.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Breast | Myoepithelial cells | High | Protein (IHC) | HPA → |
| Cerebellum | Purkinje cells | High | Protein (IHC) | HPA → |
| Cerebral cortex | Neuronal cells | High | Protein (IHC) | HPA → |
| Epididymis | Glandular cells | High | Protein (IHC) | HPA → |
| Hippocampus | Neuronal cells | High | Protein (IHC) | HPA → |
Section 3
Advanced STARD3NL IHC Tips
Troubleshoot STARD3NL staining in paraffin-section IHC by checking retrieval, cellular distribution, controls, and scoring before interpreting chromogenic signal.
Which retrieval conditions should I try first for weak STARD3NL staining?
Start with citrate buffer at pH 6.0 for heat-induced epitope retrieval at 95–98 °C for 20 min (page retrieval setting). If staining remains weak, compare a neighboring section using microwave retrieval in 10 mM PBS, pH 7.2, the condition reported for the 1:100 A11121 paraffin-section image (A11121 tissue-IHC caption). Keep section thickness, antibody incubation, and chromogen development matched so that retrieval is the variable being assessed (standard IHC practice). Watch for tissue lifting or damaged morphology as signs to reduce retrieval intensity (standard IHC practice). Judge improvement by cytoplasmic staining in the same cell population, rather than by stronger diffuse color alone (HPA: ubiquitous cytoplasmic expression; standard IHC practice).
How should I handle fixation when STARD3NL staining varies between blocks?
Target-specific fixation sensitivity is unknown; the A11121 paraffin-section caption does not state a fixative (A11121 tissue-IHC caption). Record the fixative and processing history for each block, then compare sections processed and stained together before attributing differences to STARD3NL abundance (standard IHC practice). Use the same retrieval setting, citrate pH 6.0 at 95–98 °C for 20 min, when assessing those differences (page retrieval setting). Check morphology and preservation of cytoplasmic detail, since poorly preserved sections make cellular scoring unreliable (standard IHC practice). Include a reference section in each staining run to distinguish block variation from a change in the staining procedure (standard IHC practice).
What cellular pattern should count as plausible STARD3NL staining?
Score STARD3NL primarily as cytoplasmic staining with a vesicular pattern, rather than as a nuclear marker (HPA tissue: ubiquitous cytoplasmic expression; HPA subcellular: vesicles supported). Its reported late-endosome membrane location makes punctate or granular cytoplasmic signal plausible at adequate resolution (UniProt O95772: late endosome membrane). Contacts with the endoplasmic reticulum involve VAPA, VAPB, or MOSPD2, but a chromogenic tissue section alone cannot resolve those contact sites (UniProt O95772: localization; standard IHC practice). Compare staining within identified cell types and inspect an adjacent negative control for diffuse chromogen (standard IHC practice). Treat a nuclear-only pattern as requiring antibody and detection controls before assigning it to STARD3NL (HPA tissue; standard IHC practice).
Could isoforms or epitope position explain inconsistent staining?
Two STARD3NL isoforms are listed, but the supplied evidence does not map the A11121 epitope or establish which isoforms it detects (UniProt O95772: isoforms 1 and 2; A11121 tissue-IHC caption). The protein has four transmembrane segments and cytoplasmic regions at residues 1–53, 119–122, and 172–234 (UniProt O95772: topology). Its other listed loops face the noncytoplasmic side, so epitope position could affect access after processing and retrieval (UniProt O95772: topology; standard IHC practice). Compare retrieval conditions on neighboring sections before calling a weak result isoform-specific (standard IHC practice). Interpret discrepancies cautiously because the supplied record also lists phosphorylation sites without showing their effect on this antibody (UniProt O95772: modified residues).
How can IF help check an ambiguous chromogenic STARD3NL pattern?
Use IF as a separate corroborating experiment and compare its cellular distribution with the paraffin-section IHC result (standard IHC/IF practice). Pair STARD3NL with a validated marker for the expected cell type; HPA reports high IHC staining in Purkinje cells and breast myoepithelial cells, among others (HPA tissue: high staining). Select fluorophores after checking tissue autofluorescence and include unstained and single-label controls for channel bleed-through (standard IF practice). Match permeabilisation to the antibody’s mapped epitope: cytoplasmic regions and noncytoplasmic loops occupy different sides of the membrane, while the A11121 epitope is unspecified here (UniProt O95772: topology; A11121 tissue-IHC caption). Assess whether puncta agree with the supported vesicular localization (HPA subcellular: vesicles supported).
What should I check when STARD3NL staining looks diffuse?
First compare the stained section with a no-primary control to identify signal generated by the detection system (standard IHC practice). Apply an appropriate endogenous peroxidase block before enzyme-based chromogenic detection, and keep its timing consistent across sections (standard IHC practice). If color remains broadly diffuse, optimize antibody concentration and development time on matched sections; the A11121 image reports 1:100, which is a tested image condition rather than a universal dilution (A11121 tissue-IHC caption; standard IHC practice). Review section edges, folds, and drying artifacts before scoring stained cells (standard IHC practice). Prefer cellular cytoplasmic signal over uniform extracellular or nuclear color when assessing STARD3NL (HPA tissue: cytoplasmic expression; standard IHC practice).
How should I quantify STARD3NL across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and tissue area before scoring, since HPA describes widespread cytoplasmic staining with different intensities among cell types (HPA tissue: ubiquitous cytoplasmic expression; HPA tissue: cell-level staining). For a chromogenic section, report the percentage of positive cells and an H-score based on intensity categories 0–3, using identical thresholds across specimens (standard IHC practice). If counting positive cells per area, express density per mm² of viable, evaluable tissue (standard IHC practice). Normalize comparisons to the same cell type or compartment and the same viable tissue denominator, excluding folds and necrosis by a predefined rule (standard IHC practice). Keep exposure, staining batch, and scoring rules consistent, and report whether scoring was blinded (standard IHC practice).
When is a positive STARD3NL result convincing?
A convincing result places reproducible cytoplasmic signal in identifiable cells and agrees with control sections (HPA tissue: ubiquitous cytoplasmic expression; standard IHC practice). HPA reports high staining in Purkinje, neuronal, Leydig, and breast myoepithelial cells, while adipocytes and esophageal squamous epithelial cells were not detected in its tissue observations (HPA tissue: cell-level staining). Use those observations as context, accounting for HPA’s reported medium consistency between antibody staining and RNA data (HPA tissue: Enhanced reliability description). Question nuclear-only staining, color concentrated at section edges or necrosis, and signal persisting without primary antibody (HPA tissue: cytoplasmic expression; standard IHC practice). Check endogenous enzyme background before interpreting diffuse chromogen as STARD3NL (standard IHC practice).
Boster reagents
Best STARD3NL / STARD3 N-terminal-like protein IHC Antibodies
A11121 has real paraffin-section IHC images from human colon carcinoma and rat brain (catalog image captions). Mouse is listed as reactive, but no IF/ICC data are provided (catalog reactivity; applications; image list).
Real IHC data
Anti-STARD3NL Antibody
Cat # A11121
A11121 is the sole card and lists IHC for human, mouse and rat (catalog applications; reactivity). Its images show staining of paraffin-embedded human colon carcinoma and rat brain at 1:100, with microwave retrieval in 10 mM PBS, pH 7.2 (A11121 image captions).
Which to pick: Choose A11121 for paraffin-section IHC: it is a rabbit polyclonal antibody with those two tissue images and a listed IHC dilution of 1:50–1:200 (A11121 image captions; catalog IHC dilution). Its listed reactivity covers human, mouse and rat, although the images document human and rat tissue only (catalog reactivity; A11121 image captions). No listed SKU has IF/ICC data, and the fixative used for the imaged paraffin sections is unreported (catalog applications; IF image list; A11121 image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O95772 (STR3N_HUMAN, STARD3 N-terminal-like protein).
- Human Protein Atlas. STARD3NL tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. STARD3NL subcellular location (ICC-IF): Localized to vesicles..
- Human Protein Atlas. STARD3NL antibody validation summary (1 antibodies).
- STARD3NL as a prognostic marker related to an immunosuppressive tumor microenvironment in hepatocellular carcinoma. Frontiers in oncology 2026 — PMC13485826.
- PubMed PMID:12393907 — UniProt-cited evidence.
- PubMed PMID:12975309 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for STARD3NL (STARD3 N-terminal-like protein). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A11121 at 1:50-1:200 (the product's own IHC validation image is shown). Controls (HPA): positive Breast (Myoepithelial cells); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded Human colon carcinoma tissue; fixative not specified (datasheet A11121); 2. Fixation: Image fixative and duration unreported (datasheet A11121); 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-STARD3NL, 1:50-1:200 (datasheet A11121); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific). Selected-image fixative and duration unreported (datasheet A11121); verify before use.; Caveat: Adipocytes and esophageal squamous cells may be unstained (HPA tissue IHC); Isoform / epitope: Two isoforms; epitope differences are unspecified (UniProt); Regulation: No expression regulator annotated (UniProt). Evidence: UniProt O95772, HPA tissue IHC · Enhanced, HPA ICC-IF · vesicles., Datasheet A11121, PMC13485826. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/STARD3NL/immunohistochemistry-ihc-guide.