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SKIL / Ski-like protein · IHC design guide
Design Immunohistochemistry for SKIL
Plan paraffin-section SKIL staining using the catalog antibody at 2–5 μg/mL with chromogenic detection (datasheet A04131-2). Compare epithelial staining across tissues, and interpret the pattern cautiously because antibody staining and RNA expression show low consistency (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
SKIL 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 and membranous staining (HPA tissue IHC) | |
| Staining pattern | Broad cytoplasmic/membranous staining outside lymphoid tissue and CNS (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A04131-2) | |
| Positive control | Appendix+4 more · see all | |
| Negative control | Cerebellum+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 | Low antibody–RNA concordance; verify staining (HPA tissue IHC) | |
| Regulation | Isoform expression varies by tissue (UniProt) | |
| Isoform / epitope | 5 isoforms; SNOI is restricted to skeletal muscle (UniProt) |
Section 1
Recommended SKIL IHC & IF Protocols
The catalog antibody protocol uses EDTA pH 8.0 heat retrieval (datasheet A04131-2). The published SKIL IHC protocols below provide three tissue staining examples (PMC5047385; PMC10928349; PMC7710697).
| Sample | Paraffin-embedded human esophageal squamous carcinoma tissue; fixative not specified (datasheet A04131-2) |
| Fixation | Image fixative and duration unreported (datasheet A04131-2); 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 A04131-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A04131-2) |
| Primary antibody | Rabbit anti-SKIL, 2-5 μg/ml (datasheet A04131-2) |
| Primary incubation | Overnight at 4 °C (datasheet A04131-2) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A04131-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | SKIL-positive staining in glandular cells of appendix (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic and membranous expression in essentially all cell types, except lymphoid tissue and CNS. No signal in the no-primary control. |
💡Decision noteStart with EDTA pH 8.0 heat retrieval for the catalog antibody (datasheet A04131-2); assess the published citrate or Tris-EDTA conditions when adapting those protocols (PMC5047385; PMC7710697).
Section 2
What Is the Expected SKIL Staining Pattern?
In paraffin tissue IHC, SKIL shows mainly cytoplasmic and membranous staining across many cell types, including glandular and respiratory epithelial cells (HPA tissue IHC). HPA rates the tissue pattern Uncertain because antibody staining has low consistency with RNA data (HPA tissue IHC). ICC-IF instead places SKIL mainly in the nucleoplasm, with additional cytosolic signal (HPA subcellular). SKIL has no transmembrane segment (UniProt P12757 topology).
| Cytoplasmic staining in appendix or colon glandular cells, or bronchial respiratory epithelium (HPA tissue IHC). | These cells are reported High by tissue IHC (HPA tissue IHC). Compare the cellular pattern with a negative control; tissue staining alone is provisional because HPA rates its IHC reliability Uncertain (HPA tissue IHC; general IHC practice). |
| A crisp, exclusively surface or luminal rim with no intracellular staining (HPA tissue IHC; HPA subcellular). | Treat an isolated rim as a compartment mismatch to investigate: tissue IHC reports cytoplasmic and membranous staining, while ICC-IF supports nucleoplasm and cytosol (HPA tissue IHC; HPA subcellular). Check morphology and detection controls before assigning that rim to SKIL (general IHC practice). |
| Strong signal in lymph-node germinal center cells or heart cardiomyocytes (HPA tissue IHC). | Both populations are reported Not detected (HPA tissue IHC). Consider cross-reactivity or endogenous detection activity; compare an adjacent known-positive region and a no-primary control before interpreting the signal (general IHC practice). |
| Uniform chromogen across cells, stroma and empty spaces (general IHC practice). | This lacks the cellular distribution needed for interpretation (general IHC practice). Check no-primary and detection-only controls for background, then reassess blocking, wash steps and primary-antibody concentration (general IHC practice). |
| No staining in appendix glandular cells or bronchial respiratory epithelium (HPA tissue IHC). | Those populations are reported High, so first check section integrity, retrieval, antibody application and detection controls (HPA tissue IHC; general IHC practice). A negative result remains possible because the reference tissue pattern has Uncertain reliability (HPA tissue IHC). |
💡Expected SKIL appearanceA plausible positive shows cellular cytoplasmic staining in High appendix or colon glandular cells, with possible membranous signal (HPA tissue IHC); uniform background or an isolated surface rim warrants control checks rather than a positive call (general IHC practice; HPA subcellular).
| Compartment evidence | Tissue IHC describes cytoplasmic and membranous staining, whereas ICC-IF supports nucleoplasm with additional cytosol (HPA tissue IHC; HPA subcellular). Interpret each assay against its own reference pattern; the difference is unresolved by these payloads (HPA tissue IHC; HPA subcellular). |
| Tissue and isoform context | Isoforms SNON and SNOA are widely expressed, with highest reported expression in skeletal muscle, then placenta and lung (UniProt P12757 tissue specificity). Yet HPA tissue IHC calls skeletal myocytes Low; expression and staining should not be treated as interchangeable readouts (HPA tissue IHC; UniProt P12757 tissue specificity). |
| Antibody validation | The HPA tissue IHC profile is Uncertain; HPA008472 is IHC Uncertain, while HPA014233 has no IHC status listed (HPA tissue IHC; HPA antibodies). Reproducing the expected distribution does not independently establish specificity (HPA tissue IHC; general IHC practice). |
| Topology and processing | SKIL has no transmembrane segment or signal peptide, and its annotated chain spans residues 1–684 (UniProt P12757 topology and processing). Membranous tissue staining therefore needs corroboration; these annotations alone do not prove an artefact or establish shedding (UniProt P12757 topology; HPA tissue IHC). |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected High glandular tissue is blank (HPA tissue IHC). | Assay failure or a true difference from the Uncertain reference pattern is possible (HPA tissue IHC; general IHC practice). | Review section integrity, retrieval conditions, primary-antibody application and detection control; repeat alongside another reported High tissue if available (HPA tissue IHC; general IHC practice). |
| Only a sharp membrane rim is visible (HPA tissue IHC). | The tissue IHC profile includes membranous staining, but ICC-IF supports nucleoplasm and cytosol; a rim alone is ambiguous (HPA tissue IHC; HPA subcellular). | Check cellular morphology and no-primary control, then compare cytoplasmic staining in reported High cells before scoring (HPA tissue IHC; general IHC practice). |
| Negative-reference cells stain strongly (HPA tissue IHC). | Cross-reactivity or endogenous chromogenic activity may contribute; germinal center cells are reported Not detected (HPA tissue IHC; general IHC practice). | Run no-primary and detection controls, review endogenous-enzyme blocking, and compare the pattern with reported High cells (HPA tissue IHC; general IHC practice). |
| Diffuse brown signal obscures cell boundaries (general IHC practice). | Background can arise from nonspecific antibody binding, inadequate washing or detection chemistry (general IHC practice). | Inspect the no-primary control; optimize blocking, wash steps, primary-antibody concentration and chromogen development one variable at a time (general IHC practice). |
| Skeletal muscle appears weaker than expected from expression data (UniProt P12757 tissue specificity). | UniProt reports high skeletal-muscle expression, whereas HPA tissue IHC scores myocytes Low (UniProt P12757 tissue specificity; HPA tissue IHC). | Record the observed cell type and intensity; compare with reported High glandular tissue and avoid calling muscle a failed stain from expression data alone (HPA tissue IHC; general IHC practice). |
| IF/ICC Q: Should nuclear signal be rejected because tissue IHC looks cytoplasmic? (HPA tissue IHC; HPA subcellular) | A: HPA supports nucleoplasmic ICC-IF signal with additional cytosol, while its tissue IHC profile is Uncertain (HPA subcellular; HPA tissue IHC). | Assess IF/ICC against its own subcellular reference and controls; do not use the uncertain chromogenic tissue pattern as a rule that excludes nuclear IF signal (HPA subcellular; HPA tissue IHC; general IF practice). |
Experiment evidence
IHC & IF images showing SKIL staining
A04131-2 · IHCIHC analysis of SnoN/SNO/SKIL using anti-SnoN/SNO/SKIL antibody (A04131-2). SnoN/SNO/SKIL was detected in a paraffin-embedded section of hum
A04131-2 · IHCIHC analysis of SnoN/SNO/SKIL using anti-SnoN/SNO/SKIL antibody (A04131-2). SnoN/SNO/SKIL was detected in a paraffin-embedded section of hum
A04131-2 · IFIF analysis of SnoN/SNO/SKIL using anti-SnoN/SNO/SKIL antibody (A04131-2). SnoN/SNO/SKIL was detected in an immunocytochemical section of A4
A04131-1 · IHCImmunohistochemistry of SnoN in mouse lung tissue with SnoN antibody at 5 μg/mL.
A04131-1 · IFImmunofluorescence of SnoN in Mouse Lung cells with SnoN antibody at 20 μg/mL.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000136603-SKIL/tissue/cerebral+cortex#imid_2548856
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000136603-SKIL/tissue/colon#imid_2548774
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000136603-SKIL/tissue/liver#imid_2548791
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000136603-SKIL/tissue/kidney#imid_2548784
HPA · ICC-IF EFO-21Human Protein Atlas immunofluorescence, EFO-21, antibody HPA014233; green = SKIL, blue = nucleus, red = microtubules.
HPA · ICC-IF EFO-21Human Protein Atlas immunofluorescence, EFO-21, antibody HPA014233; green = SKIL, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for SKIL IHC & IF
🧪Run appendix first: its glandular cells should stain for SKIL (HPA: High in appendix glandular cells). Use heart muscle cardiomyocytes as the negative tissue (HPA: Not detected in cardiomyocytes); on the appendix slide, assess nonglandular cells as internal background, without assuming they are SKIL-negative (HPA: appendix result specifies glandular cells).
Positive control tissue: Appendix (Glandular cells, HPA High)
Negative control tissue: Cerebellum (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show SKIL in EFO-21, SiHa, U2OS, A-431, U-251MG, with annotated localisation: Nucleoplasm (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control, a matched rabbit isotype control if the primary is monoclonal or nonimmune rabbit IgG if it is polyclonal, and SKIL-knockout material as a biological negative (caption: rabbit primary; standard IHC practice). Quench endogenous peroxidase and check for endogenous biotin in the appendix section when using the caption’s biotinylated secondary, streptavidin–biotin complex and DAB detection (caption: SABC/DAB; standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A04131-2 tissue-IHC caption does not state the fixative (caption: fixative not stated). The paraffin-section example uses heat retrieval in EDTA at pH 8.0; it does not establish whether frozen sections or IF would be easier (caption: EDTA pH 8.0 retrieval). In appendix, glandular staining should be judged against the no-primary control because endogenous peroxidase or biotin can complicate chromogenic detection (HPA: High in appendix glandular cells; caption: SABC/DAB; standard IHC practice).
HPA tissue IHC evidence for SKIL
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Uncertain — Low consistency between antibody staining and RNA expression data. Pending external verification.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Appendix | Glandular cells | High | Protein (IHC) | HPA → |
| Breast | Glandular cells | High | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | High | Protein (IHC) | HPA → |
| Cervix | Glandular cells | High | Protein (IHC) | HPA → |
| Colon | Glandular cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Cerebellum | Cells in granular layer | Not detected | Protein (IHC) | HPA → |
| Heart muscle | Cardiomyocytes | Not detected | Protein (IHC) | HPA → |
| Hippocampus | Glial cells | Not detected | Protein (IHC) | HPA → |
| Lymph node | Germinal center cells | Not detected | Protein (IHC) | HPA → |
| Ovary | Ovarian stroma cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced SKIL IHC Tips
Troubleshoot SKIL staining in paraffin sections using the catalog antibody’s tissue IHC conditions while checking compartment, cell type and control concordance.
Which retrieval condition should I start with for weak SKIL staining?
Start with heat-mediated antigen retrieval in EDTA pH 8.0 for paraffin sections (datasheet A04131-2). The selected tissue image used this retrieval before 2 μg/ml primary antibody overnight at 4°C, so keep those conditions consistent while assessing retrieval (caption A04131-2). If staining remains weak, compare a controlled retrieval time series on adjacent sections and inspect morphology for heat damage before changing buffer (standard IHC practice). Include a known stained section and a primary-antibody omission control in each run; a stronger DAB signal alone cannot establish SKIL specificity (standard IHC practice; HPA tissue IHC: Uncertain).
Could fixation explain variable SKIL staining between paraffin blocks?
The selected paraffin-section caption does not report a fixative, and target-specific fixation sensitivity is unknown (caption A04131-2). Record the fixative, fixation duration, block age and processing history for each specimen, then compare sections processed under matched conditions (standard IHC practice). Apply EDTA pH 8.0 heat retrieval and the same antibody concentration across the comparison so retrieval and staining do not obscure a processing difference (datasheet A04131-2; standard IHC practice). If a block stains poorly, assess tissue preservation and a suitable control stain before attributing the loss to SKIL or increasing primary-antibody exposure (standard IHC practice).
How should I assess nuclear versus cytoplasmic SKIL staining in tissue?
Score nuclear and cytoplasmic DAB signal separately within identified cell types, using the counterstain to define nuclei (standard IHC practice). SKIL has supported nucleoplasmic and additional approved cytosolic localisation in cell imaging, while tissue IHC reports widespread cytoplasmic and membranous staining with uncertain reliability (HPA subcellular; HPA tissue IHC). Do not treat a membrane outline alone as confirmation: SKIL has no annotated transmembrane segment, and the tissue staining has low agreement with RNA expression (UniProt P12757 topology; HPA tissue IHC). Compare the pattern across serial sections, a stained reference and primary-antibody omission controls before assigning compartment-specific biological meaning (standard IHC practice).
Can this stain distinguish SKIL isoforms or phosphorylation states?
Do not assign a positive DAB signal to one SKIL isoform unless the antibody’s mapped epitope and isoform reactivity are established (standard IHC interpretation). SKIL has 5 listed isoforms; SNON and SNOA are widely expressed, whereas SNOI expression is restricted to skeletal muscle (UniProt P12757). A modified residue includes phosphoserine at 452, but the supplied antibody caption gives no epitope or phospho-specificity information (UniProt P12757; caption A04131-2). Compare staining with independently validated isoform- or modification-specific evidence if that distinction matters, and report this chromogenic result as SKIL staining without a narrower assignment (standard IHC practice).
How can IF help check an ambiguous SKIL IHC pattern?
Use a parallel IF/ICC assessment as a compartment check, while keeping the paraffin-section chromogenic result as the IHC readout (standard IHC/IF practice). Multiplex SKIL with a marker for the expected cell type, such as an epithelial marker when examining the captioned carcinoma, and assess nucleoplasmic signal separately from cytosol (caption A04131-2; HPA subcellular; standard IF practice). Choose fluorophores after inspecting tissue autofluorescence, favoring a spectrally separated channel when background is high, and include single-label controls (standard IF practice). Because SKIL has no transmembrane segment and its supported location is nucleoplasmic, assess permeabilisation for intracellular epitope access; IF-specific fixation and antibody performance are unreported here (UniProt P12757 topology; HPA subcellular; supplied evidence).
What should I check when SKIL DAB staining is diffuse?
First compare a primary-antibody omission section with the stained section to locate signal arising from the detection system (standard IHC practice). The captioned workflow used biotinylated anti-rabbit secondary antibody, a streptavidin-biotin complex and DAB, so evaluate endogenous biotin and peroxidase activity with appropriate detection controls and blocking (caption A04131-2; standard IHC practice). Check whether background follows section edges, damaged tissue or folds, and keep development and washes consistent between sections (standard IHC practice). Only then titrate the 2 μg/ml primary concentration or incubation conditions; preserve a stained reference because SKIL tissue IHC reliability is uncertain (caption A04131-2; HPA tissue IHC).
How should I quantify SKIL staining across tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring, then report the percentage of positive cells and staining intensity separately for nuclear and cytoplasmic DAB (standard IHC practice; HPA subcellular). An H-score can combine intensity categories with the percentage of cells in each category on a 0–300 scale, provided thresholds are fixed before comparison (standard IHC practice). Normalise counts to the number of eligible cells, or positive-cell density to analysed tissue area in mm², while excluding folds and necrosis consistently (standard IHC practice). Keep retrieval, exposure and development matched across sections, and state that HPA tissue staining has uncertain reliability when interpreting differences (datasheet A04131-2; HPA tissue IHC; standard IHC practice).
Which SKIL staining patterns warrant extra validation before interpretation?
Give greatest weight to reproducible staining in intact cells that tracks a defined cell population and exceeds primary-antibody omission controls (standard IHC practice). Treat isolated edge staining, necrotic regions and diffuse DAB from endogenous enzyme activity as suspect until control sections resolve them (standard IHC practice). Evaluate strong membrane-only staining cautiously: SKIL lacks an annotated transmembrane segment, whereas cell imaging supports nucleoplasmic and additional cytosolic localisation (UniProt P12757 topology; HPA subcellular). HPA tissue IHC also reports cytoplasmic and membranous signal but rates it uncertain, so resolve conflicting compartments with an independent antibody or orthogonal evidence before calling a tissue-specific SKIL pattern (HPA tissue IHC; standard IHC practice).
Boster reagents
Best SKIL / Ski-like protein IHC Antibodies
Anti-SKIL antibodies have IHC images from human paraffin sections and mouse lung tissue, and IF images from A431 and mouse lung cells (catalog image captions).
Real IHC data
Anti-SnoN/SNO/SKIL Antibody ®
Cat # A04131-2
Real IHC data
Anti-SnoN SKIL Antibody
Cat # A04131-1
A04131-2 shows IHC in human esophageal squamous carcinoma and tonsil paraffin sections, plus IF in A431 cells (catalog image captions). A04131-1 shows IHC in mouse lung tissue and IF in mouse lung cells (catalog image captions).
Which to pick: For tissue IHC, choose A04131-2 for human paraffin sections or A04131-1 for mouse lung IHC-P; neither IHC caption reports the fixative (catalog IHC image captions; catalog application list). For IF/ICC, A04131-2 lists both applications and shows IF in A431 cells, while A04131-1 lists IF and shows it in mouse lung cells (catalog application lists and IF image captions). Both list Human, Mouse, and Rat reactivity, but their pictured IHC evidence covers human and mouse respectively; clonality is unreported (catalog reactivity, IHC image captions, and clone fields).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P12757 (SKIL_HUMAN, Ski-like protein).
- Human Protein Atlas. SKIL tissue IHC expression (reliability: Uncertain).
- Human Protein Atlas. SKIL subcellular location (ICC-IF): Mainly localized to the nucleoplasm. In addition localized to the cytosol..
- Human Protein Atlas. SKIL antibody validation summary (2 antibodies).
- Expression and clinical significance of the transforming growth factor-β signalling pathway in endometrial cancer. Histopathology 2011 — PMC5047385.
- Recurrent SKIL-activating rearrangements in ETS-negative prostate cancer. Oncotarget 2015 — PMC4467434.
- NSUN2 promotes colorectal cancer progression by enhancing SKIL mRNA stabilization. Clinical and translational medicine 2024 — PMC10928349.
- SKIL facilitates tumorigenesis and immune escape of NSCLC via upregulating TAZ/autophagy axis. Cell death & disease 2020 — PMC7710697.
- PubMed PMID:2762147 — UniProt-cited evidence.
- PubMed PMID:9207045 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for SKIL (Ski-like protein). Expected localisation Cytoplasmic and membranous staining (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A04131-2). Validated IHC antibody: A04131-2 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Appendix (Glandular cells); negative Cerebellum. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human esophageal squamous carcinoma tissue; fixative not specified (datasheet A04131-2); 2. Fixation: Image fixative and duration unreported (datasheet A04131-2); 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 A04131-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A04131-2); 8. Primary antibody: Rabbit anti-SKIL, 2-5 μg/ml (datasheet A04131-2); 9. Primary incubation: Overnight at 4 °C (datasheet A04131-2). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Caveat: Low antibody–RNA concordance; verify staining (HPA tissue IHC); Isoform / epitope: 5 isoforms; SNOI is restricted to skeletal muscle (UniProt); Regulation: Isoform expression varies by tissue (UniProt). Evidence: UniProt P12757, HPA tissue IHC · Uncertain, HPA ICC-IF · Mainly localized to the nucleoplasm. In addition localized to the…, Datasheet A04131-2, PMC5047385, PMC10928349. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/SKIL/immunohistochemistry-ihc-guide.