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SLC20A1 / Sodium-dependent phosphate transporter 1 · IHC design guide
Design Immunohistochemistry for SLC20A1
Plan chromogenic IHC for SLC20A1 using the catalog antibody’s paraffin-section conditions (datasheet A03537-1). Compare the observed cytoplasmic tissue pattern with the protein’s annotated membrane location, using high-staining gut glandular cells as a reference (HPA tissue IHC; UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
SLC20A1 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); cell membrane localization (UniProt) | |
| Staining pattern | Cytoplasmic staining in gut glandular cells (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A03537-1) | |
| Positive control | Appendix+4 more · see all | |
| Negative control | Adipose tissue |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A03537-1) | |
| Caveat | Staining and RNA expression show medium consistency (HPA tissue IHC) | |
| Regulation | No specific expression regulator annotated (UniProt) | |
| Isoform / epitope | No isoforms annotated; epitope side matters across 10 membrane spans (UniProt) |
Section 1
Recommended SLC20A1 IHC & IF Protocols
The catalog antibody has an IHC-P protocol (datasheet A03537-1). The published protocols below report additional SLC20A1 staining conditions (PMC12612327; PMC11024302; PMC3537628; PMC7426641).
| Sample | Paraffin-embedded human breast cancer tissue; fixative not specified (datasheet A03537-1) |
| Fixation | Image fixative and duration unreported (datasheet A03537-1); 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 A03537-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A03537-1) |
| Primary antibody | Rabbit anti-SLC20A1, 2-5 μg/ml (datasheet A03537-1) |
| Primary incubation | Overnight at 4 °C (datasheet A03537-1) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A03537-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | SLC20A1-positive staining in glandular cells of appendix (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in most tissues. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 for the catalog antibody (datasheet A03537-1). Trypsin retrieval was reported for mouse bladder sections (PMC11024302).
Section 2
What Is the Expected SLC20A1 Staining Pattern?
SLC20A1 is a cell membrane protein with 10 transmembrane segments (UniProt Q8WUM9 topology). In tissue IHC, expect staining in many cell types, including glandular cells of the appendix, colon, duodenum, rectum, and stomach, and hepatocytes in liver (HPA: tissue IHC). HPA describes the observed tissue pattern as predominantly cytoplasmic; its IHC reliability is Approved, with medium consistency between staining and RNA expression (HPA: tissue IHC).
| Glandular cells stain strongly in colon or duodenum (HPA: High in glandular cells). | This matches an observed IHC pattern. Assess the signal in the named cells; HPA reports cytoplasmic expression in most tissues and supported plasma membrane localisation by ICC-IF (HPA: tissue IHC; HPA: subcellular). |
| The dominant signal is nuclear, with little staining in the expected cells. | A nuclear-dominant pattern is unsupported by the supplied localisation records (UniProt Q8WUM9: cell membrane; HPA: tissue IHC; HPA: subcellular). Consider nonspecific staining or a detection artefact before assigning it to SLC20A1 (general IHC practice). |
| Adipocytes stain strongly in adipose tissue (HPA: Not detected in adipocytes). | This conflicts with the HPA tissue observation and warrants a specificity check; cross-reactivity or endogenous detection activity are possibilities, not established causes (HPA: tissue IHC; general IHC practice). |
| Colour spreads across stroma or blank areas without a clear cell pattern. | Diffuse background cannot establish SLC20A1 localisation. Review the no-primary control, blocking, washes, and chromogen development to locate nonspecific or detection-related signal (general IHC practice). |
| No signal appears in glandular cells of appendix or hepatocytes of liver. | Both are reported as High in HPA tissue IHC, so a blank result raises a technical or reagent concern. Check tissue integrity and run the same antibody with appropriate controls before interpreting absence of expression (HPA: tissue IHC; general IHC practice). |
💡Expected SLC20A1 appearanceCall the result positive when the expected glandular cells or hepatocytes show clear, preferably strong staining, consistent with HPA's cytoplasmic tissue IHC pattern; isolated nuclear staining or strong adipocyte staining is suspect (HPA: High in named cells; HPA: Not detected in adipocytes; HPA: tissue IHC).
| Readout and compartment | UniProt places SLC20A1 at the cell membrane, and HPA supports plasma membrane localisation in ICC-IF; HPA tissue IHC nevertheless describes cytoplasmic expression in most tissues. Interpret paraffin IHC against its observed tissue pattern rather than requiring a crisp membrane outline (UniProt Q8WUM9; HPA: subcellular; HPA: tissue IHC). |
| Choice of tissue and cell type | HPA reports High staining in glandular cells of appendix, colon, duodenum, rectum, and stomach, and in liver hepatocytes and placenta decidual cells. It reports adipocytes as Not detected; use those observations as comparisons, with tissue context retained (HPA: tissue IHC). |
| Expression breadth | UniProt describes SLC20A1 as ubiquitously expressed, while HPA assigns low tissue RNA specificity and reports variable IHC levels across named cells. A broadly positive slide therefore needs cell-specific interpretation; expression breadth alone does not validate staining in every cell (UniProt Q8WUM9: tissue specificity; HPA: tissue IHC). |
| Antibody evidence | Two listed antibodies have IHC status Approved (HPA035834 and CAB019279), whereas HPA064386 has ICC status Approved and no listed IHC status. These labels identify the supplied validation context; they do not prove that any staining pattern is specific in an individual run (HPA: antibodies). |
| Topology and unknown epitope | The protein has 10 annotated transmembrane segments, but the supplied record does not map an antibody epitope or document target-specific retrieval sensitivity. Choose and assess retrieval conditions as a general paraffin IHC workflow variable, without predicting an SLC20A1-specific effect (UniProt Q8WUM9 topology; general IHC practice). |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected high-staining cells are blank (HPA: High in colon glandular cells or liver hepatocytes). | The run may have weak detection, unsuitable antibody working conditions, or compromised tissue; the blank slide alone cannot identify which (general IHC practice). | Check section quality and a same-run positive tissue control; review the IHC-validated antibody's documented retrieval and dilution instructions, then verify detection reagents (general IHC practice). |
| Signal is mainly nuclear. | This compartment disagrees with the supplied membrane and tissue IHC localisation evidence; nonspecific staining or detection artefact is possible (UniProt Q8WUM9; HPA: tissue IHC; general IHC practice). | Compare no-primary and positive tissue controls, then reassess antibody concentration and detection conditions before scoring the nuclear signal (general IHC practice). |
| Adipocytes show strong staining. | HPA reports adipocytes as Not detected; antibody cross-reactivity or endogenous activity could explain the discrepancy, but neither is established by that observation (HPA: tissue IHC; general IHC practice). | Inspect a no-primary control and the expected positive cells in the same run; investigate endogenous enzyme activity if the chromogenic control is positive (general IHC practice). |
| The whole section has diffuse colour. | Background may reflect insufficient blocking or washing, excessive antibody or detection reagent, or prolonged chromogen development (general IHC practice). | Use a no-primary control to localise the source; adjust one general workflow variable at a time and preserve the named positive-cell pattern when judging improvement (general IHC practice; HPA: tissue IHC). |
| Only a faint membrane rim appears, with little cytoplasmic tissue signal. | A membrane rim is compatible with protein localisation, but HPA describes predominantly cytoplasmic expression in tissue IHC; staining intensity may also vary by cell type (UniProt Q8WUM9; HPA: subcellular; HPA: tissue IHC). | Score the specified cells against a same-run positive tissue and controls. Do not require ICC-IF membrane sharpness as the sole criterion for paraffin IHC (HPA: tissue IHC; HPA: subcellular; general IHC practice). |
| An ICC-IF image appears membrane-positive while paraffin IHC looks cytoplasmic. | The two HPA readouts describe different observed appearances: supported plasma membrane localisation by ICC-IF and cytoplasmic expression in most tissue IHC samples (HPA: subcellular; HPA: tissue IHC). | Interpret each image within its assay and controls. Use the HPA tissue IHC pattern for this paraffin IHC decision; consult the separate IF/ICC guide for IF workflow (HPA: tissue IHC; HPA: subcellular; general IHC practice). |
Experiment evidence
IHC & IF images showing SLC20A1 staining
A03537-1 · IHCIHC analysis of SLC20A1 using anti-SLC20A1 antibody (A03537-1). SLC20A1 was detected in a paraffin-embedded section of human breast cancer t
A03537-1 · IHCIHC analysis of SLC20A1 using anti-SLC20A1 antibody (A03537-1). SLC20A1 was detected in a paraffin-embedded section of human colon adenocarc
A03537-1 · IFIF analysis of SLC20A1 using anti-SLC20A1 antibody (A03537-1). SLC20A1 was detected in a paraffin-embedded section of human rectal cancer ti
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000144136-SLC20A1/tissue/cerebral+cortex#imid_18250103
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000144136-SLC20A1/tissue/colon#imid_18250029
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000144136-SLC20A1/tissue/liver#imid_18250046
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000144136-SLC20A1/tissue/kidney#imid_18250031
HPA · ICC-IF PC-3Human Protein Atlas immunofluorescence, PC-3, antibody HPA064386; green = SLC20A1, blue = nucleus, red = microtubules.
HPA · ICC-IF PC-3Human Protein Atlas immunofluorescence, PC-3, antibody HPA064386; green = SLC20A1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for SLC20A1 IHC & IF
🧪Run colon first and look for staining in glandular cells (HPA: colon glandular cells High). Use adipose tissue adipocytes as the negative tissue (HPA: adipocytes Not detected); on the colon slide, nuclei should lack target-specific staining, while unstained nonglandular cells are background comparators rather than established biological negatives (HPA: plasma membrane supported; UniProt Q8WUM9: ubiquitously expressed).
Positive control tissue: Appendix (Glandular cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show SLC20A1 in PC-3, RT-4, U2OS, with annotated localisation: Plasma membrane (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control, a rabbit IgG isotype control matched to the primary antibody’s clonality, and SLC20A1-knockout material processed in parallel (selected tissue-IHC caption: rabbit primary; standard IHC practice). Quench endogenous peroxidase in colon sections before HRP/DAB detection (selected tissue-IHC caption: HRP/DAB; standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the exact A03537-1 tissue-IHC caption does not state the fixative (selected tissue-IHC caption: fixative not stated). The demonstrated paraffin-section procedure uses heat-mediated retrieval in EDTA at pH 8.0; retrieval dependence has not been established by a comparison with unretrieved sections (selected tissue-IHC caption: EDTA pH 8.0). Frozen sections are not established as easier by the supplied evidence, while IF/ICC offers a supported plasma-membrane localization reference; in colon, glandular staining should be distinguished from endogenous peroxidase background (HPA: plasma membrane supported; HPA: colon glandular cells High; standard IHC practice).
HPA tissue IHC evidence for SLC20A1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — 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 |
|---|---|---|---|---|
| Appendix | Glandular cells | High | Protein (IHC) | HPA → |
| Colon | Glandular cells | High | Protein (IHC) | HPA → |
| Duodenum | Glandular cells | High | Protein (IHC) | HPA → |
| Liver | Hepatocytes | High | Protein (IHC) | HPA → |
| Placenta | Decidual cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced SLC20A1 IHC Tips
Troubleshoot SLC20A1 staining in paraffin sections by checking retrieval, cellular localisation, controls and scoring before interpreting differences in signal.
How should I retrieve SLC20A1 in paraffin sections when staining is weak?
Start with heat-mediated retrieval in EDTA at pH 8.0 for paraffin sections (datasheet A03537-1). The same tissue-IHC example used 2 μg/ml primary antibody overnight at 4°C, so keep antibody exposure consistent while assessing retrieval (datasheet A03537-1). Compare a retrieval-treated section with a matched section processed without retrieval, and inspect tissue preservation alongside signal (standard IHC practice). If staining remains weak, optimise heating duration on adjacent sections before considering another buffer as a fallback (standard IHC practice). Assess the result in expected cellular compartments, since SLC20A1 has 10 transmembrane segments and a supported plasma-membrane location (UniProt Q8WUM9 topology; HPA subcellular).
Could fixation explain weak or uneven SLC20A1 staining?
The selected paraffin-section example does not state its fixative, so target-specific fixation sensitivity is unknown (datasheet A03537-1 caption). Record the fixative, fixation duration and processing history for each specimen before comparing staining across sections (standard IHC practice). Assess matched sections with the same EDTA pH 8.0 retrieval and 2 μg/ml primary antibody used in the documented example (datasheet A03537-1). Check morphology and whether weak signal follows processing batches or extends across the whole section (standard IHC practice). Do not assign a fixation effect to SLC20A1 from its topology or tissue staining pattern; neither establishes fixation sensitivity (UniProt Q8WUM9 topology; HPA tissue IHC).
Should SLC20A1 appear at the membrane or throughout the cytoplasm?
Use plasma-membrane enrichment as the main localisation check: SLC20A1 is annotated at the cell membrane, and HPA supports a plasma-membrane location (UniProt Q8WUM9 subcellular; HPA subcellular). HPA nevertheless describes cytoplasmic staining in most tissue sections, so record membrane and cytoplasmic signal separately (HPA tissue IHC). Its 10 predicted transmembrane segments support a membrane-protein interpretation but do not make every cytoplasmic pixel artefactual (UniProt Q8WUM9 topology). Compare intact cells in matched tissue regions and note staining confined to cut edges or damaged areas (standard IHC practice). Treat diffuse staining without plausible cellular structure cautiously, particularly if the control lacking primary antibody also stains (standard IHC practice).
How should epitope uncertainty affect interpretation of an unusual staining pattern?
The supplied record lists 0 isoforms and 10 transmembrane segments, but it does not identify the catalog antibody's epitope (UniProt Q8WUM9 record; datasheet A03537-1 caption). Therefore, do not attribute a membrane-versus-cytoplasmic difference to isoform selectivity or to a particular loop (UniProt Q8WUM9 record; datasheet A03537-1 caption). The record notes phosphoserines at positions 265 and 269, without evidence that they alter this antibody's tissue staining (UniProt Q8WUM9 modified residues). If epitope position becomes available, map it against the annotated transmembrane intervals before changing retrieval conditions (UniProt Q8WUM9 topology; standard IHC practice). Until then, compare compartments and controls under the documented EDTA pH 8.0 workflow (datasheet A03537-1; standard IHC practice).
How can IF help resolve which cells carry SLC20A1 signal?
Use IF as a complementary localisation check, with a marker for the expected cell population in the tissue being examined (standard IF practice). For example, HPA reports high SLC20A1 staining in colon glandular cells, so a glandular-cell marker can help assign signal there (HPA tissue IHC). Choose fluorophores in channels with low tissue autofluorescence and include single-colour and unstained controls before judging overlap (standard IF practice). Because the antibody epitope's membrane side is unspecified, test permeabilised and nonpermeabilised preparations according to the epitope information available, rather than assuming intracellular access is required (datasheet A03537-1 caption; standard IF practice). Evaluate membrane enrichment against HPA's supported plasma-membrane localisation (HPA subcellular).
How do I separate SLC20A1 staining from chromogenic background?
Begin by examining a section processed without primary antibody and a matched section with the IHC-validated antibody (standard IHC practice). The documented example used 10% goat-serum blocking, 2 μg/ml primary antibody overnight at 4°C, and DAB detection (datasheet A03537-1). Include an endogenous-peroxidase block before HRP detection and check whether DAB appears in both sections (standard IHC practice). If both stain, examine blocking, wash steps and detection reagents before assigning signal to SLC20A1 (standard IHC practice). If background occurs only with primary antibody, titrate primary concentration and compare localisation with the supported plasma-membrane pattern (standard IHC practice; HPA subcellular).
What scoring method makes SLC20A1 IHC comparisons reproducible? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cellular compartment and tissue region before scoring, and analyse equivalent areas across specimens (standard IHC practice). Report the percentage of positive cells and an H-score calculated from staining intensity and positive-cell fractions; document whether membrane and cytoplasmic staining were scored separately (standard IHC practice; HPA tissue IHC). For a spatial question, report positive-cell density per mm² of viable tissue, excluding folds and necrotic areas by a stated rule (standard IHC practice). Normalise counts to the number of eligible cells or viable area, and hold imaging and DAB assessment settings constant (standard IHC practice). State the antibody concentration, including 2 μg/ml if following the documented example (datasheet A03537-1).
When is an apparent SLC20A1-positive cell convincing?
A convincing result has cellular staining in a plausible compartment, with plasma-membrane enrichment consistent with SLC20A1 localisation (UniProt Q8WUM9 subcellular; HPA subcellular). HPA also reports cytoplasmic tissue staining, so assess its cell-by-cell pattern rather than rejecting it automatically (HPA tissue IHC). Check cell identity against the sampled tissue: HPA reports high staining in colon glandular cells but no detection in adipocytes (HPA tissue IHC). Treat staining limited to section edges, necrotic areas or the no-primary control as possible processing or endogenous-enzyme artefact (standard IHC practice). Finally, interpret weak differences cautiously because HPA rates its tissue IHC as Approved with medium consistency against RNA expression (HPA tissue IHC).
Boster reagents
Best SLC20A1 / Sodium-dependent phosphate transporter 1 IHC Antibodies
A03537-1 has IHC images from human paraffin sections and an IF image from a human paraffin section (catalog image captions); IHC reactivity is listed for human, mouse and rat (catalog applications).
Real IHC data
Anti-SLC20A1 Antibody ®
Cat # A03537-1
A03537-1 is listed for IHC in human, mouse and rat and IF in human (catalog applications). Its images show IHC in human breast, colon, larynx and liver cancers, plus IF in human rectal cancer, all on paraffin sections (catalog image captions).
Which to pick: Choose A03537-1 for tissue IHC: its own images show chromogenic staining of human paraffin sections (IHC image captions), with a listed starting concentration of 2–5 μg/ml (catalog dilution). For IF, A03537-1 has a human paraffin-section image at 5 μg/ml (IF image caption); ICC validation is unreported (catalog applications and images). The catalog lists human, mouse and rat IHC reactivity (catalog applications), although the pictured IHC sections are human (IHC image captions); the fixative is unreported (catalog image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q8WUM9 (S20A1_HUMAN, Sodium-dependent phosphate transporter 1).
- Human Protein Atlas. SLC20A1 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. SLC20A1 subcellular location (ICC-IF): Localized to the plasma membrane..
- Human Protein Atlas. SLC20A1 antibody validation summary (3 antibodies).
- A matrix stiffness gene signature identifies SLC20A1 as a novel mechano-immunological checkpoint enabling synergistic immunotherapy in pancreatic ductal adenocarcinoma. Cancer immunology, immunotherapy : CII 2025 — PMC12612327.
- Uropathogenic Escherichia coli infection: innate immune disorder, bladder damage, and Tailin Fang II. Frontiers in cellular and infection microbiology 2024 — PMC11024302.
- High expression of the Pi-transporter SLC20A1/Pit1 in calcific aortic valve disease promotes mineralization through regulation of Akt-1. PloS one 2013 — PMC3537628.
- SLC20A1 Is Involved in Urinary Tract and Urorectal Development. Frontiers in cell and developmental biology 2020 — PMC7426641.
- PubMed PMID:2078500 — UniProt-cited evidence.
- PubMed PMID:15815621 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for SLC20A1 (Sodium-dependent phosphate transporter 1). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC); cell membrane localization (UniProt). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A03537-1). Validated IHC antibody: A03537-1 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 breast cancer tissue; fixative not specified (datasheet A03537-1); 2. Fixation: Image fixative and duration unreported (datasheet A03537-1); verify before use.; 3. Sectioning: 4–5 µm sections on charged slides (standard); 4. Deparaffinisation: Xylene, graded ethanol series to water (standard); 5. Antigen retrieval: Heat retrieval: EDTA pH 8.0 (datasheet A03537-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A03537-1); 8. Primary antibody: Rabbit anti-SLC20A1, 2-5 μg/ml (datasheet A03537-1); 9. Primary incubation: Overnight at 4 °C (datasheet A03537-1). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A03537-1); Caveat: Staining and RNA expression show medium consistency (HPA tissue IHC); Isoform / epitope: No isoforms annotated; epitope side matters across 10 membrane spans (UniProt); Regulation: No specific expression regulator annotated (UniProt). Evidence: UniProt Q8WUM9, HPA tissue IHC · Approved, HPA ICC-IF · plasma membrane., Datasheet A03537-1, PMC12612327, PMC11024302. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/SLC20A1/immunohistochemistry-ihc-guide.