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FABP3 / Fatty acid-binding protein, heart · IHC design guide
Design Immunohistochemistry for FABP3
Plan FABP3 paraffin-section IHC around cytoplasmic staining in kidney distal tubules and cardiomyocytes (HPA tissue IHC). Start with the catalog antibody's 0.5–1 μg/mL IHC range (datasheet A01734-1) and include adipose adipocytes, where staining was not detected, as a comparison (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
FABP3 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 | Cytoplasmic in distal tubules and cardiomyocytes; low in myocytes (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6 HIER, heat-mediated (datasheet A01734-1) | |
| Positive control | Kidney+1 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 | Skeletal muscle RNA is enriched, but myocyte staining is low (HPA tissue IHC) | |
| Regulation | Expression regulation not annotated (UniProt) | |
| Isoform / epitope | No isoforms or signal peptide annotated; cytoplasmic target (UniProt) |
Section 1
Recommended FABP3 IHC & IF Protocols
The catalog antibody uses citrate pH 6 heat retrieval (datasheet A01734-1). The published IHC protocols below cover esophageal, muscle, cardiac, and liver specimens (PMC12335710; PMC8489205; PMC12134909).
| Sample | Paraffin-embedded human oesophagus squama cancer tissue; fixative not specified (datasheet A01734-1) |
| Fixation | Image fixative and duration unreported (datasheet A01734-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Citrate pH 6, 20 min (datasheet A01734-1) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A01734-1) |
| Primary antibody | Rabbit anti-FABP3, 0.5-1μg/ml recommended; image 2μg/ml (datasheet A01734-1) |
| Primary incubation | Overnight at 4 °C (datasheet A01734-1) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A01734-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | FABP3-positive staining in distal tubules of kidney (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression mainly in heart and skeletal muscle, and kidney. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6 heat retrieval for the catalog antibody (datasheet A01734-1); the esophageal study instead used Tris-EDTA pH 9 under pressure (PMC12335710).
Section 2
What Is the Expected FABP3 Staining Pattern?
FABP3 is a cytoplasmic protein with no transmembrane segment (UniProt P05413). In IHC, expect staining chiefly in kidney distal tubules, cardiomyocytes, and more weakly in skeletal myocytes (HPA tissue IHC). HPA rates its tissue IHC evidence Enhanced, while reporting medium consistency between antibody staining and RNA expression (HPA tissue IHC).
| Distal tubular cells show clear cytoplasmic staining, with less staining in nearby cells. | This matches HPA's High staining in kidney distal tubules (HPA tissue IHC) and FABP3's cytoplasmic location (UniProt P05413). Assess the named cells rather than assigning one score to the whole kidney section (general IHC practice). |
| Cardiomyocytes stain at moderate intensity; skeletal myocytes stain weakly. | These are compatible with HPA's Medium cardiomyocyte and Low skeletal myocyte observations (HPA tissue IHC). Intensity is relative to the reference material and staining run; a weak skeletal muscle result alone is a less useful failure check than kidney distal tubules (general IHC practice; HPA tissue IHC). |
| Signal appears predominantly nuclear or as a sharp membrane rim in otherwise positive cells. | A dominant nuclear or membrane pattern conflicts with the expected cytoplasmic tissue IHC pattern (UniProt P05413; HPA tissue IHC). Review morphology, counterstain, detection deposits, and controls before calling it FABP3 staining (general IHC practice). |
| Strong staining appears in adipocytes or adrenal glandular cells. | HPA reports FABP3 as Not detected in those cell types (HPA tissue IHC). Check for cross-reactivity or endogenous detection activity, particularly if staining also appears in a control without primary antibody (general IHC practice). |
| Color covers tissue broadly without resolving cell borders or cytoplasm. | Diffuse background cannot establish the cell-specific FABP3 pattern reported by HPA (HPA tissue IHC). Compare a control without primary antibody and inspect whether precipitate, uneven blocking, or detection background obscures tissue detail (general IHC practice). |
💡Expected FABP3 appearanceCall a positive result when distal tubular cytoplasm stains strongly or cardiomyocyte cytoplasm stains moderately (HPA tissue IHC; UniProt P05413); dominant nuclear staining or strong staining of adipocytes warrants a false-positive check (HPA tissue IHC; general IHC practice).
| Cell and tissue choice | Kidney distal tubules provide a High-staining reference; cardiomyocytes are Medium and skeletal myocytes Low (HPA tissue IHC). Adipocytes are reported Not detected (HPA tissue IHC). Choose the cell population before scoring (general IHC practice). |
| Localization and topology | UniProt places FABP3 in the cytoplasm and lists no transmembrane segment (UniProt P05413). Interpret chromogenic tissue IHC in that context; a membrane-only or nuclear-only result needs control review (HPA tissue IHC; general IHC practice). |
| Antibody evidence | HPA lists IHC as Enhanced for HPA055754 and CAB017830, but describes medium consistency between antibody staining and RNA expression (HPA antibodies; HPA tissue IHC). Treat that validation as support for the reported pattern, while checking each run's controls (general IHC practice). |
| Does the ICC-IF location redefine the IHC pattern? | No. HPA's ICC-IF summary reports focal adhesions as uncertain, Golgi as approved, and plasma membrane as uncertain (HPA subcellular). Its tissue IHC profile is cytoplasmic (HPA tissue IHC); interpret each assay against its own reported pattern. |
| Fixation sensitivity | Target-specific fixation sensitivity is unreported in the supplied UniProt and HPA records. Compare routine section-processing controls when troubleshooting, without attributing a changed FABP3 signal to fixation alone (general IHC practice). |
| Situation | Likely cause | Next action |
|---|---|---|
| Kidney distal tubules have no visible signal. | The expected High-staining reference is absent (HPA tissue IHC); the staining run or section may have failed (general IHC practice). | Check tissue morphology and whether a separate run control stained. Review the antibody's validated IHC-P instructions, retrieval step, incubation, and detection reagents before interpreting the section as FABP3-negative (general IHC practice). |
| Cardiomyocytes stain, but skeletal myocytes look negative. | HPA reports Medium staining in cardiomyocytes and only Low staining in skeletal myocytes (HPA tissue IHC). A weak signal may be hard to distinguish from background (general IHC practice). | Assess intact myocytes beside a run control and judge signal above local background. Use kidney distal tubules as the stronger reference when available (HPA tissue IHC; general IHC practice). |
| Signal is mainly nuclear or outlines membranes. | That distribution differs from the cytoplasmic tissue IHC pattern (UniProt P05413; HPA tissue IHC). Detection deposits or nonspecific binding are possible (general IHC practice). | Inspect the counterstain and cell borders at higher magnification; compare the control without primary antibody. Reassess antibody specificity if the discordant pattern persists (general IHC practice). |
| Adipocytes or adrenal glandular cells stain strongly. | Those cells are reported Not detected (HPA tissue IHC). Cross-reactivity or endogenous detection activity may account for unexpected color (general IHC practice). | Compare a control without primary antibody, confirm the stained cell identity, and check endogenous activity control steps appropriate to the detection system (general IHC practice). |
| The section has uniform brown haze or scattered precipitate. | Background can obscure the cell-specific pattern and make intensity scoring unreliable (general IHC practice). | Inspect the control without primary antibody, reagent cleanliness, blocking, washes, and detection development. Score FABP3 only where cellular cytoplasm remains distinguishable (general IHC practice; UniProt P05413). |
| Two antibodies give different tissue patterns. | HPA lists both antibodies as IHC Enhanced but reports only medium staining-to-RNA consistency overall (HPA antibodies; HPA tissue IHC). Discordance needs investigation (general IHC practice). | Compare the same cell populations and controls across matched sections. Prioritize the reported cytoplasmic distal tubular and cardiomyocyte patterns; document unresolved disagreement rather than pooling scores (HPA tissue IHC; general IHC practice). |
Experiment evidence
IHC & IF images showing FABP3 staining
A01734-1 · IHCIHC analysis of Cardiac FABP using anti-Cardiac FABP antibody (A01734-1). Cardiac FABP was detected in paraffin-embedded section of human oe
A01734-1 · IHCIHC analysis of Cardiac FABP using anti-Cardiac FABP antibody (A01734-1). Cardiac FABP was detected in paraffin-embedded section of human to
PA1336 · IHCCardiac FABP was detected in paraffin-embedded sections of human intestinal cancer tissues using rabbit anti-Cardiac FABP Antigen Affinity p
PA1336 · IHCCardiac FABP was detected in paraffin-embedded sections of rat cardiac muscle tissues using rabbit anti-Cardiac FABP Antigen Affinity purifi
A01734-2 · IHCImmunohistochemical analysis of paraffin-embedded H. heart section using FABP3. A01734-2 was diluted at 1:25 dilution. A peroxidase-conjugat
A01734-2 · IHCImmunohistochemical analysis of paraffin-embedded M. heart section using FABP3. A01734-2 was diluted at 1:25 dilution. A peroxidase-conjugat
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000121769-FABP3/tissue/cerebral+cortex#imid_16639575
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000121769-FABP3/tissue/colon#imid_16639517
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000121769-FABP3/tissue/liver#imid_16639502
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000121769-FABP3/tissue/kidney#imid_16639511
HPA · ICC-IF ASC52teloHuman Protein Atlas immunofluorescence, ASC52telo, antibody HPA055754; green = FABP3, blue = nucleus, red = microtubules.
HPA · ICC-IF ASC52teloHuman Protein Atlas immunofluorescence, ASC52telo, antibody HPA055754; green = FABP3, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for FABP3 IHC & IF
🧪Run kidney first and require staining in distal tubules (HPA: High in kidney distal tubules). Run adipose tissue as the negative, where adipocytes are not detected (HPA: Not detected in adipocytes); use cells outside the distal tubules on the kidney slide as internal background comparators, without assuming HPA has classified those cells as negative.
Positive control tissue: Kidney (Distal tubules, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show FABP3 in ASC52telo, Hep-G2, U2OS, with annotated localisation: Focal adhesion sites (uncertain) (HPA subcellular).
Technical controls: Include a no-primary (secondary-only) control, host-matched nonimmune rabbit IgG as an isotype control, and knockout tissue or cells if available as a biological negative (caption: rabbit primary antibody; standard IHC practice). For kidney staining, quench endogenous peroxidase and block endogenous biotin when using biotin-based detection (caption: biotinylated secondary and SABC-DAB; standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A01734-1 paraffin-section caption does not state a fixative (caption: fixative not stated). Heat retrieval in citrate buffer at pH 6 for 20 minutes was used, but the evidence does not establish that retrieval is required (caption: citrate retrieval). Paraffin IHC has a documented workflow; the supplied evidence does not establish whether frozen sections or IF are easier, and kidney tubules require attention to endogenous biotin background with biotin-based detection (caption: paraffin IHC with SABC-DAB; standard IHC practice).
HPA tissue IHC evidence for FABP3
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 |
|---|---|---|---|---|
| Kidney | Distal tubules | High | Protein (IHC) | HPA → |
| Heart muscle | Cardiomyocytes | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Appendix | Endocrine cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced FABP3 IHC Tips
Troubleshoot FABP3 staining by checking retrieval, cytoplasmic localisation, cell type, and control sections before comparing signal across samples.
What retrieval should I start with for FABP3 in paraffin sections?
Start with heat-mediated citrate retrieval at pH 6 for 20 minutes in paraffin sections (datasheet A01734-1). The selected image used that retrieval, followed by 10% goat serum block, 2 µg/mL primary antibody overnight at 4°C, and chromogenic detection (datasheet A01734-1). If staining is weak, first compare freshly prepared citrate buffer, controlled heating and cooling, and a known positive section in the same run (standard IHC practice; HPA: high in kidney distal tubules). Record retrieval time and tissue integrity together, because excessive heating can make damaged sections difficult to interpret (standard IHC practice).
How should I troubleshoot weak FABP3 staining when fixation history varies?
The selected paraffin-section caption does not state a fixative, so target-specific FABP3 sensitivity to fixation is unknown (datasheet A01734-1). Document each specimen’s fixative, fixation duration, processing history, and section age before comparing staining intensity across batches (standard IHC practice). Run the same retrieval and antibody conditions on a known positive control alongside the affected sections; kidney distal tubules provide an HPA-supported positive cell population (datasheet A01734-1; HPA: high in kidney distal tubules). If only one processing batch loses signal, test adjacent sections with a controlled retrieval time series while assessing morphology, without assigning the loss specifically to FABP3 fixation sensitivity (standard IHC practice).
Where should convincing FABP3 staining appear in tissue sections?
Expect predominantly cytoplasmic FABP3 staining in the relevant tissue cells: HPA describes cytoplasmic expression mainly in heart, skeletal muscle, and kidney (UniProt P05413: cytoplasm; HPA: tissue IHC profile). Kidney distal tubules show high staining, cardiomyocytes medium staining, and skeletal myocytes low staining in the supplied HPA profile (HPA: tissue IHC). Evaluate localisation within intact cells using a counterstain and compare matched positive and reagent-control sections (standard IHC practice). HPA’s focal-adhesion, Golgi, and plasma-membrane observations come from subcellular ICC/IF data; the focal-adhesion and membrane assignments are uncertain and should not override tissue-IHC interpretation (HPA: subcellular; HPA: tissue IHC).
Could an isoform or epitope issue explain inconsistent FABP3 IHC?
The supplied UniProt record lists 0 isoforms and no transmembrane segment, so an isoform switch or membrane-sided epitope is not established by this evidence (UniProt P05413: isoforms and topology). Its chain spans residues 2–133, and the record lists several modified residues, including phosphorylation sites, but gives no antibody epitope (UniProt P05413: processing and modified residues; datasheet A01734-1: epitope unreported). Do not attribute a staining difference to a particular modification without epitope mapping and direct testing (standard IHC interpretation). Compare the catalog antibody with an independently validated reagent or a suitable specificity control on serial sections, keeping retrieval and detection constant (standard IHC practice).
How can I adapt this FABP3 IHC evidence to multiplex IF?
Treat multiplex IF as a separate validation exercise: the selected antibody caption documents paraffin-section chromogenic IHC, while HPA subcellular observations come from ICC/IF (datasheet A01734-1; HPA: subcellular). Pair FABP3 with a validated marker identifying the expected cell population, such as cardiomyocytes or kidney distal-tubule cells, and confirm each channel independently (HPA: tissue IHC; standard IF practice). Choose a fluorophore and imaging channel after measuring tissue autofluorescence with an unstained section, then include single-label controls for spectral bleed-through (standard IF practice). FABP3 has no transmembrane segment and is annotated as cytoplasmic, so use controlled permeabilisation for intracellular access while checking morphology and background (UniProt P05413: topology and cytoplasm; standard IF practice).
What should I check when FABP3 DAB staining looks diffuse or widespread?
Inspect a no-primary control and a detection-only control to identify staining contributed by the secondary reagent or chromogenic detection system (standard IHC practice). The selected protocol uses a biotinylated secondary, streptavidin–biotin complex, and DAB; assess endogenous peroxidase and biotin-related signal with appropriate controls and blocking where needed (datasheet A01734-1; standard IHC practice). Compare suspect staining with intact-cell cytoplasm in a positive control, because HPA reports cytoplasmic tissue expression and high signal in kidney distal tubules (HPA: tissue IHC). If background persists, optimise antibody concentration, wash stringency, blocking, and DAB development while preserving the documented pH 6 retrieval starting point (datasheet A01734-1; standard IHC practice).
How should I quantify FABP3 chromogenic staining across specimens? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and tissue region before scoring, then record the percentage of positive viable cells and staining intensity within that population (standard IHC practice). An H-score can combine intensity grades 0–3 with their percentages to give a 0–300 summary; apply the same thresholds and imaging conditions across sections (standard IHC practice). For cell counts, report positive cells per mm² of viable tissue or normalise to the number of eligible cells, and exclude blank space and necrosis by a prespecified rule (standard IHC practice). Keep cardiomyocytes, distal tubules, and skeletal myocytes separate because their supplied reference staining levels differ (HPA: tissue IHC).
How do I distinguish genuine FABP3 positivity from staining artefacts?
Look for staining within intact cytoplasm and in an appropriate cell population; HPA reports high signal in kidney distal tubules, medium signal in cardiomyocytes, and low signal in skeletal myocytes (UniProt P05413: cytoplasm; HPA: tissue IHC). Isolated nuclear staining, staining concentrated at section edges or necrotic areas, and signal reproduced in no-primary controls require investigation before calling cells positive (standard IHC practice). Check endogenous peroxidase contributions when using DAB, and assess the biotin-based detection controls used with the selected protocol (datasheet A01734-1; standard IHC practice). Interpret weak or unexpected tissue staining cautiously because the supplied HPA tissue profile reports only medium consistency between antibody staining and RNA expression (HPA: Enhanced reliability description).
Boster reagents
Best FABP3 / Fatty acid-binding protein, heart IHC Antibodies
The catalog antibodies have IHC images from paraffin sections of human oesophagus, intestine, and heart; mouse heart and skeletal muscle; and rat heart (catalog IHC captions).
Real IHC data
Anti-Cardiac FABP/FABP3 Antibody ®
Cat # A01734-1
Real IHC data
Anti-Cardiac FABP/FABP3 Antibody ®
Cat # PA1336
Real IHC data
Anti-FABP3 Antibody
Cat # A01734-2
A01734-1 has IHC images from human oesophagus cancer, mouse heart, and rat heart (A01734-1 IHC captions); PA1336 has images from human intestinal cancer, rat cardiac muscle, and mouse skeletal muscle (PA1336 IHC captions). A01734-2 has a human heart IHC image and lists human reactivity (A01734-2 IHC caption and catalog applications/reactivity).
Which to pick: For human heart paraffin-section IHC, choose A01734-2, a rabbit polyclonal with a 1:25 IHC-P dilution shown with DAB detection (A01734-2 catalog and IHC caption). For cross-species tissue IHC, choose A01734-1 or PA1336: both list human, mouse, and rat reactivity and show paraffin-section IHC in those species (A01734-1 and PA1336 catalog and IHC captions); the captions do not report the fixative. None of these SKUs lists IF/ICC or provides an IF image, so there is no IF/ICC-validated choice in this payload (catalog applications and IF image fields).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P05413 (FABPH_HUMAN, Fatty acid-binding protein, heart).
- Human Protein Atlas. FABP3 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. FABP3 subcellular location (ICC-IF): Mainly localized to the focal adhesion sites. In addition localized to the plasma membrane and the Golgi apparatus..
- Human Protein Atlas. FABP3 antibody validation summary (2 antibodies).
- A nine-gene signature with potential targets for predicting the prognosis of patients with esophageal cancer. Translational cancer research 2025 — PMC12335710.
- Fatty acid binding protein 3 is associated with peripheral arterial disease. JVS-vascular science 2020 — PMC8489205.
- Fatty Acid-Binding Protein 3 Expression in the Brain and Skin in Human Synucleinopathies. Frontiers in aging neuroscience 2021 — PMC8026871.
- Oleanolic Acid Restores Drug Sensitivity in Sorafenib-resistant Hepatocellular Carcinoma: Evidence from In Vitro and In Vivo Studies. Journal of clinical and translational hepatology 2025 — PMC12134909.
- PubMed PMID:1710107 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:16710414 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for FABP3 (Fatty acid-binding protein, heart). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC). Antigen retrieval: Citrate pH 6 HIER, heat-mediated (datasheet A01734-1). Validated IHC antibody: A01734-1 at 0.5-1μg/ml recommended; image 2μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Kidney (Distal tubules); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human oesophagus squama cancer tissue; fixative not specified (datasheet A01734-1); 2. Fixation: Image fixative and duration unreported (datasheet A01734-1); 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: Citrate pH 6 , 20 min (datasheet A01734-1); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A01734-1); 8. Primary antibody: Rabbit anti-FABP3, 0.5-1μg/ml recommended; image 2μg/ml (datasheet A01734-1); 9. Primary incubation: Overnight at 4 °C (datasheet A01734-1). Watch for: Fixation: Keep fixation consistent across sections. (standard IHC practice; not target-specific); Caveat: Skeletal muscle RNA is enriched, but myocyte staining is low (HPA tissue IHC); Isoform / epitope: No isoforms or signal peptide annotated; cytoplasmic target (UniProt); Regulation: Expression regulation not annotated (UniProt). Evidence: UniProt P05413, HPA tissue IHC · Enhanced, HPA ICC-IF · Mainly localized to the focal adhesion sites. In addition localized…, Datasheet A01734-1, PMC12335710, PMC8489205. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/FABP3/immunohistochemistry-ihc-guide.