This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
BAG4 / BAG family molecular chaperone regulator 4 · IHC design guide
Design Immunohistochemistry for BAG4
Plan BAG4 IHC in paraffin sections using tissue staining and catalog antibody evidence. Expect general cytoplasmic staining (HPA tissue IHC), and compare signal by cell type when scoring.
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
BAG4 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 | General cytoplasmic staining across cell types (HPA tissue IHC) | |
| Antigen retrieval | Tris-EDTA pH 9.0 HIER, heat-mediated (datasheet A06722-1) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | None in HPA (detected in all 45 tissues); use no-primary + isotype controls |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific) | |
| Caveat | Glial cells and myocytes may stain weakly (HPA tissue IHC) | |
| Regulation | Specific stimulus response unreported (UniProt) | |
| Isoform / epitope | 2 isoforms; shared epitope status unspecified (UniProt) |
Section 1
Recommended BAG4 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is followed by published BAG4 staining methods for colon tissue microarrays and patient paraffin sections (PMC5420499; PMC12048998).
| Sample | Paraffin-embedded human tonsil tissue; fixative not specified (datasheet A06722-1) |
| Fixation | Image fixative and duration unreported (datasheet A06722-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Tris-EDTA pH 9.0 (datasheet A06722-1); 20 min, 95–100 °C (standard) |
| 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-BAG4, 1:100-1:300 (datasheet A06722-1) |
| 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 | BAG4-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic expression. No signal in the no-primary control. |
💡Decision noteStart with the catalog antibody’s Tris-EDTA pH 9.0 heat retrieval (datasheet A06722-1); the published methods used other retrieval conditions (PMC5420499; PMC12048998).
Section 2
What Is the Expected BAG4 Staining Pattern?
BAG4 is expected mainly in the cytoplasm, consistent with its lack of a transmembrane segment (UniProt O95429: cytoplasm; no transmembrane segment). In paraffin sections, look for staining in glandular cells, kidney tubule cells and colon endothelial cells (HPA: High in these cells). HPA describes a general cytoplasmic pattern and rates its tissue IHC evidence Approved, with medium consistency between staining and RNA expression (HPA: tissue IHC).
| Cytoplasmic staining in glandular cells of appendix or duodenum (HPA: High in both). | This matches the reported compartment and cell pattern (HPA: general cytoplasmic expression; High in glandular cells). Compare with the same run's controls before scoring intensity (general IHC practice). |
| Predominantly nuclear staining with little cytoplasmic signal. | This conflicts with the reported main pattern (UniProt O95429: cytoplasm; HPA: general cytoplasmic expression). Treat it as suspect and check detection controls and staining conditions (general IHC practice). |
| Strong signal confined to an unexpected cell population while the documented population is unstained. | Consider cross-reactivity or endogenous detection activity (general IHC practice). BAG4 is broadly expressed, so an unlisted cell type alone does not prove a false positive (UniProt O95429: ubiquitous; HPA: low tissue specificity). |
| Diffuse color across multiple compartments and the surrounding section. | Poorly resolved staining prevents a reliable compartment call (general IHC practice). Background may reflect detection or blocking conditions; compare reagent controls before attributing it to BAG4 (general IHC practice). |
| No signal in kidney tubules or appendix glandular cells (HPA: High in both). | An absent signal in these reported high-staining populations weakens confidence in the run (HPA: tissue IHC). Check section quality, retrieval and detection controls before interpreting other areas as negative (general IHC practice). |
💡Expected BAG4 appearanceCall a positive result when defined cytoplasmic staining appears in HPA-reported high-staining cells, such as kidney tubules; isolated nuclear color or diffuse background warrants control review (HPA: general cytoplasmic expression; High in kidney tubules; general IHC practice).
| Compartment and topology (UniProt O95429). | BAG4 is cytoplasmic and has no transmembrane segment; score the cytoplasm as the main expected compartment (UniProt O95429: subcellular location; topology). |
| Cell and tissue variation (HPA: tissue IHC). | Reported High staining includes adrenal and gallbladder glandular cells; glial cells in caudate and skeletal myocytes are Low (HPA: tissue IHC). Compare like cell populations when judging intensity (general IHC practice). |
| Ciliary exception (HPA: fallopian tube). | HPA also reports High staining at the cilia axoneme of fallopian tube ciliated cells (HPA: tissue IHC). Evaluate that finding separately from the general cytoplasmic profile (HPA: tissue IHC). |
| Isoforms and antibody recognition (UniProt O95429). | UniProt lists 2 isoforms (UniProt O95429: isoforms). The supplied evidence gives no antibody epitope or isoform coverage, so isoform-specific staining cannot be predicted. |
| Strength of tissue evidence (HPA: antibody validation). | HPA rates tissue staining Approved with medium RNA agreement and lists 2 IHC-Approved antibodies (HPA: tissue IHC; HPA018951, CAB013716). This does not establish an Enhanced validation rating. |
| Can IF/ICC provide a reference? (HPA: subcellular). | HPA supplies no ICC-IF images or main location assignment (HPA: subcellular). Use the UniProt cytoplasmic annotation as context, but do not infer a confirmed IF pattern (UniProt O95429: cytoplasm). |
| Situation | Likely cause | Next action |
|---|---|---|
| Kidney tubules lack stain although they are reported High (HPA: kidney). | The run may have lost sensitivity; this slide alone cannot identify why (general IHC practice). | Check section integrity, the run's positive control, retrieval conditions and detection reagents before calling the sample negative (general IHC practice). |
| Color is mainly nuclear rather than cytoplasmic (UniProt O95429: cytoplasm). | Non-specific signal or detection background is possible (general IHC practice). | Review a reagent control and assess whether cytoplasmic staining appears in a reported positive population (HPA: tissue IHC; general IHC practice). |
| Background obscures glandular cells reported High (HPA: appendix, duodenum). | Insufficiently controlled detection or blocking can obscure cellular boundaries (general IHC practice). | Compare reagent controls; adjust blocking, washing or detection conditions within the assay workflow (general IHC practice). |
| Colon endothelial cells stain strongly, but nearby cells differ (HPA: colon endothelial cells High). | Staining level can vary by cell population (HPA: tissue IHC). | Score endothelial cells separately and compare the observed compartment with the general cytoplasmic pattern (HPA: tissue IHC; general IHC practice). |
| Fallopian tube cilia are prominent while other compartments are faint (HPA: cilia axoneme High). | The ciliary finding is reported for this cell population (HPA: fallopian tube). | Record ciliary and cytoplasmic staining separately; avoid treating ciliary signal alone as proof that all other staining is specific (HPA: tissue IHC; general IHC practice). |
| Two sections give different staining intensity. | Biological variation or run conditions may contribute (general IHC practice); target-specific fixation sensitivity is unreported in the supplied evidence. | Compare matched cell populations and run controls under the same scoring criteria; record processing differences without assigning them a BAG4-specific effect (general IHC practice). |
Experiment evidence
IHC & IF images showing BAG4 staining
A06722-1 · IHCImmunohistochemical analysis of paraffin-embedded human tonsil. 1, Antibody was diluted at 1:200 (4° overnight). 2, Tris-EDTA, pH9.0 was use
A06722 · IFImmunocytochemistry of SODD in HeLa cells with SODD antibody at 5 μg/mL.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000156735-BAG4/tissue/cerebral+cortex#imid_5097692
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000156735-BAG4/tissue/colon#imid_5097626
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000156735-BAG4/tissue/liver#imid_5097627
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000156735-BAG4/tissue/kidney#imid_5097620
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for BAG4 IHC & IF
🧪Run adrenal gland first and look for staining in its glandular cells (HPA: High in adrenal gland glandular cells). HPA detects BAG4 in all 45 scored tissues, so there is no supported negative tissue; use no-primary and isotype controls, and treat unstained non-glandular cells on the positive slide as local background comparators rather than proven BAG4-negative cells (HPA: no negative rows; BAG4 detected in all 45 tissues).
Positive control tissue: Adrenal gland (Glandular cells, HPA High)
Negative control tissue: None in HPA: BAG4 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for BAG4; derive a cell-line control from the positive tissue's cell type (Glandular cells) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only slide and a control antibody matched to the primary antibody’s host species and immunoglobulin isotype, with a format appropriate to its clonality; if available, add a BAG4 knockout specimen or a validated immunizing-peptide block as a biological specificity control (standard IHC practice). For chromogenic adrenal sections, block endogenous peroxidase and check pigmented areas against the controls before scoring staining (standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A06722-1 paraffin-section caption does not state the fixative (selected-SKU tissue-IHC caption: fixative not stated). That caption uses Tris-EDTA at pH 9.0 for retrieval and a 1:200 primary dilution overnight at 4°C, but it does not establish that BAG4 staining depends on that retrieval condition (selected-SKU tissue-IHC caption). There is no supplied comparison showing that frozen sections or IF are easier; assess adrenal pigment against the chromogenic controls when scoring (HPA: no ICC-IF image cell lines; standard IHC practice).
HPA tissue IHC evidence for BAG4
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 |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Appendix | Glandular cells | High | Protein (IHC) | HPA → |
| Colon | Endothelial cells | High | Protein (IHC) | HPA → |
| Duodenum | Glandular cells | High | Protein (IHC) | HPA → |
| Endometrium | Cells in endometrial stroma | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: BAG4 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced BAG4 IHC Tips
Troubleshoot BAG4 staining in paraffin sections by checking retrieval, compartment, controls, and cell-specific scoring; IF/ICC requires separate validation.
What should I change if BAG4 staining is weak after antigen retrieval?
Use heat-mediated Tris-EDTA, pH 9.0, for BAG4 antigen retrieval in paraffin sections (datasheet A06722-1). The catalog antibody’s human tonsil image used this retrieval with primary antibody at 1:200, incubated at 4°C overnight (caption A06722-1). If staining is weak, first check that sections were fully deparaffinised and that the retrieval bath reached its intended temperature throughout the run (standard IHC practice). Compare a repeat section with a known staining run while holding antibody concentration and detection conditions constant (standard IHC practice). Excessive retrieval can damage tissue morphology, so assess staining alongside section integrity (standard IHC practice).
Could fixation explain variable BAG4 staining between paraffin blocks?
Target-specific fixation sensitivity for BAG4 is unknown: the selected image describes paraffin-embedded human tonsil but does not state a fixative (caption A06722-1). Record the fixative, fixation duration, tissue thickness, and processing history for each block before attributing differences to BAG4 abundance (standard IHC practice). Compare blocks processed alike, and include a shared reference section in each staining run to reveal processing or detection variation (standard IHC practice). If fixation differs, test matched sections with the stated Tris-EDTA, pH 9.0, retrieval before changing antibody concentration (datasheet A06722-1). Do not use tissue staining patterns to infer a BAG4-specific fixation effect.
Is nuclear or membrane-rim staining consistent with BAG4?
Expect predominantly cytoplasmic BAG4 signal: UniProt assigns BAG4 to the cytoplasm, and HPA describes general cytoplasmic tissue expression (UniProt O95429 localisation; HPA tissue IHC). BAG4 has no transmembrane segment, so a crisp membrane rim without cytoplasmic signal warrants scrutiny (UniProt O95429 topology). Examine nuclear staining against a counterstain and compare the same cell types across adjacent sections before calling a new compartment (standard IHC practice). HPA reports high staining in kidney tubular cells and several glandular cell populations, which can guide cell selection without proving specificity in your specimen (HPA tissue IHC). Document mixed patterns separately rather than folding them into one positive score (standard IHC practice).
How should isoforms and epitope position affect BAG4 IHC troubleshooting?
BAG4 has 2 listed isoforms, but the supplied antibody caption does not identify its epitope or establish isoform recognition (UniProt O95429 isoforms; caption A06722-1). Its BAG domain spans residues 379–456, so an antibody targeting that region would need separate evidence before assigning staining to either isoform (UniProt O95429 domains and isoforms). UniProt lists modifications including phosphoserine at residue 7 and methylarginines at 40, 53, 108, and 185 (UniProt O95429 modified residues). If staining changes after processing, consider epitope accessibility as a hypothesis rather than assigning a modification-specific effect. Resolve discordant patterns with an independently validated antibody to a documented epitope, if available (standard IHC practice).
How can I assess BAG4 by multiplex IF without overcalling fluorescence?
Treat IF/ICC staining with this antibody as requiring separate validation; the supplied product image documents paraffin-section IHC, and HPA lists no ICC/IF images here (caption A06722-1; HPA subcellular). For a glandular-cell specimen, pair BAG4 with a suitable cell-identity marker, such as pan-cytokeratin where appropriate, and score signal within the marker-defined cells (HPA tissue IHC; standard IF practice). Choose a red or far-red fluorophore after checking the specimen’s autofluorescence in each channel (standard IF practice). Because BAG4 is cytoplasmic and has no transmembrane segment, test mild permeabilisation to give the antibody access to intracellular epitopes (UniProt O95429 localisation and topology; standard IF practice). Include single-label and secondary-only controls when interpreting overlap (standard IF practice).
How do I distinguish BAG4 signal from chromogenic background?
Start with the catalog conditions of primary antibody at 1:200 and secondary antibody at 1:200 for 30 minutes at room temperature (caption A06722-1). Use appropriate protein blocking, wash consistently, and titrate the primary if staining spreads diffusely across compartments (standard IHC practice). For a peroxidase and DAB workflow, block endogenous peroxidase and inspect a no-primary control; these are general detection controls, not BAG4-specific validation (standard IHC practice). Compare background with the expected cytoplasmic pattern in intact cells (UniProt O95429 localisation; HPA tissue IHC). If both target and control sections darken together, troubleshoot detection and washing before changing antigen retrieval (standard IHC practice).
What is a defensible way to score BAG4 IHC across specimens? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and scoring area before reading slides, then score cytoplasmic staining separately from other compartments (UniProt O95429 localisation; standard IHC practice). An H-score combines the percentage of cells at each intensity with intensity on a 0–3 scale; report both its components and the resulting 0–300 score (standard IHC practice). Alternatively, report the percentage of positive cells or positive-cell density per mm², with the threshold stated (standard IHC practice). Normalise density to viable tissue area and compare like cell types, since HPA reports different staining levels among tissue cell populations (HPA tissue IHC). Keep staining runs and image-analysis settings consistent across groups (standard IHC practice).
When should an apparent BAG4-positive area be called artefact?
A convincing result should show intracellular cytoplasmic staining in intact cells and agree with the pattern of an appropriate control section (UniProt O95429 localisation; HPA tissue IHC; standard IHC practice). Investigate isolated nuclear or sharp membrane-rim signal because the supplied record places BAG4 in the cytoplasm and lists no transmembrane segment (UniProt O95429 localisation and topology). Compare the stained cell type with the tissue architecture; HPA reports high signal in kidney tubular and several glandular cell populations but does not validate every specimen (HPA tissue IHC). Discount staining concentrated at section edges or necrotic regions, and check a no-primary control for endogenous enzyme signal (standard IHC practice). Report unresolved staining as indeterminate rather than BAG4-positive (standard IHC practice).
Boster reagents
Best BAG4 / BAG family molecular chaperone regulator 4 IHC Antibodies
BAG4 antibodies have pictured IHC staining in paraffin-embedded human tonsil (A06722-1 image caption) and IF/ICC staining in HeLa cells (A06722 image captions); both list Human, Mouse and Rat reactivity (catalog).
Real IHC data
Anti-Bag-4 Antibody
Cat # A06722-1
Real IF data
Anti-SODD BAG4 Antibody
Cat # A06722
A06722-1 lists IHC and IF applications and shows IHC staining in paraffin-embedded human tonsil (catalog; A06722-1 image caption). A06722 lists IF and ICC applications and shows staining in HeLa cells (catalog; A06722 image captions).
Which to pick: Choose A06722-1 for tissue IHC: its pictured protocol uses paraffin-embedded human tonsil, Tris-EDTA retrieval at pH 9.0 and primary antibody at 1:200 overnight at 4°C; the fixative is unreported (A06722-1 image caption). Choose A06722 for IF/ICC in cells because its images show HeLa staining; its application list does not include IHC (A06722 image captions; catalog). Both list Human, Mouse and Rat reactivity, but the pictured samples are human, so staining in Mouse or Rat samples needs validation (catalog; image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O95429 (BAG4_HUMAN, BAG family molecular chaperone regulator 4).
- Human Protein Atlas. BAG4 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. BAG4 subcellular location (ICC-IF): Highest expression in K-562: 28.0 nTPM.
- Human Protein Atlas. BAG4 antibody validation summary (2 antibodies).
- Bcl‑2 associated athanogene 4 promotes proliferation, migration and invasion of gastric cancer cells. Molecular medicine reports 2017 — PMC5646952.
- Protein and glycomic plasma markers for early detection of adenoma and colon cancer. Gut 2018 — PMC5420499.
- USP14 inhibits mitophagy and promotes tumorigenesis and chemosensitivity through deubiquitinating BAG4 in microsatellite instability-high colorectal cancer. Molecular medicine (Cambridge, Mass.) 2025 — PMC12048998.
- SODD Promotes Lung Cancer Tumorigenesis by Activating the PDK1/AKT and RAF/MEK/ERK Signaling. Genes 2023 — PMC10137428.
- PubMed PMID:9873016 — UniProt-cited evidence.
- PubMed PMID:9915703 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for BAG4 (BAG family molecular chaperone regulator 4). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC). Antigen retrieval: Tris-EDTA pH 9.0 HIER, heat-mediated (datasheet A06722-1). Validated IHC antibody: A06722-1 at 1:100-1:300 (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative None in HPA (detected in all 45 tissues); use no-primary + isotype controls. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human tonsil tissue; fixative not specified (datasheet A06722-1); 2. Fixation: Image fixative and duration unreported (datasheet A06722-1); 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: Tris-EDTA pH 9.0 (datasheet A06722-1); 20 min, 95–100 °C (standard); 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-BAG4, 1:100-1:300 (datasheet A06722-1); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific); Caveat: Glial cells and myocytes may stain weakly (HPA tissue IHC); Isoform / epitope: 2 isoforms; shared epitope status unspecified (UniProt); Regulation: Specific stimulus response unreported (UniProt). Evidence: UniProt O95429, HPA tissue IHC · Approved, HPA cell-line RNA · Highest expression in K-562: 28.0 nTPM, Datasheet A06722-1, PMC5420499, PMC12048998. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/BAG4/immunohistochemistry-ihc-guide.