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BAG1 / BAG family molecular chaperone regulator 1 · IHC design guide
Design Immunohistochemistry for BAG1
Plan BAG1 paraffin IHC around predominantly nuclear tissue staining (HPA tissue IHC). Use documented high staining and not detected cell populations to guide controls and scoring (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
BAG1 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 | Nuclear in most tissues (HPA tissue IHC) | |
| Staining pattern | Nuclear staining in glandular and endocrine cells (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A02423-2) | |
| Positive control | Appendix+4 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A02423-2) | |
| Caveat | Staining and RNA show medium consistency (HPA tissue IHC) | |
| Regulation | Isoform 4 expression varies by tissue (UniProt) | |
| Isoform / epitope | 4 isoforms; check antibody epitope coverage (UniProt) |
Section 1
Recommended BAG1 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is accompanied by published BAG1 staining methods for patient tumor tissue and human lung cancer tissue (PMC4734146; PMC8247369).
| Sample | Paraffin-embedded human breast cancer tissue; fixative not specified (datasheet A02423-2) |
| Fixation | Image fixative and duration unreported (datasheet A02423-2); 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 A02423-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A02423-2) |
| Primary antibody | Rabbit anti-BAG1, 2-5μg/ml (datasheet A02423-2) |
| Primary incubation | Overnight at 4 °C (datasheet A02423-2) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A02423-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | BAG1-positive staining in endocrine cells of appendix (HPA tissue IHC: High). HPA tissue profile: Nuclear expression in most tissues. No signal in the no-primary control. |
💡Decision noteStart with the catalog antibody’s heat-mediated EDTA retrieval at pH 8.0 (datasheet A02423-2); the published excerpts do not specify retrieval conditions (PMC4734146; PMC8247369).
Section 2
What Is the Expected BAG1 Staining Pattern?
BAG1 is a nuclear and cytoplasmic protein without a transmembrane segment (UniProt Q99933). In paraffin sections, expect predominantly nuclear staining across many tissues, with High staining reported in selected endocrine, glandular and lung alveolar type II cells (HPA tissue IHC: Supported). HPA reports medium consistency between antibody staining and RNA expression, so interpret a result alongside cell identity and controls (HPA tissue IHC).
| Clear nuclear staining in appendix endocrine cells, with lighter staining elsewhere. | This fits a reported High cell population and the predominantly nuclear tissue pattern (HPA tissue IHC). Compare cells within the same section; HPA's Supported rating reflects medium consistency with RNA data (HPA tissue IHC). |
| Strong membrane-only staining, or staining confined to extracellular material. | Treat this as a suspect compartment pattern: BAG1 has no transmembrane segment and is annotated in nucleus and cytoplasm (UniProt Q99933). Review morphology and controls before scoring it as BAG1; cytoplasmic staining alone can be plausible (UniProt Q99933). |
| Strong staining in adipocytes while expected positive cells show little signal. | Adipocytes are listed as Not detected, so investigate cross-reactivity or endogenous detection activity (HPA tissue IHC; standard IHC practice). That HPA category describes the sampled cell population and is not an absolute rule for every specimen. |
| Haze covers nuclei, cytoplasm and cell-free spaces with little cell-to-cell distinction. | Diffuse staining cannot establish the expected nuclear pattern (HPA tissue IHC). Check the no-primary control, detection reagents and washing for background before interpreting intensity; these are general IHC checks, not reported BAG1-specific effects (standard IHC practice). |
| No staining in appendix endocrine or lung alveolar type II cells. | These are reported High populations, making them useful positive comparators (HPA tissue IHC). A blank result calls for a workflow and tissue-quality check; it does not establish that BAG1 is absent from the specimen (standard IHC practice). |
💡Expected BAG1 appearanceCall a result positive when identifiable endocrine, glandular or alveolar type II cells show clear, predominantly nuclear staining, potentially with cytoplasmic signal; isolated membrane staining or uniform haze is suspect (HPA tissue IHC; UniProt Q99933; standard IHC practice).
| Compartment and isoform | Isoform 1 is predominantly nuclear, while BAG1 is annotated in both nucleus and cytoplasm; do not require every cell to be exclusively nuclear (UniProt Q99933). |
| Cell-specific tissue distribution | HPA reports High staining in selected endocrine and glandular cells, but Not detected staining in adipocytes and smooth muscle cells (HPA tissue IHC). |
| Antibody validation | HPA018121 and CAB002486 have Supported IHC status; validation is antibody-specific, so transfer that status only to the named reagent (HPA antibodies). |
| Isoform coverage | BAG1 has 4 isoforms, and isoform 4 is most abundant in the UniProt tissue-specificity account; staining alone cannot assign an isoform without epitope information (UniProt Q99933). |
| Processing and topology | No signal peptide, propeptide or transmembrane segment is annotated; a secreted or membrane-only interpretation lacks support from this record (UniProt Q99933). |
| IF/ICC Q: What pattern is expected? | A: Mainly nucleoplasmic, with additional cytosolic staining (HPA subcellular ICC-IF: supported); this localisation evidence does not specify an IF/ICC protocol. |
| Situation | Likely cause | Next action |
|---|---|---|
| The positive comparator is blank. | Signal loss may arise at an IHC workflow step; the record supplies no BAG1-specific fixation-sensitivity finding (standard IHC practice; supplied UniProt/HPA records). | Confirm cell identity, tissue preservation and that the intended IHC detection workflow ran; compare with a reported High population (standard IHC practice; HPA tissue IHC). |
| All cells show similar brown staining. | Endogenous chromogenic activity or detection background can obscure cell-specific localisation (standard IHC practice). | Inspect the no-primary control and apply detection-system blocking and washing checks appropriate to the chromogen; then reassess nuclear contrast (standard IHC practice; HPA tissue IHC). |
| Only membranes appear positive. | The pattern conflicts with annotated nuclear and cytoplasmic localisation and lack of a transmembrane segment (UniProt Q99933). | Review morphology, no-primary staining and the antibody's IHC validation before accepting the signal as BAG1 (standard IHC practice; HPA antibodies). |
| Cytoplasm stains along with nuclei. | Cytoplasmic BAG1 is annotated, although the HPA tissue summary emphasizes nuclear expression (UniProt Q99933; HPA tissue IHC). | Score nuclear and cytoplasmic compartments separately and use background controls; do not discard a controlled cytoplasmic signal solely for its location (standard IHC practice; UniProt Q99933). |
| A presumed negative tissue has some positive cells. | HPA's Not detected calls apply to specified cell types, and BAG1 has low tissue specificity at the RNA level (HPA tissue IHC). | Identify the stained cell type and compare it with the matching HPA entry before treating the entire tissue as a negative control (HPA tissue IHC). |
| ICC-IF localisation differs from the paraffin-section result. | HPA ICC-IF reports nucleoplasm plus cytosol, whereas its tissue IHC summary emphasizes nuclear expression (HPA subcellular ICC-IF; HPA tissue IHC). | Compare compartment calls within each assay and check its own controls; do not use an ICC-IF image as an IHC protocol or a direct intensity standard (standard IHC practice). |
Experiment evidence
IHC & IF images showing BAG1 staining
A02423-2 · IHCIHC analysis of Bag1 using anti-Bag1 antibody (A02423-2). Bag1 was detected in a paraffin-embedded section of human breast cancer tissue. He
A02423-2 · IHCIHC analysis of Bag1 using anti-Bag1 antibody (A02423-2). Bag1 was detected in a paraffin-embedded section of human colorectal adenocarcinom
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000107262-BAG1/tissue/cerebral+cortex#imid_754752
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000107262-BAG1/tissue/colon#imid_754694
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000107262-BAG1/tissue/liver#imid_754687
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000107262-BAG1/tissue/kidney#imid_754688
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB002486; green = BAG1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB002486; green = BAG1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for BAG1 IHC & IF
🧪Run appendix first: its endocrine cells should stain strongly (HPA: High in appendix endocrine cells). Use adipose tissue adipocytes as the negative tissue (HPA: Not detected in adipocytes); on the appendix slide, compare endocrine-cell staining with adjacent non-endocrine cells, whose BAG1-negative status is unverified by the supplied HPA row (HPA: appendix endocrine-cell row only).
Positive control tissue: Appendix (Endocrine cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show BAG1 in A-431, U-251MG, HeLa, SiHa, U2OS, with annotated localisation: Nucleoplasm (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control and a host- and immunoglobulin-class-matched rabbit isotype control alongside a BAG1-knockout biological negative (caption: rabbit primary; standard IHC practice). Block endogenous peroxidase before HRP/DAB detection, particularly when evaluating peroxidase-containing cells in appendix (caption: HRP/DAB detection; standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A02423-2 paraffin-section caption does not state a fixative (selected-SKU tissue-IHC caption). That caption uses heat retrieval in EDTA at pH 8.0, which provides a starting condition but does not establish that retrieval is required for appendix (selected-SKU tissue-IHC caption: breast cancer section). Frozen-section performance and whether IF is easier are unreported; for appendix IHC, endogenous peroxidase may produce misleading DAB signal unless controlled (selected-SKU tissue-IHC caption: HRP/DAB; standard IHC practice).
HPA tissue IHC evidence for BAG1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — 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 | Endocrine cells | High | Protein (IHC) | HPA → |
| Cervix | Glandular cells | High | Protein (IHC) | HPA → |
| Colon | Endocrine cells | High | Protein (IHC) | HPA → |
| Duodenum | Endocrine cells | High | Protein (IHC) | HPA → |
| Epididymis | Glandular cells | High | 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 → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Smooth muscle | Smooth muscle cells | Not detected | Protein (IHC) | HPA → |
| Soft tissue | Fibroblasts | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced BAG1 IHC Tips
Troubleshoot BAG1 staining in paraffin section chromogenic IHC, using the catalog antibody’s tissue result and established localisation evidence as reference points.
What retrieval should I try first when BAG1 staining is weak?
Start with heat-mediated retrieval in EDTA pH 8.0 for paraffin sections (datasheet A02423-2). The documented BAG1 tissue staining used this retrieval, followed by 10% goat serum blocking and 2 μg/ml primary antibody overnight at 4°C (caption A02423-2). If signal remains weak, compare retrieval heating and cooling consistency across sections before changing antibody concentration (standard IHC practice). Check whether nuclei stain in an expected positive cell population, since predominantly nuclear tissue expression provides a useful localisation check (HPA tissue IHC), while cytoplasmic BAG1 is also possible (UniProt Q99933).
Could fixation explain weak or uneven BAG1 staining?
Target-specific sensitivity of BAG1 to fixation is unknown from the supplied evidence; the catalog tissue caption identifies a paraffin section but does not state its fixative (caption A02423-2). Record fixative, fixation duration, section age and processing history for each specimen before comparing staining intensity (standard IHC practice). Run sections processed together with the same EDTA pH 8.0 retrieval and 2 μg/ml primary antibody conditions to reduce procedural variation (caption A02423-2; standard IHC practice). If only one processing batch fails, investigate that batch, but do not assign the failure to a BAG1-specific fixation effect without a controlled comparison (standard IHC practice).
Should BAG1 staining be nuclear, cytoplasmic, or both?
Expect predominantly nuclear staining across many tissues (HPA tissue IHC); nucleoplasmic localisation is supported, with additional cytosolic localisation (HPA subcellular). BAG1 is also annotated in the nucleus and cytoplasm, and isoform 1 is predominantly nuclear (UniProt Q99933). Score nuclear and cytoplasmic DAB separately in the relevant cells, using a counterstain to define nuclei and avoiding a single combined intensity score (standard IHC practice). If staining appears exclusively along cell membranes, check morphology, section edges and background controls before treating it as BAG1 localisation, because the record identifies no transmembrane segment (UniProt Q99933 topology; standard IHC practice).
Can this stain distinguish BAG1 isoforms or a modified epitope?
Do not assign an IHC signal to a specific BAG1 isoform without epitope mapping and isoform-selective validation for this antibody (standard IHC practice). BAG1 has 4 annotated isoforms, and isoform 1 is predominantly nuclear, so compartment alone cannot prove which isoform produced the DAB signal (UniProt Q99933). The protein contains a ubiquitin-like region at residues 144–224, a BAG region at 246–326, and an annotated phosphoserine at 223 (UniProt Q99933). Check the antibody’s documented immunogen and epitope before interpreting regional or treatment-associated staining differences as isoform abundance or phosphorylation changes (standard IHC practice).
How should I investigate BAG1 localisation by IF alongside this IHC guide?
Use the separate IF/ICC guide for fluorescence assay setup; the selected tissue image documents chromogenic staining of a paraffin section, with its fixative unreported (caption A02423-2). For multiplex localisation, pair BAG1 with a marker identifying the expected cell population and a nuclear counterstain, then inspect nuclear and cytosolic channels separately (HPA tissue IHC; HPA subcellular; standard IF practice). Choose fluorophores after checking specimen autofluorescence and include single-channel controls to assess bleed-through (standard IF practice). If intracellular epitopes require access, optimise permeabilisation for nuclear and cytosolic staining; BAG1 has no transmembrane segment, so a membrane-facing epitope assumption is unsupported (UniProt Q99933 topology; standard IF practice).
How can I separate BAG1 signal from diffuse DAB background?
Compare the stained section with a no-primary control to identify secondary reagent, endogenous enzyme or tissue pigment contributions (standard IHC practice). The documented workflow used 10% goat serum blocking, 2 μg/ml primary antibody overnight at 4°C, and a peroxidase-linked secondary for 30 minutes at 37°C before DAB development (caption A02423-2). Check peroxidase blocking, wash stringency and DAB development time as general chromogenic workflow variables (standard IHC practice). Evaluate whether retained signal follows cells and includes the expected nuclear pattern, since widespread featureless deposit is difficult to reconcile with predominantly nuclear tissue expression (HPA tissue IHC; standard IHC practice).
How should I score BAG1 IHC across specimens? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and region of interest before scoring, and record nuclear and cytoplasmic staining separately (HPA tissue IHC; HPA subcellular; standard IHC practice). An H-score combines the percentage of cells at intensity grades 0–3 into a 0–300 score; alternatively report percentage of positive cells using a prespecified threshold (standard IHC practice). Normalise counts to the number of evaluable cells in the same compartment and report sampled area in mm² when using positive-cell density (standard IHC practice). Keep retrieval, development and imaging conditions consistent, and exclude folds, necrosis and section edges from comparisons (standard IHC practice).
What would make a BAG1-positive IHC result convincing?
Look for cellular staining with a strong nuclear component in an appropriate population, while allowing cytoplasmic signal because both compartments are documented (HPA tissue IHC; HPA subcellular; UniProt Q99933). High staining in appendix endocrine cells, cervix glandular cells and lung alveolar type II cells offers tissue-specific reference patterns (HPA tissue IHC). Treat a signal confined to section edges, necrotic areas or cell-free spaces cautiously, and compare it with a no-primary control and peroxidase-block assessment (standard IHC practice). A membrane-only pattern is less consistent with the annotated localisation and absence of a transmembrane segment; review morphology and controls before assigning it to BAG1 (UniProt Q99933 topology; standard IHC practice).
Boster reagents
Best BAG1 / BAG family molecular chaperone regulator 1 IHC Antibodies
BAG1 IHC is illustrated in human breast cancer, colorectal adenocarcinoma and tonsil, and mouse colon paraffin sections (A02423-2 image captions). IF/ICC is listed without an image (catalog: M02423-2 applications/image alts).
Real IHC data
Anti-Bag1 Antibody ®
Cat # A02423-2
A02423-2 lists human, mouse and rat IHC reactivity; its images show staining in human breast cancer, colorectal adenocarcinoma and tonsil, and mouse colon paraffin sections (catalog: A02423-2 applications/reactivity; A02423-2 image captions). M02423-2 lists human, mouse and rat IHC and ICC/IF reactivity, but has no supplied IHC or IF images (catalog: M02423-2 applications/reactivity/image alts).
Which to pick: For paraffin-section tissue IHC, choose A02423-2: its own captions show human and mouse staining after EDTA retrieval at pH 8.0 with 2 μg/ml primary antibody; the fixative is unreported (A02423-2 image captions). For IF/ICC, M02423-2 is the listed rabbit monoclonal, clone 28B16, although no IF/ICC image is supplied (catalog: M02423-2 applications/host/clone/image alts). Both list human, mouse and rat reactivity, while the supplied cross-species IHC images cover human and mouse only for A02423-2 (catalog: A02423-2 and M02423-2 reactivity; A02423-2 image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q99933 (BAG1_HUMAN, BAG family molecular chaperone regulator 1).
- Human Protein Atlas. BAG1 tissue IHC expression (reliability: Supported).
- Human Protein Atlas. BAG1 subcellular location (ICC-IF): Mainly localized to the nucleoplasm. In addition localized to the cytosol..
- Human Protein Atlas. BAG1 antibody validation summary (3 antibodies).
- Role of BCL2-associated athanogene in resistance to platinum-based chemotherapy in non-small-cell lung cancer. Oncology letters 2016 — PMC4734146.
- ALDH3A1 driving tumor metastasis is mediated by p53/BAG1 in lung adenocarcinoma. Journal of Cancer 2021 — PMC8247369.
- BAG1: the guardian of anti-apoptotic proteins in acute myeloid leukemia. PloS one 2011 — PMC3189928.
- PubMed PMID:8524784 — UniProt-cited evidence.
- PubMed PMID:8812483 — UniProt-cited evidence.
- PubMed PMID:15986447 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for BAG1 (BAG family molecular chaperone regulator 1). Expected localisation Nuclear in most tissues (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A02423-2). Validated IHC antibody: A02423-2 at 2-5μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Appendix (Endocrine 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 A02423-2); 2. Fixation: Image fixative and duration unreported (datasheet A02423-2); 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 A02423-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A02423-2); 8. Primary antibody: Rabbit anti-BAG1, 2-5μg/ml (datasheet A02423-2); 9. Primary incubation: Overnight at 4 °C (datasheet A02423-2). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A02423-2); Caveat: Staining and RNA show medium consistency (HPA tissue IHC); Isoform / epitope: 4 isoforms; check antibody epitope coverage (UniProt); Regulation: Isoform 4 expression varies by tissue (UniProt). Evidence: UniProt Q99933, HPA tissue IHC · Supported, HPA ICC-IF · Mainly localized to the nucleoplasm. In addition localized to the…, Datasheet A02423-2, PMC4734146, PMC8247369. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/BAG1/immunohistochemistry-ihc-guide.