This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
RAB3GAP1 / Rab3 GTPase-activating protein catalytic subunit · IHC design guide
Design Immunohistochemistry for RAB3GAP1
Plan RAB3GAP1 paraffin-section IHC around cytoplasmic staining and tissue controls (HPA tissue IHC). This guide covers consistent fixation, the catalog antibody at 2–5 μg/ml (datasheet A04789-2), and chromogenic scoring.
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
RAB3GAP1 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 most tissues; Purkinje cells stain strongly (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A04789-2) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | Seminal vesicle+2 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 A04789-2) | |
| Caveat | Neuronal staining is high in cortex but low in caudate (HPA tissue IHC) | |
| Regulation | Ubiquitous expression; no inducer specified (UniProt) | |
| Isoform / epitope | 3 isoforms; check antibody epitope coverage (UniProt) |
Section 1
Recommended RAB3GAP1 IHC & IF Protocols
The catalog antibody has an IHC-P protocol (datasheet A04789-2). The published method below describes chromogenic staining of rat epidermal cultures (PMC3995087 methods).
| Sample | Paraffin-embedded human glioblastoma tissue; fixative not specified (datasheet A04789-2) |
| Fixation | Image fixative and duration unreported (datasheet A04789-2); 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 A04789-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A04789-2) |
| Primary antibody | Rabbit anti-RAB3GAP1, 2-5 μg/ml (datasheet A04789-2) |
| Primary incubation | Overnight at 4 °C (datasheet A04789-2) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A04789-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | RAB3GAP1-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in most tissues. No signal in the no-primary control. |
💡Decision noteStart with EDTA pH 8.0 heat retrieval for the catalog antibody (datasheet A04789-2); the published culture method does not specify retrieval (PMC3995087 methods).
Section 2
What Is the Expected RAB3GAP1 Staining Pattern?
In paraffin-section IHC, expect mainly cytoplasmic RAB3GAP1 staining across many tissues, with strong staining in selected glandular, neuronal, epithelial and lymphoid cells (HPA: tissue IHC). RAB3GAP1 is also assigned to the ER and cis-Golgi and has no transmembrane segment (UniProt Q15042: subcellular location and topology). HPA rates the tissue staining Approved, with medium consistency against RNA data and external verification pending (HPA: tissue IHC reliability).
| Cytoplasmic staining in adrenal glandular cells or cerebellar Purkinje cells. | This matches the reported compartment and two High cell-specific results (HPA: cytoplasmic expression in most tissues; High in adrenal glandular cells and Purkinje cells). Use the distribution across cells when judging a section; a dark area alone does not establish a specific result (general IHC practice). |
| Predominantly nuclear staining in paraffin-section IHC. | Review this as a compartment mismatch against the reported cytoplasmic tissue IHC pattern (HPA: tissue IHC). It is not, by itself, proof of an artefact: HPA reports mainly nucleoplasmic staining in ICC-IF, with additional cytosol staining (HPA: subcellular ICC-IF). |
| Strong staining in skeletal myocytes or smooth muscle cells. | These cell types are reported as Not detected in tissue IHC (HPA: skeletal muscle myocytes; smooth muscle cells). Check whether the signal follows tissue structures, nonspecific antibody binding, or the chromogenic detection system before calling it RAB3GAP1 (general IHC practice). |
| Similar diffuse color across cells, stroma and empty areas. | A broad haze obscures the cell-specific cytoplasmic pattern expected in positive tissue (HPA: tissue IHC). Uneven washing, excessive antibody concentration or detection background are general IHC possibilities; the supplied sources do not identify a RAB3GAP1-specific cause (general IHC practice). |
| No staining in a known-positive cell population. | Adrenal glandular cells and cerebellar Purkinje cells are reported High, so a blank result there needs a technical check (HPA: tissue IHC). Compare tissue integrity and controls, then review the antibody and detection steps; a blank section alone cannot establish biological absence (general IHC practice). |
💡Expected RAB3GAP1 appearanceCall a result consistent when defined positive cells show cytoplasmic color, including High adrenal glandular or Purkinje-cell staining (HPA: tissue IHC); isolated nuclear IHC or strong staining of reported Not detected muscle cells warrants review, not an automatic positive call (HPA: tissue IHC).
| Assay-dependent compartment | Tissue IHC is described as cytoplasmic, whereas ICC-IF is mainly nucleoplasmic with additional cytosol staining (HPA: tissue IHC; subcellular ICC-IF). Assess each result against its own assay evidence. |
| Choice of comparison cells | HPA reports High staining in several cell populations, Medium in endometrial glandular cells, and Not detected in skeletal myocytes (HPA: tissue IHC). The comparison cell type changes how informative a weak or absent signal is. |
| Strength of validation | Tissue IHC is Approved but has medium RNA agreement and awaits external verification (HPA: tissue IHC reliability). HPA034494 is IHC Approved; HPA034495 has ICC Uncertain status (HPA: antibody validation). These ratings support cautious interpretation, not absolute specificity. |
| Protein form and location | UniProt lists three isoforms, no signal peptide or propeptide, and no transmembrane segment (UniProt Q15042: isoforms, processing and topology). The supplied record gives no antibody epitope, so it cannot predict isoform-specific staining or retrieval needs. |
| IF/ICC Q&A | Q: Should IF/ICC show only cytoplasm? A: No. HPA reports an approved main nucleoplasmic location plus an approved cytosol location in ICC-IF (HPA: subcellular ICC-IF). Use the separate IF/ICC guide for that application. |
| Situation | Likely cause | Next action |
|---|---|---|
| A positive-control section is blank. | The assay may have failed at staining or detection; biological absence cannot be inferred from one blank section (general IHC practice). | Use a reported High population, such as adrenal glandular cells, as the comparison (HPA: tissue IHC). Check section integrity, antibody application and the chromogenic detection controls (general IHC practice). |
| The slide has widespread diffuse background. | Excess antibody or incomplete blocking or washing can produce background in chromogenic IHC (general IHC practice). | Compare with a no-primary control, then review blocking, antibody dilution and washes under the established IHC procedure (general IHC practice). Judge whether cytoplasmic cell boundaries become readable (HPA: tissue IHC). |
| Signal appears confined to nuclei in IHC. | The location differs from the reported cytoplasmic tissue IHC profile (HPA: tissue IHC). HPA's nucleoplasmic observation belongs to ICC-IF (HPA: subcellular ICC-IF). | Check counterstain and no-primary controls, then compare another reported positive cell population before interpreting the nuclear signal (general IHC practice; HPA: tissue IHC). |
| Muscle cells stain strongly. | Strong signal conflicts with the reported Not detected results for skeletal myocytes and smooth muscle cells (HPA: tissue IHC); cross-reactivity or detection background are possibilities (general IHC practice). | Inspect cell identity and staining boundaries, compare a no-primary control, and seek agreement with a reported positive population in the same run (general IHC practice; HPA: tissue IHC). |
| Color persists without primary antibody. | The primary antibody cannot explain color in its absence; endogenous enzyme activity or detection-reagent background may contribute, depending on the detection system (general IHC practice). | Check the detection-only control and apply the appropriate endogenous-activity block for the chromogen system in use (general IHC practice). |
| A low-signal tissue looks negative. | Caudate neuronal cells, parathyroid glandular cells and liver hepatocytes are reported Low (HPA: tissue IHC); weak signal there may be difficult to score. | First confirm that a reported High cell population stains in the same run, then score the low-signal tissue with its cell type and controls in view (HPA: tissue IHC; general IHC practice). |
Experiment evidence
IHC & IF images showing RAB3GAP1 staining
A04789-2 · IHCIHC analysis of RAB3GAP1 using anti-RAB3GAP1 antibody (A04789-2). RAB3GAP1 was detected in a paraffin-embedded section of human glioblastoma
A04789-2 · IHCIHC analysis of RAB3GAP1 using anti-RAB3GAP1 antibody (A04789-2). RAB3GAP1 was detected in a paraffin-embedded section of human breast cance
A04789-2 · IFIF analysis of RAB3GAP1 using anti-RAB3GAP1 antibody (A04789-2) and Anti-Beta Tubulin Antibody (M01857-3). RAB3GAP1 was detected in an immun
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000115839-RAB3GAP1/tissue/cerebral+cortex#imid_8796360
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000115839-RAB3GAP1/tissue/colon#imid_8796294
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000115839-RAB3GAP1/tissue/liver#imid_8796295
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000115839-RAB3GAP1/tissue/kidney#imid_8796296
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA034495; green = RAB3GAP1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA034495; green = RAB3GAP1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for RAB3GAP1 IHC & IF
🧪Run adrenal gland first; its glandular cells should stain (HPA: High in adrenal gland glandular cells). Use seminal vesicle glandular cells as the negative tissue (HPA: Not detected); on the adrenal slide, treat cells outside the annotated glandular compartment as an internal background comparison only if their staining is at background level, since RAB3GAP1 is described as ubiquitous (UniProt Q15042: tissue specificity).
Positive control tissue: Adrenal gland (Glandular cells, HPA High)
Negative control tissue: Seminal vesicle (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show RAB3GAP1 in A-431, U-251MG, U2OS, with annotated localisation: Nucleoplasm (approved) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only slide; a rabbit IgG isotype control matched to the primary antibody’s clonality; and RAB3GAP1 knockout material or immunizing-peptide competition where available (caption: rabbit primary antibody). For HRP/DAB staining, quench endogenous peroxidase and compare adrenal pigment or background with the no-primary slide before scoring (caption: HRP/DAB detection; HPA: High in adrenal gland glandular cells).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A04789-2 paraffin-section caption does not state the fixative (caption: fixative unreported). The pictured IHC example used heat retrieval in EDTA at pH 8.0; whether retrieval is required or frozen sections are easier is unreported (caption: EDTA retrieval). IF/ICC images are available for A-431, U-251MG and U2OS, with approved nucleoplasmic and cytosolic localization (HPA: subcellular); assess autofluorescence separately if using fluorescent detection (standard IF practice).
HPA tissue IHC evidence for RAB3GAP1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Medium consistency between antibody staining and RNA expression data. Pending external verification.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Appendix | Lymphoid tissue | High | Protein (IHC) | HPA → |
| Cerebellum | Purkinje cells | High | Protein (IHC) | HPA → |
| Cerebral cortex | Neuronal cells | High | Protein (IHC) | HPA → |
| Endometrium | Glandular cells | Medium | Protein (IHC) | HPA → |
Section 3
Advanced RAB3GAP1 IHC Tips
Troubleshoot paraffin-section RAB3GAP1 IHC by checking retrieval, compartment, controls, and scoring; use the IF guidance only when adapting the assay.
What retrieval should I try first when RAB3GAP1 staining is weak?
Start with heat-mediated retrieval in EDTA at pH 8.0 for paraffin sections (datasheet A04789-2). The selected tissue image used this retrieval before staining with 2 μg/ml antibody overnight at 4°C (datasheet A04789-2). Hold antibody concentration and detection conditions constant while comparing retrieval duration across adjacent sections, and include a no-primary control (standard IHC practice). If staining remains weak, test another retrieval buffer or pH as a fallback on matched sections, recording both signal and tissue damage (standard IHC practice). Judge improvement by cellular staining in an expected compartment, since RAB3GAP1 has cytoplasmic, ER and Golgi annotations (UniProt Q15042 localisation).
Could fixation explain weak or uneven RAB3GAP1 staining?
Target-specific fixation sensitivity is unknown: the selected paraffin-section caption does not state a fixative (datasheet A04789-2). Record the fixative, fixation duration and processing history for each specimen before attributing a weak result to RAB3GAP1 loss (standard IHC practice). Compare matched sections with the same EDTA pH 8.0 retrieval and antibody conditions, changing only one processing variable at a time (datasheet A04789-2; standard IHC practice). Check whether weak regions track folds, section edges or damaged morphology, and retain a no-primary control (standard IHC practice). Neither the tissue staining profile nor the protein's topology establishes a fixation effect (HPA tissue IHC; UniProt Q15042 topology).
How should I assess cytoplasmic versus nuclear RAB3GAP1 staining?
Expect a substantial cytoplasmic component in tissue sections, while allowing regional ER or cis-Golgi enrichment where morphology supports it (HPA tissue IHC; UniProt Q15042 localisation). HPA tissue IHC describes cytoplasmic expression in most tissues, whereas HPA ICC/IF calls nucleoplasm the main location and cytosol an additional location (HPA tissue IHC; HPA subcellular). Treat that difference as a reason to validate compartment calls with controls, not as proof that either pattern is artefactual (standard IHC practice). Score nuclear and cytoplasmic signals separately on matched sections, using identical retrieval and exposure conditions (standard IHC practice). Exclude precipitate and edge staining before assigning a compartment (standard IHC practice).
Can isoforms or epitope accessibility explain discordant IHC results?
RAB3GAP1 has 3 annotated isoforms and several reported phosphoserines, including residues 83, 379 and 537 (UniProt Q15042 isoforms; UniProt Q15042 modified residues). The supplied antibody caption does not identify its epitope, so these annotations cannot establish isoform coverage or a phosphorylation-dependent staining effect (datasheet A04789-2; UniProt Q15042). Obtain the antibody's immunogen or epitope information before interpreting discordant sections as isoform-specific expression (standard IHC practice). Keep retrieval at EDTA pH 8.0 while comparing matched specimens, and document any later retrieval change (datasheet A04789-2; standard IHC practice). If possible, evaluate specificity with an independent epitope-directed antibody or a validated loss-of-target control (standard IHC practice).
How can I adapt this IHC result to multiplex IF?
Treat IF as a separate validation task: the selected antibody evidence describes chromogenic staining of a paraffin section, with fixation unreported (datasheet A04789-2). Pair RAB3GAP1 with a validated marker for the expected cell type, such as neuronal cells in cerebral cortex or Purkinje cells in cerebellum (HPA tissue IHC; standard IF practice). Choose spectrally separated fluorophores after measuring tissue autofluorescence, and include single-stain and no-primary controls (standard IF practice). RAB3GAP1 has no transmembrane segment and is annotated in cytoplasm, ER and Golgi, so assess whether permeabilisation exposes the relevant intracellular epitope (UniProt Q15042 topology; UniProt Q15042 localisation). Optimise fixation and permeabilisation empirically for IF rather than transferring an unstated fixative from the IHC image (datasheet A04789-2; standard IF practice).
What should I adjust when diffuse DAB obscures RAB3GAP1 staining?
First compare a no-primary section and a reagent-only detection control with the stained section to locate background from the detection workflow (standard IHC practice). The selected image used 10% goat serum blocking, 2 μg/ml primary antibody overnight at 4°C, and peroxidase detection with DAB (datasheet A04789-2). Include an endogenous peroxidase block before HRP detection, and check whether staining persists without primary antibody (standard IHC practice). If background remains primary-dependent, titrate antibody concentration and incubation while keeping EDTA pH 8.0 retrieval constant (datasheet A04789-2; standard IHC practice). Assess cytoplasmic signal against the expected tissue pattern rather than counting diffuse chromogen deposits (HPA tissue IHC; standard IHC practice).
How should I quantify RAB3GAP1 across tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring: HPA reports cytoplasmic staining in most tissues, with high signal in cerebral cortical neuronal cells and cerebellar Purkinje cells (HPA tissue IHC). For chromogenic IHC, record percent positive cells and an intensity-based H-score within the same annotated region (standard IHC practice). If counting discrete positive cells, report density per mm² of evaluable tissue and exclude folds, necrosis and section edges (standard IHC practice). Normalise counts to the relevant cell population or evaluable tissue area, and use identical thresholds across batches (standard IHC practice). Record retrieval, antibody concentration and detection batch alongside each score to identify technical shifts (standard IHC practice).
When is apparent RAB3GAP1 positivity likely an artefact?
A plausible tissue pattern includes cytoplasmic staining in many cell populations, while HPA reports high staining in cerebral cortical neuronal cells and cerebellar Purkinje cells (HPA tissue IHC). Interpret isolated nuclear staining cautiously because tissue IHC is described as cytoplasmic, although HPA ICC/IF reports nucleoplasmic signal (HPA tissue IHC; HPA subcellular). Compare the apparent positive cells with local morphology and a matched no-primary control before assigning specificity (standard IHC practice). Edge-restricted signal, necrotic deposits or staining that persists without primary antibody warrants investigation of processing or endogenous enzyme activity (standard IHC practice). Concordance across intact cells, expected compartments and independent controls supports a stronger interpretation (UniProt Q15042 localisation; standard IHC practice).
Boster reagents
Best RAB3GAP1 / Rab3 GTPase-activating protein catalytic subunit IHC Antibodies
A04789-2 has IHC images from human paraffin sections and IF images from human paraffin sections and Siha cells (catalog image captions; catalog reactivity: Human).
Real IHC data
Anti-RAB3GAP1 Antibody ®
Cat # A04789-2
A04789-2 has IHC images from paraffin sections of human glioblastoma, breast cancer, liver cancer, and lung adenocarcinoma (A04789-2 IHC captions). The same SKU lists IF and ICC applications, with IF images from Siha cells and paraffin sections of human lung and liver cancer (A04789-2 applications and IF captions).
Which to pick: Choose A04789-2 for chromogenic IHC on human paraffin sections: its IHC captions show EDTA retrieval at pH 8.0 and primary antibody at 2 μg/ml; the fixative is unreported (A04789-2 IHC captions). For IF/ICC, A04789-2 lists both applications and has IF images at 5 μg/ml (A04789-2 applications and IF captions). No cross-species choice is supported because the only listed reactivity is Human; clonality is unreported (catalog reactivity and clone field).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q15042 (RB3GP_HUMAN, Rab3 GTPase-activating protein catalytic subunit).
- Human Protein Atlas. RAB3GAP1 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. RAB3GAP1 subcellular location (ICC-IF): Mainly localized to the nucleoplasm. In addition localized to the cytosol..
- Human Protein Atlas. RAB3GAP1 antibody validation summary (2 antibodies).
- Rab3Gap1 mediates exocytosis of Claudin-1 and tight junction formation during epidermal barrier acquisition. Developmental biology 2013 — PMC3995087.
- PubMed PMID:7584044 — UniProt-cited evidence.
- PubMed PMID:15815621 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for RAB3GAP1 (Rab3 GTPase-activating protein catalytic subunit). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A04789-2). Validated IHC antibody: A04789-2 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative Seminal vesicle. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human glioblastoma tissue; fixative not specified (datasheet A04789-2); 2. Fixation: Image fixative and duration unreported (datasheet A04789-2); 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 A04789-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A04789-2); 8. Primary antibody: Rabbit anti-RAB3GAP1, 2-5 μg/ml (datasheet A04789-2); 9. Primary incubation: Overnight at 4 °C (datasheet A04789-2). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A04789-2); Caveat: Neuronal staining is high in cortex but low in caudate (HPA tissue IHC); Isoform / epitope: 3 isoforms; check antibody epitope coverage (UniProt); Regulation: Ubiquitous expression; no inducer specified (UniProt). Evidence: UniProt Q15042, HPA tissue IHC · Approved, HPA ICC-IF · Mainly localized to the nucleoplasm. In addition localized to the…, Datasheet A04789-2, PMC3995087. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/RAB3GAP1/immunohistochemistry-ihc-guide.