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RAB27B / Ras-related protein Rab-27B · IHC design guide
Design Immunohistochemistry for RAB27B
Plan RAB27B staining in paraffin sections using glandular, renal tubular and urothelial cells as tissue comparators (HPA tissue IHC). This guide covers fixation consistency, chromogenic detection with the catalog antibody, and interpretation of cytoplasmic and membranous staining (datasheet A04890-1; HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
RAB27B 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 | Observed cytoplasmic and membranous staining (HPA tissue IHC) | |
| Staining pattern | Glandular, tubular and urothelial cells: cytoplasmic/membranous (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A04890-1) | |
| Positive control | Colon+4 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 | Medium IHC–RNA consistency; verify staining (HPA tissue IHC) | |
| Regulation | Tissue-enhanced RNA in stomach (HPA tissue RNA) | |
| Isoform / epitope | No isoforms annotated; mature chain spans 2–218 (UniProt) |
Section 1
Recommended RAB27B IHC & IF Protocols
The catalog antibody protocol is paired with published chromogenic IHC methods for pancreatic and lung cancer tissue (PMC4714634; PMC6360262).
| Sample | Paraffin-embedded human bladder cancer tissue; fixative not specified (datasheet A04890-1) |
| Fixation | Image fixative and duration unreported (datasheet A04890-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: EDTA pH 8.0 (datasheet A04890-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A04890-1) |
| Primary antibody | Rabbit anti-RAB27B, 2-5 μg/ml (datasheet A04890-1) |
| Primary incubation | Overnight at 4 °C (datasheet A04890-1) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A04890-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | RAB27B-positive staining in glandular cells of colon (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic and membranous expression mainly in glandular cells of gastrointestinal tract, breast, salivary gland, prostate, cells in renal tubules and urothelial cells. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet: A04890-1); the pancreatic study used microwave citrate pH 6.0 (PMC4714634).
Section 2
What Is the Expected RAB27B Staining Pattern?
RAB27B staining in paraffin sections is expected mainly in the cytoplasm and along cell membranes of glandular epithelial cells, renal tubular cells and urothelial cells (HPA: tissue IHC profile). RAB27B is associated with membranes and late endosomes but has no transmembrane segment (UniProt O00194: localization and topology). HPA rates its tissue staining reliability Enhanced, with medium consistency against RNA data and external verification pending (HPA: tissue IHC reliability).
| Glandular cells show cytoplasmic and membranous staining, with strong signal in colon or prostate (HPA: tissue IHC, High). | This matches the reported distribution and supports a positive IHC result (HPA: tissue IHC profile). Compare staining within the identified cell population; adjacent cells need not share its intensity (standard IHC practice). |
| Staining is confined to nuclei, with little cytoplasmic or membranous signal. | A nucleus-only pattern does not match the reported tissue pattern or membrane and late-endosome localization (HPA: tissue IHC; UniProt O00194: localization). Check counterstain and nonspecific detection before scoring it positive (standard IHC practice). |
| Strong signal appears in adipocytes or bronchial respiratory epithelium while expected positive cells are unstained. | Those cell types are reported as Not detected (HPA: tissue IHC). Consider cross-reactivity or endogenous detection activity, then assess controls; a mismatched pattern alone cannot identify the cause (standard IHC practice). |
| Color covers many compartments or the section broadly, obscuring cell boundaries. | Diffuse background prevents a reliable call on the cytoplasmic and membranous pattern (HPA: tissue IHC profile). Inspect the detection-only control and adjust blocking, washing or detection conditions as appropriate (standard IHC practice). |
| No signal appears in colon glandular cells or renal tubular cells, both reported High (HPA: tissue IHC). | The run may have failed, or this specimen may differ from the HPA examples. Verify section integrity, antibody application and detection controls before calling the tissue negative (standard IHC practice). |
💡Expected RAB27B appearanceCall a section positive when the appropriate glandular, renal tubular or urothelial cells show predominantly cytoplasmic and membranous signal, potentially High in the listed tissues; isolated nuclear or widespread cell-independent color is suspect (HPA: tissue IHC; standard IHC practice).
| Cell population and tissue | HPA reports High staining in colon, duodenal, small-intestinal and prostate glandular cells, renal tubular cells and urothelial cells; stomach glandular cells are Medium (HPA: tissue IHC). Select and score the specific cell population (standard IHC practice). |
| Subcellular interpretation | The tissue IHC profile is cytoplasmic and membranous (HPA: tissue IHC). Membrane and late-endosome localization is consistent with that pattern, while absence of a transmembrane segment does not require a continuous membrane outline (UniProt O00194: localization and topology). |
| Evidence strength | HPA019849 has Enhanced IHC validation and CAB017712 has Approved IHC validation (HPA: antibodies). The overall tissue profile is also rated Enhanced, but its RNA agreement is only medium and external verification remains pending (HPA: tissue IHC reliability). |
| Choice of comparator | UniProt describes expression primarily in testis, whereas HPA reports staining across several epithelial cell populations (UniProt O00194: tissue specificity; HPA: tissue IHC). Use HPA's cell-level observations when choosing an IHC comparator, and retain this source difference when interpreting it. |
| Situation | Likely cause | Next action |
|---|---|---|
| Known-positive glandular cells have no chromogenic signal. | Colon and prostate glandular cells are reported High, so absence conflicts with the reference pattern (HPA: tissue IHC); a failed staining run remains possible (standard IHC practice). | Check section quality, primary-antibody application and detection controls; repeat alongside a tissue with the expected positive cell population before interpreting the specimen (standard IHC practice). |
| Only nuclei stain strongly. | Nucleus-only staining conflicts with the cytoplasmic and membranous tissue pattern (HPA: tissue IHC) and reported membrane and late-endosome localization (UniProt O00194: localization). | Review the counterstain and detection-only control, then reassess whether convincing cytoplasmic or membranous staining is present in the expected cells (standard IHC practice). |
| Adipocytes or bronchial respiratory epithelial cells stain strongly. | HPA reports RAB27B as Not detected in those cell populations (HPA: tissue IHC). Cross-reactivity or endogenous detection activity are possibilities, not diagnoses from appearance alone (standard IHC practice). | Compare a detection-only control and a reported positive tissue; investigate the detection system before treating the unexpected cells as RAB27B-positive (standard IHC practice). |
| Diffuse color makes glandular or tubular cell boundaries hard to read. | Background can obscure the reported cytoplasmic and membranous pattern (HPA: tissue IHC profile; standard IHC practice). | Check detection-only controls, blocking and wash steps, and evaluate the primary-antibody concentration before scoring intensity (standard IHC practice). No target-specific dilution is supplied here. |
| Stomach glandular cells stain less strongly than colon glandular cells. | This can fit the reference observations: stomach is Medium and colon is High in the listed cell populations (HPA: tissue IHC). | Identify the stained cell types and compare each tissue with its own HPA level; do not require equal intensity across these sites (HPA: tissue IHC; standard IHC practice). |
| Q: Is Golgi-enriched signal in IF/ICC compatible with RAB27B? | HPA places IF/ICC signal mainly at the Golgi apparatus and plasma membrane, with additional cytosolic localization (HPA: subcellular ICC-IF). | A: Yes, interpret that pattern against the IF/ICC observations (HPA: subcellular ICC-IF). Use the separate IF/ICC guide for its methods; this IHC-P section supplies no IF/ICC protocol. |
Experiment evidence
IHC & IF images showing RAB27B staining
A04890-1 · IHCIHC analysis of RAB27B using anti-RAB27B antibody (A04890-1). RAB27B was detected in a paraffin-embedded section of human bladder cancer tis
A04890-1 · IHCIHC analysis of RAB27B using anti-RAB27B antibody (A04890-1). RAB27B was detected in a paraffin-embedded section of human stomach cancer tis
A04890-1 · IFIF analysis of RAB27B using anti-RAB27B antibody (A04890-1). RAB27B was detected in an immunocytochemical section of A549 cells. Enzyme anti
A04890-2 · IHCIHC analysis of RAB27B using anti-RAB27B antibody (A04890-2). RAB27B was detected in a paraffin-embedded section of human prostatic cancer t
A04890-2 · IHCIHC analysis of RAB27B using anti-RAB27B antibody (A04890-2). RAB27B was detected in a paraffin-embedded section of mouse stomach tissue. He
A04890-2 · IFIF analysis of RAB27B using anti-RAB27B antibody (A04890-2). RAB27B was detected in an immunocytochemical section of A549 cells. Enzyme anti
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000041353-RAB27B/tissue/cerebral+cortex#imid_5202244
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000041353-RAB27B/tissue/colon#imid_5202154
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000041353-RAB27B/tissue/liver#imid_5202171
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000041353-RAB27B/tissue/kidney#imid_4464788
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA019849; green = RAB27B, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA019849; green = RAB27B, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for RAB27B IHC & IF
🧪Run colon first and look for staining in glandular cells (HPA: High in colon glandular cells); run adipose tissue as the negative, assessing adipocytes (HPA: Not detected in adipocytes). On the colon slide, use adjacent nonglandular cells with little or no staining as internal comparators, without assuming HPA has validated those cells as negative (HPA: colon glandular-cell result only).
Positive control tissue: Colon (Glandular cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show RAB27B in A-431, U-251MG, U2OS, with annotated localisation: Golgi apparatus (supported), Plasma membrane (approved) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control; a rabbit IgG isotype control matched to the primary antibody’s clonality; and, where available, RAB27B-knockout tissue or a peptide-block control (selected-SKU IHC caption: rabbit primary; standard IHC practice). For chromogenic colon IHC, block endogenous peroxidase and check for nonspecific staining in glandular lumens (selected-SKU IHC caption: HRP/DAB detection; standard IHC practice).
⚠️Feasibility: A RAB27B-specific fixation window or fixation effect is unreported, and the selected A04890-1 paraffin-section caption does not state a fixative (selected-SKU IHC caption). Heat retrieval with EDTA at pH 8.0 was used in that caption, but a requirement for retrieval and any advantage of frozen sections or IF are unreported (selected-SKU IHC caption). In colon, assess glandular-lumen background against the no-primary control before scoring cellular staining (standard IHC practice).
HPA tissue IHC evidence for RAB27B
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — 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 |
|---|---|---|---|---|
| Colon | Glandular cells | High | Protein (IHC) | HPA → |
| Duodenum | Glandular cells | High | Protein (IHC) | HPA → |
| Kidney | Cells in tubules | High | Protein (IHC) | HPA → |
| Prostate | Glandular cells | High | Protein (IHC) | HPA → |
| Small intestine | 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 → |
| Bronchus | Respiratory epithelial cells | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
| Cervix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Heart muscle | Cardiomyocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced RAB27B IHC Tips
Use compartment and cell type controls to troubleshoot RAB27B staining in paraffin sections; interpret IF as a complementary localisation check.
What should I change if RAB27B staining is weak after antigen retrieval?
Start with heat mediated retrieval in EDTA at pH 8.0 for this catalog antibody (datasheet A04890-1). Its paraffin section image used that retrieval before an overnight incubation at 4°C with 2 μg/ml primary antibody (datasheet A04890-1). If staining remains weak, compare retrieval heating and cooling times on adjacent sections while keeping antibody concentration and DAB development constant (standard IHC practice). Include a urinary bladder section with urothelial cells as a positive comparison and adipose tissue adipocytes as a low signal comparison (HPA tissue IHC: High in urothelial cells; Not detected in adipocytes). Assess cellular staining before increasing retrieval intensity, since tissue damage can make an apparent gain misleading (standard IHC practice).
How can I troubleshoot fixation related loss of RAB27B staining?
Target specific fixation sensitivity is unknown because the selected paraffin section caption does not state its fixative (datasheet A04890-1). Record the fixative, fixation duration, block age and section thickness for each case, then compare matched sections processed under the same retrieval and detection conditions (standard IHC practice). Keep EDTA retrieval at pH 8.0 as the starting condition for this antibody (datasheet A04890-1). If an internal positive population stains in one block but not another, repeat staining with identical primary incubation and DAB development before attributing the difference to biology (standard IHC practice). The caption’s 2 μg/ml overnight primary incubation offers a documented comparison condition (datasheet A04890-1).
Which staining compartments support a RAB27B interpretation in paraffin sections?
Look for cytoplasmic and membranous staining in appropriate cells; those patterns appear in the tissue profile (HPA tissue IHC: cytoplasmic and membranous expression). A peripheral or punctate pattern is biologically plausible because RAB27B is associated with membranes and late endosomes (UniProt O00194: subcellular location). Golgi, plasma membrane and cytosolic localisation have also been reported by cellular imaging, but they do not establish the identity of a DAB positive structure in tissue (HPA subcellular: main and additional locations). Compare high signal urothelial cells with adjacent morphology and a negative reagent control (HPA tissue IHC: High in urothelial cells; standard IHC practice). Diffuse nuclear only staining needs independent validation before being scored as RAB27B (standard IHC practice).
Could isoforms or epitope accessibility explain discordant RAB27B staining?
No isoforms are annotated for RAB27B in the supplied record, so an isoform specific explanation lacks support here (UniProt O00194: isoforms 0). The protein has no transmembrane segment, while membrane association and prenylation are annotated; epitope location and antibody binding site are not supplied (UniProt O00194: topology, keywords; datasheet A04890-1: epitope unspecified). Check whether a comparison antibody recognises a documented region before using agreement between stains as evidence of specificity (standard IHC practice). Keep retrieval at EDTA pH 8.0 for the catalog antibody and compare matched sections with identical detection settings (datasheet A04890-1; standard IHC practice). Do not assign altered staining to the annotated terminal modifications without epitope mapping (UniProt O00194: modified residues).
How should IF help resolve ambiguous RAB27B staining in tissue?
Use IF as a complementary localisation check, and multiplex RAB27B with a validated marker of the expected cell type, such as urothelial cells in bladder sections (HPA tissue IHC: High in urothelial cells; standard IF practice). Choose a fluorophore channel with low tissue autofluorescence and inspect an unstained or secondary only section in every channel (standard IF practice). Because RAB27B has no transmembrane segment and is associated with intracellular membranes, optimise permeabilisation for access to the antibody’s epitope, whose location is unspecified (UniProt O00194: topology and subcellular location; datasheet A04890-1: epitope unspecified). Compare cellular overlap and punctate distribution with the chromogenic section while retaining separate exposure settings for controls (standard IF practice). IF conditions require their own optimisation; the supplied paraffin IHC caption does not specify an IF procedure (datasheet A04890-1).
What causes widespread DAB signal outside expected RAB27B positive cells?
First compare the stained section with a no primary control and inspect whether signal follows tissue edges, folds or damaged areas (standard IHC practice). Use a peroxidase block before HRP detection, then limit DAB development to a matched interval across test and control sections (standard chromogenic IHC practice). The selected image used 10% goat serum blocking, peroxidase conjugated secondary detection and DAB, providing a documented starting workflow for this antibody (datasheet A04890-1). Titrate primary antibody around its reported 2 μg/ml condition if background persists, keeping retrieval fixed at EDTA pH 8.0 (datasheet A04890-1; standard IHC practice). Compare expected urothelial signal with adipocytes reported as undetected, while accounting for tissue handling differences (HPA tissue IHC: High in urothelial cells; Not detected in adipocytes).
How should I score RAB27B staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring, because the tissue profile describes cytoplasmic and membranous RAB27B expression (HPA tissue IHC: expression profile). For comparable sections, report the percentage of positive cells and an H-score from intensity categories 0–3, using the same thresholds and DAB development interval throughout (standard IHC practice). Normalise counts to the number of evaluable cells in the specified compartment, or report positive cells per mm² of viable annotated tissue when cellular segmentation is unreliable (standard IHC practice). Exclude folds, necrosis and section edges using criteria set before analysis (standard IHC practice). Keep urothelial and glandular populations separate rather than averaging them into a whole section score (HPA tissue IHC: urothelial and glandular expression; standard IHC practice).
When is a RAB27B positive IHC result convincing rather than artefactual?
A convincing result has reproducible cytoplasmic or membranous signal in a morphologically appropriate population, such as urothelial cells, with little signal in a no primary control (HPA tissue IHC: expression profile and High in urothelial cells; standard IHC practice). Interpret isolated nuclear staining cautiously because the supplied localisation evidence places RAB27B at membranes, late endosomes, Golgi and cytosol (UniProt O00194: subcellular location; HPA subcellular: main and additional locations). Reject apparent positives confined to section edges, necrosis or sites of endogenous peroxidase activity after reviewing the corresponding control (standard IHC practice). The tissue profile has medium consistency with RNA data and awaits external verification, so staining alone cannot establish target specificity (HPA tissue IHC: reliability description). Compare patterns across 2 independently stained sections when material permits (standard IHC practice).
Boster reagents
Best RAB27B / Ras-related protein Rab-27B IHC Antibodies
Both anti-RAB27B antibodies have IHC images from human paraffin sections and mouse and rat stomach sections, plus A549 ICC/IF images (catalog image captions: A04890-1, A04890-2).
Real IHC data
Anti-RAB27B Antibody ®
Cat # A04890-1
Real IHC data
Anti-RAB27B Antibody ®
Cat # A04890-2
A04890-1 has IHC images from human bladder and stomach cancer and mouse and rat stomach, plus A549 ICC/IF (catalog A04890-1 image captions). A04890-2 has IHC images from human prostatic cancer and mouse and rat stomach, plus A549 ICC/IF and human bladder paraffin-section IF (catalog A04890-2 image captions).
Which to pick: For tissue IHC, choose A04890-1 if its human bladder or stomach examples match your study; its recommended IHC concentration is 2–5 μg/ml (catalog A04890-1 IHC captions; datasheet: A04890-1). For IF/ICC, choose A04890-2 if you also need a paraffin-section IF example: its images include A549 ICC/IF and human bladder IF, and it is listed as polyclonal (catalog A04890-2 IF captions; datasheet: A04890-2). For cross-species IHC, either SKU has mouse and rat stomach paraffin-section images and listed Human/Mouse/Rat reactivity; neither IHC caption reports the fixative (catalog IHC captions and reactivity: A04890-1, A04890-2).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O00194 (RB27B_HUMAN, Ras-related protein Rab-27B).
- Human Protein Atlas. RAB27B tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. RAB27B subcellular location (ICC-IF): Mainly localized to the plasma membrane and the Golgi apparatus. In addition localized to the cytosol..
- Human Protein Atlas. RAB27B antibody validation summary (2 antibodies).
- Correlation Between RAB27B and p53 Expression and Overall Survival in Pancreatic Cancer. Pancreas 2016 — PMC4714634.
- Prognostic role of Rab27A and Rab27B expression in patients with non-small cell lung carcinoma. Thoracic cancer 2019 — PMC6360262.
- Actions of Rab27B-GTPase on mammalian central excitatory synaptic transmission. Physiological reports 2020 — PMC7195558.
- LINC00511 drives invasive behavior in hepatocellular carcinoma by regulating exosome secretion and invadopodia formation. Journal of experimental & clinical cancer research : CR 2021 — PMC8176717.
- PubMed PMID:9066979 — UniProt-cited evidence.
- PubMed PMID:11178108 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for RAB27B (Ras-related protein Rab-27B). Expected localisation Observed cytoplasmic and membranous staining (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A04890-1). Validated IHC antibody: A04890-1 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Colon (Glandular cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human bladder cancer tissue; fixative not specified (datasheet A04890-1); 2. Fixation: Image fixative and duration unreported (datasheet A04890-1); verify before use.; 3. Sectioning: 4–5 µm sections on charged slides (standard); 4. Deparaffinisation: Xylene, graded ethanol series to water (standard); 5. Antigen retrieval: Heat retrieval: EDTA pH 8.0 (datasheet A04890-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A04890-1); 8. Primary antibody: Rabbit anti-RAB27B, 2-5 μg/ml (datasheet A04890-1); 9. Primary incubation: Overnight at 4 °C (datasheet A04890-1). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Caveat: Medium IHC–RNA consistency; verify staining (HPA tissue IHC); Isoform / epitope: No isoforms annotated; mature chain spans 2–218 (UniProt); Regulation: Tissue-enhanced RNA in stomach (HPA tissue RNA). Evidence: UniProt O00194, HPA tissue IHC · Enhanced, HPA ICC-IF · Mainly localized to the plasma membrane and the Golgi apparatus. In…, Datasheet A04890-1, PMC4714634, PMC6360262. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/RAB27B/immunohistochemistry-ihc-guide.