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RAC2 / Ras-related C3 botulinum toxin substrate 2 · IHC design guide
Design Immunohistochemistry for RAC2
Plan RAC2 staining in paraffin sections using cytoplasmic immune-cell staining as the expected pattern (HPA tissue IHC). Compare bone marrow, lymph node, spleen or tonsil positive cells with an appropriate negative control, and check for endogenous peroxidase signal in marrow (HPA tissue IHC; standard IHC practice).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
RAC2 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 cytoplasm (HPA tissue IHC); membrane-associated when active (UniProt) | |
| Staining pattern | Cytoplasmic staining most abundant in immune cells (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Bone marrow+3 more · see all | |
| Negative control | Cervix+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across paraffin sections (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A01714-1) | |
| Caveat | Marrow peroxidase can mimic chromogenic signal (HPA tissue IHC; standard IHC practice) | |
| Regulation | Hematopoietic-specific expression (UniProt) | |
| Isoform / epitope | No annotated isoforms; C-terminal processing may affect epitopes (UniProt) |
Section 1
Recommended RAC2 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is followed by 4 published RAC2 IHC protocols (PMC10750086; PMC7028469; PMC10198763; PMC6685597).
| Sample | Paraffin-embedded rat brain tissue; fixative not specified (datasheet A01714-1) |
| Fixation | Image fixative and duration unreported (datasheet A01714-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat-induced epitope retrieval in citrate buffer, pH 6.0, 20 min at 95–98 °C (standard rule: cytoplasmic / membrane antigen) |
| 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-RAC2, 1:50-1:100 (datasheet A01714-1) |
| 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 | RAC2-positive staining in hematopoietic cells of bone marrow (HPA tissue IHC: Medium). HPA tissue profile: Cytoplasmic expression in several tissues, most abundant in immune cells. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 retrieval at 95–98 °C for 20 min (page antigen retrieval rule); one published protocol also uses citrate with a pressure cooker (PMC10198763).
Section 2
What Is the Expected RAC2 Staining Pattern?
RAC2 staining should be mainly cytoplasmic in hematopoietic and other immune cells; membrane association can occur when RAC2 is activated (UniProt P15153). In tissue IHC, HPA reports cytoplasmic expression across several tissues, most abundant in immune cells, with medium staining in selected marrow and lymphoid compartments (HPA tissue IHC). HPA rates its tissue profile “Enhanced” but describes only medium consistency between staining and RNA data (HPA tissue IHC). RAC2 has no transmembrane segment (UniProt P15153 topology).
| Cytoplasmic staining in bone marrow hematopoietic cells and lymph node or tonsil non-germinal center cells. | This matches the reported cell and compartment pattern; HPA grades each listed cell population Medium, so compare signal within the identified cells rather than treating every cell in the section as positive (HPA tissue IHC). |
| A predominantly nuclear signal, or a crisp membrane-only outline without cytoplasmic staining. | Question the staining pattern and check controls: UniProt places RAC2 in the cytoplasm and notes membrane association when activated, while HPA reports cytoplasmic tissue expression (UniProt P15153; HPA tissue IHC). Compartment mismatch alone does not identify the artefact. |
| Strong staining in glandular or epithelial cells where the supplied HPA examples report no detection. | Investigate antibody cross-reactivity or endogenous chromogen-generating activity before assigning RAC2 positivity (general IHC practice). HPA reports no detection in cervix and duodenum glandular cells and esophageal squamous epithelial cells; that finding concerns those cells, not every cell in those tissues (HPA tissue IHC). |
| Diffuse color across tissue, extracellular space, or the negative control. | Interpret localization cautiously: broad background can obscure a cell-restricted cytoplasmic result (general IHC practice). HPA’s reported pattern is cytoplasmic and most abundant in immune cells, so diffuse color alone does not establish RAC2 staining (HPA tissue IHC). |
| No signal in the expected cell population of an otherwise evaluable bone marrow, lymph node, spleen, or tonsil section. | Treat the run as unresolved before calling the sample negative: HPA reports Medium staining in the specified hematopoietic, non-germinal center, or white-pulp cells (HPA tissue IHC). Check that those cells are present and that the positive and detection controls worked (general IHC practice). |
💡Expected RAC2 appearanceCall a result consistent with RAC2 when identifiable hematopoietic or lymphoid cells show cytoplasmic staining around the Medium level reported in HPA examples; isolated strong nuclear, unrelated epithelial, or diffuse background color is a suspect result requiring controls (HPA tissue IHC; UniProt P15153; general IHC practice).
| Cell population and tissue context | HPA reports Medium staining in marrow hematopoietic cells, lymph node and tonsil non-germinal center cells, and spleen white-pulp cells; select and score the named cells rather than a whole-tissue average (HPA tissue IHC). |
| Negative comparison cells | HPA reports no detection in specific cells, including cervix glandular cells, colon endothelial cells, and liver cholangiocytes. These are cell-level observations, not proof that the entire tissue lacks RAC2-positive immune cells (HPA tissue IHC). |
| Localization and activation | RAC2 is cytoplasmic and can associate with the membrane when activated; it has no transmembrane segment. Membrane accentuation may be compatible with its biology, but this record supplies no activation-state IHC scoring rule (UniProt P15153). |
| Antibody evidence | HPA lists IHC status as Approved for HPA047820 and Enhanced for CAB022946. Those statuses support different validation strengths; neither establishes the performance of an unlisted antibody or a particular staining run (HPA antibodies). |
| Epitope, processing, and retrieval | UniProt annotates a chain spanning residues 1–189 and a 190–192 propeptide, but the supplied record gives no antibody epitope or RAC2-specific retrieval condition. Optimize retrieval against a known-positive control without claiming a target-specific fixation effect (UniProt P15153; general IHC practice). |
| IF/ICC: what pattern is supported? | A cytoplasmic signal is biologically plausible, with possible activation-associated membrane signal (UniProt P15153). HPA supplies no ICC-IF images or assigned subcellular location, and neither listed antibody has an ICC status here; this record cannot validate an IF/ICC pattern (HPA subcellular; HPA antibodies). |
| Situation | Likely cause | Next action |
|---|---|---|
| Known-positive immune cells show no chromogenic signal. | The target cells may be absent from the viewed area, or the IHC run may have failed; HPA reports Medium staining only in specified cells of its positive examples (HPA tissue IHC; general IHC practice). | Confirm cell identity on the counterstained section, then review the positive control, antibody conditions, retrieval, and detection reagents in that order (general IHC practice). Do not infer a RAC2-specific retrieval requirement from this record. |
| Only nuclei stain in a section containing identifiable immune cells. | The dominant compartment conflicts with cytoplasmic tissue expression and UniProt cytoplasmic localization (HPA tissue IHC; UniProt P15153). The pattern itself cannot distinguish non-specific binding from detection background (general IHC practice). | Compare with a matched negative control and an expected-positive cell population; review counterstain and detection background before assigning a RAC2 result (general IHC practice). |
| Glandular or squamous epithelial cells appear strongly positive. | HPA reports no detection in the specified cervix and duodenum glandular cells and esophageal squamous epithelial cells; cross-reactivity or endogenous detection activity is possible (HPA tissue IHC; general IHC practice). | Check cell identity and an appropriate negative control; assess endogenous enzyme blocking for the chromogenic detection system, then compare adjacent immune cells where present (general IHC practice). Do not label the whole tissue negative. |
| Color is widespread, including the negative control. | Diffuse background can arise from non-specific reagent binding or endogenous detection activity, preventing reliable cell-level interpretation (general IHC practice). It does not resemble the reported immune-cell-rich cytoplasmic profile (HPA tissue IHC). | Review blocking and washes, verify the negative control, and adjust detection conditions using the same positive and negative comparison sections (general IHC practice). |
| A membrane rim is seen alongside cytoplasmic staining. | Membrane association can occur when RAC2 is activated, although UniProt describes no transmembrane segment (UniProt P15153). A chromogenic rim does not by itself measure activation state. | Score the cytoplasmic signal and record the rim separately; compare its distribution with the negative control and avoid an activation claim without independent evidence (UniProt P15153; general IHC practice). |
| Two antibodies give different tissue patterns. | The supplied HPA entries have different IHC validation statuses: HPA047820 is Approved and CAB022946 is Enhanced. HPA’s tissue reliability description also notes medium staining–RNA consistency (HPA antibodies; HPA tissue IHC). | Compare the same named cell populations and controls across runs, document each antibody’s pattern, and treat discordant cells as unresolved rather than combining the stains into one positive call (HPA tissue IHC; general IHC practice). |
Experiment evidence
IHC & IF images showing RAC2 staining
A01714-1 · IHCImmunohistochemistry of paraffin-embedded rat brain using RAC2 antibody at dilution of 1:100 .Perform microwave antigen retrieval with 10 mM
M01714 · IFImmunofluorescent analysis of 4% paraformaldehyde-fixed, 0.1% Triton X-100 permeabilized NIH/3T3 (mouse embryonic fibroblast cell line) cell
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000128340-RAC2/tissue/cerebral+cortex#imid_6210944
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000128340-RAC2/tissue/colon#imid_6210878
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000128340-RAC2/tissue/liver#imid_6210871
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000128340-RAC2/tissue/kidney#imid_6210872
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for RAC2 IHC & IF
🧪Run bone marrow first: hematopoietic cells should stain (HPA: Bone marrow, hematopoietic cells, Medium). Use cervix glandular cells as the tissue negative (HPA: Cervix, glandular cells, Not detected); nonhematopoietic cells on the bone marrow slide should lack specific staining (UniProt P15153: hematopoietic specific).
Positive control tissue: Bone marrow (Hematopoietic cells, HPA Medium)
Negative control tissue: Cervix (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for RAC2; derive a cell-line control from the positive tissue's cell type (Hematopoietic cells) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only control; a host-species- and isotype-matched control for a monoclonal primary, or matched nonimmune IgG for a polyclonal primary; and RAC2-knockout tissue as a biological negative (standard IHC practice). Quench endogenous peroxidase in bone marrow before chromogenic detection and check the no-primary slide for residual signal (standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported in the supplied evidence; the selected A01714-1 paraffin-section caption also leaves the fixative unreported (A01714-1 tissue-IHC caption). That caption uses microwave retrieval in 10 mM PBS, pH 7.2, with antibody at 1:100; it reports a procedure, not whether RAC2 staining depends on retrieval (A01714-1 tissue-IHC caption). There is no supplied IF/ICC image or frozen-section comparison to establish that either is easier (HPA subcellular: no cell lines with ICC-IF images); bone marrow endogenous peroxidase can complicate chromogenic interpretation (standard IHC practice).
HPA tissue IHC evidence for RAC2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Medium consistency between antibody staining and RNA expression data. Antibody staining in cells/structures not annotated, view images.). 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 |
|---|---|---|---|---|
| Bone marrow | Hematopoietic cells | Medium | Protein (IHC) | HPA → |
| Lymph node | Non-germinal center cells | Medium | Protein (IHC) | HPA → |
| Spleen | Cells in white pulp | Medium | Protein (IHC) | HPA → |
| Tonsil | Non-germinal center cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Cervix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Colon | Endothelial cells | Not detected | Protein (IHC) | HPA → |
| Duodenum | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Endometrium | Cells in endometrial stroma | Not detected | Protein (IHC) | HPA → |
| Epididymis | Glandular cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced RAC2 IHC Tips
Troubleshoot RAC2 staining in paraffin sections by checking retrieval, cell identity and cytoplasmic localisation before interpreting chromogenic signal.
What retrieval conditions should I try when RAC2 staining is weak in paraffin sections?
Start with citrate buffer at pH 6.0, heated to 95–98 °C for 20 min (page retrieval rule: cytoplasmic / membrane antigen). If staining remains weak, test microwave retrieval in 10 mM PBS at pH 7.2 on an adjacent section, as reported for catalog antibody A01714-1 in paraffin-embedded rat brain (A01714-1 tissue-IHC caption). Use the reported 1:100 dilution only when evaluating that catalog antibody, and keep detection and exposure conditions matched between sections (A01714-1 tissue-IHC caption; standard IHC practice). Compare signal in identifiable immune cells with background and tissue preservation before selecting a condition (HPA: cytoplasmic expression most abundant in immune cells; standard IHC practice).
Could fixation explain weak or uneven RAC2 staining?
Target-specific RAC2 sensitivity to fixation is unknown from the supplied evidence; the selected paraffin-section caption does not state its fixative (A01714-1 tissue-IHC caption). Record the fixative, fixation duration and tissue-processing history for every section, then compare sections processed together before changing retrieval or antibody concentration (standard IHC practice). Examine section edges, folds and poorly preserved regions separately, since these can produce uneven chromogenic staining independent of antigen distribution (standard IHC practice). If fixation histories differ, use matched control tissue and one staining run to assess whether the difference persists, while treating any fixation effect on RAC2 as an experimental finding rather than an established property (standard IHC practice).
Where should RAC2 staining appear within a positive cell?
Expect predominantly cytoplasmic RAC2 staining, with possible membrane-associated signal when RAC2 is activated (UniProt P15153: subcellular location; HPA: tissue IHC profile). RAC2 has no annotated transmembrane segment, so a membrane-like chromogenic rim alone does not establish an integral membrane protein or an activated state (UniProt P15153: topology and function). Compare the suspected rim with cytoplasm in the same well-preserved cell and with nearby unstained structures, using the counterstain to define cell boundaries (standard IHC practice). Score cell-associated staining separately from extracellular deposits, section edges and diffuse staining across unrelated cell populations (HPA: expression most abundant in immune cells; standard IHC practice).
How should RAC2 processing and modifications affect epitope troubleshooting?
The supplied record lists 0 isoforms and a RAC2 chain spanning residues 1–189, with processing noted at residues 190–192 (UniProt P15153: isoforms and processing). An antibody epitope has not been supplied, so do not attribute weak staining to a particular terminus or modification without antibody-specific mapping (supplied antibody evidence: epitope unspecified). RAC2 has annotated modifications at residues 39, 147 and 189, but this record does not show whether any alters tissue-IHC recognition (UniProt P15153: modified residues). Compare retrieval conditions and appropriate control sections first, and request epitope documentation if discrepancies remain (standard IHC practice).
How can I investigate RAC2 localisation by IF alongside chromogenic IHC?
Use this as a separate IF validation experiment and multiplex RAC2 with an independently validated marker for the expected immune-cell population (HPA: expression most abundant in immune cells; standard IF practice). Select spectrally separated fluorophores after checking tissue autofluorescence in an unstained section, and include single-label controls to assess bleed-through (standard IF practice). RAC2 is cytoplasmic and can associate with membranes when activated; choose permeabilisation that permits antibody access to a cytoplasm-facing epitope, once that epitope is known (UniProt P15153: subcellular location; standard IF practice). Compare cellular localisation with the IHC pattern, while validating the IF antibody and fixation conditions independently because the supplied paraffin caption provides no IF protocol (A01714-1 tissue-IHC caption; standard IF practice).
How can I reduce diffuse or immune-cell-associated chromogenic background?
First distinguish genuine immune-cell staining from diffuse deposits: RAC2 is hematopoietic-specific in the supplied record, and HPA reports its strongest tissue expression in immune cells (UniProt P15153: tissue specificity; HPA: tissue IHC profile). Include a no-primary control, assess the secondary detection system and block endogenous peroxidase before chromogen development (standard chromogenic IHC practice). If background persists, optimise blocking, washes and the primary antibody concentration on matched sections; 1:100 is reported only for the selected rat-brain caption (standard IHC practice; A01714-1 tissue-IHC caption). Compare any proposed reduction against retained staining in a defined positive cell population, since excessive optimisation can erase weak signal (standard IHC practice).
What should I measure when comparing RAC2 staining across sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the tissue compartment and cell population before scoring, because RAC2-rich immune cells may vary in abundance between sections (HPA: tissue IHC profile; standard IHC practice). Within that population, record the percentage of positive cells and staining intensity, or calculate an H-score from intensity categories; for infiltrates, positive cells per mm² is another useful measure (standard IHC practice). Normalise cell-based scores to the number of evaluable cells of the same type, and density measurements to analysed tissue area (standard IHC practice). Keep retrieval, detection and image thresholds consistent, and exclude necrotic, folded or poorly preserved regions using predefined criteria (standard IHC practice).
How do I distinguish a true RAC2-positive result from artefact?
A credible result should show cell-associated, mainly cytoplasmic staining in an appropriate cell population, with possible membrane association that cannot by itself prove activation (HPA: tissue IHC profile; UniProt P15153: subcellular location). Check immune-rich areas against the tissue counterstain and compare with a no-primary control; HPA reports medium staining in bone-marrow hematopoietic cells and selected lymphoid populations (HPA: positive tissue IHC; standard IHC practice). Treat isolated nuclear staining, edge-restricted signal, necrotic deposits and diffuse chromogen in the no-primary control as reasons to investigate artefact (UniProt P15153: subcellular location; standard IHC practice). Endogenous peroxidase can also produce misleading chromogen, so confirm the peroxidase block and repeat the comparison on preserved sections (standard chromogenic IHC practice).
Boster reagents
Best RAC2 / Ras-related C3 botulinum toxin substrate 2 IHC Antibodies
Anti-RAC2 options include a paraffin-section IHC image from rat brain and an IF image from mouse NIH/3T3 cells; catalog reactivity also includes human samples (catalog figures; catalog reactivity).
Real IHC data
Anti-RAC2 Antibody
Cat # A01714-1
Real IF data
Anti-RAC2 Antibody (C-term)
Cat # M01714
A01714-1 will render with its paraffin-section rat brain IHC figure, stained at 1:100 after microwave retrieval in 10 mM PBS, pH 7.2 (A01714-1 IHC caption). M01714 will render with its IF figure from paraformaldehyde-fixed, permeabilized NIH/3T3 cells, stained at 1:25 (M01714 IF caption).
Which to pick: Choose A01714-1 for paraffin-section tissue IHC: its own figure documents rat brain staining, while the fixative is unreported (A01714-1 IHC caption). Choose M01714 when a documented cell IF example matters; A01714-1 also lists ICC/IF, whereas M01714 lists IF but not ICC (M01714 IF caption; catalog applications). For work across human, mouse and rat, A01714-1 lists reactivity with all three, though its IHC figure documents rat only (catalog reactivity; A01714-1 IHC caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P15153 (RAC2_HUMAN, Ras-related C3 botulinum toxin substrate 2).
- Human Protein Atlas. RAC2 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. RAC2 subcellular location (ICC-IF): Variation in transcript expression is correlated to the cell cycle..
- Human Protein Atlas. RAC2 antibody validation summary (2 antibodies).
- Expression Analysis of the Small GTP-Binding Protein Rac in Pterygium. Turkish journal of ophthalmology 2023 — PMC10750086.
- Differentially Expressed Genes in Matched Normal, Cancer, and Lymph Node Metastases Predict Clinical Outcomes in Patients With Breast Cancer. Applied immunohistochemistry & molecular morphology : AIMM 2020 — PMC7028469.
- Pancancer Analysis Revealed the Value of RAC2 in Immunotherapy and Cancer Stem Cell. Stem cells international 2023 — PMC10198763.
- RAC2 acts as a prognostic biomarker and promotes the progression of clear cell renal cell carcinoma. International journal of oncology 2019 — PMC6685597.
- PubMed PMID:2674130 — UniProt-cited evidence.
- PubMed PMID:15461802 — UniProt-cited evidence.
- PubMed PMID:10591208 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for RAC2 (Ras-related C3 botulinum toxin substrate 2). Expected localisation Observed cytoplasm (HPA tissue IHC); membrane-associated when active (UniProt). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A01714-1 at 1:50-1:100 (the product's own IHC validation image is shown). Controls (HPA): positive Bone marrow (Hematopoietic cells); negative Cervix. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded rat brain tissue; fixative not specified (datasheet A01714-1); 2. Fixation: Image fixative and duration unreported (datasheet A01714-1); 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-induced epitope retrieval in citrate buffer, pH 6.0 , 20 min at 95–98 °C…; 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-RAC2, 1:50-1:100 (datasheet A01714-1); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across paraffin sections (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A01714-1); Caveat: Marrow peroxidase can mimic chromogenic signal (HPA tissue IHC; standard IHC practice); Isoform / epitope: No annotated isoforms; C-terminal processing may affect epitopes (UniProt); Regulation: Hematopoietic-specific expression (UniProt). Evidence: UniProt P15153, HPA tissue IHC · Enhanced, HPA cell-line RNA · Variation in transcript expression is correlated to the cell cycle., Datasheet A01714-1, PMC10750086, PMC7028469. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/RAC2/immunohistochemistry-ihc-guide.