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IQGAP2 / Ras GTPase-activating-like protein IQGAP2 · IHC design guide
Design Immunohistochemistry for IQGAP2
Plan chromogenic IQGAP2 IHC in paraffin sections using the catalog antibody’s documented conditions. Compare cytoplasmic and membranous staining with tissue controls, bearing in mind that HPA rates its tissue IHC evidence uncertain (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
IQGAP2 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 and membranous in most cell types (HPA tissue IHC) | |
| Staining pattern | Most cell types show cytoplasmic and membranous staining (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A04787-1) | |
| Positive control | Gallbladder+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 A04787-1) | |
| Caveat | Low agreement between IHC staining and RNA expression (HPA tissue IHC) | |
| Regulation | Isoform 2 is enhanced in testis (UniProt) | |
| Isoform / epitope | Three isoforms; check antibody epitope coverage (UniProt) |
Section 1
Recommended IQGAP2 IHC & IF Protocols
The catalog antibody protocol uses EDTA retrieval (datasheet A04787-1). The published chromogenic IHC protocols below provide citrate retrieval conditions and IQGAP2 antibody dilutions (PMC2988069; PMC5658114; PMC9628040).
| Sample | Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet A04787-1) |
| Fixation | Image fixative and duration unreported (datasheet A04787-1); 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 A04787-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A04787-1) |
| Primary antibody | Rabbit anti-IQGAP2, 0.5-1μg/ml (datasheet A04787-1) |
| Primary incubation | Overnight at 4 °C (datasheet A04787-1) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A04787-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | IQGAP2-positive staining in glandular cells of gallbladder (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic and membranous expression in most cell types. No signal in the no-primary control. |
💡Decision noteStart with EDTA pH 8.0 heat retrieval (datasheet A04787-1). If staining is weak, compare citrate retrieval (PMC2988069; PMC5658114; PMC9628040).
Section 2
What Is the Expected IQGAP2 Staining Pattern?
IQGAP2 staining is reported in the cytoplasm and at cell membranes in many cell types, with high staining in several glandular epithelia (HPA tissue IHC). Interpret this as a provisional pattern: HPA rates its tissue IHC reliability Uncertain because antibody staining has low consistency with RNA data (HPA tissue IHC). IQGAP2 has no transmembrane segment, so membrane staining does not imply an integral membrane protein (UniProt Q13576 topology).
| Glandular cells show cytoplasmic staining with a membrane component, strongest in gallbladder, prostate, rectum, seminal vesicle, small intestine, or stomach. | This matches the reported High staining in those glandular cells and the broader cytoplasmic and membranous profile (HPA tissue IHC). Compare intensity within the same run; the HPA tissue result remains Uncertain (HPA tissue IHC). |
| Staining is exclusively nuclear, with no convincing cytoplasmic or membrane signal. | A nuclear-only result is outside the reported tissue pattern and approved ICC-IF locations (HPA tissue IHC; HPA subcellular). Treat it as a possible artefact; review controls and antibody conditions before calling it IQGAP2. |
| Strong signal appears in adipocytes, skeletal myocytes, or urothelial cells. | Those cell populations were Not detected in HPA tissue IHC. Cross-reactivity or endogenous detection activity is possible; use a no-primary control and compare morphology. HPA's Uncertain reliability means their reported absence is not definitive (HPA tissue IHC). |
| Color covers stroma, empty spaces, and several cell types without a clear cellular pattern. | Diffuse staining does not establish the reported cytoplasmic and membranous pattern (HPA tissue IHC). Check the no-primary control, blocking, detection chemistry, and wash stringency (general IHC practice); do not score the haze as positive cells. |
| A glandular positive-control section has no detectable signal. | First verify that the section contains the relevant cells: several glandular populations were reported High, while liver hepatocytes were Low by IHC despite liver-enhanced RNA (HPA tissue IHC). Then review the antibody, retrieval, detection, and control run (general IHC practice). |
💡Expected IQGAP2 appearanceCall a result provisionally positive when identifiable glandular cells show clear cytoplasmic and membranous staining, potentially High in the listed glandular tissues; nuclear-only staining or diffuse color without cell boundaries should prompt a false-positive check (HPA tissue IHC; HPA subcellular).
| Tissue choice and RNA–protein mismatch | Use a reported High glandular cell population to assess the pattern (HPA tissue IHC). Liver hepatocytes were Low by IHC although RNA was liver-enhanced; RNA alone does not set the expected chromogenic intensity (HPA tissue IHC). |
| Antibody validation | All three listed antibodies have Uncertain IHC status, and HPA calls the tissue profile Uncertain (HPA antibodies; HPA tissue IHC). Require a convincing control pattern before treating an unusual result as biology. |
| Membrane association and processing | IQGAP2 has no transmembrane segment, signal peptide, propeptide, or annotated cleavage product (UniProt Q13576 topology and processing). A membrane-associated signal is plausible from HPA observations; these records do not support expecting a secreted or shed staining pattern (HPA tissue IHC; UniProt Q13576). |
| Isoforms and epitope coverage | UniProt lists three isoforms and enhanced expression of isoform 2 in testis (UniProt Q13576). No epitope location or isoform-specific IHC pattern is supplied, so do not infer antibody recognition or expected testis staining from that annotation. |
| IF/ICC Q&A: where should signal appear? | HPA reports approved plasma-membrane and vesicle locations in ICC-IF (HPA subcellular). Use that as a localisation cross-check, while judging paraffin-section chromogenic staining against the separate tissue IHC profile (HPA tissue IHC). |
| Situation | Likely cause | Next action |
|---|---|---|
| The positive-control glandular cells are blank. | The chosen cells may have lower reported staining than expected, or the IHC run may have failed (HPA tissue IHC; general IHC practice). | Confirm the cell identity and use a reported High glandular population; check retrieval, primary antibody, detection reagents, and a run control (HPA tissue IHC; general IHC practice). |
| Only nuclei stain. | Nuclear-only staining conflicts with the reported cytoplasmic and membranous tissue profile and approved membrane/vesicle ICC-IF locations (HPA tissue IHC; HPA subcellular). | Check a no-primary section, examine counterstain and morphology, and repeat under validated IHC conditions before assigning a nuclear location (general IHC practice). |
| Muscle, adipocytes, or urothelium stain strongly. | These populations were Not detected in HPA tissue IHC; cross-reactivity or endogenous detection activity may contribute (HPA tissue IHC; general IHC practice). | Compare a no-primary section and the positive control; address endogenous enzyme activity where relevant to the chromogen, then reassess cellular specificity (general IHC practice). |
| The whole section has diffuse color. | Nonspecific reagent binding, insufficient washing, or detection background can obscure cellular localisation (general IHC practice). | Review no-primary background, blocking, primary-antibody dilution, wash steps, and detection exposure; score only discrete cellular staining (general IHC practice). |
| Liver is faint despite liver-enhanced RNA. | HPA reports Low hepatocyte IHC staining while classifying IQGAP2 RNA as liver-enhanced; the tissue IHC evidence is Uncertain (HPA tissue IHC). | Assess the same run with a reported High glandular control. Do not raise the IHC positivity threshold or declare assay failure from liver RNA alone (HPA tissue IHC). |
| Atypical staining varies across antibodies or runs. | Each listed antibody has Uncertain IHC validation, so an atypical signal needs independent scrutiny (HPA antibodies). | Compare matched controls and tissue morphology across runs; record the antibody and conditions, and avoid a definitive localisation claim until the pattern is reproducible (general IHC practice). |
Experiment evidence
IHC & IF images showing IQGAP2 staining
A04787-1 · IHCIHC analysis of IQGAP2 using antiIQGAP2 antibody (A04787-1). IQGAP2 was detected in paraffin-embedded section of human lung cancer tissue. H
A04787-1 · IHCIHC analysis of IQGAP2 using antiIQGAP2 antibody (A04787-1). IQGAP2 was detected in paraffin-embedded section of human mammary cancer tissue
A04787-1 · IFIF analysis of IQGAP2 using anti-IQGAP2 antibody (A04787-1). IQGAP2 was detected in immunocytochemical section of MCF7 cells. Enzyme antigen
M04787 · IHCIHC analysis of IQGAP2 using anti-IQGAP2 antibody (M04787). IQGAP2 was detected in a paraffin-embedded section of human liver cancer tissue.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000145703-IQGAP2/tissue/cerebral+cortex#imid_15232382
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000145703-IQGAP2/tissue/colon#imid_15203480
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000145703-IQGAP2/tissue/liver#imid_15203481
HPA · PancreasHuman Protein Atlas IHC, Pancreas. Source: https://www.proteinatlas.org/ENSG00000145703-IQGAP2/tissue/pancreas#imid_15203432
HPA · ICC-IF CACO-2Human Protein Atlas immunofluorescence, CACO-2, antibody HPA037404; green = IQGAP2, blue = nucleus, red = microtubules.
HPA · ICC-IF CACO-2Human Protein Atlas immunofluorescence, CACO-2, antibody HPA037404; green = IQGAP2, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for IQGAP2 IHC & IF
🧪Run gallbladder first: glandular cells should stain (HPA: High in gallbladder glandular cells). Use skeletal muscle myocytes as the negative tissue (HPA: Not detected in skeletal muscle myocytes); on the gallbladder slide, count non-glandular cells as an internal negative only if they show no staining above the matched no-primary background.
Positive control tissue: Gallbladder (Glandular cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show IQGAP2 in CACO-2, Hep-G2, U2OS, with annotated localisation: Vesicles (approved), Plasma membrane (approved) (HPA subcellular).
Technical controls: Include no-primary (secondary-only) and host- and clonality-matched rabbit IgG isotype controls, plus an IQGAP2-knockout biological negative where available; the selected antibody is rabbit-derived (A04787-1 tissue-IHC caption). Quench endogenous peroxidase before DAB detection and assess endogenous biotin background when using the caption’s streptavidin–biotin detection method (A04787-1 tissue-IHC caption).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported in the supplied evidence, and the exact selected-SKU caption leaves the fixative unreported (A04787-1 tissue-IHC caption). Heat retrieval in EDTA at pH 8.0 was used for a paraffin-embedded lung cancer section; its necessity for gallbladder is unreported (A04787-1 tissue-IHC caption). The supplied evidence does not establish that frozen sections or IF are easier; inspect gallbladder glandular lumens and section edges for nonspecific deposits during scoring (HPA: High in gallbladder glandular cells).
HPA tissue IHC evidence for IQGAP2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Uncertain — Low 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 |
|---|---|---|---|---|
| Gallbladder | Glandular cells | High | Protein (IHC) | HPA → |
| Prostate | Glandular cells | High | Protein (IHC) | HPA → |
| Rectum | Glandular cells | High | Protein (IHC) | HPA → |
| Seminal vesicle | 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 → |
| Lymph node | Germinal center cells | Not detected | Protein (IHC) | HPA → |
| Oral mucosa | Squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
| Skeletal muscle | Myocytes | Not detected | Protein (IHC) | HPA → |
| Smooth muscle | Smooth muscle cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced IQGAP2 IHC Tips
Troubleshoot IQGAP2 staining in paraffin sections by checking retrieval, compartment, controls, and cell-specific scoring before interpreting DAB intensity.
Which retrieval conditions should I start with for weak IQGAP2 staining?
Start with heat-mediated retrieval in EDTA at pH 8.0 for paraffin sections (datasheet A04787-1). The selected image used this retrieval before overnight incubation at 4°C with 1 μg/mL primary antibody (datasheet A04787-1). If staining remains weak, vary heating and cooling within your validated instrument workflow while keeping the buffer fixed, and compare sections from the same block. Include a known positive glandular-cell section, such as gallbladder, alongside a primary-antibody omission control (HPA: High in gallbladder glandular cells). Excessive retrieval can damage morphology, so judge signal against intact tissue architecture and background.
Could fixation explain variable IQGAP2 staining between paraffin blocks?
Target-specific fixation sensitivity is unknown: the selected paraffin-section caption does not state a fixative (datasheet A04787-1). Record each block’s fixation history when available, then compare blocks using the same EDTA pH 8.0 retrieval and staining run (datasheet A04787-1). As general IHC practice, prolonged or inconsistent fixation can alter epitope accessibility, but variation alone does not establish an IQGAP2-specific fixation effect. Check whether glandular cells and nearby tissue structures remain interpretable, and include a reference section in every run. Avoid attributing differences to fixation until retrieval, antibody incubation, detection, and tissue preservation have been compared.
Where should IQGAP2 DAB staining appear within a positive cell?
Assess cytoplasmic and membranous staining as the expected tissue pattern (HPA tissue IHC: cytoplasmic and membranous expression in most cell types). Plasma-membrane and vesicular localisation in cell images can help frame the assessment, although those images do not prove a particular tissue pattern (HPA subcellular: approved plasma membrane and vesicles). UniProt does not annotate a subcellular location, and IQGAP2 has no transmembrane segment (UniProt Q13576: subcellular annotation and topology). Compare staining with cell boundaries, cytoplasm, and the counterstained nuclei at high magnification. Predominantly nuclear or extracellular DAB should prompt control review before assigning it to IQGAP2.
Can an IQGAP2 antibody miss an isoform or fixation-sensitive epitope?
Yes, epitope coverage remains unresolved unless the antibody’s immunogen or mapped epitope is known; the supplied caption does not provide that mapping (datasheet A04787-1). IQGAP2 has 3 annotated isoforms, and isoform 2 expression is enhanced in testis (UniProt Q13576: isoforms and tissue specificity). Its CH, WW, IQ, and Ras-GAP regions provide distinct possible antibody targets, but their presence does not identify this antibody’s binding site (UniProt Q13576: domains). Compare staining across independently validated antibodies with different known epitopes when available, using the same paraffin sections. Do not call an unstained compartment or sample isoform-negative on DAB appearance alone.
How can IF help check ambiguous IQGAP2 IHC localisation?
On the separate IF/ICC workflow, multiplex IQGAP2 with a marker for the cell type being assessed; glandular cells are a relevant comparison in several tissues (HPA tissue IHC: High in gallbladder and prostate glandular cells). Choose spectrally separated fluorophores and check unstained tissue for autofluorescence before interpreting overlap. IQGAP2 lacks a transmembrane segment, while its mapped antibody epitope is not supplied (UniProt Q13576: topology; datasheet A04787-1: epitope unspecified). If the epitope faces the cytoplasm, compare gentle permeabilisation with an unpermeabilised control; avoid assuming which membrane side the antibody recognises. Treat IF colocalisation as supporting evidence and confirm the corresponding cell pattern independently in chromogenic IHC.
How do I reduce diffuse brown background without losing IQGAP2 signal?
First compare a primary-antibody omission section with the test section to distinguish detection-system staining from antibody-dependent signal. The selected paraffin image used 10% goat serum blocking, 1 μg/mL primary antibody overnight at 4°C, and a biotin-based DAB detection system (datasheet A04787-1). For a peroxidase-based workflow, check the peroxidase block; also assess whether endogenous biotin contributes to background with this detection chemistry. Titrate primary antibody and DAB development against a positive glandular-cell reference rather than suppressing all weak cytoplasmic staining (HPA tissue IHC: High in gallbladder glandular cells). Score only signal that remains spatially distinct from the omission control.
How should I score heterogeneous IQGAP2 DAB staining across glandular cells? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and tissue region before scoring; several glandular-cell populations are reported as High, whereas hepatocytes are Low (HPA tissue IHC: gallbladder glandular cells High; liver hepatocytes Low). For cell-level staining, record the percentage of eligible cells at each intensity and calculate an H-score as 1 × % weak + 2 × % moderate + 3 × % strong. Use the number of evaluable target cells as the denominator, excluding necrosis and poorly preserved edges. If counting discrete positive cells, report density per mm² of evaluable tissue and retain compartment-specific scores. Keep illumination, threshold, counterstain assessment, and reference controls consistent across batches.
When is an apparent IQGAP2-positive region likely to be artefactual?
Give greatest weight to staining in the expected cytoplasmic or membranous compartment and in an identified cell population (HPA tissue IHC: cytoplasmic and membranous expression in most cell types). High staining has been reported in gallbladder glandular cells, while adipocytes were not detected; these are reference patterns, not absolute controls for every specimen (HPA tissue IHC: gallbladder and adipose tissue). Staining confined to section edges, necrotic areas, or the omission control warrants investigation of processing or endogenous enzyme activity. Purely nuclear DAB also conflicts with the reported tissue pattern (HPA tissue IHC: cytoplasmic and membranous expression). Interpret weak positives cautiously because the tissue IHC reliability is Uncertain, with low staining-to-RNA consistency (HPA tissue IHC: reliability).
Boster reagents
Best IQGAP2 / Ras GTPase-activating-like protein IQGAP2 IHC Antibodies
Catalog antibodies cover human and mouse IHC (catalog: applications and reactivity); the supplied images show paraffin-section IHC in human lung and liver cancer tissue and IF/ICC in MCF7 cells (image captions).
Real IHC data
Anti-IQGAP2 Antibody ®
Cat # A04787-1
Real IHC data
Anti-IQGAP2 Rabbit Monoclonal Antibody
Cat # M04787
A04787-1 shows IHC in paraffin sections of human lung cancer tissue and IF/ICC in MCF7 cells (A04787-1 image captions). M04787 shows IHC in a paraffin section of human liver cancer tissue (M04787 image caption).
Which to pick: For paraffin-section IHC, choose A04787-1 for the illustrated lung cancer tissue procedure or M04787 for the illustrated liver cancer tissue procedure; both captions report EDTA pH 8.0 retrieval, and neither reports the fixative (respective IHC image captions). For IF/ICC, choose A04787-1 at the listed 2 μg/ml starting dilution; its MCF7 image shows IF/ICC, while M04787 lists IHC but no IF/ICC application (A04787-1 datasheet and IF image caption; M04787 application list). For human and mouse IHC, either SKU lists both species; A04787-1 also lists IF/ICC for both, though the supplied images demonstrate human samples only (catalog applications and reactivity; image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q13576 (IQGA2_HUMAN, Ras GTPase-activating-like protein IQGAP2).
- Human Protein Atlas. IQGAP2 tissue IHC expression (reliability: Uncertain).
- Human Protein Atlas. IQGAP2 subcellular location (ICC-IF): Localized to the plasma membrane and vesicles..
- Human Protein Atlas. IQGAP2 antibody validation summary (3 antibodies).
- IQGAP1 and IQGAP2 are reciprocally altered in hepatocellular carcinoma. BMC gastroenterology 2010 — PMC2988069.
- Reduced expression of IQGAP2 and higher expression of IQGAP3 correlates with poor prognosis in cancers. PloS one 2017 — PMC5658114.
- Comprehensive analysis of the expression and prognosis for IQ motif-containing GTPase-activating proteins in hepatocellular carcinoma. BMC cancer 2022 — PMC9628040.
- Depletion of IQ motif-containing GTPase activating protein 2 (IQGAP2) reduces hepatic glycogen and impairs insulin signaling. The Journal of biological chemistry 2023 — PMC10652104.
- PubMed PMID:8756646 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:15372022 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for IQGAP2 (Ras GTPase-activating-like protein IQGAP2). Expected localisation Cytoplasmic and membranous in most cell types (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A04787-1). Validated IHC antibody: A04787-1 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Gallbladder (Glandular cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet A04787-1); 2. Fixation: Image fixative and duration unreported (datasheet A04787-1); 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 A04787-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A04787-1); 8. Primary antibody: Rabbit anti-IQGAP2, 0.5-1μg/ml (datasheet A04787-1); 9. Primary incubation: Overnight at 4 °C (datasheet A04787-1). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A04787-1); Caveat: Low agreement between IHC staining and RNA expression (HPA tissue IHC); Isoform / epitope: Three isoforms; check antibody epitope coverage (UniProt); Regulation: Isoform 2 is enhanced in testis (UniProt). Evidence: UniProt Q13576, HPA tissue IHC · Uncertain, HPA ICC-IF · plasma membrane and vesicles., Datasheet A04787-1, PMC2988069, PMC5658114. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/IQGAP2/immunohistochemistry-ihc-guide.