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CCM2 / Cerebral cavernous malformations 2 protein · IHC design guide
Design Immunohistochemistry for CCM2
Plan chromogenic IHC for CCM2 in paraffin sections using its cytoplasmic tissue pattern (HPA tissue IHC). Compare high staining in testis spermatogonia or tonsil germinal center cells with medium staining in cerebral cortex neurons (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
CCM2 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 | General cytoplasmic staining across tissues (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Testis+4 more · see all | |
| Negative control | Liver |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep paraffin-section fixation consistent. (standard IHC practice; not target-specific) | |
| Caveat | Brain-enriched RNA differs from the strongest IHC sites (HPA tissue IHC) | |
| Regulation | Expression regulation not annotated (UniProt) | |
| Isoform / epitope | 4 isoforms; epitope coverage is unspecified (UniProt) |
Section 1
Recommended CCM2 IHC & IF Protocols
Compare the catalog antibody’s IHC protocol with three published CCM2 chromogenic IHC protocols (datasheet; PMC2640205; PMC7160551; PMC2856024).
| Sample | Paraffin-embedded human liver tissue; fixative not specified (datasheet A01908) |
| Fixation | Image fixative and duration unreported (datasheet A01908); 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-CCM2, 1:50-1:200 (datasheet A01908) |
| 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 | CCM2-positive staining in spermatogonia cells of testis (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic expression. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 retrieval at 95–98 °C for 20 min (page retrieval); adjust for the chosen antibody and specimen.
Section 2
What Is the Expected CCM2 Staining Pattern?
CCM2 should show predominantly cytoplasmic staining in paraffin sections (UniProt Q9BSQ5: cytoplasm; HPA: general cytoplasmic expression). Expect strong signal in testicular spermatogonia and tonsillar germinal center cells, with moderate signal in cerebral cortical neurons (HPA: tissue IHC). CCM2 has no transmembrane segment (UniProt Q9BSQ5: topology). HPA rates the tissue staining “Supported,” citing medium consistency with RNA expression (HPA: tissue IHC reliability).
| Cytoplasmic signal is strong in spermatogonia or tonsillar germinal center cells. | This matches the reported high staining in those cells (HPA: tissue IHC). Compare stained cells with tissue morphology and the counterstain when scoring (standard IHC practice). |
| Moderate cytoplasmic signal appears in cerebral cortical neurons. | This fits the reported medium neuronal staining (HPA: tissue IHC). Brain-enhanced RNA expression does not specify that cortical protein staining must be the strongest (HPA: RNA specificity; tissue IHC). |
| Signal is predominantly nuclear or outlines cell membranes, without convincing cytoplasmic staining. | That distribution conflicts with the reported IHC pattern and UniProt location (HPA: general cytoplasmic expression; UniProt Q9BSQ5: cytoplasm). Treat it as suspect until controls support specificity (standard IHC practice). |
| Cholangiocytes stain strongly while expected positive cells do not. | Cholangiocytes are reported as not detected (HPA: liver tissue IHC). Check for cross-reactivity or endogenous detection activity; this observation alone cannot identify which caused the signal (standard IHC practice). |
| Diffuse color covers tissue and surrounding areas, obscuring individual cells. | The result cannot establish a cell-specific CCM2 pattern (standard IHC practice). Review background controls and staining conditions before interpreting intensity (standard IHC practice). |
💡Expected CCM2 appearanceCall an IHC result positive when identifiable spermatogonia or tonsillar germinal center cells show strong cytoplasmic staining, or cortical neurons show moderate cytoplasmic staining (HPA: tissue IHC); dominant nuclear signal or strong cholangiocyte staining is suspect (UniProt Q9BSQ5: cytoplasm; HPA: liver tissue IHC).
| Cell type and tissue (HPA: tissue IHC) | HPA reports high staining in spermatogonia and tonsillar germinal center cells, medium staining in cortical neurons, and no detected staining in cholangiocytes (HPA: tissue IHC). Score the specified cells, not whole-section color (standard IHC practice). |
| IHC antibody evidence (HPA: antibody validation) | HPA020273 and HPA021669 each have “Supported” IHC status (HPA: antibody validation). That status and the medium RNA–staining consistency support cautious interpretation; neither establishes performance for an unspecified catalog antibody (HPA: tissue IHC reliability). |
| Protein location and topology (UniProt Q9BSQ5) | UniProt assigns CCM2 to the cytoplasm and reports no transmembrane segment (UniProt Q9BSQ5: subcellular location, topology). Use cytoplasmic distribution as the IHC reference pattern alongside HPA tissue observations (HPA: tissue IHC). |
| Isoforms and processing (UniProt Q9BSQ5) | Four isoforms are listed, with no signal peptide or propeptide and one annotated chain spanning residues 1–444 (UniProt Q9BSQ5: isoforms, processing). The supplied record gives no antibody epitope, so isoform-specific staining cannot be inferred. |
| IF/ICC Q: Is a mitochondrial pattern expected? | A: HPA reports enhanced mitochondrial localization in ICC-IF images from A-431, U-251MG, U2OS and MCF-7 (HPA: subcellular ICC-IF). Tissue IHC is described as generally cytoplasmic (HPA: tissue IHC); interpret each assay against its own evidence. |
| Situation | Likely cause | Next action |
|---|---|---|
| No staining in spermatogonia or tonsillar germinal center cells. | These are reported high-staining cells (HPA: tissue IHC); a blank result could reflect assay failure or specimen quality (standard IHC practice). | Confirm the cells are present on the section, then review antigen retrieval, primary antibody use, detection reagents and a working positive control (standard IHC practice). |
| Only nuclei stain in an otherwise interpretable section. | Nuclear dominance disagrees with the reported cytoplasmic location (UniProt Q9BSQ5: subcellular location; HPA: tissue IHC). The pattern alone does not establish its cause. | Check primary-omission and other appropriate controls, then reassess antibody specificity and the detection workflow (standard IHC practice). |
| Cholangiocytes show convincing signal. | HPA reports cholangiocytes as not detected (HPA: liver tissue IHC); cross-reactivity or endogenous detection activity warrants investigation (standard IHC practice). | Compare with a primary-omission control and assess endogenous detection activity before assigning the stain to CCM2 (standard IHC practice). |
| Broad, uneven background prevents cell-level scoring. | Nonspecific reagent binding, insufficient blocking or incomplete washes can produce background (standard IHC practice); no CCM2-specific cause is established by the supplied sources. | Review blocking, washes, primary antibody concentration and detection controls; rescore only when cell boundaries and compartments are clear (standard IHC practice). |
| Cortical neurons stain less strongly than the high-positive tissues. | Cortical neurons are reported at medium intensity, versus high intensity in spermatogonia and tonsillar germinal center cells (HPA: tissue IHC). | Compare like cell types and slide conditions; do not treat weaker cortical staining alone as assay failure (HPA: tissue IHC; standard IHC practice). |
| IF/ICC shows mitochondrial puncta while tissue IHC looks broadly cytoplasmic. | HPA describes enhanced mitochondrial ICC-IF localization and general cytoplasmic tissue IHC staining (HPA: subcellular ICC-IF; tissue IHC). | Record the assay and cell context with each observation; assess the IHC section against its tissue controls and the IF/ICC result against its own controls (standard IHC practice). |
Experiment evidence
IHC & IF images showing CCM2 staining
A01908 · IHCImmunohistochemistry of paraffin-embedded human liver using CCM2 antibody at dilution of 1:100 .Perform microwave antigen retrieval with 10
A01908 · IHCImmunohistochemistry of paraffin-embedded rat heart using CCM2 antibody at dilution of 1:100 .Perform microwave antigen retrieval with 10 mM
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000136280-CCM2/tissue/cerebral+cortex#imid_6049048
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000136280-CCM2/tissue/colon#imid_6048966
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000136280-CCM2/tissue/liver#imid_6048959
HPA · PancreasHuman Protein Atlas IHC, Pancreas. Source: https://www.proteinatlas.org/ENSG00000136280-CCM2/tissue/pancreas#imid_6048926
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA020273; green = CCM2, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA020273; green = CCM2, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for CCM2 IHC & IF
🧪Run tonsil first and look for CCM2 staining in germinal center cells (HPA: High in tonsil germinal center cells). Use liver cholangiocytes as the negative tissue readout (HPA: Not detected in liver cholangiocytes); on the tonsil slide, cells without specific staining should show counterstain alone, but the supplied HPA rows do not identify a particular tonsil cell type as negative (HPA: tonsil germinal center cells High).
Positive control tissue: Testis (Spermatogonia cells, HPA High)
Negative control tissue: Liver (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show CCM2 in A-431, U-251MG, U2OS, MCF-7, with annotated localisation: Mitochondria (enhanced) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control; an isotype control matched to the primary antibody’s host species, immunoglobulin class and concentration; and a CCM2 knockout control or peptide block if the immunizing peptide is available (standard IHC practice). For chromogenic tonsil IHC, quench endogenous peroxidase and block endogenous biotin if using avidin–biotin detection; for IF, check autofluorescence with an unstained section (standard IHC/IF practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported in the supplied evidence; the selected A01908 paraffin-section liver caption also leaves the fixative unreported (A01908 tissue-IHC caption). That caption uses microwave retrieval in 10 mM PBS, pH 7.2, before staining at 1:100, but does not establish that retrieval is required (A01908 tissue-IHC caption). Frozen sections and IF cannot be ranked as easier from this evidence; interpret liver staining by cell type because HPA reports cholangiocytes as not detected while the catalog caption describes staining in a liver section without identifying the stained cells (HPA: liver cholangiocytes Not detected; A01908 tissue-IHC caption).
HPA tissue IHC evidence for CCM2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — Medium consistency between antibody staining and RNA expression data.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Testis | Spermatogonia cells | High | Protein (IHC) | HPA → |
| Tonsil | Germinal center cells | High | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Medium | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Medium | Protein (IHC) | HPA → |
| Cerebral cortex | Neuronal cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Liver | Cholangiocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced CCM2 IHC Tips
Troubleshoot CCM2 staining in paraffin sections by checking retrieval, compartment, cell identity and controls before interpreting chromogenic signal.
How should I retrieve CCM2 in paraffin sections when the signal is weak?
Start with citrate buffer at pH 6.0, heated to 95–98 °C for 20 min (page retrieval protocol). If staining remains weak, compare an adjacent section retrieved by microwave in 10 mM PBS, pH 7.2, the method reported for catalog antibody A01908 in paraffin-embedded human liver (A01908 tissue-IHC caption). Cool sections consistently, then keep antibody incubation and chromogen development matched so the comparison isolates retrieval (standard IHC practice). Judge improvement by clearer cytoplasmic staining in expected cells, while checking whether either condition increases diffuse background (UniProt Q9BSQ5 subcellular location; HPA tissue IHC profile; standard IHC practice).
How can I troubleshoot uneven CCM2 staining after fixation?
Target-specific CCM2 sensitivity to fixative choice or fixation duration is unknown from the supplied evidence (supplied CCM2 evidence). The A01908 image documents paraffin-embedded human liver, but its caption does not state a fixative or fixation time (A01908 tissue-IHC caption). Record those variables for each specimen, then compare adjacent sections under the same retrieval, antibody incubation and chromogen development conditions (standard IHC practice). If signal varies between blocks, check tissue preservation and section adhesion before assigning the difference to CCM2 abundance; include a consistently processed comparison section in each staining run (standard IHC practice).
Where should CCM2 staining appear, and how should I handle conflicting patterns?
Expect a predominantly cytoplasmic pattern in tissue IHC, consistent with the reported general cytoplasmic profile and UniProt location (HPA tissue IHC profile; UniProt Q9BSQ5 subcellular location). CCM2 has no annotated transmembrane segment, so a sharp membrane-only rim needs scrutiny against adjacent cytoplasm and background controls (UniProt Q9BSQ5 topology; standard IHC practice). An enhanced mitochondrial location is reported in cell imaging, creating a compartment difference that tissue chromogenic resolution may not settle (HPA subcellular profile; standard IHC practice). Compare cellular morphology and a matched negative control, and describe granular cytoplasmic signal without claiming mitochondrial identity from DAB alone (standard IHC practice).
Could CCM2 isoforms or epitope accessibility explain inconsistent staining?
CCM2 has 4 annotated isoforms and a PID domain spanning residues 59–248, so epitope placement matters when comparing antibodies (UniProt Q9BSQ5 isoforms and domains). Check the catalog antibody’s stated immunogen or mapped epitope against each isoform before interpreting absent staining as absent total CCM2 (UniProt Q9BSQ5 isoforms; standard IHC practice). Several phosphorylated residues are annotated, including serines 15 and 164, but no supplied evidence establishes that they alter this antibody’s staining (UniProt Q9BSQ5 modified residues; supplied CCM2 evidence). Compare retrieval conditions and a second independently mapped epitope, if available, using matched sections and controls (standard IHC practice).
How can IF help check CCM2 localisation seen by chromogenic IHC?
On the separate IF/ICC workflow, multiplex CCM2 with a validated marker for the cell population being assessed, using distinct host species or a validated sequential staining scheme (standard IF practice). Select spectrally separated fluorophores and inspect an unstained section in each channel to identify tissue autofluorescence before assigning a weak CCM2 signal (standard IF practice). Because CCM2 lacks a transmembrane segment and is annotated in the cytoplasm, use an appropriately controlled permeabilisation step to expose intracellular epitopes (UniProt Q9BSQ5 topology and subcellular location; standard IF practice). Compare the resulting pattern with mitochondrial markers if testing the reported enhanced mitochondrial localisation, while keeping IF and chromogenic IHC interpretations distinct (HPA subcellular profile; standard IF practice).
What controls help distinguish CCM2 signal from chromogenic background?
Run a no-primary control beside the test section to reveal secondary reagent, endogenous enzyme and chromogen background (standard IHC practice). Include a peroxidase block before DAB development and assess whether staining persists in the no-primary section (standard chromogenic IHC practice). Titrate the catalog antibody around the caption’s 1:100 condition while keeping retrieval, incubation and DAB development constant (A01908 tissue-IHC caption; standard IHC practice). Prefer cell-associated cytoplasmic staining over diffuse deposits, and inspect section edges and damaged areas separately because these can exaggerate apparent positivity (HPA tissue IHC profile; standard IHC practice).
How should I score CCM2 IHC across specimens? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and region before scoring, then report the percentage of positive cells and staining intensity separately or combine them into an H-score (standard IHC quantification practice). For cell-rich regions, positive-cell density per mm² can supplement the percentage, provided the counted tissue area is documented (standard IHC quantification practice). Normalise to the number of eligible cells or evaluable tissue area within the same compartment, excluding folds and damaged regions consistently (standard IHC quantification practice). Keep retrieval, antibody dilution and DAB development matched across specimens, and avoid pooling neuronal and glandular cell scores when their reported staining levels differ (HPA tissue IHC profile; standard IHC practice).
When is apparent CCM2 positivity likely to be an artefact?
A credible result shows cell-associated cytoplasmic staining in an anatomically identified population and little signal in matched negative controls (HPA tissue IHC profile; UniProt Q9BSQ5 subcellular location; standard IHC practice). HPA reports high staining in spermatogonia and tonsillar germinal center cells, but no detected staining in liver cholangiocytes, so identify the stained cell before comparing tissues (HPA tissue IHC profile). Question isolated membrane-only signal, edge accentuation, necrotic deposits or staining reproduced in a no-primary control; check endogenous peroxidase when using DAB (UniProt Q9BSQ5 topology; standard IHC practice). Interpret the A01908 liver image as evidence of a staining method, without assuming that every liver cell should be positive (A01908 tissue-IHC caption; HPA tissue IHC profile).
Boster reagents
Best CCM2 / Cerebral cavernous malformations 2 protein IHC Antibodies
A01908 has real IHC images from paraffin-embedded human liver, rat heart and mouse heart (catalog image captions). No IF image or IF application is listed (catalog applications; image captions).
Real IHC data
Anti-CCM2 Antibody
Cat # A01908
A01908 is listed for IHC in human, mouse and rat samples (catalog applications; reactivity). Its IHC images show paraffin-embedded human liver, rat heart and mouse heart (catalog image captions).
Which to pick: Choose A01908 for tissue IHC across human, mouse and rat: its application list includes IHC, and its own images show paraffin sections from all three species (catalog applications; reactivity; image captions). The image captions do not report the fixative (catalog image captions). No listed SKU is validated for IF/ICC, and A01908 has no reported clone designation (catalog applications; clone field).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9BSQ5 (CCM2_HUMAN, Cerebral cavernous malformations 2 protein).
- Human Protein Atlas. CCM2 tissue IHC expression (reliability: Supported).
- Human Protein Atlas. CCM2 subcellular location (ICC-IF): Localized to the mitochondria..
- Human Protein Atlas. CCM2 antibody validation summary (3 antibodies).
- A two-hit mechanism causes cerebral cavernous malformations: complete inactivation of CCM1, CCM2 or CCM3 in affected endothelial cells. Human molecular genetics 2009 — PMC2640205.
- Emerging roles of CCM genes during tumorigenesis with potential application as novel biomarkers across major types of cancers. Oncology reports 2020 — PMC7160551.
- Cerebral cavernous malformations proteins inhibit Rho kinase to stabilize vascular integrity. The Journal of experimental medicine 2010 — PMC2856024.
- Epicardial CCM2 Promotes Cardiac Development and Repair Via its Regulation on Cytoskeletal Reorganization. JACC. Basic to translational science 2024 — PMC10950406.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:15498874 — UniProt-cited evidence.
- PubMed PMID:12853948 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for CCM2 (Cerebral cavernous malformations 2 protein). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A01908 at 1:50-1:200 (the product's own IHC validation image is shown). Controls (HPA): positive Testis (Spermatogonia cells); negative Liver. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human liver tissue; fixative not specified (datasheet A01908); 2. Fixation: Image fixative and duration unreported (datasheet A01908); 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-CCM2, 1:50-1:200 (datasheet A01908); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep paraffin-section fixation consistent. (standard IHC practice; not target-specific); Caveat: Brain-enriched RNA differs from the strongest IHC sites (HPA tissue IHC); Isoform / epitope: 4 isoforms; epitope coverage is unspecified (UniProt); Regulation: Expression regulation not annotated (UniProt). Evidence: UniProt Q9BSQ5, HPA tissue IHC · Supported, HPA ICC-IF · mitochondria., Datasheet A01908, PMC2640205, PMC7160551. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/CCM2/immunohistochemistry-ihc-guide.