This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
CTNNA1 / Catenin alpha-1 · IHC design guide
Design Immunohistochemistry for CTNNA1
Plan CTNNA1 IHC in paraffin sections around membranous and cytoplasmic staining (HPA tissue IHC). Human breast glandular cells provide a high-staining reference (HPA tissue IHC); compare their staining with your test sections using the catalog antibody’s chromogenic protocol (datasheet PB9137).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
CTNNA1 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 | Membranous and cytoplasmic staining (HPA tissue IHC) | |
| Staining pattern | Membranous and cytoplasmic signal varies by tissue (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6 HIER, heat-mediated (datasheet PB9137) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | Adipose tissue |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across 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 PB9137) | |
| Caveat | Adipocytes may lack detectable signal (HPA tissue IHC) | |
| Regulation | Variable tissue expression (HPA tissue IHC) | |
| Isoform / epitope | 3 isoforms; check antibody epitope coverage (UniProt) |
Section 1
Recommended CTNNA1 IHC & IF Protocols
The catalog antibody’s IHC-P protocol (datasheet PB9137) is accompanied by 3 published CTNNA1 IHC protocols (PMC7200596; PMC12206905; PMC7751797).
| Sample | Paraffin-embedded rat intestine tissue; fixative not specified (datasheet PB9137) |
| Fixation | Image fixative and duration unreported (datasheet PB9137); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Citrate pH 6, 20 min (datasheet PB9137) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet PB9137) |
| Primary antibody | Rabbit anti-CTNNA1, 0.5-1μg/ml (datasheet PB9137) |
| Primary incubation | Overnight at 4 °C (datasheet PB9137) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet PB9137) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | CTNNA1-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Membranous and cytoplasmic expression at variable levels in all tissues. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated citrate pH 6 retrieval for the catalog antibody (datasheet PB9137). Use a paper’s reported retrieval conditions when reproducing its assay.
Section 2
What Is the Expected CTNNA1 Staining Pattern?
CTNNA1 is expected at cell junctions and in the cytoplasm, with membranous and cytoplasmic staining at variable levels across tissues (UniProt P35221 subcellular location; HPA tissue IHC). Glandular cells in breast, appendix and duodenum, and respiratory epithelial cells in bronchus, are examples of high staining (HPA tissue IHC). HPA rates the tissue pattern Supported, with medium consistency between antibody staining and RNA expression (HPA tissue IHC). CTNNA1 has no transmembrane segment (UniProt P35221 topology).
| Membranous staining outlines cell boundaries, accompanied by cytoplasmic staining in expected cells (HPA tissue IHC). | This fits the reported IHC pattern and CTNNA1 localisation at adherens junctions and in the cytoplasm (HPA tissue IHC; UniProt P35221 subcellular location). Judge the distribution within identifiable cells; colour at a tissue edge alone does not establish a cellular pattern (standard IHC practice). |
| Strong, isolated nuclear staining appears without the expected boundary or cytoplasmic pattern (HPA tissue IHC). | Treat this as discordant with the predominant tissue IHC pattern and investigate artefact before scoring it positive (HPA tissue IHC; standard IHC practice). Nuclear localisation is listed by UniProt, so nuclear signal alone cannot be declared biologically impossible (UniProt P35221 subcellular location). |
| Adipocytes stain strongly, despite being listed as not detected in adipose tissue (HPA tissue IHC). | Check cell identification, antibody cross-reactivity and endogenous detection activity with appropriate controls (standard IHC practice). This is a discrepancy from that HPA observation, not proof of nonspecific binding: expression varies among tissues and cells (HPA tissue IHC). |
| Colour spreads across extracellular spaces, blank areas or many cell types without clear boundaries (standard IHC practice). | Diffuse background makes localisation and cell-specific scoring unreliable (standard IHC practice). Review the no-primary control, blocking, washes and chromogen development before interpreting a broad signal as CTNNA1 (standard IHC practice). |
| No staining appears in glandular cells of breast or duodenum, both reported high by HPA (HPA tissue IHC). | First check whether the run detected its positive control, then review antibody dilution, retrieval and detection conditions (standard IHC practice). A failed control does not establish CTNNA1 absence in the specimen (standard IHC practice). |
💡Expected CTNNA1 appearanceCall a convincing positive when clear cell-boundary and cytoplasmic staining is visible in identifiable expected cells, such as HPA-high glandular or respiratory epithelial cells; intensity can vary by tissue (HPA tissue IHC). Diffuse colour lacking cellular localisation is a suspect positive (standard IHC practice).
| Tissue and cell selection | HPA reports variable membranous and cytoplasmic expression across tissues, including high staining in bronchial respiratory epithelium and no detected staining in adipocytes (HPA tissue IHC). Select and score the specific cell population, rather than treating every cell in a section as an equivalent control (standard IHC practice). |
| Strength of the reference pattern | HPA labels the tissue IHC pattern Supported and describes medium consistency with RNA expression; the listed antibodies have Supported IHC status (HPA tissue IHC; HPA antibodies). These ratings support comparison with the observed pattern but do not validate every unexpected compartment or cell type (standard IHC interpretation). |
| Topology and processing | CTNNA1 lacks a transmembrane segment and signal peptide, and its annotated chain spans residues 2–906 (UniProt P35221 topology and processing). Interpret boundary staining alongside its reported junctional localisation; these annotations do not identify the catalog antibody’s epitope or predict retrieval performance (UniProt P35221; standard IHC interpretation). |
| Isoforms and modified residues | UniProt lists three isoforms and modified residues, including phosphoserines (UniProt P35221 isoforms and modified residues). Without an antibody epitope map or isoform-specific validation in the supplied evidence, do not assign staining differences to an isoform or modification (standard IHC interpretation). |
| IF/ICC Q: What localisation is expected? | A: HPA reports supported plasma-membrane and cell-junction localisation in ICC-IF; Golgi and vesicle locations are marked uncertain (HPA subcellular ICC-IF). Use the separate IF/ICC guide for that application; these observations do not supply an IHC-P protocol (HPA subcellular ICC-IF). |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected positive cells show no signal (HPA tissue IHC). | The run may have inadequate detection, retrieval or primary-antibody signal (standard IHC practice). | Check a known-positive section in the same run, then review the validated IHC-P conditions and reagent performance; avoid calling the sample negative if the control failed (standard IHC practice). |
| A no-primary control develops colour (standard IHC practice). | Endogenous detection activity or nonspecific detection-reagent binding may contribute signal (standard IHC practice). | Address the relevant endogenous activity, review blocking and detection reagents, and repeat the control before attributing colour to CTNNA1 (standard IHC practice). |
| Junctional outlines are obscured by diffuse colour (HPA tissue IHC). | Excess background, concentrated antibody or prolonged chromogen development can obscure cellular detail (standard IHC practice). | Review dilution, blocking, washes and development time against the IHC-P workflow; score only cells whose boundaries remain interpretable (standard IHC practice). |
| Only a nuclear pattern is prominent (HPA tissue IHC). | The result is atypical for HPA tissue IHC, although UniProt also lists nuclear localisation (HPA tissue IHC; UniProt P35221 subcellular location). | Compare with a positive tissue and no-primary control, and verify morphology before deciding whether the nuclear signal is credible (standard IHC practice). |
| High colour appears in adipocytes (HPA tissue IHC). | HPA lists adipocytes as not detected; cell misidentification, cross-reactivity or endogenous activity are possible explanations (HPA tissue IHC; standard IHC practice). | Confirm the stained cell type and inspect control sections before interpreting the discrepancy as CTNNA1 expression (standard IHC practice). |
| Signal differs between tissues or cell populations (HPA tissue IHC). | HPA reports variable staining despite low tissue RNA specificity, so uniform intensity is not expected (HPA tissue IHC). | Compare the same cell type and compartment across sections, with run controls, before assigning a technical failure (standard IHC practice). |
Experiment evidence
IHC & IF images showing CTNNA1 staining
PB9137 · IHCIHC analysis of CTNNA1 using anti-CTNNA1 antibody (PB9137). CTNNA1 was detected in paraffin-embedded section of rat intestine tissue. Heat m
PB9137 · IHCIHC analysis of CTNNA1 using anti-CTNNA1 antibody (PB9137). CTNNA1 was detected in paraffin-embedded section of human mammary tissue. Heat m
PB9137 · IFIF analysis of CTNNA1 using anti-CTNNA1 antibody (PB9137). CTNNA1 was detected in immunocytochemical section of U20S cells. Enzyme antigen r
M01617-1 · IHCIHC analysis of CTNNA1 using anti-CTNNA1 antibody (M01617-1). CTNNA1 was detected in paraffin-embedded section of human mammary cancer tissu
M01617 · IHCImmunohistochemical analysis of paraffin-embedded human lung cancer, using Catenin alpha 1 Antibody.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000044115-CTNNA1/tissue/cerebral+cortex#imid_15340954
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000044115-CTNNA1/tissue/colon#imid_15340872
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000044115-CTNNA1/tissue/liver#imid_15340881
HPA · GallbladderHuman Protein Atlas IHC, Gallbladder. Source: https://www.proteinatlas.org/ENSG00000044115-CTNNA1/tissue/gallbladder#imid_15340865
HPA · ICC-IF CACO-2Human Protein Atlas immunofluorescence, CACO-2, antibody HPA063535; green = CTNNA1, blue = nucleus, red = microtubules.
HPA · ICC-IF CACO-2Human Protein Atlas immunofluorescence, CACO-2, antibody HPA063535; green = CTNNA1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for CTNNA1 IHC & IF
🧪Run breast first: glandular cells should stain (HPA: High in breast glandular cells). Use adipose tissue as the negative section (HPA: Not detected in adipocytes); no named cell type on the breast slide is established as an internal negative, so any cells used for that comparison should show only background staining beside positive glandular cells (UniProt P35221: ubiquitously expressed; cell-junction localization).
Positive control tissue: Adrenal gland (Glandular cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show CTNNA1 in CACO-2, SiHa, U2OS, RPTEC/TERT1, hTERT-RPE1 (serum starved), Sperm, with annotated localisation: Plasma membrane (supported), Cell Junctions (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control and a rabbit isotype control matched to the catalog antibody’s clonality when known (caption: rabbit primary; standard IHC practice). Process a CTNNA1-knockout specimen in parallel, or use peptide competition if the immunizing peptide is available (standard IHC practice). For the caption’s biotin-based DAB detection, check endogenous peroxidase and biotin background in the positive section (caption: biotinylated secondary and SABC-DAB; standard IHC practice).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported, and the selected PB9137 tissue-IHC caption does not state a fixative (selected-SKU caption: fixative unreported). The caption uses heat retrieval in citrate buffer at pH 6 for 20 minutes on rat intestine, but does not establish that retrieval is required in breast tissue (selected-SKU caption). The supplied evidence does not establish that frozen sections or IF are easier; in breast IHC, blood-associated endogenous peroxidase can produce DAB background that should be distinguished from glandular cell staining (HPA: High in breast glandular cells; standard IHC practice).
HPA tissue IHC evidence for CTNNA1
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 |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Appendix | Glandular cells | High | Protein (IHC) | HPA → |
| Breast | Glandular cells | High | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | High | Protein (IHC) | HPA → |
| Cerebral cortex | Endothelial cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced CTNNA1 IHC Tips
Troubleshoot CTNNA1 staining by checking retrieval, compartment, controls and scoring in paraffin sections before interpreting changes in junctional signal.
Which retrieval conditions should I start with for CTNNA1 in paraffin sections?
Start with heat-mediated retrieval in citrate buffer at pH 6 for 20 minutes (datasheet PB9137). The catalog antibody produced CTNNA1 staining in a paraffin-embedded rat intestine section under those conditions, although the caption does not report its fixative (datasheet PB9137). If staining is weak, compare a modest change in heating time on matched sections while holding antibody concentration and detection constant (standard IHC practice). Record both junctional and cytoplasmic signal, since CTNNA1 occurs in those compartments (UniProt P35221; HPA tissue IHC). Excessively harsh retrieval can damage section morphology, making apparent loss at cell boundaries difficult to judge (standard IHC practice).
Could fixation explain weak CTNNA1 staining or damaged junctions?
Target-specific fixation sensitivity for CTNNA1 is unknown from the supplied evidence; the PB9137 tissue caption describes a paraffin section but does not state its fixative (datasheet PB9137). Document the fixative, fixation duration and tissue processing for each case, then compare sections processed alike before attributing a signal difference to CTNNA1 biology (standard IHC practice). Check morphology and adjacent cell boundaries alongside staining, because poorly preserved sections can make junctional staining hard to assess (standard IHC practice; HPA subcellular). Keep citrate retrieval at pH 6 for 20 minutes as the initial reference condition while assessing processing effects (datasheet PB9137).
How should I assess junctional versus cytoplasmic CTNNA1 staining?
Look first for staining along cell-cell boundaries, then assess cytoplasmic signal separately: CTNNA1 is reported at adherens junctions, in the cytoplasm and at the cell membrane (UniProt P35221). HPA describes variable membranous and cytoplasmic staining across tissues, with plasma membrane and cell junction localisation supported by subcellular data (HPA tissue IHC; HPA subcellular). Use a counterstain and intact tissue architecture to identify which cells carry each pattern, and compare equivalent regions across sections (standard IHC practice). Avoid treating every diffuse deposit as CTNNA1: assess whether it follows cellular outlines and persists outside folds, edges or damaged areas (standard IHC practice).
Can this stain distinguish CTNNA1 isoforms or a modified epitope?
Do not assign a particular splice isoform from this stain without antibody epitope mapping or isoform-specific validation: CTNNA1 has 3 annotated isoforms (UniProt P35221). Its topology has no transmembrane segment, and the record lists modified residues including phosphoserines at positions 264, 268, 295 and 297 (UniProt P35221). Those annotations alone do not establish whether the catalog antibody detects every isoform or whether modification alters its binding (UniProt P35221; datasheet PB9137). For an unexpected pattern, compare independently validated antibodies with known epitopes on matched sections and report the epitope information available for each reagent (standard IHC practice).
How can IF help resolve ambiguous CTNNA1 IHC localisation?
Use IF on a separately validated preparation to inspect whether CTNNA1 outlines cell junctions, its supported subcellular location (HPA subcellular). Multiplex with a validated marker for the cell type being assessed, so overlapping signal identifies the stained cells rather than merely nearby structures (standard IF practice). Select fluorophores and channels after checking tissue autofluorescence and include single-stain controls to assess channel bleed-through (standard IF practice). Because CTNNA1 has no transmembrane segment and associates with the cytoplasmic side of adhesion complexes, optimise permeabilisation for access to that epitope while preserving junctions (UniProt P35221; standard IF practice). Do not transfer the PB9137 paraffin-section retrieval conditions to IF without validation (datasheet PB9137).
What controls help identify nonspecific CTNNA1 chromogenic staining?
Run a no-primary control through the same secondary antibody, enzyme and chromogen steps to reveal detection-system background (standard IHC practice). The PB9137 example used 10% goat serum blocking, biotinylated goat anti-rabbit secondary antibody and DAB development (datasheet PB9137). For comparable runs, keep blocking and detection conditions fixed, and apply a peroxidase block where the chromogenic workflow requires it (standard IHC practice). Inspect endogenous pigment, section folds and tissue edges before scoring brown deposits as CTNNA1 (standard IHC practice). Genuine signal should be evaluated against the reported membranous and cytoplasmic pattern, rather than judged by stain intensity alone (HPA tissue IHC).
How should I quantify variable CTNNA1 staining across sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and anatomical region before measuring CTNNA1, since HPA reports variable membranous and cytoplasmic expression across tissues (HPA tissue IHC). Score junctional and cytoplasmic staining separately using percentage of positive cells and an intensity-based H-score, with the scoring thresholds fixed across cases (standard IHC practice). Normalise counts to the number of eligible cells in each region, or report positive-cell density per mm² when tissue area is the sampling unit (standard IHC practice). Keep retrieval, detection, counterstaining and image acquisition comparable, and exclude folds, necrosis and damaged edges from the prespecified analysis area (standard IHC practice).
When should I question an apparent loss or gain of CTNNA1?
Treat a change in junctional signal as interpretable only when adjacent cells and their boundaries are preserved, because CTNNA1 is reported at cell junctions and in the cytoplasm (UniProt P35221; HPA tissue IHC). Confirm the stained cell population: HPA reports high signal in several glandular or epithelial populations and endothelial cells in specified tissues, while adipocytes in adipose tissue are listed as not detected (HPA tissue IHC). Recheck staining confined to cut edges, necrotic areas or folds, and compare it with the no-primary control for detection-system background (standard IHC practice). Nuclear signal alone needs additional validation because junctional localisation is supported, whereas UniProt also lists nuclear localisation (HPA subcellular; UniProt P35221).
Boster reagents
Best CTNNA1 / Catenin alpha-1 IHC Antibodies
Anti-CTNNA1 antibodies have IHC images from paraffin sections of human, mouse, and rat tissue (catalog IHC captions); PB9137 also has a cell-based IF image (catalog IF caption).
Real IHC data
Anti-alpha 1 Catenin/CTNNA1 Antibody ®
Cat # PB9137
Real IHC data
Anti-alpha 1 Catenin/CTNNA1 Antibody ® (monoclonal, 10I2)
Cat # M01617-1
Real IHC data
Anti-Catenin alpha 1 CTNNA1 Rabbit Monoclonal Antibody
Cat # M01617
PB9137 has IHC images from rat and mouse intestine and human mammary tissue, plus an IF image from U20S cells (catalog image captions). M01617-1 has an IHC image from human mammary cancer, while M01617 has one from human lung cancer (catalog IHC captions).
Which to pick: For human tissue IHC, M01617-1 is a mouse monoclonal with a paraffin-section image using EDTA retrieval; M01617 is a rabbit monoclonal with a paraffin-section image (catalog product records and IHC captions). For IF/ICC, choose PB9137, which lists both applications and has a cell-based IF image; M01617 lists IF/ICC but has no IF image in this payload (catalog applications and image captions). For IHC across human, mouse, and rat, PB9137 has images from all three species, with citrate retrieval shown in paraffin sections; the fixative is unreported (catalog IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P35221 (CTNA1_HUMAN, Catenin alpha-1).
- Human Protein Atlas. CTNNA1 tissue IHC expression (reliability: Supported).
- Human Protein Atlas. CTNNA1 subcellular location (ICC-IF): Mainly localized to the plasma membrane and cell junctions. In addition localized to the Golgi apparatus, vesicles, connecting piece, mid piece and principal piece..
- Human Protein Atlas. CTNNA1 antibody validation summary (3 antibodies).
- Loss-of-function variants in CTNNA1 detected on multigene panel testing in individuals with gastric or breast cancer. Genetics in medicine : official journal of the American College of Medical Genetics 2020 — PMC7200596.
- Role of germline aberrations affecting CTNNA1, MAP3K6 and MYD88 in gastric cancer susceptibility. Journal of medical genetics 2018 — PMC6161648.
- Exploration and Validation of Key Genes and Immune Infiltration in Alcoholic Hepatitis. Journal of inflammation research 2025 — PMC12206905.
- α-E-Catenin (CTNNA1) Inhibits Cell Proliferation, Invasion and EMT of Bladder Cancer. Cancer management and research 2020 — PMC7751797.
- PubMed PMID:8404069 — UniProt-cited evidence.
- PubMed PMID:8323564 — UniProt-cited evidence.
- PubMed PMID:7945318 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for CTNNA1 (Catenin alpha-1). Expected localisation Membranous and cytoplasmic staining (HPA tissue IHC). Antigen retrieval: Citrate pH 6 HIER, heat-mediated (datasheet PB9137). Validated IHC antibody: PB9137 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded rat intestine tissue; fixative not specified (datasheet PB9137); 2. Fixation: Image fixative and duration unreported (datasheet PB9137); 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: Citrate pH 6 , 20 min (datasheet PB9137); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet PB9137); 8. Primary antibody: Rabbit anti-CTNNA1, 0.5-1μg/ml (datasheet PB9137); 9. Primary incubation: Overnight at 4 °C (datasheet PB9137). Watch for: Fixation: Keep fixation consistent across 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 PB9137); Caveat: Adipocytes may lack detectable signal (HPA tissue IHC); Isoform / epitope: 3 isoforms; check antibody epitope coverage (UniProt); Regulation: Variable tissue expression (HPA tissue IHC). Evidence: UniProt P35221, HPA tissue IHC · Supported, HPA ICC-IF · Mainly localized to the plasma membrane and cell junctions. In…, Datasheet PB9137, PMC7200596, PMC12206905. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/CTNNA1/immunohistochemistry-ihc-guide.