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RDX / Radixin · IHC design guide
Design Immunohistochemistry for RDX
Plan RDX IHC in paraffin sections using adrenal glandular cells and kidney proximal tubules as strong-staining references (HPA tissue IHC). Start with the catalog antibody at 1:50 (datasheet M01926), then score cytoplasmic and membranous staining (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
RDX 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 staining (HPA tissue IHC) | |
| Staining pattern | Variable cytoplasmic/membranous staining; highest in adrenal gland and renal tubules (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet M01926) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections (standard IHC practice; not target-specific) | |
| Caveat | Antibody may detect proteins from more than one gene (HPA tissue IHC) | |
| Regulation | Stimulus-dependent regulation is unreported (UniProt) | |
| Isoform / epitope | 5 isoforms; epitope coverage is unspecified (UniProt; datasheet M01926) |
Section 1
Recommended RDX IHC & IF Protocols
Compare the catalog antibody’s IHC-P protocol (datasheet M01926) with one published paraffin-section, chromogenic RDX protocol (PMC2766609).
| Sample | Paraffin-embedded human breast cancer tissue; fixative not specified (datasheet M01926) |
| Fixation | Image fixative and duration unreported (datasheet M01926); 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 M01926); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet M01926) |
| Primary antibody | Rabbit monoclonal (clone FBC-18) anti-RDX, 1:50 (datasheet M01926) |
| Primary incubation | Overnight at 4 °C (datasheet M01926) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet M01926) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | RDX-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic and membranous expression at variable levels in several different cell types. Most abundant in adrenal gland and renal tubules. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 for the catalog antibody (datasheet M01926); the published protocol does not specify retrieval (PMC2766609).
Section 2
What Is the Expected RDX Staining Pattern?
RDX should show cytoplasmic and membranous staining, with prominent signal in adrenal glandular cells and renal proximal tubule microvilli (HPA tissue IHC). Its localisation at the cell membrane, cytoskeleton and cell projections supports a peripheral or apical pattern (UniProt P35241 localisation). RDX has no transmembrane segment (UniProt P35241 topology). HPA rates tissue IHC reliability as Enhanced but cautions that the staining may include protein from more than one gene (HPA tissue IHC).
| Strong apical staining outlines renal proximal tubule microvilli, with relatively little signal away from the brush border. | This matches the reported High proximal tubule microvillus signal (HPA tissue IHC) and RDX localisation to microvilli and the membrane-associated cytoskeleton (UniProt P35241 localisation). Evaluate the apical edge separately from general cytoplasmic colour; the two patterns carry different localisation information (general IHC practice). |
| Adrenal glandular cells stain strongly, while endocrine cells in colon or duodenum also show clear signal. | These are reported High cell-specific observations (HPA tissue IHC). Variable cytoplasmic and membranous staining elsewhere is compatible with the broader tissue profile (HPA tissue IHC). Judge intensity within the stated cell population rather than treating every cell in a positive organ as an expected positive (HPA tissue IHC; general IHC practice). |
| Predominantly nuclear staining replaces the expected peripheral, apical or cytoplasmic pattern. | Review this as a possible artefact or nonspecific result against the membrane and cytoskeletal localisation (UniProt P35241 localisation). HPA ICC-IF reports additional nucleoplasmic localisation with uncertain support, so nuclear signal alone cannot establish a specific RDX IHC pattern (HPA subcellular ICC-IF). |
| Strong colour appears in a cell type listed as not detected, or colour covers the section without cell boundaries. | Compare the named cell type with HPA's negative observations before calling a mismatch (HPA tissue IHC). Cross-reactivity or endogenous detection activity can contribute to unexpected colour (general IHC practice). HPA also cautions that its tissue staining may detect protein from more than one gene, so staining alone does not prove RDX identity (HPA tissue IHC). |
| A known-positive adrenal or renal proximal tubule section has little or no staining. | The missing expected High signal makes the run or reagent performance worth checking before interpreting test sections as negative (HPA tissue IHC; general IHC practice). Confirm that the relevant glandular cells or proximal tubule microvilli are present and assess the control alongside the test slide (HPA tissue IHC; general IHC practice). |
💡Expected RDX appearanceCall a positive result when cell-associated cytoplasmic or membranous colour includes High adrenal glandular or renal proximal tubule microvillus staining (HPA tissue IHC); widespread featureless colour or dominant nuclear-only staining warrants investigation rather than an RDX-specific call (general IHC practice; HPA subcellular ICC-IF).
| Subcellular distribution | RDX is associated with the cell membrane, cytoskeleton, microvilli and adherens junction undercoat (UniProt P35241 localisation). Its lack of a transmembrane segment means membrane-associated staining need not form a uniform outline of every cell (UniProt P35241 topology; general IHC interpretation). |
| Cell-specific tissue pattern | HPA reports High staining at the tips of fallopian tube cilia and in renal proximal tubule microvilli, alongside high adrenal glandular staining (HPA tissue IHC). These are compartment and cell-specific reference patterns; organ-wide intensity alone is a less precise comparison (HPA tissue IHC; general IHC practice). |
| Isoforms and epitope | UniProt lists 5 RDX isoforms and a FERM domain at residues 5–295 (UniProt P35241). The supplied record gives no epitope for the IHC-validated antibody, so isoform coverage and domain-specific staining cannot be inferred from the tissue pattern (UniProt P35241; HPA antibody records). |
| Evidence strength | HPA marks the tissue profile Enhanced while describing medium agreement between staining and RNA expression and cautioning that the signal may include protein from more than one gene (HPA tissue IHC). Antibody-level IHC ratings differ: HPA000263 is Supported; HPA000763 and CAB037312 are Enhanced (HPA antibody records). |
| Retrieval and detection | Target-specific fixation effects are not established by the supplied assay evidence. Verify with a matched IHC source before attributing a result to fixation. |
| Situation | Likely cause | Next action |
|---|---|---|
| Renal proximal tubules stain, but the apical microvillus edge is indistinct. | Diffuse colour or limited structural resolution can obscure the cell-specific High microvillus pattern (HPA tissue IHC; general IHC practice). | Inspect a well-preserved proximal tubule field and compare the apical edge with adjacent cytoplasm; check background and detection conditions before scoring localisation (HPA tissue IHC; general IHC practice). |
| A listed negative cell population stains strongly. | The result conflicts with that population's HPA observation; cross-reactivity or endogenous detection activity is possible (HPA tissue IHC; general IHC practice). | Verify cell identity, compare the positive control and run an appropriate detection control. Treat unexpected colour cautiously because HPA warns that staining may include protein from more than one gene (HPA tissue IHC; general IHC practice). |
| Colour is diffuse across tissue, including areas without a recognisable cell-associated pattern. | Background from blocking, antibody concentration or chromogenic detection can obscure interpretable staining (general IHC practice). | Review negative detection controls and optimise blocking, antibody concentration and wash steps using the antibody's IHC instructions; score only localised cellular signal (general IHC practice). |
| The known-positive adrenal or renal control is negative. | The control does not reproduce the reported High glandular or proximal tubule microvillus pattern, so a run-level problem is possible (HPA tissue IHC; general IHC practice). | Confirm the expected cells are present, then review retrieval, antibody application and detection against the antibody's IHC instructions before interpreting test-slide negatives (HPA tissue IHC; general IHC practice). |
| The only convincing signal is nuclear. | Nucleoplasmic localisation has uncertain support in HPA ICC-IF, while membrane localisation is supported there and peripheral sites are listed by UniProt (HPA subcellular ICC-IF; UniProt P35241 localisation). | Check the positive tissue and detection controls and report the compartment explicitly; avoid calling nuclear-only chromogenic staining a confirmed RDX pattern (HPA tissue IHC; HPA subcellular ICC-IF; general IHC practice). |
| Can IF/ICC settle an ambiguous IHC localisation? | HPA ICC-IF supports plasma membrane localisation and lists nucleoplasmic localisation as uncertain; it is a separate application from tissue IHC (HPA subcellular ICC-IF; HPA tissue IHC). | Use the separate IF/ICC guide for that experiment. Compare any IF/ICC result with its own controls and report it separately from the chromogenic tissue result (HPA subcellular ICC-IF; general IHC/IF practice). |
Experiment evidence
IHC & IF images showing RDX staining
M01926 · IHCIHC analysis of smc4 using anti-smc4 antibody (M01926). smc4 was detected in a paraffin-embedded section of human breast cancer tissue. Heat
A01926-1 · IFIF analysis of RDX using anti-RDX antibody (A01926-1). RDX was detected in immunocytochemical section of Hela cells. Enzyme antigen retrieva
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000137710-RDX/tissue/cerebral+cortex#imid_298790
HPA · Adrenal glandHuman Protein Atlas IHC, Adrenal gland. Source: https://www.proteinatlas.org/ENSG00000137710-RDX/tissue/adrenal+gland#imid_298774
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000137710-RDX/tissue/colon#imid_298708
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000137710-RDX/tissue/liver#imid_298709
HPA · ICC-IF SiHaHuman Protein Atlas immunofluorescence, SiHa, antibody CAB037312; green = RDX, blue = nucleus, red = microtubules.
HPA · ICC-IF SiHaHuman Protein Atlas immunofluorescence, SiHa, antibody CAB037312; green = RDX, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for RDX IHC & IF
🧪Run kidney first: proximal-tubule microvilli should stain strongly (HPA: High in kidney proximal-tubule microvilli); use adipose tissue adipocytes as the negative comparator (HPA: Not detected in adipocytes). On the kidney slide, use morphologically identified cells lacking a brush border as internal background references: they should lack the strong apical microvillar pattern, but should not automatically be scored as RDX-negative (HPA: High in proximal-tubule microvilli).
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 RDX in SiHa, U-251MG, U2OS, with annotated localisation: Plasma membrane (supported) (HPA subcellular).
Technical controls: Include no-primary (secondary-only), primary-host-species and isotype-matched nonimmune IgG, and RDX-knockout tissue controls (standard IHC control practice). For kidney chromogenic IHC, quench endogenous peroxidase and block endogenous biotin if using avidin–biotin detection; assess tissue autofluorescence for IF (standard IHC/IF practice).
⚠️Feasibility: No RDX-specific fixation window or retrieval dependency is reported in the supplied evidence; the selected M01926 caption concerns smc4 and does not report a fixative (caption: smc4; fixative not stated). Paraffin IHC offers a defined apical readout in kidney, but retrieval needs empirical optimization, and the smc4 caption’s EDTA condition cannot establish an RDX condition (HPA: High in kidney proximal-tubule microvilli; caption: smc4). The evidence does not establish whether frozen sections or IF are easier; endogenous renal biotin can confound avidin–biotin detection (standard IHC practice).
HPA tissue IHC evidence for RDX
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Medium consistency between antibody staining and RNA expression data. Caution, targets protein from more than one gene.). 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 → |
| Colon | Endocrine cells | High | Protein (IHC) | HPA → |
| Duodenum | Endocrine cells | High | Protein (IHC) | HPA → |
| Fallopian tube | Ciliated cells (tip of cilia) | High | Protein (IHC) | HPA → |
| Kidney | Proximal tubules (microvilli) | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Bronchus | Basal cells | Not detected | Protein (IHC) | HPA → |
| Cerebellum | Cells in granular layer | Not detected | Protein (IHC) | HPA → |
| Cervix | Glandular cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced RDX IHC Tips
Troubleshoot chromogenic RDX staining in paraffin sections by checking retrieval, compartment, cell identity and controls before comparing staining intensity.
How should I adjust retrieval when RDX staining is weak or uneven?
Start with heat-mediated retrieval in EDTA pH 8.0 for this page’s catalog antibody (datasheet M01926). Keep heating and cooling conditions consistent across sections, then compare stained and negative-control slides in the same run (standard IHC practice). If staining remains weak, test a second retrieval condition on adjacent sections while keeping antibody and detection conditions fixed (standard IHC practice). Score membrane and microvillus staining separately from diffuse cytoplasm because these are relevant RDX locations (UniProt P35241 localization; HPA: proximal tubule microvilli). The supplied M01926 image caption names smc4, so its image cannot establish RDX retrieval performance (M01926 caption).
Could fixation explain weak RDX staining in paraffin sections?
Target-specific RDX sensitivity to fixation is unknown from the supplied evidence; the selected caption does not state a fixative (M01926 caption). Record the actual fixative, fixation duration and processing history for each block before comparing staining between samples (standard IHC practice). If archived blocks vary, stain adjacent positive-control and test sections together and evaluate whether morphology and internal staining remain interpretable (standard IHC practice). Avoid assigning a weak result to a particular RDX epitope or phosphorylation state without an antibody epitope map and direct validation (UniProt P35241: FERM domain and Thr564 phosphorylation; standard IHC practice). Compare sections only after excluding differences in retrieval and detection conditions (standard IHC practice).
Where should convincing RDX staining appear in tissue sections?
Prioritize membranous and cortical cytoplasmic staining, especially cell projections, because RDX links the plasma membrane and actin cytoskeleton (UniProt P35241 localization and function). In kidney, inspect proximal tubule microvilli as a compartment-level reference, while recognizing that HPA also reports variable cytoplasmic and membranous staining (HPA: High in proximal tubule microvilli; HPA tissue profile). Distinguish a crisp luminal border from diffuse cytoplasmic chromogen by reviewing morphology at matched magnification and exposure (standard IHC practice). HPA lists nucleoplasmic localization as uncertain, so isolated nuclear staining needs independent support before interpretation as RDX (HPA subcellular: uncertain nucleoplasm). Do not require every positive cell to show identical membrane intensity (HPA tissue profile: variable levels).
Can this antibody distinguish RDX isoforms or phosphorylation states?
Do not assign a stained cell to a specific RDX isoform without an epitope map and isoform-specific validation (UniProt P35241: 5 isoforms; standard IHC practice). The FERM domain spans residues 5–295, and Thr564 is a reported phosphorylation site, but these annotations do not identify this antibody’s binding site (UniProt P35241 domains and modified residues). Compare retrieval conditions using the same section type because epitope exposure can change during paraffin processing (standard IHC practice). A pan-RDX interpretation also needs specificity controls, particularly because the HPA tissue antibody may recognize protein from more than one gene (HPA tissue reliability description). Report the antibody identifier and validated epitope, if known, alongside any isoform claim (standard IHC practice).
How can IF help resolve ambiguous chromogenic RDX localisation?
Use IF on a separate, validated workflow to check whether RDX signal follows the cell boundary or a projection (UniProt P35241 localization; standard IF practice). Multiplex with a marker for the expected cell type, such as a validated proximal tubule marker when examining kidney microvilli (HPA: High in proximal tubule microvilli; standard IF practice). Choose fluorophores after inspecting unstained tissue autofluorescence, and use single-color controls to assess bleed-through (standard IF practice). Because RDX has no transmembrane segment, select permeabilisation for an intracellular, membrane-associated epitope while checking whether that treatment disrupts cortical signal (UniProt P35241 topology and localization; standard IF practice). No antibody-specific IF fixation or permeabilisation result is supplied here (provided evidence).
What should I check when DAB obscures the RDX staining pattern?
Review the no-primary control and a matched section for diffuse DAB, endogenous enzyme activity and nonspecific secondary binding (standard chromogenic IHC practice). Apply a peroxidase block and optimize blocking and washes as general workflow steps, then keep DAB development comparable across slides (standard chromogenic IHC practice). Examine whether pigment or section folds mimic the narrow membranous and microvillus pattern expected for RDX (UniProt P35241 localization; standard IHC practice). Titrate the antibody only within a validated range for RDX; the supplied 1:50 caption describes smc4 and cannot establish an RDX dilution (M01926 caption). Record background in unstained and no-primary controls before changing retrieval (standard IHC practice).
How should I score RDX staining across tissue samples? ⚠ ANSWER MARKED FOR VERIFICATION
Define the relevant compartment and cell population before scoring, such as the proximal tubule microvillus border in kidney (HPA: High in proximal tubule microvilli; standard IHC practice). For cell-based scoring, record percentage positive and intensity on a 0–3 scale, yielding an H-score of 0–300 (standard IHC practice). For a narrow border, quantify DAB-positive length or area against the corresponding evaluable epithelial border or tissue area (standard image-analysis practice). Normalize comparisons to the same compartment, section area, staining batch and exposure settings, while excluding folds and necrotic regions (standard IHC practice). Report background-corrected values and the number of evaluable cells or regions (standard IHC practice).
How can I separate true RDX signal from artefact?
A plausible positive pattern follows cell membranes or projections and occurs in an expected cell population, such as kidney proximal tubules (UniProt P35241 localization; HPA: High in proximal tubule microvilli). Be cautious with strong isolated nuclear staining, since HPA marks nucleoplasmic RDX localization as uncertain (HPA subcellular: uncertain nucleoplasm). Check section edges, necrotic regions and the no-primary control for staining caused by processing or endogenous peroxidase (standard chromogenic IHC practice). HPA reports enhanced reliability but cautions that its tissue antibody may detect protein from more than one gene, so its pattern alone cannot prove antibody specificity (HPA tissue reliability description). The supplied M01926 caption identifies smc4, so that image does not validate RDX staining (M01926 caption).
Boster reagents
Best RDX / Radixin IHC Antibodies
Catalog anti-RDX antibodies list human, mouse, and rat reactivity; the supplied figures cover a paraffin-embedded human tissue section and HeLa-cell IF (catalog: reactivity; image captions).
Real IHC data
Anti-Radixin Rabbit Monoclonal Antibody
Cat # M01926
Real IF data
Anti-Radixin/RDX Antibody ®
Cat # A01926-1
M01926 lists IHC and IF, but its paraffin-embedded human breast cancer IHC caption identifies the stained target as smc4, so the figure does not establish RDX staining (catalog: applications; M01926 image caption). A01926-1 lists IF/ICC and shows RDX staining in HeLa cells at 2 μg/mL (catalog: applications; A01926-1 image caption).
Which to pick: For paraffin-section IHC, M01926 is the listed rabbit monoclonal option (catalog: applications/clone); its caption describes EDTA retrieval at pH 8.0 and primary antibody at 1:50, but names smc4 and does not report the fixative (M01926 image caption). For IF/ICC, A01926-1 is the listed rabbit polyclonal option with an RDX HeLa-cell IF figure (catalog: applications/dilution_raw; A01926-1 image caption). Both list human, mouse, and rat reactivity, while the supplied figures cover human samples only (catalog: reactivity; image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P35241 (RADI_HUMAN, Radixin).
- Human Protein Atlas. RDX tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. RDX subcellular location (ICC-IF): Mainly localized to the plasma membrane. In addition localized to the nucleoplasm..
- Human Protein Atlas. RDX antibody validation summary (3 antibodies).
- Monoallelic loss of the F-actin-binding protein radixin facilitates startle reactivity and pre-pulse inhibition in mice. Frontiers in cell and developmental biology 2022 — PMC9742549.
- A pleiotropically acting microRNA, miR-31, inhibits breast cancer metastasis. Cell 2009 — PMC2766609.
- PubMed PMID:8486357 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:17226784 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for RDX (Radixin). Expected localisation Cytoplasmic and membranous staining (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet M01926). Validated IHC antibody: M01926 at 1:50 (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 human breast cancer tissue; fixative not specified (datasheet M01926); 2. Fixation: Image fixative and duration unreported (datasheet M01926); 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 M01926); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet M01926); 8. Primary antibody: Rabbit monoclonal (clone FBC-18) anti-RDX, 1:50 (datasheet M01926); 9. Primary incubation: Overnight at 4 °C (datasheet M01926). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Caveat: Antibody may detect proteins from more than one gene (HPA tissue IHC); Isoform / epitope: 5 isoforms; epitope coverage is unspecified (UniProt; datasheet M01926); Regulation: Stimulus-dependent regulation is unreported (UniProt). Evidence: UniProt P35241, HPA tissue IHC · Enhanced, HPA ICC-IF · Mainly localized to the plasma membrane. In addition localized to…, Datasheet M01926, PMC2766609. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/RDX/immunohistochemistry-ihc-guide.