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APLNR / Apelin receptor · IHC design guide
Design Immunohistochemistry for APLNR
Plan paraffin-section APLNR IHC using the reported cytoplasmic tissue pattern and medium staining in heart cardiomyocytes (HPA tissue IHC). Start the catalog antibody at 1:100–1:300 (datasheet) and include a no-primary control (standard IHC practice).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
APLNR 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 in tissue (HPA tissue IHC); cell membrane (UniProt) | |
| Staining pattern | Cytoplasmic staining in several tissue cell types (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Caudate+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 A05042) | |
| Caveat | Staining has low consistency with RNA expression (HPA tissue IHC) | |
| Regulation | APLN/APELA drive internalization (UniProt) | |
| Isoform / epitope | No isoforms annotated; extracellular versus cytoplasmic epitope matters (UniProt) |
Section 1
Recommended APLNR IHC & IF Protocols
The catalog antibody’s IHC protocol is accompanied by published APLNR IHC methods for kidney, cuprizone model sections, and renal carcinoma tissue (PMC11351430; PMC11641372; PMC6461937; PMC13208026).
| Sample | Paraffin-embedded Human breast cancer tissue; fixative not specified (datasheet A05042) |
| Fixation | Image fixative and duration unreported (datasheet A05042); 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-APLNR, 1:100-1:300 (datasheet A05042) |
| 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 | APLNR-positive staining in neuronal cells of caudate (HPA tissue IHC: Medium). HPA tissue profile: Cytoplasmic expression in several tissues. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 retrieval at 95–98 °C for 20 min (page retrieval rule); adjust for the specimen and antibody using the published conditions below.
Section 2
What Is the Expected APLNR Staining Pattern?
APLNR is a seven-pass cell-membrane receptor (UniProt P35414 topology). In paraffin-section IHC, look for staining in the appropriate cells, including cardiomyocytes and selected neuronal or glial cells with medium staining reported by HPA (HPA tissue IHC). Cytoplasmic staining can be plausible: HPA describes cytoplasmic expression in several tissues, and UniProt reports receptor internalization and recycling. Interpret cautiously because HPA rates the tissue IHC antibody Approved but reports low consistency with RNA expression (HPA tissue IHC).
| Membrane-associated staining in cardiomyocytes, caudate neuronal cells, or cortical glial cells. | This fits the receptor's cell-membrane location (UniProt P35414) and HPA's medium IHC staining in those named cells (HPA tissue IHC). A visible membrane outline supports the expected compartment; judge it alongside cell identity and controls because HPA reports low consistency between antibody staining and RNA expression (HPA tissue IHC). |
| Cytoplasmic puncta or a cytoplasmic signal accompany staining in an expected cell type. | Cytoplasmic staining is reported across several tissues (HPA tissue IHC). Ligand exposure can move APLNR into an endosomal recycling compartment (UniProt P35414 subcellular location), so cytoplasmic signal alone is not proof of an artefact. Predominantly nuclear staining has no support in the supplied APLNR localization records (UniProt P35414; HPA tissue IHC). |
| Strong staining appears in a cell population other than the reported positive population. | Check cell identity before assigning the signal to APLNR. For example, HPA reports medium staining in cortical glial cells and caudate neuronal cells, but no detection in lymph-node germinal-center cells (HPA tissue IHC). Unexpected staining raises the possibility of cross-reactivity or endogenous chromogenic activity; a no-primary control can help distinguish detection background (general IHC practice). |
| Chromogen is diffuse across tissue, including cells expected to be unstained. | A widespread haze does not establish receptor localization. Compare a no-primary control and inspect tissue-edge or damaged areas for nonspecific deposition (general IHC practice). HPA's cytoplasmic-expression summary does not make uniform staining of every cell an expected APLNR result (HPA tissue IHC). |
| No signal is visible in heart-muscle cardiomyocytes or cerebral-cortex glial cells. | Both are reported as medium-staining populations, so absence of signal warrants checking the run (HPA tissue IHC). Verify the positive-control section, antibody and detection steps, and section integrity (general IHC practice). HPA's Approved rating and low RNA–staining consistency mean a negative result in one specimen cannot, by itself, establish absent APLNR protein (HPA tissue IHC). |
💡Expected APLNR appearanceCall an IHC result convincing when the expected cell population shows discernible membrane-associated, possibly accompanying cytoplasmic, staining around HPA's reported medium level; isolated nuclear signal or uniform tissue-wide haze is suspect (UniProt P35414 subcellular location; HPA tissue IHC).
| Seven-pass topology and trafficking (UniProt P35414). | APLNR spans the membrane seven times, with extracellular and cytoplasmic regions (UniProt P35414 topology). Apelin or APELA exposure can drive internalization into a recycling compartment (UniProt P35414 subcellular location); assess membrane and cytoplasmic signal together rather than requiring a continuous membrane rim. |
| Choice of cells for interpretation (HPA tissue IHC). | HPA reports medium staining in heart-muscle cardiomyocytes, hippocampal glial cells, and several other named populations (HPA tissue IHC). It reports no detection in colon glandular cells and lymph-node germinal-center cells under its IHC conditions (HPA tissue IHC). Those observations guide comparisons; they do not prove every specimen of a tissue will behave identically. |
| Strength of IHC evidence (HPA tissue IHC; HPA antibody record). | The listed mouse monoclonal antibody CAB025842 is IHC Approved, while the tissue profile notes low consistency between staining and RNA expression (HPA antibody record; HPA tissue IHC). Treat a matching pattern as supportive evidence and investigate unexpected cell types or compartments before assigning biological meaning. |
| What does IF/ICC evidence add? (HPA subcellular record). | HPA summarizes APLNR as membrane-localized for ICC-IF, but lists no main location or cell-line images (HPA subcellular record). That summary supports a localization expectation; it supplies no image-backed IF/ICC pattern here. IF/ICC methods belong in their own guide. |
| Fixation and retrieval evidence (UniProt P35414; HPA tissue IHC). | 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 |
|---|---|---|
| No staining in a positive-control heart-muscle section (HPA tissue IHC: medium in cardiomyocytes). | The staining run may have failed, or the sampled cells may be difficult to identify; one absent signal does not establish absent receptor. | Confirm cardiomyocyte morphology, section integrity, antibody application, chromogenic detection, and a working positive control (general IHC practice). Record HPA's low RNA–staining consistency when interpreting the result (HPA tissue IHC). |
| Signal is confined to nuclei in an otherwise interpretable section. | Nuclear localization is unsupported by the supplied membrane and cytoplasmic APLNR records (UniProt P35414; HPA tissue IHC). | Review a no-primary control, counterstain, and nonspecific chromogen deposition (general IHC practice). Do not score nuclear-only staining as a convincing APLNR-positive pattern. |
| Every cell has similar cytoplasmic color, obscuring the reported positive populations. | Diffuse background can conceal cell-restricted staining (general IHC practice); HPA reports cytoplasmic expression in several tissues, not a uniform all-cell pattern (HPA tissue IHC). | Compare no-primary and positive-control sections, then reassess blocking, antibody concentration, washes, and detection development as general IHC variables. |
| A cell population reported as undetected stains strongly, such as colon glandular cells (HPA tissue IHC). | Possible explanations include misidentified cells, cross-reactivity, or endogenous chromogenic activity (general IHC practice). HPA's undetected call describes its tested conditions, not an absolute biological negative. | Check cell identity and the no-primary control; assess endogenous enzyme activity if relevant to the detection system (general IHC practice). Compare the result with a named medium-staining HPA population (HPA tissue IHC). |
| Cytoplasmic staining lacks a crisp membrane rim in an otherwise expected cell population. | HPA reports cytoplasmic tissue staining, and UniProt describes internalization and recycling after ligand exposure (HPA tissue IHC; UniProt P35414). The supplied evidence does not establish ligand exposure in this particular section. | Score the cell type and distribution, compare controls, and describe the observed compartment precisely. Avoid assigning trafficking as the cause without independent evidence. |
| ICC-IF expectations are being used to judge a chromogenic paraffin section. | HPA's ICC-IF entry says Membrane but provides no cell-line images, whereas its tissue IHC profile describes cytoplasmic expression (HPA subcellular record; HPA tissue IHC). | Use the tissue IHC observations and their reliability caveat for this section (HPA tissue IHC). Treat the ICC-IF summary as limited localization context and consult the separate IF/ICC guide for that application. |
Experiment evidence
IHC & IF images showing APLNR staining
A05042 · IHCImmunohistochemistry validation of APLNR using Anti-Apelin receptor APLNR Antibody (A05042). Immunohistochemical analysis of paraffin-embedd
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000134817-APLNR/tissue/cerebral+cortex#imid_6771296
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000134817-APLNR/tissue/colon#imid_6771222
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000134817-APLNR/tissue/liver#imid_6771223
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000134817-APLNR/tissue/kidney#imid_6771224
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for APLNR IHC & IF
🧪Run heart muscle first and assess cardiomyocytes for APLNR staining (HPA: Medium in cardiomyocytes). Use adipose tissue as the negative comparator (HPA: Not detected in adipocytes); on the heart slide, use noncardiomyocyte interstitial cells as an internal background reference, while avoiding an assumption that every such cell is APLNR-negative (HPA: heart result is specific to cardiomyocytes).
Positive control tissue: Caudate (Neuronal cells, HPA Medium)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for APLNR; derive a cell-line control from the positive tissue's cell type (Neuronal cells) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only slide and a primary replacement matched for host species, immunoglobulin class, and monoclonal or polyclonal format; confirm specificity with APLNR knockout material or a validated immunizing-peptide block (standard IHC practice). For chromogenic heart sections, quench endogenous peroxidase and distinguish vascular or blood pigment from reaction product (standard IHC practice).
⚠️Feasibility: A target-specific fixation window and retrieval dependency are unreported in the supplied evidence; the A05042 paraffin-section caption does not report its fixative (A05042 caption). Compare antigen-retrieval conditions empirically, and assess membrane-associated staining in light of possible ligand-induced internalization (UniProt P35414 subcellular location; standard IHC practice). The supplied evidence does not establish whether frozen sections or IF are easier for APLNR, and blood pigment can complicate interpretation in heart muscle (HPA: heart muscle, Medium in cardiomyocytes; standard IHC practice).
HPA tissue IHC evidence for APLNR
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Low 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 |
|---|---|---|---|---|
| Caudate | Neuronal cells | Medium | Protein (IHC) | HPA → |
| Cerebral cortex | Glial cells | Medium | Protein (IHC) | HPA → |
| Epididymis | Glandular cells | Medium | Protein (IHC) | HPA → |
| Gallbladder | Glandular cells | Medium | Protein (IHC) | HPA → |
| Heart muscle | Cardiomyocytes | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Not detected | Protein (IHC) | HPA → |
| Cerebellum | Cells in granular layer | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced APLNR IHC Tips
APLNR is a seven-pass membrane receptor that can recycle through endosomes after ligand exposure (UniProt P35414). These questions focus on chromogenic IHC of paraffin sections.
What retrieval should I try first if APLNR staining is weak in paraffin sections?
Use citrate pH 6.0 heat-induced retrieval at 95–98 °C for 20 min as the first condition for APLNR paraffin IHC (page retrieval rule: membrane antigen). Let sections cool in the retrieval solution before washing, and keep heating and cooling consistent across slides (standard IHC practice). If staining remains weak, compare a longer citrate treatment or an alternative retrieval buffer on matched sections, while checking for tissue damage and increased background (standard IHC practice). Assess membrane-associated staining as well as cytoplasmic staining, because APLNR is a membrane receptor that can enter a recycling compartment after ligand exposure (UniProt P35414; HPA: cytoplasmic tissue staining).
Could fixation explain weak APLNR staining in my paraffin sections?
Target-specific fixation sensitivity for APLNR is unknown from the supplied evidence; the selected A05042 image describes paraffin-embedded breast cancer but does not state its fixative (A05042 IHC caption). Record the fixative, fixation duration, processing history and section age for each case before comparing staining intensity (standard IHC practice). If fixation varies, stain matched sections from differently processed blocks in the same run and include a known staining control (standard IHC practice). Changes in signal should be attributed to fixation only after that controlled comparison, because differences in retrieval, antibody exposure and detection can also alter chromogenic IHC staining (standard IHC practice).
Should convincing APLNR staining be membranous or cytoplasmic?
Expect membrane-associated staining because APLNR is annotated at the cell membrane and has seven transmembrane segments (UniProt P35414). Cytoplasmic puncta may also be biologically plausible: ligand exposure can move the receptor into an endosomal recycling compartment, and HPA reports cytoplasmic staining in several tissues (UniProt P35414; HPA tissue IHC). Interpret a purely diffuse cytoplasmic signal cautiously, especially when it lacks a convincing cellular pattern or appears equally in a negative control (standard IHC practice). Compare membrane and cytoplasmic compartments separately within intact cells, using the same scoring rules across cases; chromogenic staining alone cannot establish that ligand-driven internalisation occurred (standard IHC practice; UniProt P35414).
How does epitope position affect APLNR staining after retrieval?
APLNR has no annotated isoforms in the supplied record, so a staining difference should not automatically be assigned to an isoform (UniProt P35414). Its extracellular regions include residues 1–30, 87–99, 165–198 and 271–289, whereas the cytoplasmic tail spans 313–380 (UniProt P35414 topology). Confirm the catalog antibody’s immunogen or mapped epitope before interpreting how retrieval might expose it; that information is absent from the selected caption (A05042 IHC caption). Glycosylation sites at residues 15 and 175 could matter for an overlapping extracellular epitope, but their effect on this antibody’s IHC staining has not been established (UniProt P35414; A05042 IHC caption).
How can IF help check a chromogenic APLNR IHC pattern?
Use IF as a separate localisation check, pairing APLNR with a marker for the cell population being evaluated; HPA reports medium IHC staining in heart cardiomyocytes and cortical glial cells (HPA tissue IHC). Choose fluorophores after inspecting unstained tissue for autofluorescence, and assign the dimmer expected signal to a spectrally cleaner channel (standard IF practice). If the antibody epitope is cytoplasmic, permeabilise sufficiently to reach it; for an extracellular epitope, compare conditions with limited permeabilisation because access requirements differ (UniProt P35414 topology; standard IF practice). Use single-label and omission controls to assess bleed-through and background, then compare cellular localisation with the chromogenic IHC result (standard IF and IHC practice).
What should I check when APLNR DAB staining appears widespread?
Check a primary-antibody omission control to separate detection-system background from antibody-dependent staining (standard IHC practice). Block endogenous peroxidase before DAB development, particularly where blood or inflammatory cells complicate interpretation, and review pigment in an unstained section (standard chromogenic IHC practice). Titrate the catalog antibody around the reported 1:100 condition without treating that breast-cancer caption as validation for every tissue or processing method (A05042 IHC caption). Compare the disputed signal with tissue architecture and HPA cell-level patterns: HPA reports medium staining in heart cardiomyocytes but no detection in colon glandular cells, while also flagging low staining-to-RNA consistency (HPA tissue IHC).
How should I score APLNR chromogenic IHC across samples? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring, because APLNR has a membrane annotation while HPA describes cytoplasmic tissue staining (UniProt P35414; HPA tissue IHC). For a cellular readout, record the percentage of positive eligible cells and staining intensity, then calculate an H-score on its conventional 0–300 scale (standard IHC scoring practice). If spatial distribution matters, report positive cells per mm² of viable tissue, with membrane and cytoplasmic results tabulated separately (standard IHC scoring practice). Normalise counts to the measured viable area or eligible cell population, and apply one threshold, exposure and sampling scheme across all slides (standard IHC practice).
When is an apparent APLNR-positive cell likely to be an artefact?
A plausible positive cell should show reproducible cellular staining in an expected compartment; APLNR is membrane-associated and can recycle through an endosomal compartment (UniProt P35414). Check cell identity against the tissue context: HPA reports medium staining in cortical glia and heart cardiomyocytes, but its overall tissue-IHC profile has low consistency with RNA data (HPA tissue IHC). Discount staining confined to section edges, necrotic areas or endogenous-pigment deposits, and compare it with primary-antibody omission and peroxidase-block controls (standard chromogenic IHC practice). Do not infer receptor activation from chromogenic intensity or cytoplasmic location alone; the localisation annotation describes ligand-associated internalisation, not a validated activation readout in these sections (UniProt P35414).
Boster reagents
Best APLNR / Apelin receptor IHC Antibodies
A05042 has real IHC data from paraffin-embedded human breast cancer and catalog-listed IF; its stated reactivity covers human, mouse, and rat (A05042 IHC image caption; catalog applications/reactivity).
Real IHC data
Anti-Apelin receptor APLNR Antibody
Cat # A05042
A05042 is the sole card and shows IHC on paraffin-embedded human breast cancer at 1:100 (A05042 IHC image caption). Its catalog lists IF and human, mouse, and rat reactivity, but provides no IF figure (A05042 catalog applications/reactivity; IF image alts).
Which to pick: For tissue IHC, choose A05042: its own figure documents paraffin-embedded human breast cancer at 1:100; the fixative is unreported (A05042 IHC image caption). For IF, A05042 is listed at 1:200–1:1000, but no IF figure or ICC validation is supplied (A05042 catalog applications/dilutions; IF image alts). For cross-species work, A05042 lists human, mouse, and rat reactivity, while its supplied tissue figure covers human only; clonality is unreported (A05042 catalog reactivity/clone; IHC image caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P35414 (APJ_HUMAN, Apelin receptor).
- Human Protein Atlas. APLNR tissue IHC expression (reliability: Approved).
- Human Protein Atlas. APLNR subcellular location (ICC-IF): Membrane.
- Human Protein Atlas. APLNR antibody validation summary (1 antibodies).
- Unraveling the Complex Molecular Interplay and Vascular Adaptive Changes in Hypertension-Induced Kidney Disease. Biomedicines 2024 — PMC11351430.
- A Morphological and Behavioral Study of Demyelination and Remyelination in the Cuprizone Model: Insights into APLNR and NG2+ Cell Dynamics. International journal of molecular sciences 2024 — PMC11641372.
- Apelin and apelin receptor expression in renal cell carcinoma. British journal of cancer 2019 — PMC6461937.
- Spatiotemporal APLNR Expression Dynamics During Oligodendroglial Remodeling of the Corpus Callosum in the Cuprizone Model. International journal of molecular sciences 2026 — PMC13208026.
- PubMed PMID:8294032 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
- PubMed PMID:11090199 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for APLNR (Apelin receptor). Expected localisation Cytoplasmic in tissue (HPA tissue IHC); cell membrane (UniProt). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A05042 at 1:100-1:300 (the product's own IHC validation image is shown). Controls (HPA): positive Caudate (Neuronal cells); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded Human breast cancer tissue; fixative not specified (datasheet A05042); 2. Fixation: Image fixative and duration unreported (datasheet A05042); 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-APLNR, 1:100-1:300 (datasheet A05042); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A05042); Caveat: Staining has low consistency with RNA expression (HPA tissue IHC); Isoform / epitope: No isoforms annotated; extracellular versus cytoplasmic epitope matters (UniProt); Regulation: APLN/APELA drive internalization (UniProt). Evidence: UniProt P35414, HPA tissue IHC · Approved, HPA ICC-IF · Membrane, Datasheet A05042, PMC11351430, PMC11641372. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/APLNR/immunohistochemistry-ihc-guide.