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GRK5 / G protein-coupled receptor kinase 5 · IHC design guide
Design Immunohistochemistry for GRK5
Plan GRK5 paraffin-section IHC around the predominantly cytoplasmic tissue pattern (HPA tissue IHC). Use placenta trophoblasts or lung macrophages as positive cells (HPA tissue IHC), and start the IHC-validated antibody at 0.5–1 μg/ml (datasheet PB9708).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
GRK5 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 staining in most tissues (HPA tissue IHC) | |
| Staining pattern | Positive cells show cytoplasmic staining in most tissues (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet PB9708) | |
| Positive control | Cerebellum+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). Selected-image fixative and duration unreported (datasheet PB9708); verify before use. | |
| Caveat | Low antibody–RNA concordance limits tissue predictions (HPA tissue IHC) | |
| Regulation | GPCR/Ca²⁺ regulate nuclear localisation (UniProt) | |
| Isoform / epitope | One chain, 1–590; no isoforms or transmembrane segment (UniProt) |
Section 1
Recommended GRK5 IHC & IF Protocols
Compare the catalog antibody’s IHC-P protocol with four published GRK5 IHC protocols from ovarian, synovial, rhabdomyosarcoma, and heart tissue studies (PMC8864135; PMC8131379; PMC7185065; PMC12786180).
| Sample | Paraffin-embedded rat cardiac muscle tissue; fixative not specified (datasheet PB9708) |
| Fixation | Image fixative and duration unreported (datasheet PB9708); 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 PB9708); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet PB9708) |
| Primary antibody | Rabbit anti-GRK5, 0.5-1μg/ml (datasheet PB9708) |
| Primary incubation | Overnight at 4 °C (datasheet PB9708) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet PB9708) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | GRK5-positive staining in cells in molecular layer of cerebellum (HPA tissue IHC: Medium). HPA tissue profile: Cytoplasmic expression in most tissues. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet: PB9708); the synovium study also reports EDTA pH 8.0, incubated overnight (PMC8131379).
Section 2
What Is the Expected GRK5 Staining Pattern?
In paraffin-section IHC, expect mainly cytoplasmic GRK5 staining in selected cells, including lung macrophages, placental trophoblastic cells and cerebral cortical neurons, each reported at medium intensity (HPA: tissue IHC). GRK5 can also associate with the plasma membrane and enter the nucleus; it has no transmembrane segment (UniProt P34947: localization and topology). Interpret the pattern cautiously because HPA rates tissue IHC Approved but reports low consistency with RNA expression (HPA: tissue IHC reliability).
| Cytoplasmic chromogenic staining in lung macrophages or placental trophoblastic cells, with nearby cells less conspicuous. | This matches cell-specific medium staining reported in both tissues (HPA: tissue IHC). Score the stained cell population and compartment together; a whole-tissue average can hide a localized positive population (general IHC practice). |
| Predominantly nuclear or sharply membrane-associated staining in an IHC section, with little cytoplasmic signal. | A membrane pool and regulated nuclear localization are biologically plausible (UniProt P34947: localization). Yet HPA describes cytoplasmic expression in most tissue IHC samples; assess the cell type and controls before accepting an IHC compartment shift (HPA: tissue IHC; general IHC practice). |
| Strong deposit in an unexpected cell population while the reported positive cells remain unstained. | Compare the identity of stained cells with HPA's cell-level pattern; for example, the reported lung positive population is macrophages (HPA: Medium in lung macrophages). An unexpected pattern can reflect cross-reactivity or endogenous detection activity and requires controls (general IHC practice). |
| Diffuse stain across cells and extracellular spaces, obscuring cell boundaries. | That distribution does not allow confident assignment to the cytoplasmic pattern reported for tissue IHC (HPA: tissue IHC). Uneven blocking, washing or chromogen development can contribute to background; assess a matched detection control (general IHC practice). |
| No visible deposit in the expected cell population of a known-positive section. | Lung macrophages and placental trophoblastic cells are medium-staining reference populations, not guarantees for every specimen (HPA: tissue IHC). First verify that the relevant cells are present, then evaluate the IHC staining run and antibody conditions (general IHC practice). |
💡Expected GRK5 appearanceCall a result positive when a defined population such as lung macrophages or placental trophoblastic cells shows discernible, mainly cytoplasmic, approximately medium staining (HPA: tissue IHC); widespread deposit without a matching cellular pattern is suspect background (general IHC practice).
| Tissue and cell selection | Use the reported positive cell population within a section as the comparison: cerebral cortical neurons, lung macrophages and placental trophoblastic cells each show medium staining (HPA: tissue IHC). Adipocytes and liver cholangiocytes are reported as not detected, but these findings apply to those cells rather than every cell in the tissue (HPA: tissue IHC). |
| Compartment and molecular architecture | GRK5 has no signal peptide, propeptide or transmembrane segment (UniProt P34947: processing and topology). Cytoplasmic IHC is therefore compatible with its annotation, while phospholipid-mediated cell-surface association permits a membrane pool (HPA: tissue IHC; UniProt P34947: localization). |
| Strength of tissue-IHC evidence | HPA labels its tissue IHC Approved while noting low consistency between antibody staining and RNA expression; the listed IHC antibody CAB025579 is Approved (HPA: tissue IHC reliability; HPA: antibody validation). Treat a matching pattern as supportive, rather than definitive proof of antibody specificity (general IHC practice). |
| IF/ICC Q&A: should nuclear staining be expected? | Yes, in IF/ICC HPA reports supported nuclear membrane and nuclear speckles, plus plasma membrane staining; HPA046838 is Supported for ICC (HPA: subcellular ICC-IF; HPA: antibody validation). This is a separate application readout and does not establish that those compartments must dominate chromogenic tissue IHC (HPA: tissue IHC; HPA: subcellular ICC-IF). |
| Situation | Likely cause | Next action |
|---|---|---|
| No staining in a lung section selected as a positive reference. | The reported medium signal is in macrophages, so a field lacking them may appear negative (HPA: Medium in lung macrophages). Run failure is another possibility (general IHC practice). | Locate macrophage-containing fields, then review the IHC-validated antibody's prescribed retrieval and detection conditions and a run control (general IHC practice). |
| Nuclear staining dominates the chromogenic section. | Nuclear localization is regulated and possible (UniProt P34947: localization), while HPA describes predominantly cytoplasmic tissue IHC (HPA: tissue IHC). The IF/ICC nuclear pattern cannot alone validate this IHC result (HPA: subcellular ICC-IF). | Check whether the same cell population shows a coherent cytoplasmic component; compare with a known-positive IHC section and detection control before scoring (general IHC practice). |
| Only cell outlines stain; cytoplasm appears blank. | GRK5 can associate with the plasma membrane (UniProt P34947: localization), but membrane-only tissue staining differs from HPA's broad cytoplasmic IHC profile (HPA: tissue IHC). | Confirm the deposit follows cell boundaries in the reported cell type and inspect a matched detection control for edge or nonspecific staining (general IHC practice). |
| Unexpected epithelial cells stain more strongly than the reported positive population. | The sampled epithelium may have its own HPA pattern; HPA reports medium respiratory epithelial staining in nasopharynx but no detected glandular staining in thyroid (HPA: tissue IHC). Cross-reactivity or endogenous activity remains possible (general IHC practice). | Identify the exact tissue and cell type, compare its HPA entry, and use appropriate detection controls before assigning GRK5 positivity (HPA: tissue IHC; general IHC practice). |
| Diffuse brown background obscures interpretable cells. | Nonlocalized deposit prevents comparison with HPA's cell-level cytoplasmic observations (HPA: tissue IHC). Blocking, washing or excessive detection development may contribute (general IHC practice). | Review blocking, wash and development steps against the selected IHC-P workflow; assess a matched detection control and score only clearly localized cellular signal (general IHC practice). |
| A cell type listed as not detected shows convincing staining. | HPA reports no detected staining in adipocytes and liver cholangiocytes, but its IHC data have low consistency with RNA expression (HPA: tissue IHC). A discrepancy alone neither confirms nor disproves GRK5 (general IHC practice). | Verify cell identity and controls, then compare a reported medium-positive population stained in the same run; record the discrepancy without treating one negative reference as universal (HPA: tissue IHC; general IHC practice). |
Experiment evidence
IHC & IF images showing GRK5 staining
PB9708 · IHCIHC analysis of GRK5 using anti-GRK5 antibody (PB9708). GRK5 was detected in a paraffin-embedded section of rat cardiac muscle tissue. Heat
PB9708 · IHCIHC analysis of GRK5 using anti-GRK5 antibody (PB9708). GRK5 was detected in a paraffin-embedded section of mouse lung tissue. Heat mediated
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000198873-GRK5/tissue/cerebral+cortex#imid_6552368
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000198873-GRK5/tissue/colon#imid_6556246
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000198873-GRK5/tissue/liver#imid_6556263
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000198873-GRK5/tissue/kidney#imid_6556256
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA046838; green = GRK5, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA046838; green = GRK5, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for GRK5 IHC & IF
🧪Run lung first: macrophages should show medium GRK5 staining (HPA: lung macrophages, Medium). Use oral mucosa squamous epithelial cells as the negative tissue (HPA: Not detected); on the lung slide, cells selected as internal negatives should retain counterstain without specific brown DAB staining, but neighboring cell types cannot be presumed negative from the HPA row alone (standard IHC practice; HPA: lung macrophages, Medium).
Positive control tissue: Cerebellum (Cells in molecular layer, HPA Medium)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show GRK5 in A-431, HUVEC/TERT2, Hep-G2, NIH 3T3, with annotated localisation: Nuclear membrane (supported), Nuclear speckles (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control; a matched rabbit IgG isotype control; and, if validated material is available, a GRK5 knockout specimen or peptide competition control (PB9708 caption: rabbit primary; standard IHC practice). For lung macrophages, quench endogenous peroxidase and distinguish pigment from DAB; assess endogenous biotin if using the caption’s biotin-based detection (standard IHC practice; PB9708 caption: biotinylated secondary and SABC).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the fixative for the PB9708 rat cardiac muscle paraffin-section image is unreported (PB9708 caption: fixative not stated). The caption uses heat retrieval in EDTA at pH 8.0, but does not establish that retrieval is required (PB9708 caption: heat-mediated EDTA retrieval). Whether frozen sections are easier is unreported; IF/ICC may help assess nuclear membrane, nuclear speckle, and plasma membrane localization, while lung macrophage pigment can complicate chromogenic scoring (HPA subcellular: supported locations; standard IHC practice).
HPA tissue IHC evidence for GRK5
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 |
|---|---|---|---|---|
| Cerebellum | Cells in molecular layer | Medium | Protein (IHC) | HPA → |
| Cerebral cortex | Neuronal cells | Medium | Protein (IHC) | HPA → |
| Epididymis | Glandular cells | Medium | Protein (IHC) | HPA → |
| Lung | Macrophages | Medium | Protein (IHC) | HPA → |
| Nasopharynx | Respiratory epithelial cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Fallopian tube | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Liver | Cholangiocytes | Not detected | Protein (IHC) | HPA → |
| Oral mucosa | Squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
| Thyroid gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced GRK5 IHC Tips
Use the paraffin section protocol as a starting point, then judge GRK5 staining by cell type, compartment, and controls (datasheet PB9708; HPA tissue IHC; UniProt P34947).
Which retrieval conditions should I try first for GRK5 in paraffin sections?
Start with heat-mediated antigen retrieval in EDTA at pH 8.0 for paraffin sections (datasheet PB9708). The selected cardiac muscle image used that retrieval, followed by 1 μg/ml primary antibody overnight at 4°C (datasheet PB9708). If staining is weak, vary heating time in a small pilot while keeping section thickness, antibody concentration, and detection constant (standard IHC practice). Compare signal in the tissue with a matched no-primary control, since stronger DAB alone can increase apparent background (standard IHC practice). Record retrieval conditions for each slide so a change in staining can be traced to the changed step (standard IHC practice).
How should I troubleshoot fixation-related loss of GRK5 staining?
The selected paraffin section caption does not state a fixative, so target-specific fixation sensitivity cannot be determined from it (datasheet PB9708). Record the fixative, fixation duration, and processing history for each specimen before comparing GRK5 staining across cases (standard IHC practice). If a run is weak, compare similarly processed sections using the documented EDTA pH 8.0 retrieval and 1 μg/ml primary antibody conditions (datasheet PB9708). Check section integrity and a no-primary control before changing detection strength, which can amplify background (standard IHC practice). Do not attribute a fixation effect to GRK5 without a controlled comparison of fixation conditions (standard IHC practice).
Should GRK5 stain the membrane, cytoplasm, or nucleus in IHC?
Assess membrane-associated, cytoplasmic, and nuclear staining separately: GRK5 has all three reported locations, with predominant plasma membrane localization in the UniProt record (UniProt P34947). The tissue IHC profile describes cytoplasmic expression in most tissues, while the subcellular IF profile reports nuclear membrane and speckles with additional plasma membrane staining (HPA tissue IHC; HPA subcellular). Those observations come from different assays, so annotate the compartment actually visible in each paraffin section (standard IHC practice). Score staining against the local no-primary control and tissue morphology before assigning a compartment (standard IHC practice). Nuclear signal is biologically plausible, but DAB distribution alone does not establish a change in GRK5 trafficking (UniProt P34947; standard IHC practice).
How can epitope uncertainty affect a GRK5 IHC result?
The supplied record lists 0 isoforms and one 1–590 chain, so an isoform-specific staining claim is unsupported here (UniProt P34947). GRK5 has no transmembrane segment; its membrane association involves phospholipids rather than a membrane-spanning domain (UniProt P34947). The record includes an RGS region, kinase domain, C-terminal region, and phosphorylation sites at residues 484, 485, and 579 (UniProt P34947). Because no binding epitope is supplied for PB9708, do not assume retrieval exposes a particular domain or that phosphorylation explains a staining change (datasheet PB9708; standard IHC interpretation). Test any proposed epitope-dependent explanation with an independently characterized reagent or specimen control (standard IHC practice).
How should I adapt GRK5 localisation checks to multiplex IF?
For a separate IF experiment, pair GRK5 with a marker for the expected cell type, such as a macrophage marker when examining lung macrophages (HPA tissue IHC; standard IF practice). Choose fluorophores after inspecting unstained tissue autofluorescence, and place the weaker signal in a channel with better tissue contrast (standard IF practice). GRK5 is reported at the plasma membrane and in nuclear compartments, without a transmembrane segment (UniProt P34947; HPA subcellular). If testing an intracellular epitope, pilot permeabilisation and compare it with an unpermeabilised condition; the PB9708 epitope is unspecified (datasheet PB9708; standard IF practice). Include single-stain controls when checking channel bleed-through and compartment overlap (standard IF practice).
What should I check when GRK5 DAB staining is diffuse or patchy?
The selected paraffin section method used 10% goat serum block, a biotinylated secondary, a streptavidin–biotin complex, and DAB (datasheet PB9708). Run a no-primary control through the same detection steps to identify secondary, complex, or chromogen-associated background (standard IHC practice). Check endogenous peroxidase blocking and, where relevant, endogenous biotin when troubleshooting this detection chemistry (standard IHC practice; datasheet PB9708). Compare section edges and damaged areas with intact tissue before calling diffuse color GRK5-positive (standard IHC practice). If background persists, titrate detection and primary concentration while retaining the documented 1 μg/ml condition as a reference (datasheet PB9708; standard IHC practice).
How should I score GRK5 staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring, because GRK5 staining can be cytoplasmic, membrane-associated, or nuclear (UniProt P34947; HPA tissue IHC). For an H-score, grade cellular intensity 0–3, multiply each grade by its percentage of cells, and sum the products (standard IHC practice). Alternatively, report percentage of positive cells or positive-cell density per mm² within a predefined tissue region (standard IHC practice). Normalize to the number of eligible cells or measured tissue area, and apply one threshold across the comparison set (standard IHC practice). Report compartments separately and exclude folds, necrosis, and edge artifacts from the scored region (standard IHC practice).
When is an apparent GRK5-positive cell convincing rather than an artifact?
A convincing call combines intact cell morphology, staining in a plausible compartment, and little comparable color in the matched no-primary control (UniProt P34947; standard IHC practice). In lung, macrophages are a reported medium-staining population; adipocytes in adipose tissue are reported as not detected (HPA tissue IHC). Treat staining confined to section edges, folds, or necrotic areas cautiously, and check endogenous enzyme background in the chromogenic workflow (standard IHC practice). A nuclear pattern alone does not disprove GRK5, because nuclear localization is reported and regulated by GPCR and calcium/calmodulin signaling (UniProt P34947). Interpret tissue comparisons cautiously because the HPA tissue IHC assessment reports low consistency between staining and RNA expression (HPA tissue IHC).
Boster reagents
Best GRK5 / G protein-coupled receptor kinase 5 IHC Antibodies
The IHC-validated anti-GRK5 antibody has real paraffin-section images from rat cardiac muscle, mouse lung, and human placenta (catalog: PB9708 applications and image captions).
Real IHC data
Anti-GRK5 Antibody ®
Cat # PB9708
PB9708 is listed for IHC in human, mouse, and rat (catalog: PB9708 applications and reactivity). Its IHC images show paraffin sections of rat cardiac muscle, mouse lung, and human placenta (catalog: PB9708 image captions).
Which to pick: Choose PB9708 for paraffin-section tissue IHC; it is a rabbit antibody with an IHC dilution range of 0.5–1 μg/ml (catalog: PB9708 host, applications, image captions, and IHC dilution). It is the cross-species choice for human, mouse, and rat, though the fixative used for the pictured sections is unreported (catalog: PB9708 reactivity and image captions). No SKU in this payload is listed for IF/ICC (catalog: PB9708 applications).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P34947 (GRK5_HUMAN, G protein-coupled receptor kinase 5).
- Human Protein Atlas. GRK5 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. GRK5 subcellular location (ICC-IF): Mainly localized to the nuclear speckles and nuclear membrane. In addition localized to the plasma membrane..
- Human Protein Atlas. GRK5 antibody validation summary (2 antibodies).
- Co-Overexpression of GRK5/ACTC1 Correlates With the Clinical Parameters and Poor Prognosis of Epithelial Ovarian Cancer. Frontiers in molecular biosciences 2021 — PMC8864135.
- G protein-coupled receptor kinase 5 deletion suppresses synovial inflammation in a murine model of collagen antibody-induced arthritis. Scientific reports 2021 — PMC8131379.
- Characterization of GRK5 as a novel regulator of rhabdomyosarcoma tumor cell growth and self-renewal. Oncotarget 2020 — PMC7185065.
- Potential Cardioprotective Effect of a GRK5 Inhibitor Against NF-κB-Mediated Inflammation in an Animal Model of Isoproterenol-Induced Myocardial Infarction. International journal of molecular sciences 2025 — PMC12786180.
- PubMed PMID:7685906 — UniProt-cited evidence.
- PubMed PMID:15164054 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for GRK5 (G protein-coupled receptor kinase 5). Expected localisation Cytoplasmic staining in most tissues (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet PB9708). Validated IHC antibody: PB9708 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Cerebellum (Cells in molecular layer); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded rat cardiac muscle tissue; fixative not specified (datasheet PB9708); 2. Fixation: Image fixative and duration unreported (datasheet PB9708); 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 PB9708); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet PB9708); 8. Primary antibody: Rabbit anti-GRK5, 0.5-1μg/ml (datasheet PB9708); 9. Primary incubation: Overnight at 4 °C (datasheet PB9708). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific). Selected-image fixative and duration unreported (datasheet PB9708); verify before use.; Caveat: Low antibody–RNA concordance limits tissue predictions (HPA tissue IHC); Isoform / epitope: One chain, 1–590 ; no isoforms or transmembrane segment (UniProt); Regulation: GPCR/Ca²⁺ regulate nuclear localisation (UniProt). Evidence: UniProt P34947, HPA tissue IHC · Approved, HPA ICC-IF · Mainly localized to the nuclear speckles and nuclear membrane. In…, Datasheet PB9708, PMC8864135, PMC8131379. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/GRK5/immunohistochemistry-ihc-guide.