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PPP1R3A / Protein phosphatase 1 regulatory subunit 3A · IHC design guide
Design Immunohistochemistry for PPP1R3A
Plan paraffin-section PPP1R3A IHC with heart or skeletal muscle as positive controls and cytoplasmic myocyte staining as the expected pattern (HPA tissue IHC). Start with the catalog antibody's 1:50 IHC dilution (datasheet A07755), and assess unexpected staining in light of presumed off-target binding (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
PPP1R3A 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 (HPA tissue IHC); membrane association (UniProt) | |
| Staining pattern | Cardiomyocyte and skeletal myocyte cytoplasm (HPA tissue IHC) | |
| Antigen retrieval | Tris-EDTA pH 9.0 HIER, heat-mediated (datasheet A07755) | |
| Positive control | Heart muscle+2 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 | Presumed off-target staining was disregarded (HPA tissue IHC) | |
| Regulation | Muscle-enriched expression (UniProt) | |
| Isoform / epitope | 2 isoforms; TM at 1078–1098; epitope side unknown (UniProt) |
Section 1
Recommended PPP1R3A IHC & IF Protocols
Compare the catalog antibody’s IHC-P protocol (datasheet A07755) with the published rat tendon IHC protocol (PMC10590817).
| Sample | Paraffin-embedded human tonsil tissue; fixative not specified (datasheet A07755) |
| Fixation | Image fixative and duration unreported (datasheet A07755); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Tris-EDTA pH 9.0 (datasheet A07755); 20 min, 95–100 °C (standard) |
| 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-PPP1R3A, 1:50 recommended; image 1:200 (datasheet A07755) |
| 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 | PPP1R3A-positive staining in cardiomyocytes of heart muscle (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in skeletal and heart muscle. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated Tris-EDTA at pH 9.0 for the catalog antibody (datasheet A07755). The tendon protocol does not specify retrieval (PMC10590817).
Section 2
What Is the Expected PPP1R3A Staining Pattern?
PPP1R3A should show cytoplasmic staining in skeletal myocytes and cardiomyocytes, with membrane association consistent with its single transmembrane segment at residues 1078–1098 (HPA: tissue IHC profile; UniProt Q16821: topology). HPA rates both cell types High and the tissue IHC evidence Enhanced, while noting presumed off-target binding that was disregarded in its assessment (HPA: tissue IHC; HPA: reliability description).
| Strong cytoplasmic signal in skeletal myocytes or cardiomyocytes, with cellular outlines remaining interpretable. | This matches the principal observed pattern: both cell types are rated High, and the tissue profile describes cytoplasmic expression in skeletal and heart muscle (HPA: tissue IHC). Record the stained cell type and compartment when scoring; intensity alone cannot establish specificity, particularly because HPA notes presumed off-target binding (HPA: reliability description). |
| Predominantly nuclear staining in myocytes, with little cytoplasmic signal. | A nuclear-dominant pattern conflicts with the reported cytoplasmic muscle staining and membrane annotation (HPA: tissue IHC; UniProt Q16821: subcellular location). Treat it as suspect. Check whether the signal follows nuclei across the section, then review the negative control and repeat with the IHC-validated antibody if the pattern persists (general IHC practice). |
| Prominent staining in cells outside the expected muscle populations, especially cells in a negative-reference tissue. | Consider nonspecific antibody binding or endogenous chromogenic activity before assigning the signal to PPP1R3A (general IHC practice). HPA reports adipocytes in adipose tissue as Not detected, but also reports High staining in testicular spermatogonia; location outside muscle alone is therefore insufficient to declare every signal false (HPA: tissue IHC). |
| Broad, low-contrast color across many cell types or the section background. | A field-wide haze does not reproduce HPA’s cell-resolved cytoplasmic muscle pattern (HPA: tissue IHC). Common IHC causes include excess antibody or detection reagent, incomplete blocking, or inadequate washing (general IHC practice). Compare with the negative control before changing conditions, because a weak true signal can be obscured by background (general IHC practice). |
| No convincing signal in skeletal muscle or heart muscle. | A blank known-positive section is inconclusive: HPA rates skeletal myocytes and cardiomyocytes High, but its tissue observations do not guarantee performance under every staining condition (HPA: tissue IHC). Confirm tissue preservation and the detection controls, then review retrieval and antibody conditions using the catalog antibody’s IHC-P protocol (general IHC practice). |
💡Expected PPP1R3A appearanceCall an IHC result consistent with PPP1R3A when skeletal myocytes or cardiomyocytes show strong cytoplasmic staining, while a nuclear-dominant pattern or comparable staining in HPA Not detected adipocytes calls for investigation (HPA: tissue IHC; UniProt Q16821: membrane annotation).
| Tissue and cell selection | Skeletal myocytes and cardiomyocytes provide High-staining reference populations; adipocytes in adipose tissue provide a Not detected comparison (HPA: tissue IHC). HPA also lists spermatogonia as High, so interpret testis by cell type rather than assuming an entire nonmuscle tissue is negative (HPA: tissue IHC). |
| Compartment interpretation | HPA describes cytoplasmic staining in muscle, whereas UniProt annotates PPP1R3A as membrane-associated with one transmembrane segment at residues 1078–1098 (HPA: tissue IHC; UniProt Q16821: location and topology). These descriptions can coexist in light microscopy; the supplied sources do not define an organelle-level IHC pattern or prove that every visible edge signal is specific. |
| Antibody evidence | The tissue IHC assessment is Enhanced, and HPA lists HPA070440 and HPA073138 as IHC Enhanced (HPA: reliability; HPA: antibodies). HPA nevertheless notes presumed off-target binding that was disregarded, so compare cell type, compartment, and controls when judging a new section (HPA: reliability description; general IHC practice). |
| Isoforms and epitope scope | UniProt lists two isoforms and a single protein chain spanning residues 1–1122 (UniProt Q16821: isoforms and processing). The payload supplies no antibody epitope or isoform-specific staining data; do not attribute a changed IHC pattern to a particular isoform or processing event on this evidence alone. |
| Situation | Likely cause | Next action |
|---|---|---|
| The positive-reference muscle section is blank. | A failed stain or detection run may conceal an expected High signal in skeletal myocytes or cardiomyocytes (HPA: tissue IHC; general IHC practice). | Verify tissue and reagent controls, then check the catalog antibody’s IHC-P conditions, including its specified retrieval and dilution if available (general IHC practice). The supplied evidence gives no PPP1R3A-specific fixation sensitivity, so do not diagnose fixation as the cause from a blank section alone. |
| Myocyte nuclei are dark while cytoplasm is faint. | This distribution conflicts with the reported cytoplasmic muscle pattern (HPA: tissue IHC). Counterstain or nonspecific detection may complicate visual interpretation (general IHC practice). | Inspect a negative control and distinguish chromogen from counterstain, then reassess compartment calls at the cellular level (general IHC practice). If nuclear signal remains, record the result as discordant with HPA rather than scoring it as confirmed PPP1R3A. |
| Adipocytes stain as strongly as the muscle reference. | Adipocytes in adipose tissue are reported Not detected; comparable staining raises concern for nonspecific antibody binding or endogenous chromogenic activity (HPA: tissue IHC; general IHC practice). | Compare matched negative and detection controls, review blocking and washing, and require the expected myocyte cytoplasmic pattern before accepting the run (general IHC practice; HPA: tissue IHC). |
| The slide has diffuse color and poor cell boundaries. | Excess detection signal or insufficient blocking or washing can obscure cell-specific staining (general IHC practice). HPA’s reported muscle pattern is cytoplasmic and cell-associated (HPA: tissue IHC). | Check the negative control, then adjust staining conditions in a controlled rerun and judge whether myocyte cytoplasm separates clearly from background (general IHC practice; HPA: tissue IHC). |
| A testis section shows stained spermatogonia. | HPA reports spermatogonia as High, even though its summary emphasizes skeletal and heart muscle (HPA: tissue IHC). The observation is therefore not automatically an off-target result. | Identify the stained cell population before scoring and compare its pattern with appropriate controls (general IHC practice). Keep HPA’s off-target caveat in view; the reported High level alone does not validate a new antibody result (HPA: reliability description; HPA: tissue IHC). |
| Can this IHC pattern be used as an IF/ICC protocol or a precise IF localization call? | HPA’s subcellular summary says Membrane but provides no main location or cell-line ICC-IF images; its listed antibodies have no ICC status in the payload (HPA: subcellular; HPA: antibodies). | Use the muscle IHC observations as context only (HPA: tissue IHC). Follow the separate IF/ICC guide for method design and controls; do not infer an IF dilution, permeabilisation setting, or organelle-level pattern from this IHC record. |
Experiment evidence
IHC & IF images showing PPP1R3A staining
A07755 · IHCImmunohistochemical analysis of paraffin-embedded human tonsil. 1, Antibody was diluted at 1:200(4° overnight). 2, Tris-EDTA,pH9.0 was used
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000154415-PPP1R3A/tissue/cerebral+cortex#imid_20548163
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000154415-PPP1R3A/tissue/colon#imid_20548657
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000154415-PPP1R3A/tissue/liver#imid_20548650
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000154415-PPP1R3A/tissue/kidney#imid_20548659
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for PPP1R3A IHC & IF
🧪Run heart muscle first: cardiomyocytes should stain (HPA: High in cardiomyocytes), with morphologically distinct noncardiomyocyte cells on the same slide serving as an internal background reference. Run adipose tissue as the negative tissue; adipocytes are listed as not detected (HPA: Not detected in adipocytes).
Positive control tissue: Heart muscle (Cardiomyocytes, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for PPP1R3A; derive a cell-line control from the positive tissue's cell type (Cardiomyocytes) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only control and a host-matched isotype control for a monoclonal antibody or nonimmune IgG for a polyclonal antibody (standard IHC practice); use target knockout tissue, if available, as a biological specificity control (standard IHC practice). For chromogenic staining of heart muscle, quench endogenous peroxidase and check tissue pigment against the control slide (standard IHC practice).
⚠️Feasibility: A target-specific fixation window and fixation effect are unreported, and the fixative for the selected paraffin-section image is unreported (A07755 tissue-IHC caption). That caption used Tris-EDTA at pH 9.0 for retrieval and a 1:200 primary antibody dilution, but does not establish whether retrieval is required (A07755 tissue-IHC caption). There is no supplied evidence that frozen sections or IF/ICC are easier (HPA: no ICC-IF images); for cardiac IF, assess tissue autofluorescence with an unstained section (standard IF practice).
HPA tissue IHC evidence for PPP1R3A
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Medium consistency between antibody staining and RNA expression data. Presumed off target binding observed and disregarded.). 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 |
|---|---|---|---|---|
| Heart muscle | Cardiomyocytes | High | Protein (IHC) | HPA → |
| Skeletal muscle | Myocytes | High | Protein (IHC) | HPA → |
| Testis | Spermatogonia cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced PPP1R3A IHC Tips
Troubleshoot PPP1R3A staining in paraffin sections by checking retrieval, cell identity, subcellular pattern and controls before comparing signal intensity.
What retrieval should I use when PPP1R3A staining is weak?
Start with heat-mediated retrieval in Tris-EDTA at pH 9.0 for paraffin sections (datasheet A07755). The selected antibody image used this retrieval with primary antibody at 1:200 overnight at 4°C, so reproduce those conditions before changing several variables together (datasheet A07755). Run a retrieval-time series on adjacent sections while keeping antibody dilution, detection and development time constant; compare tissue detail as well as signal (standard IHC practice). Include skeletal or heart muscle as an expected positive reference, since PPP1R3A has cytoplasmic staining in these tissues (HPA: tissue IHC profile). If staining remains weak, test another retrieval buffer as a fallback and record any change in background (standard IHC practice).
Could fixation explain absent PPP1R3A staining?
PPP1R3A-specific fixation sensitivity is unknown from the supplied evidence; the selected paraffin-section caption does not state a fixative (datasheet A07755). Record the actual fixative and fixation duration for each specimen, then compare sections processed under matched conditions before attributing a weak result to fixation (standard IHC practice). Use a known positive skeletal or heart muscle section in the same staining run to distinguish a specimen problem from a run-wide failure (HPA: cytoplasmic expression in skeletal and heart muscle; standard IHC practice). If fixation histories differ, interpret intensity comparisons cautiously and document retrieval and detection settings alongside them (standard IHC practice).
Where should convincing PPP1R3A staining appear?
Expect cytoplasmic staining in skeletal myocytes and cardiomyocytes when assessing paraffin sections (HPA: tissue IHC profile; HPA: high in skeletal myocytes and cardiomyocytes). UniProt also assigns PPP1R3A a membrane location and a transmembrane segment at residues 1078–1098, so note any reproducible membrane-associated pattern without requiring a sharply outlined cell border (UniProt Q16821: subcellular location and topology). Compare signal in the expected cells with adjacent structures at the same development time (standard IHC practice). Predominantly nuclear or diffuse extracellular staining needs additional controls before it can be assigned to PPP1R3A, because it differs from the reported tissue pattern (HPA: tissue IHC profile; standard IHC practice).
How can isoforms or epitope placement affect interpretation?
PPP1R3A has 2 listed isoforms, but the supplied caption does not identify the catalog antibody’s epitope or establish isoform recognition (UniProt Q16821: isoforms; datasheet A07755: selected caption). Check the antibody’s documented immunogen against both isoform sequences before treating staining differences as isoform-specific (standard IHC practice). The protein contains a CBM21 region at residues 122–230, several reported phosphorylation sites near its N terminus, and a transmembrane segment at 1078–1098; epitope position could therefore matter to assay design, but its effect here is untested (UniProt Q16821: domains, modified residues and topology). Validate unexpected patterns with an independently mapped antibody or orthogonal expression evidence (standard IHC practice).
How should I check PPP1R3A localisation by multiplex IF?
For exploratory IF, pair PPP1R3A staining with a validated marker of cardiomyocytes or skeletal myocytes, the cell types with high tissue-IHC signal (HPA: high in cardiomyocytes and skeletal myocytes; standard IF practice). Choose spectrally separated fluorophores after checking tissue autofluorescence in an unstained section, and include single-stain controls when comparing channels (standard IF practice). Because PPP1R3A has a membrane assignment and a transmembrane segment at residues 1078–1098, set permeabilisation according to the antibody epitope’s verified membrane-facing side; that side is not supplied here (UniProt Q16821: location and topology; standard IF practice). Treat any IF pattern as an independently tested observation, since the selected evidence documents paraffin-section chromogenic staining (datasheet A07755).
How can I reduce background without losing PPP1R3A signal?
First compare a no-primary control with the stained section to locate background from secondary detection, endogenous peroxidase or chromogen development (standard chromogenic IHC practice). Apply an appropriate peroxidase block, match the secondary reagent to the primary antibody, and shorten chromogen development if control sections stain (standard chromogenic IHC practice). The selected paraffin-section image used primary antibody at 1:200 overnight at 4°C and secondary antibody at 1:200 for 45 minutes at room temperature; use these as documented starting conditions, not universal optima (datasheet A07755). Judge any adjustment against expected myocyte staining and preserved tissue detail (HPA: tissue IHC profile; standard IHC practice).
What should I measure to compare PPP1R3A staining across sections? ⚠ ANSWER MARKED FOR VERIFICATION
Score identified cardiomyocytes or skeletal myocytes using an H-score that combines the percentage of positive cells with staining intensity, and report the scoring thresholds (HPA: high in cardiomyocytes and skeletal myocytes; standard IHC practice). Alternatively, report the percentage of positive target cells or positive area per mm² when that measure suits the tissue architecture (standard IHC practice). Normalise to the number or area of eligible target cells, rather than total section area, and exclude folds, necrosis and section edges by a prespecified rule (standard IHC practice). Keep retrieval, antibody dilution, chromogen development and image settings matched across comparison groups (standard IHC practice).
When is apparent PPP1R3A positivity likely to be artefactual?
Give greatest weight to reproducible cytoplasmic staining in cardiomyocytes or skeletal myocytes, where the tissue profile and high staining agree (HPA: tissue IHC profile; HPA: high in cardiomyocytes and skeletal myocytes). Treat isolated nuclear staining, section-edge accentuation, necrotic-area staining or signal in a no-primary control as prompts to investigate localisation and workflow artefacts (HPA: tissue IHC profile; standard IHC practice). Check endogenous peroxidase with a suitable control before interpreting chromogen deposits as antigen signal (standard chromogenic IHC practice). The selected antibody’s tonsil image documents staining conditions but does not establish the identity of positive cells, while HPA reports presumed off-target binding in its tissue assessment (datasheet A07755: selected caption; HPA: reliability description).
Boster reagents
Best PPP1R3A / Protein phosphatase 1 regulatory subunit 3A IHC Antibodies
One IHC-validated anti-PPP1R3A antibody has a figure from paraffin-embedded human tonsil (A07755 image caption); its listed reactivity covers human, mouse, and rat (A07755 catalog). No IF data are supplied (catalog).
Real IHC data
Anti-PPP1R3A Antibody
Cat # A07755
A07755 is the only card; it is listed for IHC and WB with human, mouse, and rat reactivity (A07755 catalog). Its IHC figure shows paraffin-embedded human tonsil, Tris-EDTA retrieval at pH 9.0, and a 1:200 primary dilution (A07755 image caption).
Which to pick: Choose A07755 for paraffin-section IHC based on its human tonsil figure; the caption does not report the fixative (A07755 image caption). No listed SKU supports an IF/ICC choice because A07755 has no IF application or figure (A07755 catalog). For mouse or rat tissue, A07755 is the listed cross-species candidate based on its polyclonal format and reactivity listing; its supplied IHC figure is human only (A07755 catalog; A07755 image caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q16821 (PPR3A_HUMAN, Protein phosphatase 1 regulatory subunit 3A).
- Human Protein Atlas. PPP1R3A tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. PPP1R3A subcellular location (ICC-IF): Membrane.
- Human Protein Atlas. PPP1R3A antibody validation summary (2 antibodies).
- PPP1R3A inhibits osteogenesis and negatively regulates intracellular calcium levels in calcific tendinopathy. iScience 2023 — PMC10590817.
- PubMed PMID:9726244 — UniProt-cited evidence.
- PubMed PMID:12853948 — UniProt-cited evidence.
- PubMed PMID:12690205 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for PPP1R3A (Protein phosphatase 1 regulatory subunit 3A). Expected localisation Cytoplasmic staining (HPA tissue IHC); membrane association (UniProt). Antigen retrieval: Tris-EDTA pH 9.0 HIER, heat-mediated (datasheet A07755). Validated IHC antibody: A07755 at 1:50 recommended; image 1:200 (the product's own IHC validation image is shown). Controls (HPA): positive Heart muscle (Cardiomyocytes); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human tonsil tissue; fixative not specified (datasheet A07755); 2. Fixation: Image fixative and duration unreported (datasheet A07755); 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: Tris-EDTA pH 9.0 (datasheet A07755); 20 min, 95–100 °C (standard); 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-PPP1R3A, 1:50 recommended; image 1:200 (datasheet A07755); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Caveat: Presumed off-target staining was disregarded (HPA tissue IHC); Isoform / epitope: 2 isoforms; TM at 1078–1098 ; epitope side unknown (UniProt); Regulation: Muscle-enriched expression (UniProt). Evidence: UniProt Q16821, HPA tissue IHC · Enhanced, HPA ICC-IF · Membrane, Datasheet A07755, PMC10590817. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/PPP1R3A/immunohistochemistry-ihc-guide.