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PIK3C3 / Phosphatidylinositol 3-kinase catalytic subunit type 3 · IHC design guide
Design Immunohistochemistry for PIK3C3
Plan chromogenic PIK3C3 IHC in paraffin sections around the cytoplasmic tissue pattern (HPA tissue IHC). This guide covers fixation consistency, the catalog antibody’s 1:50–1:200 IHC dilution range (datasheet), and adipocytes as a tissue cell population with no detected staining (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
PIK3C3 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 | Cytoplasm observed (HPA tissue IHC); endosomal and autophagic vesicle association expected (UniProt) | |
| Staining pattern | Broad cytoplasmic staining across tissue cells (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | Adipose tissue |
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 M02356) | |
| Caveat | Adipocytes may lack detectable staining despite broad expression (HPA tissue IHC) | |
| Regulation | Low tissue specificity (HPA tissue RNA) | |
| Isoform / epitope | No annotated isoforms; one full-length chain (UniProt) |
Section 1
Recommended PIK3C3 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is followed by 3 published PIK3C3 IHC protocols (PMC9146193; PMC7280510; PMC7111147).
| Sample | Paraffin-embedded human kidney tissue; fixative not specified (datasheet M02356) |
| Fixation | Image fixative and duration unreported (datasheet M02356); 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 monoclonal (clone CDO-16) anti-PIK3C3, 1:50-1:200 (datasheet M02356) |
| 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 | PIK3C3-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Ubiquitous cytoplasmic expression. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 HIER at 95–98 °C for 20 min (page antigen retrieval); a published protocol also uses microwave citrate retrieval (PMC7280510).
Section 2
What Is the Expected PIK3C3 Staining Pattern?
PIK3C3 should appear mainly in the cytoplasm of many cell types, consistent with its vesicle, endosome and autophagosome localization and lack of a transmembrane segment (UniProt Q8NEB9). HPA describes ubiquitous cytoplasmic tissue staining, with high staining in several epithelial and hematopoietic cell populations (HPA tissue IHC). Its tissue IHC assessment is Approved, with medium consistency between staining and RNA expression (HPA tissue IHC).
| Cytoplasmic chromogen in glandular cells of colon, duodenum or gallbladder, with limited nuclear staining. | This matches the reported high glandular-cell staining and ubiquitous cytoplasmic profile (HPA tissue IHC). A section can show variation among cells; assess the named cell population rather than assigning one intensity to the whole tissue (general IHC practice). |
| Cytoplasmic staining that looks granular or punctate, especially when examined at higher resolution. | Vesicle, late-endosome and autophagosome localization makes a cytoplasmic punctate pattern biologically plausible (UniProt Q8NEB9). Chromogenic tissue IHC may not resolve individual structures, so lack of distinct puncta alone does not invalidate otherwise appropriate staining (general IHC practice). |
| Strong staining centered in nuclei or restricted to the cell surface, with little cytoplasmic signal. | That distribution conflicts with the reported cytoplasmic tissue profile and intracellular localization (HPA tissue IHC; UniProt Q8NEB9). Review morphology and controls before interpreting it as PIK3C3; off-target staining or an imaging artifact is possible (general IHC practice). |
| Prominent chromogen in adipocytes despite an otherwise convincing section. | HPA reports PIK3C3 as not detected in adipocytes, so strong adipocyte staining merits a specificity check (HPA tissue IHC). Possible explanations include cross-reactivity or endogenous detection activity; the observation alone cannot distinguish them (general IHC practice). |
| Diffuse color across cells, stroma and blank areas, or no signal in a reported high-staining cell population. | A pattern that ignores tissue boundaries suggests background; absent signal in a reported high-staining population suggests a failed stain or detection step (general IHC practice; HPA tissue IHC). Neither result should be scored as a reliable PIK3C3 distribution without controls. |
💡Expected PIK3C3 appearanceCall the stain positive when cytoplasmic signal is clear in an HPA high-staining population, such as colon glandular cells or bone-marrow hematopoietic cells; a predominantly nuclear or strong adipocyte-only signal warrants review (HPA tissue IHC; UniProt Q8NEB9).
| Tissue and cell selection | HPA reports high staining in glandular cells of adrenal gland, appendix, colon, duodenum and gallbladder; squamous epithelial cells of cervix and esophagus; and bone-marrow hematopoietic cells (HPA tissue IHC). Adipocytes are reported as not detected (HPA tissue IHC). Use the named cell types when comparing sections. |
| Subcellular interpretation | PIK3C3 is associated with pre-autophagosome structures in complex I and predominantly endosomes in complex II; UniProt also lists late endosome and midbody localization (UniProt Q8NEB9). These annotations guide interpretation, but routine chromogenic morphology does not identify a specific vesicle or protein complex (general IHC practice). |
| Strength of IHC evidence | The HPA tissue profile is Approved with medium consistency against RNA expression; antibody HPA040718 has an Approved IHC status (HPA tissue IHC; HPA antibodies). Treat a matching pattern as supportive evidence, while using controls to assess specificity in the actual assay (general IHC practice). |
| IF/ICC: what pattern should be expected? | A cytoplasmic, potentially punctate signal is plausible from UniProt localization (UniProt Q8NEB9). HPA supplies no main ICC/IF location, cell-line images or ICC status for HPA040718, so this payload does not establish an observed IF pattern (HPA subcellular; HPA antibodies). |
| Situation | Likely cause | Next action |
|---|---|---|
| No staining in colon or duodenum glandular cells. | These are reported high-staining populations, so a blank result may reflect assay failure; the HPA designation does not guarantee every section will stain (HPA tissue IHC; general IHC practice). | Check tissue preservation, positive-control performance and each detection step; review the catalog antibody's IHC-P instructions before changing assay conditions (general IHC practice). |
| Signal is predominantly nuclear. | The distribution conflicts with the cytoplasmic HPA profile and intracellular UniProt locations; off-target binding or image interpretation may be involved (HPA tissue IHC; UniProt Q8NEB9; general IHC practice). | Compare cellular boundaries against the counterstain and examine a no-primary control before scoring the signal as PIK3C3 (general IHC practice). |
| Strong color appears in adipocytes. | HPA lists adipocytes as not detected; cross-reactivity or endogenous detection activity are possible explanations (HPA tissue IHC; general IHC practice). | Check a no-primary control and, for enzyme-based detection, the relevant endogenous-activity control; compare with a reported high-staining cell population (general IHC practice; HPA tissue IHC). |
| Color spreads across stroma and tissue-free areas. | A distribution unrelated to cell morphology is consistent with nonspecific background or detection-system deposit (general IHC practice). | Inspect no-primary and reagent controls, blocking and wash steps; interpret only signal that remains tied to recognizable cells (general IHC practice). |
| Staining is weaker in a neuronal or glial population than in a high-staining reference. | HPA reports low staining in hippocampal neuronal cells and caudate glial cells, alongside high staining in several other named populations (HPA tissue IHC). | Score the specified cell type and compare it with its HPA level; do not treat relative weakness alone as assay failure when controls perform (HPA tissue IHC; general IHC practice). |
| A proposed IF image shows bright puncta but the IHC result is uncertain. | UniProt supports vesicular localization, while the supplied HPA subcellular record provides no ICC/IF images or established main location (UniProt Q8NEB9; HPA subcellular). | Evaluate the IHC section against its cytoplasmic tissue pattern and IHC controls; do not use an unvalidated IF appearance as the sole confirmation (HPA tissue IHC; general IHC practice). |
Experiment evidence
IHC & IF images showing PIK3C3 staining
M02356 · IHCImmunohistochemical analysis of paraffin-embedded human kidney, using PI 3 Kinase Class 3 Antibody.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000078142-PIK3C3/tissue/cerebral+cortex#imid_10583677
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000078142-PIK3C3/tissue/colon#imid_10583603
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000078142-PIK3C3/tissue/liver#imid_10583604
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000078142-PIK3C3/tissue/kidney#imid_10583597
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for PIK3C3 IHC & IF
🧪Run colon first: glandular cells should stain (HPA: High in colon glandular cells). Run adipose tissue as the negative comparator (HPA: Not detected in adipocytes); within the colon section, cells without visible signal should retain a clear counterstain and no chromogen deposit, but the supplied evidence does not establish a target-negative internal cell type (HPA: colon glandular-cell row; UniProt Q8NEB9: ubiquitously expressed).
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 carries no ICC-IF cell line for PIK3C3; derive a cell-line control from the positive tissue's cell type (Glandular cells) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only control; a control immunoglobulin matched to the primary antibody’s host species and isotype where applicable; and PIK3C3-knockout tissue or a validated immunizing-peptide block as a biological specificity control (standard IHC practice). For chromogenic colon IHC, quench endogenous peroxidase and check for endogenous biotin background if using avidin–biotin detection (standard IHC practice).
⚠️Feasibility: A target-specific fixation window and antigen retrieval dependency are unreported in the supplied evidence, so optimize retrieval empirically for paraffin IHC (supplied target/application evidence). The M02356 caption documents paraffin-embedded human kidney but does not report the fixative; it does not establish fixation (M02356 tissue-IHC caption). The evidence does not establish that frozen sections or IF are easier; in colon, exclude luminal material when scoring glandular-cell staining (HPA: High in colon glandular cells; standard IHC practice). The selected M02356 tissue-IHC caption documents paraffin sections, but does not specify the fixative (selected-SKU IHC image M02356).
HPA tissue IHC evidence for PIK3C3
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Medium consistency between antibody staining and RNA expression data.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Appendix | Glandular cells | High | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Cervix | Squamous epithelial cells | High | Protein (IHC) | HPA → |
| Colon | Glandular cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced PIK3C3 IHC Tips
Use the validated paraffin-section image and the reported cytoplasmic pattern as reference points while optimising PIK3C3 chromogenic IHC (caption: M02356; HPA: tissue IHC).
How should I optimise retrieval when PIK3C3 staining is weak in paraffin sections?
Start with citrate buffer at pH 6.0, heated to 95–98 °C for 20 min (page retrieval setting). Allow sections to cool in buffer, then compare them with an otherwise identically processed section to distinguish retrieval effects from detection effects (standard IHC practice). If cytoplasmic staining remains weak, test a longer citrate incubation on adjacent sections while monitoring tissue integrity and background; the supplied product caption does not report a retrieval method (caption: M02356; standard IHC practice). Include a positive control section in each run, because PIK3C3 has a broadly cytoplasmic tissue staining profile and a negative result alone cannot establish failed retrieval (HPA: tissue IHC).
Can fixation explain weak PIK3C3 staining in these paraffin sections?
Target-specific fixation sensitivity is unknown: the selected human kidney image identifies paraffin embedding but does not state its fixative or fixation duration (caption: M02356). Record the specimen fixative and processing history, then compare similarly processed control sections before changing retrieval or antibody concentration (standard IHC practice). If fixation varies between specimens, optimise retrieval and detection on sections representing those processing conditions, and assess tissue preservation alongside signal (standard IHC practice). Do not infer PIK3C3 fixation sensitivity from its cytoplasmic staining pattern, lack of a transmembrane segment, or phosphorylation sites; those observations do not test fixation effects (HPA: tissue IHC; UniProt Q8NEB9: topology and modified residues).
What staining pattern should I expect, and how should I assess unexpected nuclear signal?
Expect predominantly cytoplasmic staining at the tissue level, with possible intracellular puncta consistent with reported late-endosome and autophagosome localisation (HPA: tissue IHC; UniProt Q8NEB9: subcellular location). PIK3C3 is also reported at the midbody and, by similarity, at ciliary structures, so assess these patterns only where cell morphology permits their identification (UniProt Q8NEB9: subcellular location). Strong isolated nuclear staining does not match the supplied predominant tissue pattern; inspect counterstain, section quality, and negative controls before assigning it to PIK3C3 (HPA: tissue IHC; standard IHC practice). Compare suspected puncta with neighbouring cells and replicate sections, since chromogenic precipitate or uneven staining can imitate fine intracellular structure (standard IHC practice).
Could isoforms or epitope masking explain discordant PIK3C3 staining?
The supplied record lists 0 isoforms and one chain spanning residues 1–887, so it provides no documented isoform explanation for discordant staining (UniProt Q8NEB9: isoforms and processing). The antibody epitope is not supplied; its position relative to the C2, helical, and catalytic domains therefore cannot be assigned (UniProt Q8NEB9: domains; supplied antibody evidence). Compare retrieval conditions on adjacent sections before interpreting a negative stain as loss of a particular protein region (standard IHC practice). PIK3C3 has reported phosphorylation sites, including AMPK-modified residues 163 and 165, but the payload does not show that these modifications alter this antibody’s IHC binding (UniProt Q8NEB9: modified residues).
How can I adapt the staining question to multiplex IF without overinterpreting puncta?
Treat IF as a separate optimisation: the supplied tissue image is paraffin-section IHC, and no ICC/IF image or fixation condition is provided (caption: M02356; HPA: subcellular data). Multiplex PIK3C3 with a validated marker for the expected cell population, choosing that marker according to the tissue under study rather than assuming all cells stain equally (HPA: tissue IHC; standard IF practice). Check unstained tissue for autofluorescence, then choose fluorophores and exposure settings that separate the marker signals from that background (standard IF practice). Because PIK3C3 has no transmembrane segment and is reported at intracellular vesicles, optimise permeabilisation for access to its intracellular epitope; the antibody’s exact epitope is unspecified (UniProt Q8NEB9: topology and subcellular location; supplied antibody evidence).
How do I reduce diffuse brown staining without losing cytoplasmic PIK3C3 signal?
Run a no-primary control alongside the IHC-validated antibody to identify background arising from secondary detection or chromogen deposition (standard IHC practice). For peroxidase-based DAB detection, block endogenous peroxidase, optimise protein blocking and washes, and inspect pigment or precipitate before raising antibody concentration (standard IHC practice). Titrate the primary antibody around the working condition established in your laboratory; the supplied caption gives no dilution, so a target-specific starting dilution cannot be inferred (caption: M02356). Preserve a matched positive control during optimisation, because a broadly cytoplasmic PIK3C3 profile can make excess diffuse background difficult to distinguish from weak specific signal (HPA: tissue IHC; standard IHC practice).
What scoring scheme will make PIK3C3 IHC comparisons interpretable across sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and cytoplasmic compartment before scoring, since PIK3C3 tissue staining is described as ubiquitous and cytoplasmic (HPA: tissue IHC). For comparable sections, report the percentage of positive cells and an H-score based on intensity categories; use positive-cell density per mm² when cell abundance itself is the outcome (standard IHC practice). Normalise each result to the relevant cell count or measured tissue area, and keep illumination, threshold, staining batch, and region-selection rules consistent (standard quantitative IHC practice). Record punctate and diffuse cytoplasmic signal separately if both are present, because PIK3C3 is associated with intracellular vesicles and endosomes (UniProt Q8NEB9: subcellular location).
How can I distinguish genuine PIK3C3 staining from section artefacts?
Give greatest weight to reproducible cytoplasmic staining in intact cells, consistent with the reported ubiquitous cytoplasmic tissue profile and intracellular vesicle localisation (HPA: tissue IHC; UniProt Q8NEB9: subcellular location). Check unexpected cell-specific absence against tissue context: HPA reports high staining in several glandular and hematopoietic populations, while adipocytes were not detected in its sampled adipose tissue (HPA: tissue IHC). Discount staining restricted to section edges, folds, or necrotic areas until it reproduces in well-preserved regions (standard IHC practice). For peroxidase detection, compare no-primary and enzyme-block controls before attributing brown deposits to PIK3C3, particularly when staining lacks a convincing cytoplasmic pattern (standard IHC practice; HPA: tissue IHC).
Boster reagents
Best PIK3C3 / Phosphatidylinositol 3-kinase catalytic subunit type 3 IHC Antibodies
M02356 has real IHC data from paraffin-embedded human kidney (M02356 image caption). Its listed reactivity covers human, mouse, and rat (M02356 catalog).
Real IHC data
Anti-PI 3 Kinase Class 3 PIK3C3 Rabbit Monoclonal Antibody
Cat # M02356
M02356 has an IHC image of paraffin-embedded human kidney (M02356 image caption). Its listed applications are IHC and WB, and its listed reactivity is human, mouse, and rat (M02356 catalog).
Which to pick: For tissue IHC, choose M02356, a rabbit monoclonal antibody with an image of paraffin-embedded human kidney; the caption does not report the fixative (M02356 catalog; M02356 image caption). For IF/ICC, M02356 has no listed IF/ICC application or IF image (M02356 catalog). For work across species, M02356 lists human, mouse, and rat reactivity, while its IHC image documents human tissue only (M02356 catalog; M02356 image caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q8NEB9 (PK3C3_HUMAN, Phosphatidylinositol 3-kinase catalytic subunit type 3).
- Human Protein Atlas. PIK3C3 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. PIK3C3 subcellular location (ICC-IF): Highest expression in REH: 83.3 nTPM.
- Human Protein Atlas. PIK3C3 antibody validation summary (1 antibodies).
- Construction of PIK3C3 Transgenic Pig and Its Pathogenesis of Liver Damage. Life (Basel, Switzerland) 2022 — PMC9146193.
- ZBED6-IGF2-PIK3C3 autophagy axis drives ccRCC progression: A multi-omics integration study. iScience 2026 — PMC12996711.
- PIK3C3 regulates the expansion of liver CSCs and PIK3C3 inhibition counteracts liver cancer stem cell activity induced by PI3K inhibitor. Cell death & disease 2020 — PMC7280510.
- PIK3C3 Acts as a Tumor Suppressor in Esophageal Squamous Cell Carcinoma and Was Regulated by MiR-340-5p. Medical science monitor : international medical journal of experimental and clinical research 2020 — PMC7111147.
- PubMed PMID:7628435 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
- PubMed PMID:14617358 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for PIK3C3 (Phosphatidylinositol 3-kinase catalytic subunit type 3). Expected localisation Cytoplasm observed (HPA tissue IHC); endosomal and autophagic vesicle association expected (UniProt). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: M02356 at 1:50-1:200 (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human kidney tissue; fixative not specified (datasheet M02356); 2. Fixation: Image fixative and duration unreported (datasheet M02356); 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 monoclonal (clone CDO-16) anti-PIK3C3, 1:50-1:200 (datasheet M02356); 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 M02356); Caveat: Adipocytes may lack detectable staining despite broad expression (HPA tissue IHC); Isoform / epitope: No annotated isoforms; one full-length chain (UniProt); Regulation: Low tissue specificity (HPA tissue RNA). Evidence: UniProt Q8NEB9, HPA tissue IHC · Approved, HPA cell-line RNA · Highest expression in REH: 83.3 nTPM, Datasheet M02356, PMC9146193, PMC7280510. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/PIK3C3/immunohistochemistry-ihc-guide.