PIK3R1 / Phosphatidylinositol 3-kinase regulatory subunit alpha · IHC design guide

Design Immunohistochemistry for PIK3R1

This guide pairs HPA’s general cytoplasmic tissue pattern with a paraffin IHC protocol for PIK3R1 (HPA tissue IHC; datasheet A00318-1). Start the IHC-validated antibody at 2 μg/ml overnight at 4°C, and score strongly staining cell populations such as lung macrophages separately (datasheet A00318-1; HPA tissue IHC).

Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use

Immunohistochemistry protocol sheet for PIK3R1 (IHC for PIK3R1): expected localisation General cytoplasmic staining (HPA tissue IHC), antibody A00318-1, validated IHC image, and IHC protocol steps — Printable **PIK3R1** IHC protocol sheet — expected localisation General cytoplasmic staining (HPA tissue IHC), antibody A00318-1, controls and protocol steps. Open the full PIK3R1 IHC guide →

Navigate to: Protocols Staining pattern Controls Antibodies

PIK3R1 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	General cytoplasmic staining (HPA tissue IHC)
	Staining pattern	Cytoplasmic staining across diverse cell types (HPA tissue IHC)
	Antigen retrieval	EDTA pH 8.0 HIER, heat-mediated (datasheet A00318-1)
	Positive control ⓘ	Bone marrow+4 more · see all
	Negative control ⓘ	None in HPA (detected in all 45 tissues); use no-primary + isotype controls

Important caveats

Reasons your staining may differ from the expected pattern.

	Fixation	Keep fixation consistent across sections (standard IHC practice; not target-specific)
	Caveat	Lung macrophages stain strongly; score cell types separately (HPA tissue IHC)
	Regulation	Tissue-dependent isoform 2 expression (UniProt)
	Isoform / epitope	Five isoforms; check cytoplasmic epitope coverage (UniProt)

Section 1

Recommended PIK3R1 IHC & IF Protocols

The catalog antibody’s IHC protocol (datasheet A00318-1) is paired with a published human hepatocellular carcinoma protocol (PMC6264640).

Recommended immunohistochemistry (IHC-P) protocol parameters
Sample	Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet A00318-1)
Fixation	Image fixative and duration unreported (datasheet A00318-1); 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 A00318-1); 20 min, 95–100 °C (standard)
Peroxidase block	3% H2O2, 10 min, room temperature (standard)
Blocking	10% goat serum (datasheet A00318-1)
Primary antibody	Rabbit anti-PIK3R1, 2-5 μg/ml (datasheet A00318-1)
Primary incubation	Overnight at 4 °C (datasheet A00318-1)
Detection	Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A00318-1)
Counterstain	Hematoxylin, blue, dehydrate and mount (standard)
Expected result	PIK3R1-positive staining in hematopoietic cells of bone marrow (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic expression. No signal in the no-primary control.

💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 (datasheet A00318-1); the published protocol used EDTA without specifying pH (PMC6264640).

Section 2

What Is the Expected PIK3R1 Staining Pattern?

PIK3R1 is a cytoplasmic protein with no transmembrane segment (UniProt P27986: subcellular location and topology). In paraffin tissue sections, expect mainly cytoplasmic staining across several cell types, including neuronal cells, cardiomyocytes, lung macrophages and placental trophoblastic cells (HPA: general cytoplasmic expression; High in those cell types). HPA rates the tissue IHC pattern Approved, with medium consistency between staining and RNA expression (HPA: tissue IHC reliability).

What am I looking at on my slide?
Cytoplasmic staining in lung macrophages or heart cardiomyocytes, with identifiable cell boundaries.	This fits the reported compartment and two reported High cell populations (UniProt P27986: Cytoplasm; HPA: High in lung macrophages and heart cardiomyocytes). Compare intensity within the same staining run; a High HPA category is a reference pattern, not a numeric intensity cutoff.
Predominantly nuclear staining, or membrane-only staining with little cytoplasmic signal.	Treat this as a localisation discrepancy and investigate an artefact before scoring it as PIK3R1 (UniProt P27986: Cytoplasm; HPA: general cytoplasmic expression). PIK3R1 can be recruited toward activated receptors at the plasma membrane, so some peripheral signal alone does not prove an error (UniProt P27986: function).
Strong staining assigned to an unexpected cell population while expected positive cells are clear.	Check cell identity and the staining controls; cross-reactivity or endogenous chromogenic detection activity may explain the contrast (general IHC practice). HPA reports Low staining in liver cholangiocytes, smooth muscle cells and soft tissue fibroblasts, rather than universal absence (HPA: tissue IHC).
Uniform chromogen over cells and surrounding tissue, with cell outlines hard to distinguish.	This diffuse background does not establish the reported cytoplasmic pattern (HPA: general cytoplasmic expression). Assess the no-primary control, blocking and detection steps to distinguish nonspecific reagent signal from cell-associated staining (general IHC practice).
No convincing cytoplasmic signal in a section containing a reported High cell population.	Treat the run as unresolved until an on-run positive control and tissue preservation are checked (general IHC practice). HPA lists High staining in bone marrow hematopoietic cells, cerebral cortex neuronal cells and other specified populations, but its Approved rating has only medium RNA-to-staining consistency (HPA: tissue IHC).

💡Expected PIK3R1 appearanceCall positive a cell-associated, predominantly cytoplasmic chromogenic signal in a reported High population, such as lung macrophages; isolated nuclear staining or uniform tissue haze is suspect (UniProt P27986: Cytoplasm; HPA: High in lung macrophages and general cytoplasmic expression).

How each factor affects the staining
Tissue and cell selection	HPA reports High staining in cerebellar molecular-layer cells, fallopian tube glandular cells, lymph-node germinal-center cells and placental trophoblastic cells (HPA: tissue IHC). Its RNA specificity is Low across tissues, so tissue-wide RNA expression alone does not identify which cells should show the strongest chromogen (HPA: RNA specificity and tissue IHC).
Antibody evidence	HPA001216 and CAB004268 each have Approved IHC status (HPA: antibody validation). The tissue profile itself is Approved with medium staining-to-RNA consistency (HPA: tissue IHC reliability). Use those ratings to set confidence; they do not guarantee that every cell or specimen will reproduce a High category.
Isoform coverage	UniProt lists five PIK3R1 isoforms and reports isoforms 2 and 4 at protein level in skeletal muscle (UniProt P27986: isoforms and tissue specificity). Without an antibody epitope map in the supplied evidence, the observed IHC pattern cannot be assigned to one isoform or assumed to detect all five.
Compartment and receptor recruitment	The baseline annotation is Cytoplasm, with no transmembrane segment (UniProt P27986: location and topology). SH2-mediated binding to activated tyrosine kinases can recruit the p110-containing complex toward the plasma membrane (UniProt P27986: function). Interpret peripheral accentuation alongside, rather than in place of, the expected cytoplasmic pattern.
IF/ICC Q: what pattern is supported?	A cytosolic pattern is the supported IF/ICC expectation (HPA: Cytosol, approved). HPA001216 has Approved ICC status, and HPA lists images from A-431, U-251MG, U2OS, ASC52telo, RPTEC/TERT1 and serum-starved hTERT-RPE1 cells (HPA: subcellular record and antibody validation).

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
Known-positive cells show no chromogen.	The run may have failed at retrieval, primary staining or detection (general IHC practice); absence alone cannot identify which step failed.	Review an on-run positive control, retrieval record and detection controls before calling the specimen negative (general IHC practice). Use a reported High population as a reference, such as lung macrophages (HPA: tissue IHC).
Signal appears mainly nuclear.	The distribution conflicts with the annotated cytoplasmic pattern (UniProt P27986: Cytoplasm; HPA: general cytoplasmic expression).	Check morphology and a no-primary control, then compare with a reported positive cell population (general IHC practice; HPA: tissue IHC). Do not score nuclear-only staining as the expected pattern.
Chromogen is widespread, including areas between cells.	Diffuse deposition may reflect nonspecific detection or endogenous enzyme activity (general chromogenic IHC practice).	Inspect the no-primary control and the assay's blocking and endogenous-activity controls; adjust the staining workflow only after locating the background source (general IHC practice).
An unexpected cell type stains more strongly than a reported High population.	Cell misidentification, cross-reactivity or detection background are possibilities (general IHC practice); HPA levels describe observed populations, not a universal rank order (HPA: tissue IHC).	Recheck cell morphology and controls, and compare another reported High population in the same run where available (general IHC practice; HPA: tissue IHC).
Mostly peripheral staining appears in otherwise positive cells.	PIK3R1 can associate with activated receptor signalling at the plasma membrane, although its annotated location is cytoplasmic (UniProt P27986: function and location).	Assess whether cytoplasmic staining is also present and whether the signal follows cell boundaries; investigate membrane-only staining as a localisation discrepancy (HPA: general cytoplasmic expression; general IHC practice).
Staining differs between specimens or antibodies.	HPA reports medium consistency between tissue staining and RNA expression, and the supplied evidence does not establish isoform recognition for either antibody (HPA: tissue IHC reliability; UniProt P27986: five isoforms).	Compare the same named cell population and controls across runs, record the antibody used, and avoid assigning the difference to an isoform without epitope evidence (general IHC practice; UniProt P27986: isoforms).

Source: UniProt P27986 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing PIK3R1 staining

IHC analysis of PI 3 Kinase p85 alpha/PIK3R1 using anti-PI 3 Kinase p85 alpha/PIK3R1 antibody (A00318-1). PI 3 Kinase p85 alpha/PIK3R1 was detected in a paraffin-embedded section of human lung cancer tissue. Heat mediated antigen retrieval was performed in EDTA buffer (pH 8.0, epitope retrieval solution). The tissue section was blocked with 10% goat serum. The tissue section was then incubated with 2 μg/ml rabbit anti-PI 3 Kinase p85 alpha/PIK3R1 Antibody (A00318-1) overnight at 4°C. Biotinylated goat anti-rabbit IgG was used as secondary antibody and incubated for 30 minutes at 37°C. The tissue section was developed using Strepavidin-Biotin-Complex (SABC) (Catalog # SA1022) with DAB as the chromogen.

A00318-1 · IHCIHC analysis of PI 3 Kinase p85 alpha/PIK3R1 using anti-PI 3 Kinase p85 alpha/PIK3R1 antibody (A00318-1). PI 3 Kinase p85 alpha/PIK3R1 was d

IF analysis of PI 3 Kinase p85 alpha/PIK3R1 using anti-PI 3 Kinase p85 alpha/PIK3R1 antibody (A00318-1). PI 3 Kinase p85 alpha/PIK3R1 was detected in an immunocytochemical section of Caco-2 cells. Enzyme antigen retrieval was performed using IHC enzyme antigen retrieval reagent (AR0022) for 15 mins. The cells were blocked with 10% goat serum. And then incubated with 5 μg/mL rabbit anti-PI 3 Kinase p85 alpha/PIK3R1 Antibody (A00318-1) overnight at 4°C. DyLight®488 Conjugated Goat Anti-Rabbit IgG (BA1127) was used as secondary antibody at 1:100 dilution and incubated for 30 minutes at 37°C. The section was counterstained with DAPI. Visualize using a fluorescence microscope and filter sets appropriate for the label used.

A00318-1 · IFIF analysis of PI 3 Kinase p85 alpha/PIK3R1 using anti-PI 3 Kinase p85 alpha/PIK3R1 antibody (A00318-1). PI 3 Kinase p85 alpha/PIK3R1 was de

M00318-3 · IHCMouse testis was stained with Anti-PI3-Kinase p85 α rabbit Antibody

M00318-3 · IHCHuman placenta was stained with Anti-PI3-Kinase p85 α rabbit Antibody

A00318Y463 · IHCImmunohistochemistry (IHC) analyzes of PI3K p85 α/γ (Y463) pAb in paraffin-embedded human breast carcinoma tissue at 1:100.

A00318Y467 · IHCImmunohistochemistry (IHC) analysis of PI3K p85α/p55γ pAb in paraffin-embedded human breast carcinoma tissue

A00318Y607 · IFImmunofluorescence analysis of BV2 cells using PI3K p85α/p55γ antibody at dilution of 1:50.

M00318-2 · IFImmunofluorescent analysis using the Antibody at 1:50 dilution.

HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000145675-PIK3R1/tissue/cerebral+cortex#imid_2168820

HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000145675-PIK3R1/tissue/colon#imid_2168746

HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000145675-PIK3R1/tissue/liver#imid_2168755

HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000145675-PIK3R1/tissue/kidney#imid_2168764

HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA001216; green = PIK3R1, blue = nucleus, red = microtubules.

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Real IHC / IF data behind the staining-pattern expectations in this section.

Sample controls for PIK3R1 IHC & IF

🧪Run bone marrow first and assess staining in hematopoietic cells (HPA: High in bone marrow hematopoietic cells). HPA detects PIK3R1 in all 45 scored tissues, so there is no supported negative tissue; use no-primary and isotype controls, and treat any cells without specific staining on the positive slide as internal background references rather than a defined negative cell population (HPA: no negative rows).

Positive control tissue: Bone marrow (Hematopoietic cells, HPA High)

Negative control tissue: None in HPA: PIK3R1 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.

ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show PIK3R1 in A-431, U-251MG, U2OS, ASC52telo, RPTEC/TERT1, hTERT-RPE1 (serum starved), with annotated localisation: Cytosol (approved) (HPA subcellular).

Technical controls: Include a no-primary, secondary-only slide and a matched rabbit IgG isotype control (selected-SKU caption: rabbit primary antibody). Where available, use PIK3R1-knockout material or immunizing-peptide competition as a biological specificity control; quench endogenous peroxidase and assess endogenous biotin in bone marrow when using the reported streptavidin–biotin/DAB detection (selected-SKU caption: SABC with DAB; HPA: bone marrow hematopoietic cells).

⚠️Feasibility: No target-specific fixation window or fixation effect is reported, and the selected-SKU paraffin-section caption does not state a fixative (selected-SKU caption: fixative unreported). That caption used heat retrieval in EDTA at pH 8.0, but does not establish that retrieval is required; the evidence also does not establish whether frozen sections or IF are easier (selected-SKU caption: EDTA heat retrieval; HPA: cytosolic ICC-IF images). For bone marrow chromogenic IHC, check endogenous peroxidase background in the hematopoietic compartment (HPA: High in bone marrow hematopoietic cells; selected-SKU caption: DAB detection).

HPA tissue IHC evidence for PIK3R1

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
Bone marrow	Hematopoietic cells	High	Protein (IHC)	HPA →
Cerebellum	Cells in molecular layer	High	Protein (IHC)	HPA →
Cerebral cortex	Neuronal cells	High	Protein (IHC)	HPA →
Fallopian tube	Glandular cells	High	Protein (IHC)	HPA →
Heart muscle	Cardiomyocytes	High	Protein (IHC)	HPA →

Undetected expression · recommended negative controls

Tissue	Cell type	Level	Evidence	Source
None in HPA: PIK3R1 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.

Section 3

Advanced PIK3R1 IHC Tips

Troubleshoot PIK3R1 staining in paraffin sections by checking retrieval, compartment, cell identity, and controls before comparing signal intensity across samples.

How should I retrieve PIK3R1 in paraffin sections when staining is weak?

Start with heat-mediated retrieval in EDTA at pH 8.0 for the catalog antibody (datasheet A00318-1). Process a known positive section alongside the test section, keeping heating, cooling, and wash conditions identical so a weak result can be traced to retrieval rather than run variation (standard IHC practice). The selected image documents PIK3R1 detection in a paraffin section after this retrieval, but does not report its fixative (caption A00318-1). If signal remains weak, compare a modestly longer retrieval with the original condition on adjacent sections, and monitor morphology and background before adopting the change (standard IHC practice).

Could fixation explain weak or uneven PIK3R1 staining?

Target-specific fixation sensitivity is unknown: the selected paraffin-section caption does not state a fixative (caption A00318-1). Record each sample’s fixative, fixation duration, section thickness, and processing history before comparing staining across specimens (standard IHC practice). Run sections with comparable processing together, using the same retrieval and detection conditions, to assess whether weak signal tracks with specimen handling (standard IHC practice). If a processing difference is suspected, test adjacent sections with one controlled retrieval adjustment at a time and check whether morphology remains interpretable (standard IHC practice). Do not assign a PIK3R1-specific fixation effect from its reported cytoplasmic location or phosphorylation sites (UniProt P27986).

Where should PIK3R1 staining appear, and how should membrane-adjacent signal be judged?

Expect predominantly cytoplasmic staining in chromogenic sections (HPA: general cytoplasmic expression; UniProt P27986: cytoplasm). PIK3R1 has no transmembrane segment, although its SH2-mediated interactions can recruit the p110 complex toward activated receptors at the plasma membrane (UniProt P27986). Assess membrane-adjacent color against the surrounding cytoplasm and cell outlines on a counterstained section; do not score a crisp membrane rim alone as proof of PIK3R1 specificity (standard IHC practice; UniProt P27986 topology). Investigate predominantly nuclear or extracellular staining with a no-primary control and a known positive section before interpreting it biologically (standard IHC practice; HPA: general cytoplasmic expression).

Can this stain distinguish PIK3R1 isoforms or phosphorylation states?

PIK3R1 has 5 listed isoforms and SH3, Rho-GAP, and 2 SH2 domains (UniProt P27986). The supplied caption reports tissue staining with A00318-1 but gives no epitope map or isoform selectivity, so a positive cell cannot be assigned a particular isoform from this image (caption A00318-1; UniProt P27986). Isoforms 2 and 4 are reported at protein level in skeletal muscle, making epitope coverage relevant when interpreting staining there (UniProt P27986). Listed phosphoserine and phosphotyrosine residues likewise do not make a conventional PIK3R1 stain a phosphorylation assay; require a validated modification-specific reagent for that question (UniProt P27986; standard IHC practice).

How can IF clarify which cells produce the PIK3R1 signal?

Use a separate IF/ICC workflow to pair PIK3R1 with a validated marker for the expected cell population, such as a macrophage marker when assessing lung tissue (HPA: high PIK3R1 staining in lung macrophages; standard IF practice). Choose a fluorophore in a spectral region with low measured tissue autofluorescence, and acquire single-stain and no-primary controls to check bleed-through and background (standard IF practice). Because PIK3R1 is cytosolic and lacks a transmembrane segment, permeabilisation must permit antibody access to intracellular epitopes (HPA: cytosol; UniProt P27986 topology). Optimise permeabilisation on matched samples, then judge colocalisation within identified cells rather than from overlapping bright areas alone (standard IF practice).

What should I check when DAB background obscures PIK3R1 staining?

Check a no-primary control and inspect whether color appears across tissue, at section edges, or in damaged regions before adjusting the antibody (standard IHC practice). The selected procedure used 10% goat serum, 2 μg/ml primary antibody overnight at 4°C, and biotin-based DAB detection (caption A00318-1). Include a peroxidase block and assess endogenous biotin where relevant, since either can complicate this general chromogenic workflow (standard IHC practice; caption A00318-1: biotin-based detection). If background persists, compare controlled changes to blocking, washing, or primary concentration on adjacent sections while preserving a known positive control (standard IHC practice).

How should I quantify PIK3R1 across sections with different cell composition? ⚠ ANSWER MARKED FOR VERIFICATION

Define the cell population and tissue area before scoring, using consistent morphology and counterstain criteria across slides (standard IHC practice). Report the percentage of positive cells and staining intensity, or calculate an H-score from those components when intensity categories are reproducible (standard IHC practice). If cell abundance varies, report positive cells per mm² and normalise the PIK3R1 result to the number of evaluable cells in the same compartment (standard IHC practice). Record staining in relevant cell types separately because HPA reports high expression in lung macrophages and several other distinct populations (HPA: tissue IHC profile). Keep imaging, thresholds, and controls consistent across comparison groups (standard IHC practice).

How can I distinguish genuine PIK3R1 staining from artefact?

A credible result follows cellular contours with predominantly cytoplasmic signal and appears in an appropriate positive control (HPA: general cytoplasmic expression; standard IHC practice). In lung sections, distinguish macrophage staining from neighboring cells before attributing signal to the tissue compartment of interest (HPA: high in lung macrophages). Treat isolated nuclear or extracellular color, section-edge enhancement, and necrotic deposits cautiously, and compare them with a no-primary control (HPA: cytosol; standard IHC practice). Check residual endogenous peroxidase when DAB appears without primary antibody, and consider detection-related background in the biotin-based workflow (standard IHC practice; caption A00318-1). HPA rates tissue staining as approved with medium RNA concordance, which supports cautious interpretation (HPA: reliability).

Boster reagents

Best PIK3R1 / Phosphatidylinositol 3-kinase regulatory subunit alpha IHC Antibodies

Catalog antibodies have IHC images from human and mouse tissues and IF images from cells (catalog image captions); listed reactivity includes human, mouse and rat (catalog reactivity).

Real IHC data

Anti-PI 3 Kinase p85 alpha/PIK3R1 Antibody ®

Cat # A00318-1

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Real IHC data Mouse testis was stained with Anti-PI3-Kinase p85 α rabbit Antibody

Anti-PI3-Kinase p85 α Rabbit Monoclonal Antibody

Cat # M00318-3

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Real IHC data Immunohistochemistry (IHC) analyzes of PI3K p85 α/γ (Y463) pAb in paraffin-embedded human breast carcinoma tissue at 1:100.

Anti-PI3K p85 Alpha /p55 Gamma (Y463) PIK3R1 Antibody

Cat # A00318Y463

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Real IHC data Immunohistochemistry (IHC) analysis of PI3K p85α/p55γ pAb in paraffin-embedded human breast carcinoma tissue

Anti-PI3K p85 Alpha /p55 Gamma (Y467/199) PIK3R1 Antibody

Cat # A00318Y467

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Real IF data Immunofluorescence analysis of BV2 cells using PI3K p85α/p55γ antibody at dilution of 1:50.

Anti-PI3K p85 Alpha /p55 Gamma (Tyr607) PIK3R1 Antibody

Cat # A00318Y607

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Real IF data Immunofluorescent analysis using the Antibody at 1:50 dilution.

Anti-PI3 Kinase p85 alpha Rabbit Monoclonal Antibody

Cat # M00318-2

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A00318-1 shows paraffin sections of human lung cancer and mouse brain (catalog IHC captions); M00318-3 shows mouse testis and human placenta (catalog IHC captions); A00318Y463 and A00318Y467 show paraffin sections of human breast carcinoma (catalog IHC captions). A00318Y607 shows IF in BV2 cells, while M00318-2 has IF images with no sample identified (catalog IF captions); both list human, mouse and rat reactivity (catalog reactivity).

Which to pick: For tissue IHC, choose A00318-1: its paraffin-section caption documents EDTA retrieval at pH 8.0 and primary antibody at 2 μg/ml overnight at 4°C (A00318-1 IHC caption); the fixative is unreported (A00318-1 IHC caption). For IF/ICC, choose M00318-2 if a rabbit monoclonal is preferred: it lists both applications and has IF images, though their sample is unidentified (M00318-2 catalog applications and IF captions). For cross-species tissue work, A00318-1 lists human, mouse and rat reactivity, with IHC images from human and mouse tissue; its captions do not document rat tissue staining (A00318-1 catalog reactivity and IHC captions).

Each figure is that product's own IHC / IF validation image from its datasheet.

References

UniProt Consortium. UniProt entry P27986 (P85A_HUMAN, Phosphatidylinositol 3-kinase regulatory subunit alpha).
Human Protein Atlas. PIK3R1 tissue IHC expression (reliability: Approved).
Human Protein Atlas. PIK3R1 subcellular location (ICC-IF): Localized to the cytosol..
Human Protein Atlas. PIK3R1 antibody validation summary (2 antibodies).
Correlation Between PIK3R1 Expression and Cell Growth in Human Breast Cancer Cell Line BT-474 and Clinical Outcomes. World journal of oncology 2025 — PMC11750754.
Overexpression of PIK3R1 promotes hepatocellular carcinoma progression. Biological research 2018 — PMC6264640.
PIK3R1 underexpression is an independent prognostic marker in breast cancer. BMC cancer 2013 — PMC4225603.
The Potential Mechanisms of Cinobufotalin Treating Colon Adenocarcinoma by Network Pharmacology. Frontiers in pharmacology 2022 — PMC9262105.
PubMed PMID:1849461 — UniProt-cited evidence.
PubMed PMID:8628286 — UniProt-cited evidence.
PubMed PMID:14702039 — UniProt-cited evidence.