PI3 · Western blot design guide

PI3 Western Blot Planning Guide

Plan a PI3 Western blot around the catalog-observed 12.3 kDa band, image-backed PB9957 evidence, HPA controls, and verified protocol records.

Evidence assembled July 2026 · For research use; verify linked source records and product datasheet before use
Western blot protocol sheet for PI3 (PI3): expected band 12.3 kDa, antibody PB9957, and guide-derived SDS-PAGE protocol steps
PI3 Western blot protocol sheet — expected band 12.3 kDa, antibody PB9957, controls and PMC citations. Open the full PI3 WB guide →

PI3 Western Blot Experimental Design Guide

Expected bands, documented protocol parameters, controls and antibodies — the at-a-glance facts below, then the full design guide.

Must know before running
Expected band 12.3 kDa
Observed band Not reported — verify product WB image
Gel 15%
Positive control ⓘ Esophagus
Negative control ⓘ Appendix
Important caveats
Reasons your observed band may differ from the expected size.
ⓘ Calculated mass 12.3 kDa
ⓘ Localization Secreted
ⓘ Processing / PTM Record-dependent
ⓘ Reactivity Human
Section 1

Real Curated PI3 Western Blot Protocols

Start with the molecular-weight rule, then compare verified publication-derived conditions.

Recommended Western blot protocol parameters
Sample / lysateEsophagus
Gel %15%
Load20-30 µg total protein per lane
TransferSemi-dry, short transfer
Membrane0.2 µm PVDF
Blocking5% non-fat milk or 5% BSA in TBST
PrimaryPB9957 at datasheet starting dilution
Primary incubationOvernight at 4 °C with gentle agitation
SecondarySpecies-matched HRP conjugate at validated dilution
Wash3 × 5 min in TBST
DetectionChemiluminescent substrate
ExposureBracket exposures to avoid saturation
Section 2

What Is the Expected PI3 Western Blot Band Size?

Use the product-observed 12.3 kDa band as the primary planning value and retain the UniProt calculated mass as context.

What am I looking at on my blot?
12.3 kDaMatches the authoritative product WB observation.
12.3 kDa calculatedUse as UniProt context, not as a replacement observed band.
Unexpected additional signalDo not assign identity without orthogonal positive/negative controls.
💡Expected PI3 appearancePlan around 12.3 kDa and keep the calculated mass as supporting context.
How each factor affects band size
Catalog-observed band12.3 kDa; use this as the primary experimental expectation.
Calculated mass12.3 kDa from UniProt P19957; retain as context.
Gel selection15%; shared with the recommended protocol and poster.
Specificity checkCompare the lead HPA positive and negative controls with PB9957.
Why is my band missing or off?
SituationLikely causeNext action
12.3 kDaMatches the authoritative product WB observation.Confirm with orthogonal controls and the linked product record.
Additional bandMay reflect processing, modification, or non-specific signal.Run a dilution series and compare positive/negative controls.
Weak signalTarget abundance or transfer may be limiting.Verify transfer, increase positive-control abundance, and bracket exposure.

Sample controls for PI3 Western blot

🧪Use Esophagus as the first positive-control candidate and Appendix as the HPA Not detected negative candidate.
Positive control: Esophagus (Medium)
Negative control: Appendix (Not detected)
HPA protein score determines control status; other expression data is supporting context only.

HPA tissue expression evidence for PI3

Comprehensive Human Protein Atlas IHC scoring per tissue. Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.

Positive expression · recommended positive controls

TissueCell typeLevelEvidenceSource
Esophagus Reported tissue cells Medium Protein (HPA) HPA →
Vagina Reported tissue cells Medium Protein (HPA) HPA →
Skin Reported tissue cells Medium Protein (HPA) HPA →
Oral mucosa Reported tissue cells Medium Protein (HPA) HPA →

Undetected expression · recommended negative controls

TissueCell typeLevelEvidenceSource
Appendix Reported tissue cells Not detected Protein (HPA) HPA →
Bone marrow Reported tissue cells Not detected Protein (HPA) HPA →
Section 3

Advanced PI3 Western Blot Tips

Deeper troubleshooting and optimisation questions for PI3, answered from its protein features.

Which band should guide the blot?
Use 12.3 kDa, the observation attached to the authoritative PB9957 WB record.
How should calculated mass be interpreted?
Treat the UniProt calculated mass as context; it does not replace the catalog-observed 12.3 kDa expectation.
Which positive control should I start with?
Start with Esophagus, the lead HPA protein-expression candidate.
Which negative control is defensible?
Use Appendix as an orthogonal HPA Not detected candidate.
Which gel should I use?
Use 15% consistently across the quick facts, protocol table, and poster.
What transfer method to use for PI3 Western blot?
Use the transfer method in the recommended protocol and verify transfer before blocking.
How should PB9957 be started?
Start at the linked datasheet condition and run a three-point primary-antibody dilution test.
Which publication-derived protocols can I compare?
No verified publication protocol was supplied; use only the deterministic recommended protocol.
Boster reagents

PI3 Western Blot Reagents

Human-reactive PI3 Western blot reagents with authoritative product imagery.

Real WB data Western blot validation image for PI3 using PB9957; observed band 12.3 kDa
Anti-Elafin/Skalp/PI3 Antibody Picoband®
Cat # PB9957

Only image-backed, WB-validated Human/Mouse/Rat recommendations from the prepared catalog evidence are shown.

Source: prepared picoband-wb product evidence; each card retains its own SKU, URL, observed band, and authoritative WB image.

References

  1. UniProt P19957
  2. Human Protein Atlas — PI3
  3. PB9957 product record
  4. PMC1887253 — Differential expression of SKALP/Elafin in human epidermal tumors (The American journal of pathology, 1993)