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- Table of Contents
SFPQ / Splicing factor, proline- and glutamine-rich · Western blot design guide
Design a Western Blot for SFPQ
Real validated SFPQ Western blot protocols, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-SFPQ WB antibodies. Everything you need to plan the experiment before you commit precious samples.
Evidence assembled September 2026 · For research use; verify linked source records and product datasheet before use
SFPQ Western Blot Experimental Design Guide
Expected bands, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before running
| Expected band | ~76.1 kDa | |
| Observed band | ~100 kDa | |
| Gel | 10% (catalog A02243-2) | |
| Positive control | Adipose tissue (IHC candidate; verify WB) +4 more | |
| Negative control | Suggested KO / knockdown lysate |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | Phosphorylated + Acetylated | |
| Caveat | Modification-state controls | |
| Gene-set association | MSigDB Hallmark membership | |
| Isoform | 2 isoform(s) |
Section 1
Real Curated SFPQ Western Blot Protocols
The A02243-2 protocol combines labelled catalog values with standard starting conditions. Published comparisons retain their own sample, reagent and detection scope.
| Sample / lysate | human Hela, human 293T, human HepG2 (catalog A02243-2) |
| Gel % | 10% (catalog A02243-2) |
| Load | 30 ug; reducing conditions (catalog A02243-2) |
| Transfer | a nitrocellulose membrane at 150 mA for 50-90 minutes (catalog A02243-2) |
| Membrane | nitrocellulose membrane (catalog A02243-2) |
| Blocking | 5% non-fat milk/TBS for 1.5 hour at RT (catalog A02243-2) |
| Primary antibody | A02243-2 · 0.5 μg/mL (catalog A02243-2) |
| Primary incubation | overnight at 4°C (catalog A02243-2) |
| Secondary antibody | goat anti-rabbit IgG-HRP, 1:5000 (catalog A02243-2) |
| Secondary incubation | 1.5 hour at RT (catalog A02243-2) |
| Wash | TBS-0.1%Tween 3 times with 5 minutes each (catalog A02243-2) |
| Detection | ECL (catalog A02243-2) |
Section 2
What Is the Expected SFPQ Western Blot Band Size?
SFPQ is predicted at 76.1 kDa but observed near 100 kDa on Western blots; the cause of this difference is not established.
| Band near 100 kDa | Empirical SFPQ band; confirm identity with appropriate controls |
| Band near 76.1 kDa | Near the sequence-predicted mass; confirm identity before assigning it to SFPQ |
| Multiple bands | Long and Short isoforms are possible contributors, but their migration is not established |
| Weak band in a cytoplasmic fraction | SFPQ is predominantly associated with the nuclear matrix |
💡Expected SFPQ appearanceUniProt predicts 76.1 kDa, while antibody QC detects SFPQ near 100 kDa under reducing conditions; the cause of the difference is unestablished, so confirm band identity with appropriate controls.
| UniProt predicted molecular weight | 76.1 kDa is the sequence-based reference; the empirical band is near 100 kDa |
| 707-residue reference sequence | Underlies the predicted mass but does not establish apparent migration |
| Long isoform | May migrate differently from Short; no isoform-specific mass is supplied |
| Short isoform | May migrate differently from Long; a resolvable second band is not established |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | Predominant nuclear-matrix association may limit recovery | Check nuclear extraction and a positive-control lysate |
| Band higher than expected | The observed 100 kDa band exceeds the 76.1 kDa prediction for an unestablished reason | Compare with the QC band and confirm identity with an independent antibody or SFPQ depletion |
| Band lower than expected | The Long and Short isoforms have unspecified migration | Confirm identity with SFPQ depletion and an antibody against another epitope |
| Multiple bands | Alternative splicing is documented, but distinct isoform bands are unproven | Use SFPQ depletion or isoform-specific controls to assign bands |
| Weak or no signal | Nuclear-matrix-associated SFPQ may be poorly recovered | Check extraction efficiency, loading, and a positive-control lysate |
| Fragments below expected size | Sample degradation is possible; no fragment mass is supplied | Prepare fresh lysate with protease inhibitors and confirm identity with another epitope |
Experiment evidence
Western blot images showing SFPQ band
A02243-2 · SFPQ
M02243 · SFPQ
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for SFPQ Western blot
🧪HPA-IHC candidate guidance (verify in WB): For positive controls for SFPQ in Western blot, you can use adipose tissue.
Positive control: Adipose tissue (IHC candidate; verify WB)
Negative control: Suggested KO / knockdown lysate
Loading controls: Run GAPDH, β-actin, and a total-protein stain alongside.
⚠️Feasibility: No HPA tissue with undetected SFPQ is listed, so use siRNA knockdown or a KO line as the negative control.
HPA tissue expression evidence for SFPQ
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.
Higher expression tissues · candidate positive controls from IHC
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | adipocytes | High | Protein (IHC) | HPA → |
| Adrenal gland | glandular cells | High | Protein (IHC) | HPA → |
| Appendix | glandular cells | High | Protein (IHC) | HPA → |
| Bone marrow | hematopoietic cells | High | Protein (IHC) | HPA → |
| Breast | glandular cells | High | Protein (IHC) | HPA → |
Lower expression tissues · IHC evidence, not confirmed WB-negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | adipocytes | High | Protein (IHC) | HPA → |
| Adrenal gland | glandular cells | High | Protein (IHC) | HPA → |
| Appendix | glandular cells | High | Protein (IHC) | HPA → |
| Bone marrow | hematopoietic cells | High | Protein (IHC) | HPA → |
| Breast | glandular cells | High | Protein (IHC) | HPA → |
Section 3
Advanced SFPQ Western Blot Tips
Deeper troubleshooting and optimisation questions for SFPQ, answered from its protein features.
How should SFPQ band migration be interpreted?
Band shift · Use the separately labelled calculated mass and catalog-observed evidence above. A sequence annotation does not establish an observed migration shift. Verify target identity with orthogonal controls.
Could SFPQ isoforms produce different bands?
Isoforms · UniProt lists Long and Short isoforms. In Short, residues 663–707 of the Long sequence are replaced by seven residues. This sequence difference could affect band position, but the record does not establish distinct visible bands. Check which isoform your antibody recognizes.
Which phosphorylation sites could guide a targeted blot?
PTM · UniProt lists phosphoserine at positions 8 and 283 by MKNK2, and phosphotyrosine at position 293 by ALK. A site-specific antibody should match the intended residue and numbering convention. These sites alone do not predict a visible band shift.
The listed sites include acetyllysine 208, 319, 338, 421 and 472, plus methylated arginines including 9, 236, 242, 245, 571, 681, 693 and 695. Some modifications are annotated as alternate at the same position. UniProt coordinates are used here; check numbering in antibody documentation. Their presence does not establish the cause of an extra band.
The listed sites include acetyllysine 208, 319, 338, 421 and 472, plus methylated arginines including 9, 236, 242, 245, 571, 681, 693 and 695. Some modifications are annotated as alternate at the same position. UniProt coordinates are used here; check numbering in antibody documentation. Their presence does not establish the cause of an extra band.
Does this guide establish induction of SFPQ?
Induction · No general induction response is established by this guide. A pathway or gene-set association is not evidence of induction in a particular specimen. Verify the relevant treatment and control in a target-specific experiment.
How should transfer be checked for SFPQ?
Transfer · Standard workflow guidance: verify transfer efficiency for the intended target size before interpreting a weak signal. Use total-protein assessment and optimize transfer for the membrane, gel and apparatus; the labelled catalog values take precedence.
How should blocking be optimized?
Blocking · Standard workflow guidance: follow the A02243-2 datasheet where specified. Otherwise compare 5% milk or 5% BSA in TBST; for a phospho-specific assay start with BSA. Optimize background and specific signal with matched controls.
How should SFPQ localization affect quantitation?
Quantitation · SFPQ is predominantly in the nuclear matrix; the record also places it in nuclear speckles and cytoplasm. Compare matched sample fractions and loading controls when quantifying SFPQ. A change in a nuclear fraction alone need not represent a change in total cellular SFPQ.
Why might SFPQ appear near 100 kDa instead of 76.1 kDa?
Interpretation · The supplied record gives a predicted mass of 76.1 kDa and reports an approximately 100 kDa SFPQ subunit in an SFPQ–NONO complex. It does not establish why the observed Western blot band runs near 100 kDa. Use the empirical band position as a guide, and confirm its identity independently.
Check the band near the empirically observed 100 kDa position, then consider the Long and Short isoforms and whether the antibody recognizes both. The listed modifications and SFPQ–NONO association are relevant context, but neither proves the identity or cause of another band. Confirm unexpected bands with an independent specificity check.
Check the band near the empirically observed 100 kDa position, then consider the Long and Short isoforms and whether the antibody recognizes both. The listed modifications and SFPQ–NONO association are relevant context, but neither proves the identity or cause of another band. Confirm unexpected bands with an independent specificity check.
Boster reagents
SFPQ Western Blot Antibodies
Catalog antibodies with Western blot application and product-specific WB images. Evaluate suitability with the reported sample, controls and experimental conditions.
Real WB data
Anti-SFPQ Antibody Picoband®
Cat # A02243-2
Real WB data
Anti-SFPQ Monoclonal Antibody
Cat # M02243
The catalog reports two anti-SFPQ antibodies with Western blot images and stated human, mouse, and rat reactivity. A02243-2 shows a band near 100 kDa, above the stated 76 kDa expectation; M02243 has a brief A431 lysate image caption.
Which to pick: Choose A02243-2 for documented blots in human cell, rat brain and C6, or mouse brain and Neuro-2a lysates, while accounting for the band-size discrepancy. M02243 is the monoclonal option with an A431 lysate blot; its caption gives fewer experimental details.
Source: BosterBio SFPQ gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry P23246.
- Human Protein Atlas. SFPQ tissue expression.
- PMC10419845 — target-verified WB comparison
- PMC5548871 — target-verified WB comparison
- PMC11406446 — target-verified WB comparison