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ATF3 / Cyclic AMP-dependent transcription factor ATF-3 · Western blot design guide
Design a Western Blot for ATF3
Real validated ATF3 Western blot protocols, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-ATF3 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
ATF3 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 | ~20.6 kDa | |
| Gel | 12–15% (standard starting point) | |
| Positive control | Fallopian tube (IHC candidate; verify WB) +4 more | |
| Negative control | Esophagus (IHC candidate; verify WB) |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | Phosphorylated + Ubl conjugation | |
| Caveat | Modification-state controls | |
| Gene-set association | MSigDB Hallmark membership | |
| Isoform | 5 isoform(s) |
Section 1
Real Curated ATF3 Western Blot Protocols
The A00904-2 protocol combines labelled catalog values with standard starting conditions. Published comparisons retain their own sample, reagent and detection scope.
| Sample / lysate | 293T-UV cells (catalog A00904-2) |
| Gel % | 12–15% (standard starting point) |
| Load | 20–30 µg total protein per lane; optimize for abundance (standard starting point) |
| Transfer | Short semi-dry transfer; verify retention (standard starting point) |
| Membrane | 0.45 µm PVDF (standard starting point) |
| Blocking | 5% milk or 5% BSA in TBST (standard starting point) |
| Primary antibody | A00904-2 · 1:500 (catalog A00904-2) |
| Primary incubation | Overnight at 4 °C (standard starting point) |
| Secondary antibody | Species-matched HRP conjugate at validated dilution (standard starting point) |
| Secondary incubation | 1 h at room temperature (standard starting point) |
| Wash | 3 × 5 min in TBST (standard starting point) |
| Detection | ECL; bracket exposures to avoid saturation (standard starting point) |
Section 2
What Is the Expected ATF3 Western Blot Band Size?
ATF3 has a predicted monomer mass of 20.6 kDa; isoforms and homodimerization could affect bands, but their migration effects are unproven.
| Band near 20.6 kDa | consistent with the predicted ATF3 monomer; confirm its identity with controls |
| Band near 41 kDa | could reflect a homodimer if it survives sample denaturation |
| Several bands at different positions | could reflect isoforms 1, 2, 3, 4, and 5; their migration is not established |
| Stronger band in nuclear than cytoplasmic extract | consistent with ATF3 nuclear localization |
💡Expected ATF3 appearanceUniProt predicts a 20.6 kDa ATF3 monomer; no empirical band size is supplied, so confirm any band near that position with antibody and sample controls.
| Predicted monomer mass | sets a 20.6 kDa reference, not a measured migration position |
| Homodimer formation | could produce a band near twice the monomer mass if the dimer survives sample denaturation |
| Splice isoforms 1 and 2 | may differ in size; individual masses and migration are not supplied |
| Splice isoforms 3, 4, and 5 | may differ in size; individual masses and migration are not supplied |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | ATF3 is nuclear and may be scarce in the sampled lysate | check a nuclear extract and a positive control |
| Band higher than expected | a homodimer may persist through sample preparation | compare thoroughly denatured samples and verify band identity |
| Band lower than expected | a splice isoform is possible, but its size is unknown | compare antibodies targeting different regions and verify band identity |
| Multiple bands | ATF3 has five named splice isoforms, though distinct migration is unproven | compare isoform coverage of antibody epitopes and use a specificity control |
| Weak or no signal | the nuclear target may be diluted in whole-cell lysate | enrich the nuclear fraction and include a positive control |
Experiment evidence
Western blot images showing ATF3 band
A00904-2 · ATF3
A00904-2 · ATF3
A00904-1 · ATF3
A00904-1 · ATF3
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for ATF3 Western blot
🧪HPA-IHC candidate guidance (verify in WB): For positive controls for ATF3 in Western blot, you can use Fallopian tube tissue, which has high HPA expression.
Positive control: Fallopian tube (IHC candidate; verify WB)
Negative control: Esophagus (IHC candidate; verify WB)
Loading controls: Run GAPDH, β-actin, and a total-protein stain such as Ponceau alongside the samples.
⚠️Feasibility: ATF3 is nuclear, so nuclear-enriched extracts may improve detection.
HPA tissue expression evidence for ATF3
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 |
|---|---|---|---|---|
| Fallopian tube | ciliated cells (tip of cilia) | High | Protein (IHC) | HPA → |
| Appendix | glandular cells | Medium | Protein (IHC) | HPA → |
| Bone marrow | hematopoietic cells | Medium | Protein (IHC) | HPA → |
| Bronchus | ciliated cells (cell body) | Medium | Protein (IHC) | HPA → |
| Caudate | neuronal cells | Medium | Protein (IHC) | HPA → |
Lower expression tissues · IHC evidence, not confirmed WB-negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Esophagus | squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
| Heart muscle | cardiomyocytes | Not detected | Protein (IHC) | HPA → |
| Lymph node | non-germinal center cells | Not detected | Protein (IHC) | HPA → |
| Ovary | ovarian stroma cells | Not detected | Protein (IHC) | HPA → |
| Skeletal muscle | myocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced ATF3 Western Blot Tips
Deeper troubleshooting and optimisation questions for ATF3, answered from its protein features.
How should ATF3 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.
How could ATF3 isoforms affect Western blot bands?
Isoforms · UniProt lists five isoforms. Isoform 5 lacks canonical residues 1–57; isoform 4 lacks 14–42. Isoform 2 replaces 116–181, while isoforms 3 and 4 replace 117–181. Check whether the antibody recognizes a region retained in the isoform of interest before assigning bands.
Specify whether the measurement represents one isoform or all recognized isoforms. The five listed isoforms differ substantially in sequence, so antibody recognition may vary. Quantify only bands whose identity and antibody coverage have been established, and use the same band definition across samples.
Specify whether the measurement represents one isoform or all recognized isoforms. The five listed isoforms differ substantially in sequence, so antibody recognition may vary. Quantify only bands whose identity and antibody coverage have been established, and use the same band definition across samples.
Which ATF3 phosphorylation site matters for blot interpretation?
PTM · UniProt lists phosphothreonine at position 162 in canonical ATF3 numbering. That region is replaced in isoforms 2, 3, and 4, so do not assume a phospho-Thr162 antibody detects them. Confirm the antibody's numbering convention and target sequence; the site alone does not establish a visible band shift.
Does this guide establish induction of ATF3?
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.
What transfer method to use for ATF3 Western blot?
Transfer · ATF3 is predicted to be 20.6 kDa. Choose and verify a transfer setup that retains proteins of this size. The supplied features do not identify a specific membrane or transfer method as best.
How should blocking be optimized?
Blocking · Standard workflow guidance: follow the A00904-2 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 ATF3 be quantified?
Quantitation · Standard workflow guidance: quantify only a validated target band within the linear exposure range. Use consistent sample preparation and loading, retain biological replicates, and avoid interpreting saturation or loading differences as regulation.
Should ATF3 run exactly at its predicted 20.6 kDa?
Interpretation · 20.6 kDa is the predicted mass for canonical ATF3. No observed band position is supplied. Its sequence variants and phosphothreonine site are reasons to investigate a different apparent position, but their presence does not establish a visible shift or explain a particular mass difference.
ATF3 binds DNA as a homodimer or heterodimer, but this does not establish that oligomers persist on a Western blot. Evaluate unexpected bands against the listed isoform sequences and antibody recognition before assigning them to ATF3 oligomers.
UniProt places ATF3 in the nucleus. Include nuclear protein when preparing samples, and keep the sampled fraction consistent across comparisons. A weak band in a fraction lacking nuclear material would not by itself establish low total ATF3 abundance.
ATF3 binds DNA as a homodimer or heterodimer, but this does not establish that oligomers persist on a Western blot. Evaluate unexpected bands against the listed isoform sequences and antibody recognition before assigning them to ATF3 oligomers.
UniProt places ATF3 in the nucleus. Include nuclear protein when preparing samples, and keep the sampled fraction consistent across comparisons. A weak band in a fraction lacking nuclear material would not by itself establish low total ATF3 abundance.
Boster reagents
ATF3 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-ATF-3 Antibody
Cat # A00904-2
Real WB data
Anti-ATF3 (N159) Antibody
Cat # A00904-1
Two the supplier anti-ATF3 antibodies have WB images: A00904-2 in 293T-UV nuclear extract and A00904-1 in four whole-cell lysates. Both captions report 1:500 dilution. These examples do not establish WB performance across every listed reactive species.
Which to pick: For mouse samples, choose A00904-2, the only SKU listing mouse reactivity. For human or rat samples, both list reactivity; A00904-2 shows a nuclear-extract WB, while A00904-1 shows whole-cell lysate WBs. Match the example to your sample preparation.
Source: BosterBio ATF3 gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry P18847.
- Human Protein Atlas. ATF3 tissue expression.
- PMC11494902 — target-verified WB comparison
- PMC8583784 — target-verified WB comparison
- PMC7734065 — target-verified WB comparison