This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
GADD45A · Western blot design guide
Design a Western Blot for GADD45A
Real validated GADD45A Western blot protocols, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-GADD45A WB antibodies. Everything you need to plan the experiment before you commit precious samples.
Last reviewed: May 2026 · Scientific review: Boster Bio technical team
GADD45A 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 | ~18.3 kDa | |
| Observed band | ~19 kDa | |
| Gel | 12–15% | |
| Negative control | siRNA / KO lysate |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | Phosphorylated | |
| Caveat | Phosphorylation-induced shift | |
| Regulation | TNFα up | |
| Isoform | 2 isoform(s) |
Section 1
Real Curated GADD45A Western Blot Protocols
Literature-validated Western blot parameters for GADD45A — gel percentage, transfer, blocking, antibody incubation and detection, extracted from published methods.
| Sample / lysate | MCF-7 . After electrophoresis, proteins were transferred to a nitrocellulose membrane at 150 mA for 50-90 minutes. Blocked the membrane with 5% non-fat milk/TBS for 1.5 hour at RT. The membrane was incubated with rabbit anti-GADD45A antigen affinity purified polyclonal antibody (Catalog # PB9945) at 0.5 μg/mL overnight at 4°C, then washed with TBS-0.1%Tween 3 times with 5 minutes each and probed with a goat anti-rabbit IgG-HRP secondary antibody at a dilution of 1:5000 for 1.5 hour at RT. The signal is developed using an Enhanced Chemiluminescent detection (ECL) kit (Catalog # EK1002) with Tanon 5200 system. A specific band was detected for GADD45A at approximately 19 kDa. The expected band size for GADD45A is at 18 kDa |
| Gel % | 12–15% |
| Load | 30 ug |
| Transfer | nitrocellulose membrane, 150 mA, 50–90 min |
| Membrane | nitrocellulose |
| Blocking | 5% non-fat milk / TBS, 1.5 h RT |
| Primary antibody | 0.5 µg/mL |
| Primary incubation | overnight at 4 °C |
| Secondary antibody | goat anti-rabbit IgG-HRP, 1:5000 |
| Wash | TBS-0.1% Tween, 3 × 5 min |
| Detection | ECL |
| Exposure / imaging | Tanon 5200 |
| Observed band | 19 kDa |
Section 2
What Is the Expected GADD45A Western Blot Band Size?
GADD45A has an 18.3 kDa predicted monomer backbone but runs at ~19 kDa on Western blots, likely reflecting its N-terminal phosphorylation and modest self-association tendency.
| Single band at ~19 kDa | Matches the empirical apparent mass for monomeric GADD45A, close to the 18.3 kDa predicted mass |
| Sharp, non-smeared band | GADD45A has no glycosylation sites, so no heterogeneous glycoform smearing is expected |
| Faint higher-mass band near double the monomer size | Reflects self-association into dimers or higher-order oligomers, which increases with protein concentration and can persist if reduction is incomplete |
| Doublet or two closely spaced bands | Consistent with expression of the two annotated splice isoforms (isoform 1 and isoform 2) |
| Band detected in unfractionated whole-cell lysate | GADD45A is nuclear rather than secreted, so it is retained intracellularly and readily detected without needing extracellular fractionation |
💡Expected GADD45A appearanceExpect a single sharp band at approximately 19 kDa, close to the 18.3 kDa predicted monomer mass, since GADD45A has no glycosylation, signal peptide, or propeptide cleavage to shift its size.
| Predicted monomer mass (18.3 kDa) | sets the baseline single-band position, closely matching the ~19 kDa empirically observed band |
| N-terminal phosphothreonine (Thr2) | can cause a slight upward mobility shift, contributing to migration a little above the unmodified predicted mass |
| Dimer/oligomer self-association | produces a faint higher apparent-mass band at roughly double the monomer size at higher protein concentrations or with incomplete reduction |
| Two annotated splice isoforms (isoform 1 and isoform 2) | can yield an additional band at a different apparent size depending on which isoform is expressed, without a defined per-isoform mass |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | GADD45A is DNA-damage/growth-arrest inducible, so basal nuclear levels can be very low in untreated, unstressed cells | Treat cells with a genotoxic or growth-arrest stimulus as a positive control and enrich for nuclear protein before loading |
| Band higher than expected | GADD45A can self-associate into dimers and higher-order oligomers as concentration increases, and incomplete reduction can preserve these species on the gel | Increase reducing agent concentration and fully denature the sample before loading to resolve the monomer near 19 kDa |
| Multiple bands | Two annotated splice isoforms can be co-expressed at different apparent masses | Confirm isoform identity against known isoform sequence or epitope mapping rather than assuming nonspecific binding |
| Weak or no signal | As a stress-inducible protein, GADD45A expression is often low under normal growth conditions | Increase total protein loaded and/or induce expression with a DNA-damage or growth-arrest stimulus before harvest |
| Fragments below expected size | GADD45A has no annotated signal peptide or propeptide, so smaller bands are not a natural cleaved form and likely reflect proteolytic degradation during lysis | Use fresh lysate with protease inhibitors and keep samples cold throughout preparation |
| Broad smear instead of sharp band | GADD45A lacks glycosylation sites, so a diffuse smear is not expected from glycoform heterogeneity and more likely reflects overloading or aggregation | Reduce the amount of protein loaded per lane and avoid overheating the sample, which can promote aggregation |
Experiment evidence
Western blot images showing GADD45A band
PB9945 · GADD45A
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for GADD45A Western blot
🧪For positive controls for GADD45A in Western blot, you can use lysate from cells exposed to a genotoxic stress, such as UV- or etoposide-treated HeLa cells, since GADD45A is a stress-inducible nuclear protein whose expression rises sharply upon DNA damage.
Positive control: UV- or etoposide-treated HeLa cells
Negative control: ubiquitously expressed; use siRNA knockdown or KO line
Loading controls: Run GAPDH and β-actin as loading controls alongside a total-protein stain such as Ponceau S, stain-free gel, or REVERT.
⚠️Feasibility: As a nuclear, DNA damage-inducible protein with no HPA tissue expression data available, basal levels in untreated lysates may be low, so a genotoxic-stress induction (e.g., UV or etoposide) is needed for a strong positive signal, and siRNA knockdown or a KO line should be used as the negative control since no confirmed not-detected tissue exists.
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
| Tissue | Cell type | Level | Evidence | Source |
|---|
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|
Section 3
Advanced GADD45A Western Blot Tips
Deeper troubleshooting and optimisation questions for GADD45A, answered from its protein features.
Why does GADD45A run close to its predicted 18.3 kDa mass?
GADD45A has no signal peptide, propeptide, glycosylation, or disulfide bonds, so its native sequence closely determines migration. The single reported modification site adds negligible mass, explaining why the observed ~19 kDa band sits near the 18.3 kDa predicted mass with only a minor SDS-PAGE shift.
Could a second isoform produce an extra GADD45A band?
GADD45A has two annotated isoforms (1 and 2) from alternative splicing. An antibody raised against a shared region may detect both, appearing as a closely spaced doublet near 18-19 kDa; confirm which isoform the antibody epitope maps to before interpreting extra bands as nonspecific.
When should GADD45A expression be strongly induced?
GADD45A is a DNA-damage- and growth-arrest-inducible gene, so expression rises after genotoxic stress (e.g., UV or DNA-damaging treatment) that triggers cell-cycle arrest. Use untreated versus stressed lysates as negative/positive controls, since basal nuclear expression can be low in unstressed, cycling cells.
Does phosphorylation affect the GADD45A Western blot pattern?
GADD45A carries one reported modified residue and is annotated as a phosphoprotein. Phosphorylation is unlikely to cause a large mobility shift given the protein's small size, but phosphatase treatment or phospho-specific antibodies can be used to confirm whether closely spaced bands reflect phosphorylation states.
What blocking approach suits nuclear GADD45A detection?
GADD45A is a small, non-glycosylated nuclear protein, so standard BSA or milk blocking is usually sufficient without special glycoprotein blocking steps. Because it is low abundance and nuclear, use nuclear-enriched lysates and confirm loading with a nuclear marker rather than a cytoplasmic housekeeping protein.
What transfer method to use for GADD45A Western blot?
Because GADD45A is only 18.3 kDa, use a low-percentage or gradient gel with a low molecular weight transfer protocol: shorter transfer time, lower voltage, and a 0.2 µm PVDF or nitrocellulose membrane to prevent the small protein from blowing through during transfer.
How should oligomerization be handled for GADD45A quantitation?
GADD45A is predominantly monomeric but forms dimers and higher oligomers as concentration increases. Ensure complete reduction and denaturation (fresh reducing agent, full boiling) so quantitation reflects the monomeric ~18-19 kDa band rather than a mix of monomer and self-associated species.
What explains higher molecular weight GADD45A bands?
GADD45A interacts with MAPK14, GADD45GIP1, and weakly with PCNA, and can self-oligomerize. Incomplete lysis or denaturation may retain these complexes, producing higher molecular weight bands above 19 kDa; confirm identity by boiling samples longer or adding fresh reducing/denaturing agent before re-running.
Boster reagents
Best GADD45A Western Blot Antibodies
BosterBio's GADD45A antibodies are among the best-performing WB antibodies on the market — well cited, thoroughly validated, and orthogonally cross-validated against negative tissues and complementary methods.
Real WB data
Anti-GADD45A Antibody Picoband®
Cat # PB9945
For GADD45A Western blotting we recommend Boster's anti-GADD45A antibody (PB9945), a best-performing, well-cited reagent that has been thoroughly validated, including a documented SDS-PAGE/WB image and orthogonal cross-validation against negative tissue and complementary detection methods for confident, reproducible results.
Which to pick: Only one Boster anti-GADD45A antibody is catalogued, PB9945, so it is the clear choice. It includes an actual validated Western blot image showing specific GADD45A detection, giving direct evidence of its performance before you order.
Source: BosterBio GADD45A gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry P24522.
- Human Protein Atlas. GADD45A tissue expression.