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RBX1 · Western blot design guide
Design a Western Blot for RBX1
Real validated RBX1 Western blot protocols, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-RBX1 WB antibodies. Everything you need to plan the experiment before you commit precious samples.
Last reviewed: May 2026 · Scientific review: Boster Bio technical team
RBX1 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 | ~12.3 kDa | |
| Observed band | Approximately 15 kDa | |
| Gel | 12–15% | |
| Negative control | siRNA / KO lysate |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | Phosphorylated + Acetylated | |
| Caveat | Phosphorylation-induced mobility shift | |
| Regulation | Dna repair | |
| Isoform | 1 isoform(s) |
Section 1
Real Curated RBX1 Western Blot Protocols
Literature-validated Western blot parameters for RBX1 — gel percentage, transfer, blocking, antibody incubation and detection, extracted from published methods.
| Sample / lysate | Rat Testis , Lane 2: Rat Brain , Lane 3: Mouse Brain , Lane 4: Mouse Spleen . 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-ROC1 antigen affinity purified polyclonal antibody (Catalog # PB9798) 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 ROC1 at approximately 15 kDa. The expected band size for ROC1 is at 15 kDa |
| Gel % | 12–15% |
| Load | 50 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 | 15 kDa |
Section 2
What Is the Expected RBX1 Western Blot Band Size?
RBX1 has a 12.3 kDa predicted mass but typically runs near 15 kDa on Western blots, likely due to anomalous SDS-PAGE migration of its compact zinc-finger RING domain.
| single band around 15 kDa | represents the full-length RBX1 monomer, migrating somewhat above its 12.3 kDa predicted mass |
| no higher-mass smeared band | RBX1 has no annotated glycosylation sites, so carbohydrate-driven smearing is not expected |
| no shift in band position under non-reducing conditions | RBX1 has no annotated disulfide bonds, so it does not form a covalent homodimer |
| one band rather than several close-migrating bands | only a single isoform is annotated for RBX1, so isoform-driven multi-banding is not expected |
| band detectable in standard cytoplasmic/whole-cell lysate | RBX1 is cytoplasmic and nuclear, not secreted, so it should be present in routine lysates rather than absent from them |
| band running noticeably above the 12.3 kDa predicted mass | the compact, zinc-coordinated RING domain of RBX1 favors anomalous, slower-than-predicted migration on SDS-PAGE |
💡Expected RBX1 appearanceExpect a single sharp RBX1 band at approximately 15 kDa, slightly above its 12.3 kDa predicted mass due to anomalous migration of this compact zinc-finger protein, with no glycosylation-related smearing, disulfide-linked dimer, or isoform-related extra bands.
| predicted mass (12.3 kDa) | sets the theoretical baseline, but the actual monomer typically runs somewhat higher, near 15 kDa |
| RING-type zinc-finger / metal-binding domain | compact zinc-coordinated folds resist full unfolding in SDS-PAGE and commonly cause slower-than-predicted migration, contributing to the ~15 kDa apparent size |
| N-terminal acetylation and processing (Met1/Ala2) | adds negligible mass but marks the mature processed N-terminus of the monomer |
| phosphorylation at Thr9 | adds negligible mass but can slightly alter charge-driven mobility |
| absence of glycosylation sites | rules out any smearing or upward mass shift from carbohydrate addition |
| absence of disulfide bonds | means RBX1 runs as a monomer rather than doubling in size as a covalent homodimer under non-reducing conditions |
| single annotated isoform | means only one specific band is expected, not multiple isoform-driven bands |
| non-covalent SCF complex membership (CUL1-SKP1-RBX1-F-box) | the complex dissociates under denaturing/reducing SDS-PAGE, so only the free ~15 kDa RBX1 monomer band should appear rather than a higher-mass complex band |
| Situation | Likely cause | Next action |
|---|---|---|
| Band higher than expected | the compact zinc-finger RING domain retains residual structure and migrates anomalously slower than its predicted mass | increase reducing agent and heat-denaturation time, and run a known RBX1 standard alongside for comparison |
| Band lower than expected | the very small predicted size (12.3 kDa) can run off standard gels or transfer through the membrane before proper resolution | use a higher-percentage gel (15-18%) or a low-molecular-weight-optimized system and shorten transfer time |
| Weak or no signal | small proteins like RBX1 can blow through the membrane during standard transfer conditions | reduce transfer voltage or time, use a low pore-size PVDF membrane, and confirm against a positive control lysate |
| Multiple bands | cross-reactivity with other RING/zinc-finger subunits of the SCF complex or incomplete dissociation of RBX1 from CUL1/SKP1 | verify specificity with an RBX1 knockdown lysate and ensure complete denaturation with SDS and heat before loading |
| Fragments below expected size | as a small single-domain protein, RBX1 is susceptible to proteolytic degradation during lysate handling | prepare lysates fresh with protease inhibitors and keep samples cold throughout processing |
| No band in lysate | insufficient loading or antibody sensitivity for a low-abundance, low-molecular-weight regulatory subunit | increase total protein loaded, use a high-sensitivity chemiluminescent substrate, and confirm with a cell line known to express RBX1 |
Experiment evidence
Western blot images showing RBX1 band
PB9798 · RBX1
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for RBX1 Western blot
🧪For positive controls for RBX1 in Western blot, you can use HeLa cell lysate, since RBX1 is a ubiquitously expressed core subunit of SCF E3 ubiquitin ligase complexes found in essentially all cultured cell lines.
Positive control: HeLa cells
Negative control: ubiquitously expressed; use siRNA knockdown or KO line
Loading controls: Run GAPDH and β-actin antibodies alongside a total-protein stain (e.g., stain-free gel, Ponceau S, or REVERT) as loading controls.
⚠️Feasibility: As an essential, ubiquitously expressed cytoplasmic/nuclear protein, RBX1 has no naturally negative tissue, so a true negative control requires siRNA knockdown or a CRISPR knockout line rather than a tissue lacking expression.
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 RBX1 Western Blot Tips
Deeper troubleshooting and optimisation questions for RBX1, answered from its protein features.
Why does RBX1 run at ~15 kDa instead of 12.3 kDa?
The 12.3 kDa value is the unmodified sequence mass. RBX1 carries three modified residues (phosphorylation, acetylation) and a zinc-coordinating finger motif, both of which can retard migration on SDS-PAGE. This commonly shifts the apparent band to around 15 kDa, a modest and expected offset rather than evidence of a problem.
Does RBX1 have isoforms that complicate blot interpretation?
UniProt lists only one RBX1 isoform, so multiple isoform-specific bands are not expected. A single band near 12-15 kDa is the norm; any additional bands more likely reflect residual complex association, degradation, or nonspecific binding rather than isoform variation.
Is RBX1 signal linked to DNA damage response activity?
RBX1 carries DNA damage and DNA repair annotations as a core subunit of SCF-type ubiquitin ligase complexes that target DNA damage response substrates for degradation. RBX1 protein levels are typically stable, but complex assembly with CUL1 and SKP1 can change with pathway activation, so co-migrating higher-order bands may vary by treatment.
How should blocking be optimized for this small zinc-finger protein?
RBX1 is small (12.3 kDa) and depends on a zinc-binding motif for its folded state. Use standard 5% non-fat milk or BSA in TBST, and avoid strongly acidic or chelating wash conditions that could disrupt metal coordination and affect antibody recognition of the native epitope.
What transfer method to use for RBX1 Western blot?
Given RBX1's small size (~12-15 kDa observed), use semi-dry or wet transfer onto 0.2 um pore PVDF or nitrocellulose, with reduced transfer time and lower methanol content in the buffer to prevent the small protein from passing through the membrane during blotting.
What loading control pairs well with RBX1 quantitation?
Because RBX1 is low molecular weight and localizes to both cytoplasm and nucleus, resolve it on a 12-15% gel to separate it clearly from common loading controls like GAPDH or beta-actin, preventing comigration and ensuring accurate densitometric quantitation of the RBX1 band.
What explains higher-molecular-weight bands above the RBX1 monomer?
RBX1 is a stable subunit of multiple Cul1-RING SCF ubiquitin ligase complexes formed with CUL1, SKP1, and a variable F-box protein. Incomplete denaturation can leave residual complex association, producing higher-molecular-weight bands; ensure thorough boiling in reducing SDS sample buffer to fully dissociate these interactions before loading.
Boster reagents
Best RBX1 Western Blot Antibodies
BosterBio's RBX1 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-ROC1/RBX1 Antibody Picoband®
Cat # PB9798
The anti-RBX1 antibodies below represent our top-performing picks for Western blot, selected for strong literature citation, rigorous in-house validation, and cross-validation against negative-control tissues and orthogonal methods—giving you confident, reproducible detection of RBX1 in your samples.
Which to pick: Only one Boster RBX1 antibody is catalogued, PB9798, which includes an actual Western blot validation image confirming specific detection—making it the clear default choice for your RBX1 WB experiments; no alternative SKUs are available to compare against.
Source: BosterBio RBX1 gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry P62877.
- Human Protein Atlas. RBX1 tissue expression.