This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
S100A1 / Protein S100-A1 · Western blot design guide
Design a Western Blot for S100A1
Source-linked S100A1 Western blot protocol options, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-S100A1 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
S100A1 Western Blot Experimental Design Guide
Expected bands, source-linked protocol options, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before running
| Expected band | ~10.5 kDa | |
| Gel | 15% (standard starting point) | |
| Positive control | Appendix (IHC candidate; verify WB) +4 more | |
| Negative control | Adrenal gland (IHC candidate; verify WB) |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | — | |
| Caveat | Modification-state controls | |
| Gene-set association | MSigDB Hallmark membership | |
| Isoform | 1 isoform(s) |
Section 1
Source-Linked S100A1 Western Blot Protocol Options
The M02503-1 protocol combines labelled catalog values with standard starting conditions. Published comparisons retain their own sample, reagent and detection scope.
| Sample / lysate | (1) Human skeletal muscle lysate; (2) RAW 264.7 cell lysate (catalog M02503-1) |
| Gel % | 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 | 0.2 µm PVDF (standard starting point) |
| Blocking | 5% milk or 5% BSA in TBST (standard starting point) |
| Primary antibody | M02503-1; use the WB datasheet starting dilution (standard starting point) |
| 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 S100A1 Western Blot Band Size?
S100A1 has a predicted 10.5 kDa monomer; its listed dimers and Cys86 modification could affect a blot, but altered migration is not demonstrated.
| Band near 10.5 kDa | Consistent with the predicted S100A1 monomer; confirm identity with a positive control. |
| Band near 21 kDa | Could reflect an alpha-chain homodimer if the complex persists during electrophoresis. |
| Bands near 10.5 and 21 kDa | Could reflect monomer alongside retained homodimer. |
| Band near 10.5 kDa without a resolved shift | Cys86 S-nitrosylation need not produce a visible mobility change. |
💡Expected S100A1 appearanceUniProt predicts a 10.5 kDa S100A1 monomer, but no empirical band size is supplied; use a positive control to assess band identity, and interpret any higher band cautiously because dimer retention during electrophoresis is unestablished.
| Predicted S100A1 monomer mass | Provides a 10.5 kDa reference, not a measured migration position. |
| Alpha-chain homodimer | Could appear near twice the monomer mass if retained during electrophoresis. |
| Alpha–beta dimer | Could alter apparent size if the mixed complex is retained; its band position is unknown. |
| S100P heterodimer | Could alter apparent size if retained; its band position is unknown. |
| Cys86 S-nitrosylation | Has no demonstrated visible band-size effect in the supplied evidence. |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | S100A1 may be below detection in the tested lysate. | Check a known S100A1-positive lysate and sample loading. |
| Band higher than expected | An S100A1-containing dimer may persist during electrophoresis. | Compare denaturing conditions and confirm identity with a positive control. |
| Band lower than expected | Identity of the smaller band is unestablished. | Compare a positive control and an independent antibody. |
| Multiple bands | Monomer and retained S100A1-containing dimers are possible. | Compare denaturing conditions and verify each band with an independent antibody. |
| Weak or no signal | The tested sample may contain little detectable S100A1. | Verify loading and antibody performance with a positive control. |
| Fragments below expected size | Sample proteolysis is possible; no physiological cleavage is listed. | Prepare fresh lysate with protease inhibitors and check band identity. |
Experiment evidence
Western blot images showing S100A1 band
M02503-1 · S100A1
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for S100A1 Western blot
🧪HPA-IHC candidate guidance (verify in WB): For positive controls for S100A1 in Western blot, you can use appendix tissue lysate, which HPA scores High.
Positive control: Appendix (IHC candidate; verify WB)
Negative control: Adrenal gland (IHC candidate; verify WB)
Loading controls: Run GAPDH, β-actin, and a total-protein stain such as Ponceau alongside the samples.
⚠️Feasibility: S100A1 is intracellular, and HPA identifies both a high-expression tissue and a tissue where it is not detected.
HPA tissue expression evidence for S100A1
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 |
|---|---|---|---|---|
| Appendix | endocrine cells | High | Protein (IHC) | HPA → |
| Cerebellum | granular cells - cytoplasm/membrane | High | Protein (IHC) | HPA → |
| Duodenum | endocrine cells | High | Protein (IHC) | HPA → |
| Heart muscle | cardiomyocytes | High | Protein (IHC) | HPA → |
| Rectum | endocrine cells | High | Protein (IHC) | HPA → |
Lower expression tissues · IHC evidence, not confirmed WB-negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Bronchus | respiratory epithelial cells | Not detected | Protein (IHC) | HPA → |
| Cervix | glandular cells | Not detected | Protein (IHC) | HPA → |
| Esophagus | squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced S100A1 Western Blot Tips
Deeper troubleshooting and optimisation questions for S100A1, answered from its protein features.
How should S100A1 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 an S100A1 isoform explain a second band?
Isoforms · The supplied record lists one isoform and no alternative sequence. It provides no isoform-based explanation for a second band.
Which S100A1 modification is relevant to band interpretation?
PTM · UniProt lists S-nitrosocysteine at position 86, using UniProt sequence numbering. This feature alone does not establish a visible band shift or explain a difference from the predicted mass.
Does this guide establish induction of S100A1?
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 S100A1 Western blot?
Transfer · S100A1 is small, with a predicted mass of 10.5 kDa. Choose transfer conditions validated for retaining proteins near that size, and verify retention on the membrane. The supplied features do not specify a particular membrane or transfer protocol.
How should blocking be optimized?
Blocking · Standard workflow guidance: follow the M02503-1 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 S100A1 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 S100A1 run at exactly 10.5 kDa?
Interpretation · 10.5 kDa is the predicted mass, not a measured Western-blot position. No observed band is supplied, so use it as an approximate reference rather than an exact migration target.
S100A1 is reported in the cytoplasm and sarcoplasmic reticulum, with mitochondrial localization also listed. Record which fraction was loaded and compare like fractions when quantifying signal; a change in fraction can change what the blot samples.
The record describes dimers and heterodimers with S100P. These interactions make a complex a possibility to investigate, but they do not establish that a higher Western-blot band is a dimer or specify its apparent mass.
The supplied features list no signal peptide or propeptide for the 94-residue sequence. They therefore provide no cleavage-based explanation for a lower band; its identity would need separate verification.
S100A1 is reported in the cytoplasm and sarcoplasmic reticulum, with mitochondrial localization also listed. Record which fraction was loaded and compare like fractions when quantifying signal; a change in fraction can change what the blot samples.
The record describes dimers and heterodimers with S100P. These interactions make a complex a possibility to investigate, but they do not establish that a higher Western-blot band is a dimer or specify its apparent mass.
The supplied features list no signal peptide or propeptide for the 94-residue sequence. They therefore provide no cleavage-based explanation for a lower band; its identity would need separate verification.
Boster reagents
S100A1 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-S100 S100A1 Rabbit Monoclonal Antibody
Cat # M02503-1
The catalog reports one anti-S100A1 antibody for Western blot, M02503-1, with reported human and mouse reactivity. Its WB image shows human skeletal muscle and RAW 264.7 cell lysates; these examples do not establish performance across all tissues or samples.
Which to pick: M02503-1 is the only listed option. Its WB image uses human skeletal muscle and RAW 264.7 lysates, so compare your sample with those tested contexts and the reported human and mouse reactivity.
Source: BosterBio S100A1 gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry P23297.
- Human Protein Atlas. S100A1 tissue expression.
- PMC9827259 — target-verified WB comparison
- PMC13579085 — target-verified WB comparison
- PMC6017223 — target-verified WB comparison