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- Table of Contents
FBN2 / Fibrillin-2 · Western blot design guide
Design a Western Blot for FBN2
Source-linked FBN2 Western blot protocol options, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-FBN2 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
FBN2 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 | ~314.8 kDa | |
| Observed band | ~315 and 250 kDa | |
| Gel | 5–20% (catalog A03408-2) | |
| Positive control | Placenta (IHC candidate; verify WB) | |
| Negative control | Adipose tissue (IHC candidate; verify WB) |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | Glycosylated + Cleaved | |
| Caveat | Processing-state controls | |
| Gene-set association | MSigDB Hallmark membership | |
| Isoform | 2 isoform(s) |
Section 1
Source-Linked FBN2 Western Blot Protocol Options
The A03408-2 protocol combines labelled catalog values with standard starting conditions. Published comparisons retain their own sample, reagent and detection scope.
| Sample / lysate | human placenta, human U20S (catalog A03408-2) |
| Gel % | 5–20% (catalog A03408-2) |
| Load | 30 ug; reducing conditions (catalog A03408-2) |
| Transfer | a nitrocellulose membrane at 150 mA for 50-90 minutes (catalog A03408-2) |
| Membrane | nitrocellulose membrane (catalog A03408-2) |
| Blocking | 5% non-fat milk/TBS for 1.5 hour at RT (catalog A03408-2) |
| Primary antibody | A03408-2 · 0.5 μg/mL (catalog A03408-2) |
| Primary incubation | overnight at 4°C (catalog A03408-2) |
| Secondary antibody | goat anti-rabbit IgG-HRP, 1:5000 (catalog A03408-2) |
| Secondary incubation | 1.5 hour at RT (catalog A03408-2) |
| Wash | TBS-0.1%Tween 3 times with 5 minutes each (catalog A03408-2) |
| Detection | ECL (catalog A03408-2) |
Section 2
What Is the Expected FBN2 Western Blot Band Size?
FBN2 has a predicted precursor mass of 314.8 kDa and reported bands near 315 and 250 kDa; the cause of the 250 kDa band is not established.
| Band near 315 kDa | Matches the reported band near the 314.8 kDa predicted precursor mass; identity still needs confirmation. |
| Band near 250 kDa | Reported empirically, but its identity and size difference are not established. |
| Band below the precursor | Could reflect signal peptide or propeptide cleavage; its migration is not established. |
| Little or no band in whole-cell lysate | Fibrillin-2 is secreted. |
| Multiple bands | Isoforms 1 and 2 or processing are possible explanations; distinct isoform migration is unestablished. |
💡Expected FBN2 appearanceUniProt predicts a 314.8 kDa precursor; antibody QC reports bands near 315 and 250 kDa, but the 250 kDa band's identity and cause require band-identity controls.
| Predicted precursor mass | UniProt predicts 314.8 kDa; antibody QC reports bands near 315 and 250 kDa without establishing the lower band's identity. |
| N-linked glycosylation at Asn492 | May affect apparent size, but the site alone does not establish a visible shift. |
| O-linked glucose at Ser298 | A single glucose at this site does not establish a visible shift or smear. |
| Signal peptide and propeptide cleavage | Removal of residues 1–28 and 29–77 yields a smaller product, without an established apparent mass. |
| Splice isoforms 1 and 2 | May differ in size; their masses and distinct migration are not supplied. |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | Fibrillin-2 is secreted. | Check conditioned medium and extracellular material alongside lysate. |
| Band higher than expected | N-linked glycosylation is possible, but its migration effect is unproven. | Compare treated and untreated samples and confirm identity with an independent antibody. |
| Band lower than expected | Processing is possible, but the reported 250 kDa band's identity is unresolved. | Compare antibodies recognizing different regions and check the band's identity. |
| Multiple bands | Isoforms or processing are possible; neither explains the reported pattern conclusively. | Check both bands with an independent antibody and compare lysate with conditioned medium. |
| Fragments below expected size | Furin separates the secreted Fibrillin-2 and Placensin chains; fragment masses are not supplied. | Probe with antibodies against different regions and compare lysate with conditioned medium. |
Experiment evidence
Western blot images showing FBN2 band
A03408-2 · FBN2
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for FBN2 Western blot
🧪HPA-IHC candidate guidance (verify in WB): For positive controls for FBN2 in Western blot, you can use placenta tissue.
Positive control: Placenta (IHC candidate; verify WB)
Negative control: Adipose tissue (IHC candidate; verify WB)
Loading controls: Run GAPDH, β-actin, and a total-protein stain alongside the samples.
⚠️Feasibility: Because FBN2 is secreted, whole-cell lysate may give a weak signal; consider conditioned medium.
HPA tissue expression evidence for FBN2
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 |
|---|---|---|---|---|
| Placenta | cytotrophoblasts | Medium | Protein (IHC) | HPA → |
Lower expression tissues · IHC evidence, not confirmed WB-negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | adipocytes | Not detected | Protein (IHC) | HPA → |
| Adrenal gland | glandular cells | Not detected | Protein (IHC) | HPA → |
| Appendix | glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced FBN2 Western Blot Tips
Deeper troubleshooting and optimisation questions for FBN2, answered from its protein features.
How should FBN2 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 FBN2 isoforms produce different bands?
Isoforms · UniProt lists two isoforms. Relative to isoform 1, isoform 2 lacks residues 113–145 and 1507–2912 and has a substitution at 1491–1506. These are UniProt sequence coordinates. Check whether the antibody recognizes a region retained in isoform 2 before assigning a band to it.
Which FBN2 glycosylation sites matter when interpreting migration?
PTM · UniProt lists 39 sites, including N-linked sites at Asn492 and Asn2808 and O-linked glucose sites at Ser298 and Thr1222. Coordinates refer to the supplied UniProt sequence. Glycosylation may affect migration, but listed sites do not establish occupancy or a particular band shift.
Does this guide establish induction of FBN2?
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 FBN2 Western blot?
Transfer · FBN2 is predicted at 314.8 kDa, and bands are reported near ~315 and ~250 kDa. Choose and verify a transfer setup suitable for proteins in that size range. The supplied features do not specify a membrane, transfer method, or settings.
How should blocking be optimized?
Blocking · Standard workflow guidance: follow the A03408-2 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 FBN2 bands be quantified?
Quantitation · Define which band is being measured and use the same band definition across samples. FBN2 has two annotated isoforms and undergoes secretion-associated processing, so summing distinct bands could mix different species. The supplied features do not establish which observed band represents which species.
Why might FBN2 bands differ from its predicted 314.8 kDa mass?
Interpretation · The 314.8 kDa prediction is for the 2,912-residue sequence. UniProt lists a signal peptide at residues 1–28, a propeptide at 29–77, and 39 glycosylation sites. Processing and glycosylation can affect apparent migration, but these features alone do not establish the cause of either observed ~315 or ~250 kDa band.
UniProt lists a signal peptide at residues 1–28 and a propeptide at 29–77. It also states that FBN2 and Placensin chains remain linked during secretion and are subsequently separated by furin. Consider processing and the antibody’s recognized region when assessing bands; these features alone do not identify the ~250 kDa band.
The supplied features cannot establish either band’s identity. The ~315 kDa band is close to the 314.8 kDa predicted sequence mass, while isoforms, processing, and glycosylation complicate interpretation. Compare antibody recognition regions with the isoform 2 deletions and processing regions before assigning the ~250 kDa band.
UniProt lists a signal peptide at residues 1–28 and a propeptide at 29–77. It also states that FBN2 and Placensin chains remain linked during secretion and are subsequently separated by furin. Consider processing and the antibody’s recognized region when assessing bands; these features alone do not identify the ~250 kDa band.
The supplied features cannot establish either band’s identity. The ~315 kDa band is close to the 314.8 kDa predicted sequence mass, while isoforms, processing, and glycosylation complicate interpretation. Compare antibody recognition regions with the isoform 2 deletions and processing regions before assigning the ~250 kDa band.
Boster reagents
FBN2 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-fibrillin 2/FBN2 Antibody Picoband®
Cat # A03408-2
The catalog reports one anti-FBN2 antibody, A03408-2, with Human reactivity and a Western blot image using human placenta and U20S lysates. The caption reports bands near 315 and 250 kDa; the expected size is 315 kDa. No publication evidence was supplied.
Which to pick: A03408-2 is the only listed option. Its WB image provides a starting reference for human placenta and U20S lysates at 0.5 μg/mL; those examples do not establish performance in other samples.
Source: BosterBio FBN2 gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry P35556.
- Human Protein Atlas. FBN2 tissue expression.
- PMC8688290 — target-verified WB comparison
- PMC8209899 — target-verified WB comparison
- PMC10133334 — target-verified WB comparison