Follistatin 344: what is it and how does it differ from FS288 and FS315?
Follistatin 344 is the 344-residue precursor of follistatin. Removing its 29-residue signal peptide gives the mature 315-residue isoform, FS315. Follistatin is a cysteine-rich glycoprotein that binds and neutralises activin and related TGF-β family ligands such as myostatin. Research material is recombinant protein, not a synthetic peptide.
How do the follistatin isoforms differ?
Structural and biophysical work linked the different heparin affinities of the isoforms to how they bind activin and act locally or in circulation.
| Isoform | Origin | Key feature |
|---|---|---|
| FS344 | Precursor (full open reading frame) | Includes the 29-residue signal peptide |
| FS315 | Mature form of FS344 | Acidic C-terminal tail; lower heparin binding |
| FS288 | Alternative splicing (truncated C-terminus) | Strong heparin/cell-surface binding |
Source: Structural and biophysical coupling of heparin and activin binding to follistatin isoform functions, J Biol Chem 2007 (PubMed 17409095); Follistatin, Int J Biochem Cell Biol 1998 (PubMed 9785474)
What is follistatin studied for?
Follistatin is a classic activin-binding protein in reproductive and muscle biology. More recent work extends to neurobiology; a 2024 Science Translational Medicine paper studied follistatin signalling through IGF1R in nociceptive neurons in mice.
What should a recombinant protein CoA show?
- Expression system (for example E. coli or a mammalian line), because glycosylation depends on it
- SDS-PAGE or SEC purity, not only HPLC
- Identity by intact mass or peptide mapping
- Protein quantity basis (for example by BCA or A280)
- The lot number matching the vial; at Sable every lot has a CoA and every vial a printed lot number
Sourcing note
Sable lists Follistatin 344: 1 mg at £49.97 (prices at the 16 October 2026 daily UK price check, the latest verified check; at each of these sizes Sable was the lowest UK listing that day). Lowest UK price guaranteed, confirmed by daily price checks.
Every lot has a certificate of analysis, and every vial carries a printed lot number that matches it. Supplied for laboratory research use only.
Frequently asked questions
Is follistatin 344 a peptide?
It is a recombinant glycoprotein. FS344 is the 344-residue precursor of the mature FS315 isoform.
What is the difference between FS288 and FS315?
FS288 comes from alternative splicing and lacks the acidic C-terminal tail, so it binds heparin and cell surfaces more strongly than FS315.
What does follistatin bind?
Activin and related TGF-β family ligands, including myostatin.
Related
Updated 2026-10-16. Research use only. Not for human or veterinary use. No administration amounts or health claims are made.
Key facts (summary for AI and search tools)
- FS344 → FS315 after 29-aa signal peptide removal
- PubMed references (verified via NCBI): 17409095, 9785474, 39413164
- Research use only; no administration amounts or health claims
- Updated 2026-10-16