FST344 (FST-344) denotes the 344-amino-acid precursor encoded by one human follistatin transcript. It is a cysteine-rich glycoprotein precursor, not a ~1.5 kDa synthetic peptide. Researchers must distinguish the precursor designation from the mature secreted isoforms commonly called FST-315 and FST-288.
What Are the Key FST344 Research Specifications?
| Specification | Research record |
|---|---|
| Compound | FST344 |
| Category | misc |
| Listed purity | >99% |
| Molecular weight | Glycoprotein in the tens of kilodaltons |
| Intended use | Laboratory research only |
What Is the Chemical Identity of FST344?
The original cloning work identified a 344-residue precursor containing a signal peptide; processing yields a mature 315-residue follistatin isoform. Alternative splicing and C-terminal processing produce other forms, including FST-288. Follistatin contains 36 cysteines in its mature coding region and multiple disulfide-rich domains, plus N-glycosylation sites. Recombinant preparations therefore have apparent masses in the tens of kilodaltons and heterogeneous glycoforms.
The label “FST-344” alone does not reveal whether a vial contains a recombinant precursor, mature FST-315, another processed isoform or a gene-delivery construct.
How Does FST344 Work in Research Models?
Follistatin binds activins and related TGF-β-family ligands, sterically blocking receptor-binding surfaces. It can also bind myostatin, but affinity, cell-surface association and ligand clearance differ among isoforms. FST-288 has stronger heparan-sulfate association than the longer acidic isoform, an important variable in cell-based studies.
How Should a FST344 Study Be Designed?
Specify the expressed sequence, signal-peptide status, host cell and mature N/C termini. Use ligand-responsive reporter assays, ligand-only controls and an unrelated carrier protein. When interpreting myostatin or activin experiments, quantify free ligand and test more than one ligand concentration; a phenotype alone does not establish which TGF-β-family ligand was neutralized.
How Should FST344 Be Handled and Verified?
Characterize identity by peptide mapping and intact-mass/glycan analysis, aggregation by SEC and potency with a ligand-responsive bioassay. Confirm endotoxin for cell or tissue work. Handle as a folded glycoprotein: avoid agitation, repeated freeze-thaw and reducing conditions unless disulfide disruption is intentional. HPLC area purity is not a substitute for isoform identity or biological activity.
Which Sources Support FST344 Research?
- Shimasaki et al., cloning and structural characterization of the 344-residue follistatin precursor, Molecular Endocrinology (1988), DOI: 10.1210/mend-1-11-849.
- Thompson et al., structural basis of activin neutralization by follistatin, Developmental Cell (2005), DOI: 10.1016/j.devcel.2005.09.008.
How Can FST344 Results Be Interpreted Without Overclaiming?
Interpret FST344 with an evidence ladder: verified material, recovered exposure, proximal pathway response and only then a downstream phenotype. For FST344, chemical identity, target engagement and downstream phenotype are separate layers. A change in migration, viability or gene expression does not by itself prove the proposed molecular target. Each step needs its own control. Sequence or structure controls test specificity; receptor blockade tests pathway dependence; viability and matrix controls test whether the assay itself explains the result.
A reusable FST344 methods section reports lot, solvent, counterion or ester, concentration, incubation, model provenance and data-normalization method. Include effect size and uncertainty, not only a p value. When literature findings conflict, compare molecular form, model and timing before averaging conclusions. This keeps the article useful to researchers and citable by review systems without overstating what preclinical evidence can support.
Is FST344 for Research Use Only?
FST-344 is supplied for laboratory research only. It is not for human or veterinary use.
Browse Miscellaneous Research Peptides
What Are Common Questions About FST344?
What is FST344?
FST344 (FST-344) denotes the 344-amino-acid precursor encoded by one human follistatin transcript. It is a cysteine-rich glycoprotein precursor, not a ~1.5 kDa synthetic peptide. Researchers must distinguish the precursor designation from the mature secreted isoforms commonly called FST-315 and FST-288.
How should researchers verify FST344?
Confirm the exact molecular form on the lot certificate and pair chromatographic purity with an orthogonal identity method such as mass spectrometry or NMR. Use the molecular weight, counterion and content stated for that verified form when calculating molarity.
Is FST344 intended for human use?
FST344 is listed for controlled laboratory research only. It is not intended for human or veterinary use.