Description
Follistatin 344 (FS-344) is the full-length 344-amino-acid precursor form of follistatin, encoded by the FST gene on chromosome 5q11.2. The “344” designation refers to the complete precursor sequence including the 29-amino-acid N-terminal signal peptide. After signal peptide cleavage, FS-344 yields the 315-amino-acid mature circulating isoform (FS-315). This processing relationship is central to understanding FS-344’s research role: it functions as the biosynthetic precursor to the predominant circulating follistatin form, and in gene therapy research it serves specifically as the standard transgene construct because cells expressing the FS-344 sequence process it to FS-315 post-translationally. Like all follistatin isoforms, FS-344 binds and neutralizes TGF-beta superfamily ligands including activin A, activin B, and myostatin (GDF-8) through a wrapping sequestration mechanism that sterically blocks ActRII and ALK4 receptor engagement.
Chemical Information
- Chemical Name: Follistatin-344 (FST precursor; full-length including signal peptide)
- Also Known As: FS-344; FST-344
- Compound Class: Endogenous glycoprotein precursor (TGF-beta superfamily antagonist)
- Amino Acid Length: 344 amino acids (full precursor including 29-amino-acid signal peptide)
- Mature processed form: FS-315 (315 amino acids, after signal peptide cleavage)
- Molecular Weight: approximately 37-45 kDa (varies by glycosylation state)
- Gene: FST (chromosome 5q11.2)
- Primary Ligands: Activin A, Activin B, Myostatin (GDF-8), GDF-11, BMP-7
- Mechanism Class: Extracellular ligand trap (wrapping/sequestration mechanism)
Applications
- Gene therapy research. FS-344 is the standard transgene construct used in adeno-associated virus (AAV) delivery systems for follistatin gene therapy studies, including the AAV1.CMV.FS344 construct used in Becker muscular dystrophy research at Nationwide Children’s Hospital; cells expressing this transgene process FS-344 to FS-315 post-translationally, making FS-344 the appropriate construct for gene delivery experimental designs
- Follistatin biosynthesis and processing research. The FS-344 to FS-315 processing pathway is itself a research variable; studies examining signal peptide cleavage, post-translational modification, and isoform-specific secretion dynamics use FS-344 as the precursor reference compound
- TGF-beta superfamily ligand sequestration studies. Same binding profile as FS-315 covering activin A, activin B, myostatin, GDF-11, and BMP-7 through the wrapping sequestration mechanism. Appropriate for cell-based models where the precursor form is the experimental condition
- Isoform comparison research. FS-344, FS-315, and FS-288 represent three distinct points in the follistatin biosynthetic and processing pathway; researchers examining how precursor processing affects tissue distribution, receptor binding affinity, and signaling outcomes use all three forms in comparative experimental designs
- Reproductive biology research. Follistatin was first identified as a follicle-stimulating hormone suppressor. FS-344 participates in activin-mediated FSH regulation through pituitary gonadotroph signaling, making it relevant in reproductive endocrinology research models
Storage and Handling
Store lyophilized protein at -20C for long-term stability. Reconstituted solutions should be stored at 2-8C and used promptly. Avoid repeated freeze-thaw cycles, which can cause aggregation and reduce binding activity in glycoprotein preparations. Protect from light and elevated temperatures. As a glycoprotein precursor, FS-344 requires careful handling conditions.
Compliance Notice
Follistatin 344 is for laboratory research use only. It is not for human or veterinary use and carries no therapeutic, diagnostic, or clinical indication. This product has not been evaluated by the FDA. By purchasing this product, the buyer confirms that they will follow appropriate institutional safety procedures and use it exclusively for controlled research.
