Follistatin (FST) is a secreted glycoprotein first identified in ovarian follicular fluid as a follicle-stimulating-hormone (FSH) regulatory factor. The human FST cDNA encodes a 344 amino-acid protein with a 29 aa signal sequence, an N-terminal TGF-binding region, three Follistatin domains containing EGF-like and Kazal-like motifs, and an acidic C-terminal tail.

Follistatin modulates ligands of the TGF-β superfamily by binding to them and preventing receptor activation. It was first described as an activin antagonist capable of suppressing FSH secretion, but has since been shown to interact with other ligands including BMP-2, -4, -6, -7, Myostatin, GDF-11, and TGF-β1. Expression occurs in multiple tissues including pituitary, ovarian, and endometrial cells.

Recombinant human Follistatin 344 is a 37.8 kDa protein composed of 344 amino acids. It is sometimes referred to as Activin-binding Protein (FST) and is naturally expressed in numerous mammalian tissues.

Scientific Background

In laboratory studies, Follistatin 344 is of interest for its role as a myostatin-binding protein — helping regulate myogenesis and tissue growth by modulating myostatin and activin signaling. Researchers use FST models to examine protein synthesis, cell differentiation, and endocrine balance within the TGF-β signaling cascade.

Research Focus Areas

• Binding interactions with myostatin and other TGF-β ligands
• Influence on muscle-growth regulatory pathways in vitro
• Metabolic and endocrine feedback models
• Tissue regeneration and cellular differentiation studies

Composition & Contents

• Active compound: Recombinant Human Follistatin 344 (FST)
• Molecular weight: ≈ 37.8 kDa
• Molecular formula: C₁₃H₁₆O₃ (reference structure)
• 2 × 500 µg vials Follistatin 344 (recombinant protein)
• 1 × 1.2 ml vial bacteriostatic water (for laboratory reconstitution)

Handling & Laboratory Use

Follistatin 344 is supplied lyophilized for controlled reconstitution. When prepared in sterile laboratory environments, it can be used in receptor-binding or protein-interaction assays to explore TGF-β family inhibition and myostatin modulation.

No administration or human dosing instructions are provided or implied.

Packaging

• 1 × 1000 µg Follistatin 344 vials
• 1 × 1.2 ml bacteriostatic water vial

For laboratory, educational, and research use only. Not for human or veterinary ingestion, injection, diagnostic, or therapeutic purposes. No performance or medical claims are made or implied. Buyer is responsible for lawful acquisition, handling, and compliance with all applicable regulations.