Follistatin 344 vs 315 research in Canada compares these two naturally occurring isoforms of Follistatin for their differential heparan sulfate proteoglycan (HSPG) binding, tissue distribution, duration of action, and myostatin antagonism profiles. Both isoforms are potent antagonists of myostatin (GDF-8), activin A, activin B, and BMP family members through high-affinity non-covalent binding that blocks their receptor signalling. The key structural difference is the C-terminal acidic domain (residues 315-344) present in FST344 but absent in FST315 — a 29-amino acid tail that critically determines tissue binding behavior.
Heparan Sulfate Binding and Tissue Localization Research
FST344’s C-terminal acidic domain (residues 315-344) facilitates binding to heparan sulfate proteoglycans on cell surfaces and extracellular matrix, causing FST344 to concentrate locally in tissues and have extended local activity. FST315 lacks this domain, resulting in poor HSPG binding and preferential circulation in plasma. Canadian cell biology researchers use FST344 for local tissue myostatin antagonism research models while FST315 is used for studying systemic circulating follistatin pharmacokinetics.
Myostatin and Activin Antagonism Research
Both FST isoforms bind myostatin (GDF-8) and activins with sub-nanomolar affinity, preventing their binding to ActRIIB and ALK4/5 receptors on muscle cells. Canadian muscle biology researchers use follistatin isoforms to study the SMAD2/3 signalling suppression that underlies myostatin’s anti-anabolic effects, providing research tools for studying the myostatin-follistatin regulatory axis in muscle biology.
Sourcing Follistatin in Canada
Research-grade Follistatin 344 and 315 are available from EhBuddy Peptides in Canada. For laboratory research use only.
