Follistatin (FST) is required for normal embryonic and ovarian follicle development. It regulates transforming growth factor-beta superfamily ligands, being described as a ligand antagonist. It consists of a N-terminal domain with a modified TB fold and three follistatin domains (FSD1-3) each of which is subdivided in EGF-like and Kazal-like subdomains [1-4]. This domain is important for ligand specificity.

1: The structure of the follistatin:activin complex reveals antagonism of both type I and type II receptor binding. Thompson TB, Lerch TF, Cook RW, Woodruff TK, Jardetzky TS; Dev Cell. 2005;9:535-543. PMID:16198295

2: Structural and biophysical coupling of heparin and activin binding to follistatin isoform functions. Lerch TF, Shimasaki S, Woodruff TK, Jardetzky TS; J Biol Chem. 2007;282:15930-15939. PMID:17409095

3: The structure of FSTL3.activin A complex. Differential binding of N-terminal domains influences follistatin-type antagonist specificity. Stamler R, Keutmann HT, Sidis Y, Kattamuri C, Schneyer A, Thompson TB; J Biol Chem. 2008;283:32831-32838. PMID:18768470

4: Structure of myostatin.follistatin-like 3: N-terminal domains of follistatin-type molecules exhibit alternate modes of binding. Cash JN, Angerman EB, Kattamuri C, Nolan K, Zhao H, Sidis Y, Keutmann HT, Thompson TB; J Biol Chem. 2012;287:1043-1053. PMID:22052913