FOLLISTATIN - A MULTIFUNCTIONAL REGULATORY PROTEIN

Follistatin was first described in 1987 as a follicle-stimulating horm one inhibiting substance present in ovarian follicular fluid. We now k now that this effect of follistatin is only one of its many properties in a number of reproductive and nonreproductive systems. A majority o f these functions are facilitated through the affinity of follistatin for activin, where activin's effects are neutralized through its bindi ng to follistatin. As such, the interplay between follistatin and acti vin represents a powerful regulatory mechanism that impinges on a vari ety of cellular processes within the body. In this review we focus on the biochemical characteristics of follistatin and its interaction wit h activin and discuss the emerging role of these proteins as potent ti ssue regulators in the gonad, pituitary gland, pregnancy membranes, va sculature, and liver. Consideration is also given to the larger family of proteins that contain follistatin-like modules, in particular with regard to their functional and structural implications. (C) 1998 Acad emic Press.