FGF-21-3

FGF21; FGF-21; fibroblast growth factor 21

Fibroblast growth factor 21 (FGF-21) is a member of the FGF gene family. Based on its structure, FGF-21 is further classified into a subfamily of FGFs along with FGF-19 and -23. At the amino acid sequence level, mature rat FGF-21 is 92% identical to mouse FGF-21. In comparison to other FGF subfamilies, a heparin-binding domain is uniquely absent in FGF-19 subfamily members. Lack of this domain confers endocrine function to FGF-19 members and enables them to freely diffuse within tissues and accumulate in the circulatory system. The biological activity of FGF-21 requires binding to Klotho beta, a co-receptor that is in complex with cell surface FGF receptors (FGF R). Binding of FGF-21 to Klotho beta facilitates FGF R activation and autophosphorylation resulting in the initiation of multiple downstream signaling cascades. FGF-21 cannot independently bind to FGF Rs, thus its effects are restricted to target tissues that express Klotho beta. FGF-21 functions as a physiological regulator of cellular metabolism, including glucose uptake in adipocytes and cellular sensitivity to insulin. FGF-21 is basally expressed in the pancreas, thymus, and liver, as well as in adipose tissue. Local and systemic metabolic stress has been shown to induce expression of FGF-21 in the liver, muscles, and fat. Modulation of FGF-21 expression is associated with a number of metabolic disorders, including obesity and diabetes.

Approximately 19.7 kDa.

Sterile Filtered White lyophilized (freeze-dried) powder.

> 95% by SDS-PAGE and HPLC analyses.