Guanylate-binding protein
In molecular biology, the guanylate-binding protein family is a family of GTPases that is induced by interferon (IFN)-gamma. GTPases induced by IFN-gamma (Interferon-inducible GTPase) are key to the protective immunity against microbial and viral pathogens. These GTPases are classified into three groups: the small 47-KD immunity-related GTPases (IRGs), the Mx proteins (MX1, MX2), and the large 65- to 67-kd GTPases. Guanylate-binding proteins (GBP) fall into the last class. In humans, there are seven GBPs (hGBP1-7). Structurally, hGBP1 consists of two domains: a compact globular N-terminal domain harbouring the  GTPase function, and an alpha-helical finger-like C-terminal domain. Human GBP1 is secreted from cells without the need of a leader peptide, and has been shown to exhibit antiviral activity against Vesicular stomatitis virus and Encephalomyocarditis virus, as well as being able to regulate the inhibition of proliferation and invasion of endothelial cells in response to IFN-gamma.