Human FGL1

Hepassocin, also known as hepatocyte-derived fibrinogen-related protein 1 (HFREP-1) and Fibrinogen-Like Protein 1 (FGL1), is a liver-specific secreted protein belonging to the fibrinogen superfamily. Human Hepassocin/FGL1 is a secreted homodimer consisting of 312 amino acids (aa) with a 22 aa signal sequence and a 290 aa mature protein. Human Hepassocin/FGL1 binds LAG-3 through its fibrinogen-like domain independently of MHC class II. Hepassocin/FGL1 inhibits antigen-specific T cell activation, with its elevated presence in plasma of cancer patients indicating poor prognoses. Its expression is regulated in Hep G2 cells by interleukin-6 (IL-6) and is found in the serum in both bound and unbound states as an acute phase reactant (1-5).