Fibrinogen-like protein 1 (FGL-1) is a protein that is structurally related to fibrinogen. In humans, FLG-1 is encoded by the FGL1 gene.Fibrinogen-like protein 1 is a member of the fibrinogen family of proteins, which also includes fibrinogen, fibrinogen-like protein 2, and clotting factors V, VIII, and XIII.Fibrinogen-like Protein 1 is a major immune inhibitory ligand of LAG-3.