Fibrinogen-like protein 1 (FGL-1) is a protein that is structurally related to fibrinogen. In humans, FGL-1 is encoded by the FGL1gene.[5][6] Four splice variants exist for this 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. FGL-1 is homologous to the carboxy terminus of the fibrinogen beta- and gamma- subunits which contains the four conserved cysteines of that are common to all members of the fibrinogen family. However, FGL-1 lacks the platelet-binding site, cross-linking region, and thrombin-sensitive site which allow the other members of the fibrinogen family to aid in fibrin clot formation.[6]
FGL-1 has also been observed to strongly bind to and activate LAG-3, a regulatory protein expressed on T cells. As LAG-3 has an important role in controlling activated T cells, manipulating FGL-1 binding to T cells has been proposed for both cancer immunotherapy and anti-inflammatory treatments.[7]
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Yan J, Yu Y, Wang N, et al. (2004). "LFIRE-1/HFREP-1, a liver-specific gene, is frequently downregulated and has growth suppressor activity in hepatocellular carcinoma". Oncogene. 23 (10): 1939–49. doi:10.1038/sj.onc.1207306. PMID14981537. S2CID9243597.
