FGL1
Description
The FGL1 (fibrinogen like 1) is a protein-coding gene located on chromosome 8.
FGL-1 is a protein structurally related to fibrinogen. In humans, FGL-1 is encoded by the FGL1 gene and is classified as a hepatokine. Four splice variants exist for this gene. FGL-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 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. 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. FGL-1 may play a role in the development of hepatocellular carcinomas.
FGL1 is an immune suppressive molecule that inhibits antigen-specific T-cell activation by acting as a major ligand of LAG3 (PubMed:30580966). It is responsible for LAG3 T-cell inhibitory function (PubMed:30580966) and binds LAG3 independently from MHC class II (MHC-II) (PubMed:30580966). FGL1 is secreted by, and promotes growth of, hepatocytes (PubMed:11470158, PubMed:19880967).
FGL1 is also known as HFREP1, HP-041, HPS, LFIRE-1, LFIRE1.
Associated Diseases
- toxemia of pregnancy
- cancer
- systemic lupus erythematosus
- nonpapillary renal cell carcinoma
- familial partial lipodystrophy, Kobberling type
- severe combined immunodeficiency due to IKK2 deficiency
- familial partial lipodystrophy, Dunnigan type
