Fibrinogen-like protein 1 (FGL-1) is a protein that is structurally related to fibrinogen. In humans, FGL-1 is encoded by the ''FGL1'' gene. Four splice variants exist for this gene.

Function

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 The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is ...

of the fibrinogen

beta Beta (, ; uppercase , lowercase , or cursive ; grc, βῆτα, bē̂ta or ell, βήτα, víta) is the second letter of the Greek alphabet. In the system of Greek numerals, it has a value of 2. In Modern Greek, it represents the voiced labiod ...

- and

gamma Gamma (uppercase , lowercase ; ''gámma'') is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. In Ancient Greek, the letter gamma represented a voiced velar stop . In Modern Greek, this letter re ...

- subunits which contains the four conserved

cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. When present as a deprotonated catalytic residue, sometime ...

s 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. FGL-1 has also been observed to strongly bind to and activate

LAG-3 Lymphocyte-activation gene 3, also known as LAG-3, is a protein which in humans is encoded by the ''LAG3'' gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." ...

, 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.

Clinical significance

FGL-1 may play a role in the development of

hepatocellular carcinoma Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer in adults and is currently the most common cause of death in people with cirrhosis. HCC is the third leading cause of cancer-related deaths worldwide. It occurs in t ...

Function

Clinical significance

References

Further reading