HRG (gene)

Histidine-rich glycoprotein is a is_associated_with::protein that in humans is encoded by the HRG is_associated_with::gene.

Function
This is_associated_with::histidine-rich is_associated_with::glycoprotein contains two is_associated_with::cystatin-like domains and is located in plasma and platelets. The physiological function has not been determined but it is known that the protein binds heme, dyes and divalent metal ions. It can inhibit rosette formation and interacts with is_associated_with::heparin, is_associated_with::thrombospondin and is_associated_with::plasminogen. Two of the protein's effects, the inhibition of fibrinolysis and the reduction of inhibition of coagulation, indicate a potential prothrombotic effect. Mutations in this gene lead to thrombophilia due to abnormal histidine-rich glycoprotein levels.

HRG is thought to have multiple roles as a protein in the human blood, including roles in immunity, is_associated_with::angiogenesis and is_associated_with::coagulation.

Clinical significance
Recently, the protein has been implicated in is_associated_with::cancer since the protein is thought be involved in is_associated_with::angiogenesis. In biomarker studies, the protein has been found to have (weak) prognostic and diagnostic value for cancer. The absence of the protein is associated with is_associated_with::thrombophilia.

In addition, HRG has been discovered to play a role in infection. Some studies have found HRG to react to infection with is_associated_with::Streptococcus pyogenes and a direct interaction between a S. pyogenes virulence factor (sHIP) and the human HRG has been identified.