SERPING1 Human, Native

The primary function of C1-INH is to inhibit the activated forms of the first component of the complement system, specifically C1r and C1s proteases. By forming a proteolytically inactive complex with these proteases, C1-INH regulates the activation of the complement cascade, which is essential for immune response and inflammation control .

C1-INH also inhibits other proteases such as chymotrypsin, kallikrein, and factor XIIa. This inhibition is vital for controlling inflammation, as it prevents excessive production of bradykinin, a peptide that increases vascular permeability and can lead to swelling .

C1-INH is synthesized primarily in the liver and is a highly glycosylated plasma protein. Its production is regulated by various factors, including inflammatory cytokines. The gene encoding C1-INH, SERPING1, is located on chromosome 11 .

Deficiency or dysfunction of C1-INH is associated with a genetic disorder known as hereditary angioedema (HAE). This condition is characterized by recurrent episodes of severe swelling (angioedema) in various parts of the body, including the extremities, face, gastrointestinal tract, and airways. There are two main types of HAE related to C1-INH:

1. Type I HAE: Caused by low levels of C1-INH in the blood.
2. Type II HAE: Caused by dysfunctional C1-INH that does not function correctly .

Both types result in excessive bradykinin production, leading to the symptoms of angioedema. Management of HAE involves the use of C1-INH replacement therapy and other medications to control bradykinin levels .

Ongoing research aims to better understand the molecular mechanisms underlying SERPING1 gene regulation and C1-INH function. Advances in genetic therapies and novel inhibitors are being explored to provide more effective treatments for HAE and other related conditions .