SERPINA4

SERPINA4, also known as alpha-1 antitrypsin (AAT), is a member of the serpin family of proteins, which are characterized by their ability to inhibit serine proteases. SERPINA4 is encoded by the SERPINA4 gene on chromosome 14q32.1. It is primarily produced in the liver and plays a crucial role in protecting tissues from damage by neutrophil elastase, a serine protease released by neutrophils during inflammation.

Alpha-1 antitrypsin is a 52-kDa glycoprotein that consists of 394 amino acids. It is synthesized as a precursor protein, which undergoes post-translational modifications, including glycosylation, to become the mature protein. The mature protein is a single-chain molecule that can form a stable quaternary structure with four identical subunits.

SERPINA4 is a major acute-phase reactant, meaning its serum concentration increases in response to inflammation. It is also a major component of the alpha-1 antitrypsin system, which is responsible for maintaining the balance between serine proteases and their inhibitors in the body. Deficiencies in SERPINA4 can lead to serious health issues, including liver disease, emphysema, and lung cancer.

The SERPINA4 gene is highly polymorphic, with several common variants that can affect the structure and function of the protein. The most well-known variant is the Z allele, which is associated with a reduced ability to inhibit neutrophil elastase and is a major risk factor for the development of alpha-1 antitrypsin deficiency. Other variants, such as the S and M alleles, are associated with increased levels of SERPINA4 and are protective against the development of alpha-1 antitrypsin deficiency.

SERPINA4 is a well-studied protein with a wide range of applications in research and medicine. It is used as a biomarker for inflammation and liver disease, and it is also a potential target for therapeutic intervention in conditions such as alpha-1 antitrypsin deficiency and lung cancer.