Alpha-1-antichymotrypsin (SERPINA3)

Alpha-1-antichymotrypsin (SERPINA3) is a secreted glycoprotein and member of the serpin (serine protease inhibitor) superfamily, encoded by the SERPINA3 gene. It functions mainly as an acute-phase protein, produced predominantly in the liver in response to inflammatory stimuli. SERPINA3 inhibits activity of multiple serine proteases, especially cathepsin G and mast cell chymase, thus protecting tissues from proteolytic damage and modulating key inflammatory and cell signaling pathways. It is implicated in the regulation of cell proliferation, apoptosis, and extracellular matrix remodeling through the PI3K/AKT and MAPK/ERK signal pathways. SERPINA3 is strongly upregulated during inflammation and in multiple pathological contexts, including cancer, neurodegenerative, and cardiovascular diseases, playing diverse and sometimes opposing roles depending on tissue and disease type. Deficiency or dysregulation of SERPINA3 is associated with a variety of pathological conditions, notably liver disease, neurodegeneration, and poor cancer prognosis.

Other names

Alpha-1-antichymotrypsinAACTACTGIG24GIG25Growth-inhibiting protein 24Growth-inhibiting protein 25Serpine peptidase inhibitor, clade A, member 3SERPINA3Cell growth-inhibiting gene 24/25 proteinSerpin A3

Direct inhibition or modulation of serine protease activity (exploited in research, not in approved therapeutics); Modulation of apoptosis and proliferation via signal transduction pathways (PI3K/AKT, MAPK/ERK)