Serine protease inhibitor A3 (SerpinA3)

Serine protease inhibitor A3 (SerpinA3), also known as α-1-antichymotrypsin, is a member of the serpin superfamily of protease inhibitors and is encoded by the SERPINA3 gene on chromosome 14q32.13[3][7]. It is predominantly synthesized in the liver and secreted into the bloodstream, but is also present intracellularly in organs such as the retina, kidney, and pancreas[6]. Its main function is to irreversibly inhibit serine proteases including chymotrypsin, cathepsin G, and mast cell chymase, and, through this action, it regulates inflammation, immune responses, apoptosis, angiogenesis, fibrosis, and tissue remodeling[2][3][4][6]. SerpinA3 also possesses DNA-binding capacity, though the physiological significance of this is not fully understood[2][3][4]. Elevated or decreased levels of SerpinA3 are associated with numerous pathological conditions such as cancer, fibrosis, neurodegenerative diseases, and metabolic and ocular diseases, making it an important biomarker for disease progression and prognosis[3][4][6][7]. Currently, there are no direct pharmacological agents targeting SerpinA3, but its pathways and protease targets are common sites for therapeutic intervention.

Other names

α-1-antichymotrypsinACTAACTSERPINA3

Inhibition of serine proteases by irreversible complex formation; Modulation of downstream proteolytic and signaling cascades (e.g., affecting PI3K/AKT/mTOR, ERK, and other pathways involved in cell proliferation and survival)[2][4]; Reduction of inflammation by limiting protease-mediated tissue damage[6]; Suppression of angiogenesis and fibrosis through protease inhibition and downstream signaling effects[2][6]