Protein C (PROC) is a vitamin K-dependent serine protease that serves as a critical negative regulator of coagulation 12. Its primary function is to inactivate coagulation factors Va and VIIIa in a calcium- and phospholipid-dependent manner, thereby limiting thrombin generation and preventing excessive clot formation 12. Beyond its anticoagulant role, protein C exerts protective effects on endothelial barrier function, contributing to vascular homeostasis 3. PROC gene expression is tightly regulated through multiple mechanisms, including promoter elements and intronic regulatory sequences located within intron 1 that enhance transcription in hepatocytes 4. These intragenic regulatory elements are conserved across species and can be disrupted by naturally occurring mutations 4. Functionally, protein C exhibits serine protease activity and participates in negative regulation of apoptosis and inflammatory responses [GO annotations]. Deficiencies in protein C result in thrombophilia, with both autosomal dominant and recessive forms of protein C deficiency causing increased thrombotic risk. The PROC gene is located on chromosome 2 and shows conserved synteny across mammalian species 5, emphasizing its fundamental importance in hemostasis.