Prosurfactant Protein C (proSP-C) is a precursor protein that plays a crucial role in the formation of pulmonary surfactant, which is essential for reducing surface tension at the alveolar air-liquid interface and maintaining lung stability during ventilation. ProSP-C is synthesized as a 21 kDa integral membrane precursor protein in alveolar type II cells and is subsequently proteolytically processed to a 3.7 kDa secretory protein, known as Surfactant Protein C (SP-C). SP-C enhances the adsorption and spreading of phospholipids at the air-liquid interface, thereby promoting the surface tension-lowering properties of surfactant.