PCSK9 is a proprotein convertase belonging to the proteinase K subfamily of the secretory subtilase family. This protein is synthesized as a soluble zymogen that undergoes autocatalytic intramolecular processing in the endoplasmic reticulum. The protein may function as a proprotein convertase. The protein plays a role in cholesterol homeostasis and may have a role in the differentiation of cortical neurons.
