Source :
https://link.springer.com/chapter/10.1007/978-3-030-56514-5_14Peter P. Toth Part of the Contemporary Cardiology book series (CONCARD) Proprotein convertase/kexin type 9 (PCSK9) is produced and secreted by hepatocytes. Once in the extracellular milieu, PCSK9 can bind to the low-density lipoprotein receptor (LDLR) and regulates its cell surface expression. PCSK9 functions as a chaperone molecule.