Biosynthesis and processing of pro CCK: recent progress and future challenges.

Pro Cholecystokinin (CCK) like other prohormones that pass through the regulated secretory pathway, undergoes a number of post-translational modifications during its biosynthesis including tyrosine sulfation, endoproteolytic cleavages, trimming by carboxypeptidase and c-terminal amidation. This minireview summarizes what is known about this process, what specific enzymes are involved in endocrine and neuronal tumor cells and in mutant and knockout mouse strains. It also points out the major challenges that remain for future research.