Skip to main content
Fig. 1 | Molecular Medicine

Fig. 1

From: Glycine-Extended Gastrin Exerts Growth-Promoting Effects on Human Colon Cancer Cells

Fig. 1

Gastrin post-translational processing. Gastrin is synthesized on the endoplasmic reticulum and then transported to the Golgi. In well-differentiated neuroendocrine cells, progastrin is sorted in the trans-Golgi network to the regulated pathway of secretion and into secretory granules that contain the enzymes necessary to complete progastrin processing. In these granules, the amino- and carboxy-terminal flanking regions are cleaved by a prohormone convertase at dibasic arginine residues (ArgArg) and the carboxy-terminal arginines removed by carboxypeptidase H revealing G34-Gly. G34-Gly can then be amidated by the peptidyl-glycine alpha-amidating monooxygenase (PAM) to form G34-NH2 or cleaved at internal lysine/lysine (LysLys) residues resulting in the production of G17-Gly. Biosynthetic studies (64) suggest that although G34-NH2 can be cleaved at the LysLys site by a prohormone convertase to yield G17-NH2, G17-Gly is not amidated by PAM. Thus, G17-Gly may be a distinct end-product of progastrin processing in antral G-cells.

Back to article page