Proglucagon
Protein that is a precursor of glucagon
Proglucagon is a protein that is a precursor of glucagon and several other components. It is cleaved from preproglucagon. Proglucagon is generated in the alpha cells of the pancreas and in the intestinal L cells in the distal ileum and colon.
Preproglucagon in humans is encoded by the GCG gene and is composed of 180 amino-acid residues.
01Function and Terminology
The “pre-” prefix of preproglucagon indicates that it is composed of proglucagon together with a signal peptide. The signal peptide is a 20 amino acid fragment that signals that the protein needs to be secreted out of the cell. Proglucagon has the “pro-“ prefix because it is a prohormone, which means it is an inactivate precursor that needs to be further modified in order to produce active hormone(s). In particular, proglucagon is cleaved (cut) into different active hormones depending on the organ. Omitting various inactive fragments, preproglucagon is cleaved into the following:
Pancreas
- Signal peptide (1-20)
- Glicentin-related pancreatic polypeptide (GRPP, 21-50)
- Glucagon (53-81)
Gut and Brain
- Signal peptide (1-20)
- Glicentin (21-89)
- Oxyntomodulin (OXY or OXM, 53-89) , A further cleavage of Glicentin
- Glucagon-like peptide 1 (GLP-1, 92-128) , first seven residues further cleaved
- Glucagon-like peptide 2 (GLP-2, 146-178)
Sources and credits
This article is adapted from the Wikipedia article “Proglucagon”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- Ideogram human chromosome 2.svg by National Center for Biotechnology Information, U.S. National Library of Medicine, Public domain
Fathomly is not affiliated with or endorsed by the Wikimedia Foundation. Spotted a problem? Tell us.