| Function
Glucagon (GLC) is a 29-residue peptide hormone that raises blood glucose levels. GLC causes , signalling the liver to convert glycogen to glucose. The effect of glucagon is opposite to that of insulin[1]. Cells sense the presence of glucagon when it binds the glucagon receptor, a G-protein coupled receptor. In solution, glucagon adopts various conformations but is mostly helical when bound to the receptor [2]. For more details and a quiz see User:Mary Ball/Glucagon.
Relevance
Glucagon is injected in cases of severe hypoglycemia[3]. It has to be reconstituted from lyophilized glucagon because in solution it quickly aggregates to form insoluble fibrils[4]. Overdose of β blockers is treated with GLCas well as cases of epinephrine-resistant low blood pressure. Pancreatic tumors may cause high levels of GLC.
- ↑ Ramnanan CJ, Edgerton DS, Kraft G, Cherrington AD. Physiologic action of glucagon on liver glucose metabolism. Diabetes Obes Metab. 2011 Oct;13 Suppl 1:118-25. doi:, 10.1111/j.1463-1326.2011.01454.x. PMID:21824265 doi:https://dx.doi.org/10.1111/j.1463-1326.2011.01454.x
- ↑ Zhang H, Qiao A, Yang L, Van Eps N, Frederiksen KS, Yang D, Dai A, Cai X, Zhang H, Yi C, Cao C, He L, Yang H, Lau J, Ernst OP, Hanson MA, Stevens RC, Wang MW, Reedtz-Runge S, Jiang H, Zhao Q, Wu B. Structure of the glucagon receptor in complex with a glucagon analogue. Nature. 2018 Jan 3;553(7686):106-110. doi: 10.1038/nature25153. PMID:29300013 doi:https://dx.doi.org/10.1038/nature25153
- ↑ Heptulla RA, Rodriguez LM, Bomgaars L, Haymond MW. The role of amylin and glucagon in the dampening of glycemic excursions in children with type 1 diabetes. Diabetes. 2005 Apr;54(4):1100-7. PMID:15793249
- ↑ Gelenter MD, Smith KJ, Liao SY, Mandala VS, Dregni AJ, Lamm MS, Tian Y, Xu W, Pochan DJ, Tucker TJ, Su Y, Hong M. The peptide hormone glucagon forms amyloid fibrils with two coexisting beta-strand conformations. Nat Struct Mol Biol. 2019 Jul;26(7):592-598. doi: 10.1038/s41594-019-0238-6. Epub, 2019 Jun 24. PMID:31235909 doi:https://dx.doi.org/10.1038/s41594-019-0238-6
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3D Structures of glucagon
Updated on 02-May-2023
Human glucagon residues 53-81
1kx6, 2m5p, 2m5q, 6nzn – hGLC - NMR
1nau – hGLC (mutant) – NMR
5otu, 5otv, 5otw, 5otx – hGLC (mutant) + GLC-like peptide 1 receptor
6phj, 6pho – hGLC preprotein
6phm, 6phq – D-hGLC preprotein
6phn – D-hGLC preprotein (mutant)
6phk, 6phl, 6php – hGLC preprotein (mutant)
5yqz - GLC (analog) bound to receptor
2g49, 6eds – hGLC preprotein + insulin-degrading enzyme
1gcn - GLC residues 33-61 - pig
References
