| Structural highlights
Disease
HXK4_HUMAN Defects in GCK are the cause of maturity-onset diabetes of the young type 2 (MODY2) [MIM:125851; also shortened MODY-2. MODY is a form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] Defects in GCK are the cause of familial hyperinsulinemic hypoglycemia type 3 (HHF3) [MIM:602485; also known as persistent hyperinsulinemic hypoglycemia of infancy (PHHI) or congenital hyperinsulinism. HHF is the most common cause of persistent hypoglycemia in infancy. Unless early and aggressive intervention is undertaken, brain damage from recurrent episodes of hypoglycemia may occur.[14]
Function
HXK4_HUMAN Catalyzes the initial step in utilization of glucose by the beta-cell and liver at physiological glucose concentration. Glucokinase has a high Km for glucose, and so it is effective only when glucose is abundant. The role of GCK is to provide G6P for the synthesis of glycogen. Pancreatic glucokinase plays an important role in modulating insulin secretion. Hepatic glucokinase helps to facilitate the uptake and conversion of glucose by acting as an insulin-sensitive determinant of hepatic glucose usage.
Publication Abstract from PubMed
Glucokinase (GK) catalyses the formation of glucose 6-phosphate from glucose and ATP. A specific feature of GK amongst hexokinases is that it can cycle between active and inactive conformations as a function of glucose concentration, resulting in a unique positive kinetic cooperativity with glucose, which turns GK into a unique key sensor of glucose metabolism, notably in the pancreas. GK is a target of antidiabetic drugs aimed at the activation of GK activity, leading to insulin secretion. Here, the first structures of a GK-glucose complex without activator, of GK-glucose-AMP-PNP and of GK-glucose-AMP-PNP with a bound activator are reported. All these structures are extremely similar, thus demonstrating that binding of GK activators does not result in conformational changes of the active protein but in stabilization of the active form of GK.
The active conformation of human glucokinase is not altered by allosteric activators.,Petit P, Antoine M, Ferry G, Boutin JA, Lagarde A, Gluais L, Vincentelli R, Vuillard L Acta Crystallogr D Biol Crystallogr. 2011 Nov;67(Pt 11):929-35. Epub 2011 Oct 19. PMID:22101819[15]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Stoffel M, Froguel P, Takeda J, Zouali H, Vionnet N, Nishi S, Weber IT, Harrison RW, Pilkis SJ, Lesage S, et al.. Human glucokinase gene: isolation, characterization, and identification of two missense mutations linked to early-onset non-insulin-dependent (type 2) diabetes mellitus. Proc Natl Acad Sci U S A. 1992 Aug 15;89(16):7698-702. PMID:1502186
- ↑ Sakura H, Eto K, Kadowaki H, Simokawa K, Ueno H, Koda N, Fukushima Y, Akanuma Y, Yazaki Y, Kadowaki T. Structure of the human glucokinase gene and identification of a missense mutation in a Japanese patient with early-onset non-insulin-dependent diabetes mellitus. J Clin Endocrinol Metab. 1992 Dec;75(6):1571-3. PMID:1464666
- ↑ Stoffel M, Patel P, Lo YM, Hattersley AT, Lucassen AM, Page R, Bell JI, Bell GI, Turner RC, Wainscoat JS. Missense glucokinase mutation in maturity-onset diabetes of the young and mutation screening in late-onset diabetes. Nat Genet. 1992 Oct;2(2):153-6. PMID:1303265 doi:http://dx.doi.org/10.1038/ng1092-153
- ↑ Stoffel M, Bell KL, Blackburn CL, Powell KL, Seo TS, Takeda J, Vionnet N, Xiang KS, Gidh-Jain M, Pilkis SJ, et al.. Identification of glucokinase mutations in subjects with gestational diabetes mellitus. Diabetes. 1993 Jun;42(6):937-40. PMID:8495817
- ↑ Takeda J, Gidh-Jain M, Xu LZ, Froguel P, Velho G, Vaxillaire M, Cohen D, Shimada F, Makino H, Nishi S, et al.. Structure/function studies of human beta-cell glucokinase. Enzymatic properties of a sequence polymorphism, mutations associated with diabetes, and other site-directed mutants. J Biol Chem. 1993 Jul 15;268(20):15200-4. PMID:8325892
- ↑ Gidh-Jain M, Takeda J, Xu LZ, Lange AJ, Vionnet N, Stoffel M, Froguel P, Velho G, Sun F, Cohen D, et al.. Glucokinase mutations associated with non-insulin-dependent (type 2) diabetes mellitus have decreased enzymatic activity: implications for structure/function relationships. Proc Natl Acad Sci U S A. 1993 Mar 1;90(5):1932-6. PMID:8446612
- ↑ Hager J, Blanche H, Sun F, Vaxillaire NV, Poller W, Cohen D, Czernichow P, Velho G, Robert JJ, Cohen N, et al.. Six mutations in the glucokinase gene identified in MODY by using a nonradioactive sensitive screening technique. Diabetes. 1994 May;43(5):730-3. PMID:8168652
- ↑ Velho G, Blanche H, Vaxillaire M, Bellanne-Chantelot C, Pardini VC, Timsit J, Passa P, Deschamps I, Robert JJ, Weber IT, Marotta D, Pilkis SJ, Lipkind GM, Bell GI, Froguel P. Identification of 14 new glucokinase mutations and description of the clinical profile of 42 MODY-2 families. Diabetologia. 1997 Feb;40(2):217-24. PMID:9049484 doi:10.1007/s001250050666
- ↑ Guazzini B, Gaffi D, Mainieri D, Multari G, Cordera R, Bertolini S, Pozza G, Meschi F, Barbetti F. Three novel missense mutations in the glucokinase gene (G80S; E221K; G227C) in Italian subjects with maturity-onset diabetes of the young (MODY). Mutations in brief no. 162. Online. Hum Mutat. 1998;12(2):136. PMID:10694920 doi:<136::AID-HUMU11>3.0.CO;2-0 10.1002/(SICI)1098-1004(1998)12:2<136::AID-HUMU11>3.0.CO;2-0
- ↑ Hattersley AT, Beards F, Ballantyne E, Appleton M, Harvey R, Ellard S. Mutations in the glucokinase gene of the fetus result in reduced birth weight. Nat Genet. 1998 Jul;19(3):268-70. PMID:9662401 doi:10.1038/953
- ↑ Ng MC, Cockburn BN, Lindner TH, Yeung VT, Chow CC, So WY, Li JK, Lo YM, Lee ZS, Cockram CS, Critchley JA, Bell GI, Chan JC. Molecular genetics of diabetes mellitus in Chinese subjects: identification of mutations in glucokinase and hepatocyte nuclear factor-1alpha genes in patients with early-onset type 2 diabetes mellitus/MODY. Diabet Med. 1999 Nov;16(11):956-63. PMID:10588527
- ↑ Nam JH, Lee HC, Kim YH, Cha BS, Song YD, Lim SK, Kim KR, Huh KB. Identification of glucokinase mutation in subjects with post-renal transplantation diabetes mellitus. Diabetes Res Clin Pract. 2000 Dec;50(3):169-76. PMID:11106831
- ↑ Njolstad PR, Sovik O, Cuesta-Munoz A, Bjorkhaug L, Massa O, Barbetti F, Undlien DE, Shiota C, Magnuson MA, Molven A, Matschinsky FM, Bell GI. Neonatal diabetes mellitus due to complete glucokinase deficiency. N Engl J Med. 2001 May 24;344(21):1588-92. PMID:11372010 doi:10.1056/NEJM200105243442104
- ↑ Glaser B, Kesavan P, Heyman M, Davis E, Cuesta A, Buchs A, Stanley CA, Thornton PS, Permutt MA, Matschinsky FM, Herold KC. Familial hyperinsulinism caused by an activating glucokinase mutation. N Engl J Med. 1998 Jan 22;338(4):226-30. PMID:9435328 doi:10.1056/NEJM199801223380404
- ↑ Petit P, Antoine M, Ferry G, Boutin JA, Lagarde A, Gluais L, Vincentelli R, Vuillard L. The active conformation of human glucokinase is not altered by allosteric activators. Acta Crystallogr D Biol Crystallogr. 2011 Nov;67(Pt 11):929-35. Epub 2011 Oct 19. PMID:22101819 doi:10.1107/S0907444911036729
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