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L-Arginine prevents cereblon-mediated ubiquitination of glucokinase and stimulates glucose-6-phosphate production in pancreatic ?-cells.

ABSTRACT: We sought to determine a mechanism by which L-arginine increases glucose-stimulated insulin secretion (GSIS) in ?-cells by finding a protein with affinity to L-arginine using arginine-immobilized magnetic nanobeads technology. Glucokinase (GCK), the key regulator of GSIS and a disease-causing gene of maturity-onset diabetes of the young type 2 (MODY2), was found to bind L-arginine. L-Arginine stimulated production of glucose-6-phosphate (G6P) and induced insulin secretion. We analyzed glucokinase mutants and identified three glutamate residues that mediate binding to L-arginine. One MODY2 patient with GCKE442* demonstrated lower C-peptide-to-glucose ratio after arginine administration. In ?-cell line, GCKE442* reduced L-arginine-induced insulin secretion compared with GCKWT. In addition, we elucidated that the binding of arginine protects glucokinase from degradation by E3 ubiquitin ligase cereblon mediated ubiquitination. We conclude that L-arginine induces insulin secretion by increasing G6P production by glucokinase through direct stimulation and by prevention of degradation.

SUBMITTER: Cho J

PROVIDER: S-EPMC7479149 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature

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L-Arginine prevents cereblon-mediated ubiquitination of glucokinase and stimulates glucose-6-phosphate production in pancreatic β-cells.

Cho Jaeyong J Horikawa Yukio Y Enya Mayumi M Takeda Jun J Imai Yoichi Y Imai Yumi Y Handa Hiroshi H Imai Takeshi T

Communications biology 20200908 1

We sought to determine a mechanism by which L-arginine increases glucose-stimulated insulin secretion (GSIS) in β-cells by finding a protein with affinity to L-arginine using arginine-immobilized magnetic nanobeads technology. Glucokinase (GCK), the key regulator of GSIS and a disease-causing gene of maturity-onset diabetes of the young type 2 (MODY2), was found to bind L-arginine. L-Arginine stimulated production of glucose-6-phosphate (G6P) and induced insulin secretion. We analyzed glucokinas ...[more]

PMID: 32901087

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Project description:Aims/introductionSrc, a non-receptor tyrosine kinase, regulates a wide range of cellular functions, and hyperactivity of Src is involved in impaired glucose metabolism in pancreatic ?-cells. However, the physiological role of Src in glucose metabolism in normal, unstressed ?-cells remains unclear. In the present study, we investigated the role of Src in insulin secretion and glucose metabolism.Materials and methodsSrc was downregulated using small interfering ribonucleic acid in INS-1 cells, and glucose-induced insulin secretion, adenosine triphosphate content, intracellular calcium concentration, glucose utilization and glucokinase activity were measured. Expression levels of messenger ribonucleic acid and protein of glucokinase were examined by semiquantitative real-time polymerase chain reaction and immunoblotting, respectively. Cells were fractionated by digitonin treatment, and subcellular localization of glucokinase was examined by immunoblotting. Interaction between glucokinase and neuronal nitric oxide synthase was estimated by immunoprecipitation.ResultsIn Src downregulated INS-1 cells, glucose-induced insulin secretion was impaired, whereas insulin secretion induced by high K(+) was not affected. Intracellular adenosine triphosphate content and elevation of intracellular calcium concentration by glucose stimulation were suppressed by Src downregulation. Src downregulation reduced glucose utilization in the presence of high glucose, which was accompanied by a reduction in glucokinase activity without affecting its expression. However, Src downregulation reduced glucokinase in soluble, cytoplasmic fraction, and increased it in pellet containing intaracellular organelles. In addition, interaction between glucokinase and neuronal nitric oxide synthase was facilitated by Src downregulation.ConclusionsSrc plays an important role in glucose-induced insulin secretion in pancreatic ?-cells through maintaining subcellular localization and activity of glucokinase.

Dataset Information

L-Arginine prevents cereblon-mediated ubiquitination of glucokinase and stimulates glucose-6-phosphate production in pancreatic ?-cells.

Publications

L-Arginine prevents cereblon-mediated ubiquitination of glucokinase and stimulates glucose-6-phosphate production in pancreatic β-cells.

Similar Datasets

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