Cytosolic and Mitochondrial Malic Enzyme Isoforms Differentially Control Insulin Secretion
نویسندگان
چکیده
منابع مشابه
Cytosolic and mitochondrial malic enzyme isoforms differentially control insulin secretion.
In islet beta-cells and INS-1 cells both the high activity of malic enzyme and the correlation of insulin secretion rates with pyruvate carboxylase (PC) flux suggest that a pyruvate-malate cycle is functionally relevant to insulin secretion. Expression of the malic enzyme isoforms in INS-1 cells and rat islets was measured, and small interfering RNA was used to selectively reduce isoform mRNA e...
متن کاملRole for malic enzyme, pyruvate carboxylation, and mitochondrial malate import in glucose-stimulated insulin secretion.
Pyruvate cycling has been implicated in glucose-stimulated insulin secretion (GSIS) from pancreatic beta-cells. The operation of some pyruvate cycling pathways is proposed to necessitate malate export from the mitochondria and NADP(+)-dependent decarboxylation of malate to pyruvate by cytosolic malic enzyme (ME1). Evidence in favor of and against a role of ME1 in GSIS has been presented by othe...
متن کاملGenetic control of mitochondrial malic enzyme in mouse brain.
A mitochondrial malic enzyme (EC 1.1.1.40; L-malate: NADP+ oxidoreductase (oxalacetate-decarboxylating) has been extensively purified from mouse heart and brain. The molecular weight of the enzyme was determined in the analytical ultracentrifuge to be 250,000 to 253,000. Sodium dodecyl sulfate-polyacrylamide gels showed one major polypeptide band of molecular weight 62,000. Thus, the native pro...
متن کاملChronic reduction of the cytosolic or mitochondrial NAD(P)-malic enzyme does not affect insulin secretion in a rat insulinoma cell line.
The cytosolic malic enzyme (ME1) has been suggested to augment insulin secretion via the malate-pyruvate and/or citrate-pyruvate shuttles, through the production of NADPH or other metabolites. We used selectable vectors expressing short hairpin RNA (shRNA) to stably decrease Me1 mRNA levels by 80-86% and ME1 enzyme activity by 78-86% with either of two shRNAs in the INS-1 832/13 insulinoma cell...
متن کاملStructural studies of the pigeon cytosolic NADP(+)-dependent malic enzyme.
Malic enzymes are widely distributed in nature, and have important biological functions. They catalyze the oxidative decarboxylation of malate to produce pyruvate and CO(2) in the presence of divalent cations (Mg(2+), Mn(2+)). Most malic enzymes have a clear selectivity for the dinucleotide cofactor, being able to use either NAD(+) or NADP(+), but not both. Structural studies of the human mitoc...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 2007
ISSN: 0021-9258
DOI: 10.1074/jbc.m602954200