Evaluation of sub-cellular distribution of glutamate dehydrogenase (GDH) in Drosophila melanogaster larvae

Tiwari, Anjana; Panda, Pragnya; Purohit, Jogeswar S.

doi:10.1016/j.acthis.2013.08.007

Cited by 5 publications

(3 citation statements)

References 33 publications

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“…More recent IHC studies in human brain revealed hGDH1 and hGDH2-specific immunostaining of the nuclear membrane of glial and neuronal cells, respectively [73]. Regarding lower organisms, the potential nuclear localization of GDH has been suggested for S. cerevisiae [74] but not for D. melanogaster [75]. …”

Section: Gdh Subcellular Localizationmentioning

confidence: 99%

The Glutamate Dehydrogenase Pathway and Its Roles in Cell and Tissue Biology in Health and Disease

Plaitakis

Kalef-Ezra

Kotzamani

et al. 2017

Biology

136

113

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Glutamate dehydrogenase (GDH) is a hexameric enzyme that catalyzes the reversible conversion of glutamate to α-ketoglutarate and ammonia while reducing NAD(P)+ to NAD(P)H. It is found in all living organisms serving both catabolic and anabolic reactions. In mammalian tissues, oxidative deamination of glutamate via GDH generates α-ketoglutarate, which is metabolized by the Krebs cycle, leading to the synthesis of ATP. In addition, the GDH pathway is linked to diverse cellular processes, including ammonia metabolism, acid-base equilibrium, redox homeostasis (via formation of fumarate), lipid biosynthesis (via oxidative generation of citrate), and lactate production. While most mammals possess a single GDH1 protein (hGDH1 in the human) that is highly expressed in the liver, humans and other primates have acquired, via duplication, an hGDH2 isoenzyme with distinct functional properties and tissue expression profile. The novel hGDH2 underwent rapid evolutionary adaptation, acquiring unique properties that enable enhanced enzyme function under conditions inhibitory to its ancestor hGDH1. These are thought to provide a biological advantage to humans with hGDH2 evolution occurring concomitantly with human brain development. hGDH2 is co-expressed with hGDH1 in human brain, kidney, testis and steroidogenic organs, but not in the liver. In human cerebral cortex, hGDH1 and hGDH2 are expressed in astrocytes, the cells responsible for removing and metabolizing transmitter glutamate, and for supplying neurons with glutamine and lactate. In human testis, hGDH2 (but not hGDH1) is densely expressed in the Sertoli cells, known to provide the spermatids with lactate and other nutrients. In steroid producing cells, hGDH1/2 is thought to generate reducing equivalents (NADPH) in the mitochondria for the biosynthesis of steroidal hormones. Lastly, up-regulation of hGDH1/2 expression occurs in cancer, permitting neoplastic cells to utilize glutamine/glutamate for their growth. In addition, deregulation of hGDH1/2 is implicated in the pathogenesis of several human disorders.

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Section: Gdh Subcellular Localizationmentioning

confidence: 99%

The Glutamate Dehydrogenase Pathway and Its Roles in Cell and Tissue Biology in Health and Disease

Plaitakis

Kalef-Ezra

Kotzamani

et al. 2017

Biology

136

113

View full text Add to dashboard Cite

show abstract

“…Glutamate dehydrogenase (GDH, EC 1.4.1.3) is a metabolic enzyme that catalyses the reversible reaction of L-glutamate to α-ketoglutarate (α-KG), with the concomitant reduction of NAD(P)+ to NAD(P)H or vice versa ( Plaitakis et al 2011 ; Mastorodemos et al 2009 , 2005 ). GDH is mainly located in the mitochondria, although recently it was shown that GDH is also present in the cytoplasm, endoplasmic reticulum and nucleus ( Tiwari et al 2014 ; Mastorodemos et al 2009 ; Prisco et al 1968 ). Yet, its functions outside the mitochondria are unknown.…”

Section: Introductionmentioning

confidence: 99%

Determination of Glutamate Dehydrogenase Activity and Its Kinetics in Mouse Tissues using Metabolic Mapping (Quantitative Enzyme Histochemistry)

Botman

Tigchelaar

Noorden

2014

J Histochem Cytochem.

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Glutamate dehydrogenase (GDH) catalyses the reversible conversion of glutamate into α-ketoglutarate with the concomitant reduction of NAD(P)+ to NAD(P)H or vice versa. GDH activity is subject to complex allosteric regulation including substrate inhibition. To determine GDH kinetics in situ, we assessed the effects of various glutamate concentrations in combination with either the coenzyme NAD+ or NADP+ on GDH activity in mouse liver cryostat sections using metabolic mapping. NAD+-dependent GDH Vmax was 2.5-fold higher than NADP+-dependent Vmax, whereas the Km was similar, 1.92 mM versus 1.66 mM, when NAD+ or NADP+ was used, respectively. With either coenzyme, Vmax was determined at 10 mM glutamate and substrate inhibition was observed at higher glutamate concentrations with a Ki of 12.2 and 3.95 for NAD+ and NADP+ used as coenzyme, respectively. NAD+- and NADP+-dependent GDH activities were examined in various mouse tissues. GDH activity was highest in liver and much lower in other tissues. In all tissues, the highest activity was found when NAD+ was used as a coenzyme. In conclusion, GDH activity in mice is highest in the liver with NAD+ as a coenzyme and highest GDH activity was determined at a glutamate concentration of 10 mM.

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“…Both Gdh and Bb8 are localized in the mitochondria, but somatic cells and post-meiotic spermatids have morphologically, and probably functionally, very different mitochondria [ 31 ]. This could explain why several testis-specific mitochondrial genes, such as fzo , parkin , Hsp60 or cyt-c-d , have increased expression in meiotic over mitotic stages [ 32 ] [ 9 ] [ 8 ] [ 33 ] [ 34 ].…”

Section: Discussionmentioning

confidence: 99%

Testis-Specific Bb8 Is Essential in the Development of Spermatid Mitochondria

et al. 2016

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Mitochondria are essential organelles of developing spermatids in Drosophila, which undergo dramatic changes in size and shape after meiotic division, where mitochondria localized in the cytoplasm, migrate near the nucleus, aggregate, fuse and create the Nebenkern. During spermatid elongation the two similar mitochondrial derivatives of the Nebenkern start to elongate parallel to the axoneme. One of the elongated mitochondrial derivatives starts to lose volume and becomes the minor mitochondrial derivative, while the other one accumulates paracrystalline and becomes the major mitochondrial derivative. Proteins and intracellular environment that are responsible for cyst elongation and paracrystalline formation in the major mitochondrial derivative need to be identified. In this work we investigate the function of the testis specific big bubble 8 (bb8) gene during spermatogenesis. We show that a Minos element insertion in bb8 gene, a predicted glutamate dehydrogenase, causes recessive male sterility. We demonstrate bb8 mRNA enrichment in spermatids and the mitochondrial localisation of Bb8 protein during spermatogenesis. We report that megamitochondria develop in the homozygous mutant testes, in elongating spermatids. Ultrastructural analysis of the cross section of elongated spermatids shows enlarged mitochondria and the production of paracrystalline in both major and minor mitochondrial derivatives. Our results suggest that the Bb8 protein and presumably glutamate metabolism has a crucial role in the normal development and establishment of the identity of the mitochondrial derivatives during spermatid elongation.

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Evaluation of sub-cellular distribution of glutamate dehydrogenase (GDH) in Drosophila melanogaster larvae

Cited by 5 publications

References 33 publications

The Glutamate Dehydrogenase Pathway and Its Roles in Cell and Tissue Biology in Health and Disease

The Glutamate Dehydrogenase Pathway and Its Roles in Cell and Tissue Biology in Health and Disease

Determination of Glutamate Dehydrogenase Activity and Its Kinetics in Mouse Tissues using Metabolic Mapping (Quantitative Enzyme Histochemistry)

Testis-Specific Bb8 Is Essential in the Development of Spermatid Mitochondria

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