Disease relevance of Dgk

• Diacylglycerol kinase defect in a Drosophila retinal degeneration mutant rdgA [1].

High impact information on Dgk

• We now find that quantum bumps in such mutants are reduced approximately 3- to 5-fold but are restored to near wild-type values by mutations in the rdgA gene encoding diacylglycerol kinase (DGK) and also by depleting intracellular ATP [2].
• Molecular basis of amplification in Drosophila phototransduction: roles for G protein, phospholipase C, and diacylglycerol kinase [2].
• The results demonstrate that amplification requires activation of multiple G protein and PLC molecules, identify DGK as a key enzyme regulating amplification, and implicate diacylglycerol as a messenger of excitation in Drosophila phototransduction [2].
• DGK-IV was different from previously identified mammalian DG kinase species, DGK-I, DGK-II, and DGK-III, in that it contained no EF-hand motifs but did contain four ankyrin-like repeats at the carboxyl terminus [3].
• The DGK cDNA has a single open reading frame that encodes 791 amino acids [4].

Biological context of Dgk

• The DGK gene was mapped to the cytogenetic position 43F1, and its DGK mRNA is abundant both in embryo and in adult fly [4].
• A Drosophila gene encoding a protein with similarity to diacylglycerol kinase (DGK) was isolated by screening a genomic DNA library with a human DGK cDNA under low-stringency hybridization conditions [5].
• The dDGK protein may be involved in regulating signal transduction in these specific neurons [5].
• This putative Drosophila DGK gene (dDGK) maps to 43E on the right arm of chromosome 2 [5].
• Diacylglycerol (DAG) plays a central role in both the synthesis of complex lipids and in intracellular signaling; diacylglycerol kinase (DGK) catalyzes the phosphorylation of DAG, which yields phosphatidic acid [6].

Anatomical context of Dgk

• In stage-16 and stage-17 embryos, dDGK transcripts are limited to the central nervous system and head [5].
• In this study, we show that retinal degeneration is prevented by the introduction of the eye-DGK gene in the rdgA mutant genome, suggesting that the DGK activity is crucial for the maintenance of the photoreceptor [7].

Associations of Dgk with chemical compounds

• The activity of the DG kinase was inhibited by deoxycholate and was not activated by Ca2+ [8].
• The apparent Km values of partially purified DG kinase were 220 microM for ATP and 540 microM for diolein, respectively [8].
• The activities against both phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol were always affected in parallel among the mutants, while the activities of other enzymes related to phosphatidylinositol metabolism, such as diacylglycerol kinase, were not [9].

Other interactions of Dgk

• We describe the identification and molecular analysis of a novel type III Drosophila diacylglycerol kinase isoform, DGKepsilon [10].
• The DG kinase was found to be localized in the retinular cell by assaying its activity in the mutants rdgA (receptor cells degenerated) and sine oculis (compound eyes absent) [11].

Analytical, diagnostic and therapeutic context of Dgk

• Molecular cloning of a Drosophila diacylglycerol kinase gene that is expressed in the nervous system and muscle [4].

References