Disease relevance of ECs5025

• We find that the protein, diacylglycerol kinase from Escherichia coli, is extremely tolerant to sequence changes with three-quarters of the residues tolerating non-conservative changes [1].
• We analyzed a previously constructed stress-sensitive Streptococcus mutans mutant Tn-1 strain resulting from disruption by transposon Tn916 of a gene encoding a protein exhibiting amino acid sequence similarity to the Escherichia coli diacylglycerol kinase [2].

High impact information on ECs5025

• Diacylglycerol kinase (DGK) regulates the level of the second messenger diacylglycerol and produces phosphatidic acid (PA), another signaling molecule [3].
• AtDGK7 harbors an N-terminal catalytic domain, but in contrast to various characterized DGKs (including AtDGK2), it lacks a cysteine-rich domain at its N terminus, and, importantly, its C-terminal DGK accessory domain is incomplete [3].
• AtDGK7 activity was affected by pH, detergents, and the DGK inhibitor R59022 [3].
• Arabidopsis AtDGK7, the smallest member of plant diacylglycerol kinases (DGKs), displays unique biochemical features and saturates at low substrate concentration: the DGK inhibitor R59022 differentially affects AtDGK2 and AtDGK7 activity in vitro and alters plant growth and development [3].
• In this contribution the kinetic mechanism and substrate specificity of Escherichia coli diacylglycerol kinase were examined [4].

Chemical compound and disease context of ECs5025

• No ceramide kinase activity was detected in control COS cells, so the activity detected in pMT2dgk transfectants must have resulted from the expressed E. coli DAG kinase [5].
• The mass of sn-1,2-diacylglycerol in crude lipid extracts from differentiated HL-60 phagocytes was measured by quantitative conversion of the diacylglycerol to [32P]-labeled phosphatidic acid catalyzed by E. coli diacylglycerol kinase [6].
• In sharp contrast, Escherichia coli diglyceride kinase phosphorylated DAG, Alkyl AG, or AAG diradyl glycerol molecular subclasses at identical rates [7].
• Escherichia coli diacylglycerol kinase is an evolutionarily optimized membrane enzyme and catalyzes direct phosphoryl transfer [4].
• Appearance of monoglyceride and triglyceride in the cell envelope of Escherichia coli mutants defective in diglyceride kinase [8].

Biological context of ECs5025

• Since the metabolic removal of DAG is determined, in large part, by the rate of its phosphorylation by diglyceride kinase, we quantified differences in the activity of diglyceride kinase utilizing individual subclasses of diradyl glycerols as substrate [7].
• DAGK was observed to maintain a high nucleotide substrate specificity, with most of this specificity being expressed in the form of reductions in kcat for ATP analogs [4].
• Diacylglycerol kinase exhibited Michaelis-Menten kinetics with respect to diacylglycerol and MgATP [9].
• Introduction of such hybrid plasmids into a mutant harboring dgkR-1 leads to a multiplicative (rather than additive) effect, resulting in specific activities of diglyceride kinase that are 35-75-fold higher than normal [10].
• Furthermore, an open reading frame encoding a 122-residue polypeptide consistent with the size of diglyceride kinase has been identified and coincides with the position of dgk determined by deletion analysis [11].

Anatomical context of ECs5025

• Neutral lipid accumulation in the membranes of Escherichia coli mutants lacking diglyceride kinase [12].
• COS cells transfected with the vector pMT2dgk expressed the DAG kinase as shown by Western analysis [5].
• Similar subclass specificities for diglyceride kinase (i.e. DAG greater than Alkyl AG much greater than AAG) were present in brain and liver cytosol as well as in liver microsomes utilizing multiple assay conditions [7].
• Immunofluorescence studies revealed that the E. coli DAG kinase was prominently but not exclusively located in the endoplasmic reticulum [5].
• The membrane-bound diacylglycerol kinase from Swiss 3T3 cells (M-DG kinase) was characterized with a mixed micellar assay system, and compared with the cytosolic diacylglycerol kinase from 3T3 cells and with the membrane-bound diacylglycerol kinase from Escherichia coli [13].

Associations of ECs5025 with chemical compounds

• No alterations in the affinity of microsomal diglyceride kinase for ATP were present (Km approximately 0.5 mM) utilizing each diradyl glycerol subclass [7].
• Diacylglycerol kinase was active in mixed micelles containing octyl glucoside and dioleoyglycerol [9].
• The kinetic data were consistent with a random equilibrium mechanism, implying that diacylglycerol kinase catalyzes direct phosphoryl transfer from MgATP to diacylglycerol [4].
• Consistent with these observations, diacylglycerol analogues modified only in the acyl chains or sn-2 ester were not diacylglycerol kinase inhibitors, whereas analogues with substitutions of the sn-1 ester or sn-3 hydroxyl frequently caused inhibition [14].
• Moreover, the final ratio of irreversibly misfolded DAGK to reversibly misfolded enzyme was highest following reactions initiated with guanidinium stock solutions and lowest when micellar stocks were used [15].

Other interactions of ECs5025

• The lipid A 4'-kinase is distinct from the diglyceride kinase of E. coli [16].

Analytical, diagnostic and therapeutic context of ECs5025

• We have compared site-directed 13C solid-state NMR spectra of [3-13C]Ala- and/or [1-13C]Val-labeled membrane proteins, including bacteriorhodopsin (bR), pharaonis phoborhodopin (ppR), its cognate transducer (pHtrII) and Escherichia coli diacylglycerol kinase (DGK), in two-dimensional (2D) crystal, lipid bilayers, and detergent [17].
• Expression, purification, crystallization and preliminary diffraction studies of the mammalian DAG kinase homologue YegS from Escherichia coli [18].

References