Diacylglycerol Kinase δ Phosphorylates Phosphatidylcholine-specific Phospholipase C-dependent, Palmitic Acid-containing Diacylglycerol Species in Response to High Glucose Levels

Abstract

Background: Diacylglycerol (DG) kinase (DGK) ␦ is activated by acute high glucose stimulation. Results: DGK␦ high glucose-dependently phosphorylates 30:0-, 32:0-, and 34:0-DG and interacts with phosphatidylcholinespecific phospholipase C (PC-PLC). Conclusion: DGK␦ utilizes palmitic acid-containing DG species and metabolically connects with PC-PLC. Significance: The newly identified PC-PLC/DGK␦ pathway could play an important role in insulin signaling and glucose uptake.

A novel diacylglycerol kinase α-selective inhibitor, CU-3, induces cancer cell apoptosis and enhances immune response

“…CU-3 on DGK ␣ in cell were determined using our newly established LC/MS method ( 30,31 ). The overexpression of DGK ␣ -⌬ 1-196 ( Fig.…”

“…Total lipids were extracted from the cells according to the method of Bligh and Dyer ( 32 ). The extracted cellular lipids (10 l) containing 65 pmol of the 28:0-PA internal standard (Sigma-Aldrich) were separated on the LC system (Accela LC Systems, Thermo Fisher Scientifi c, Tokyo, Japan) using a UK-Silica column (3 m, 150 × 2.0 mm inner diameter; Imtakt, Kyoto, Japan) ( 30,31 ). Mobile phase A consisted of chloroform-methanol-ammonia (89:10:1), and mobile phase B S -transferase-fused pig DGK ␣ was expressed in Sf9 insect cells and purifi ed with a glutathione-Sepharose column (GE Healthcare).…”

“…Determination of the DGK activity in cells by LC/MS was carried out as described previously ( 30,31 ). COS-7 cells expressing DGK ␣ -⌬ 1-196 (a constitutively active mutant) were harvested in phosphate-buffered saline.…”

Diacylglycerol Signaling Pathway in Pancreatic β-Cells: An Essential Role of Diacylglycerol Kinase in the Regulation of Insulin Secretion

“…DGKε shows substrate specificity for DAG with an arachidonoyl acyl chain at the sn-2 position, whereas DGKδ preferentially phosphorylates palmitic acid-containing DAG species. 35) Further studies are needed to elucidate the involvement of DGK in the development of insulin resistance.…”

“…Since palmitic acid is a potent inducer of β-cell lipotoxicity and contributes to β-cell deficiency and apoptosis, the dysfunction of DGKδ in β-cells may be involved in the development of type 2 diabetes. 35) 6. CONCLUSION…”