1P081 Distinct roles of two cysteine-rich domains in the arachidonate- and TPA-induced translocation of diacylglycerol kinase γ

• Published in: Journal of Pharmacological Sciences 2003, Vol.91 (suppl.1), p.126-126
• Main Authors: Kei Miyasaka, Yasuhito Shirai, Takehiro Matsubara, Norio Sakai, Naoaki Saito
• Format: Article
• Language: Japanese
• ISSN: 1347-8613

Diacylglycerol kinase (DGK) phosphorylates diacylglycerol, resulting in attenuation of PKC. At least 9 subtypes of DGK have been cloned and many of them have two cysteine-rich domains (CIA and CIB). DGKS seem to have subtype specific function but mechanism to regulate the subtype-specificity is still unknown. We have found that DGKS subtype-specifically translocate, suggesting its importance for the subtype specific functions. In this study, to investigate the molecular mechanism to arise the subtype-specific translocation, responsible region for arachidonate- (AA) and TPA-induced translocation of DGKγ was determined. When GFP-tagged DGKγ was expressed in CHO-KI cells, its fluorescence was observed throughout of the cell. Both TPA and AA induced translocation of GFP-DGKγ from the cytoplasm to the plasma membrane. A mutant of DGKγ lacking CIA domain still respond to AA, but not to TPA. In contrast, a mutant lacking C1B domain lost the ability to translocate in response to AA although it could respond to TPA. Furthermore, a mutant having an additional C1B domain instead of C1A could translocate by AA but not TPA, while a mutant having C1A domain instead of C1B could to respond to TPA. These results indicate that C1B domain is mainly responsible for AA-induced translocation of DGKγ, while CIA domain is for TPA-induced one.