c-Abl Tyrosine Kinase Regulates Serum-induced Nuclear Export of Diacylglycerol Kinase alpha by Phosphorylation at Tyr-218

[摘要]：c-Abl is a tyrosine kinase involved in many cellular processes, including cell cycle control and proliferation. However, little is known about its substrates. Here, we show that c-Abl directly phosphorylates diacylglycerol kinase alpha (DGK alpha), an important regulator of many cellular events through its conversion of diacylglycerol to phosphatidic acid. We found that DGK alpha was transported from the cytoplasm to the nucleus in response to serum starvation, and serum restoration induced the nuclear export of the enzyme to the cytoplasm. This serum-induced export involves two tyrosine kinases, c-Src and c-Abl. The latter, c-Abl, is activated by c-Src, phosphorylates DGK alpha, and shuttles between the nucleus and the cytoplasm in a direction opposite to that of DGK alpha in response to serum restoration. Moreover, an in vitro phosphorylation assay using purified mutants of DGK alpha identified Tyr-218 as a site of phosphorylation by c-Abl. We confirmed these results for endogenous DGK alpha using an antibody specific for phospho-Tyr-218, and this phosphorylation was necessary for the serum-induced export of DGK alpha. These results demonstrate that the nucleo-cytoplasmic shuttling of DGK alpha is orchestrated by tyrosine phosphorylation by the Src-activated tyrosine kinase c-Abl and that this phosphorylation is important for regulating the function of cytoplasmic and/or nuclear DGK alpha.

[全文传递流程]：

一般上传文献全文的时限在1个工作日内