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

Authors :
Ken-ichi Yoshino
Fumio Sakane
Takehiro Matsubara
Momo Ikeda
Isabel Mérida
Yuko Kiso
Naoaki Saito
Megumi Sakuma
Yasuhito Shirai
Source :
Journal of Biological Chemistry. 287:5507-5517
Publication Year :
2012
Publisher :
Elsevier BV, 2012.

Abstract

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 α (DGKα), an important regulator of many cellular events through its conversion of diacylglycerol to phosphatidic acid. We found that DGKα 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 DGKα, and shuttles between the nucleus and the cytoplasm in a direction opposite to that of DGKα in response to serum restoration. Moreover, an in vitro phosphorylation assay using purified mutants of DGKα identified Tyr-218 as a site of phosphorylation by c-Abl. We confirmed these results for endogenous DGKα using an antibody specific for phospho-Tyr-218, and this phosphorylation was necessary for the serum-induced export of DGKα. These results demonstrate that the nucleo-cytoplasmic shuttling of DGKα 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 DGKα.

Details

ISSN :
00219258
Volume :
287
Database :
OpenAIRE
Journal :
Journal of Biological Chemistry
Accession number :
edsair.doi.dedup.....9072add1e60190476b9566707c350432
Full Text :
https://doi.org/10.1074/jbc.m111.296897