We recently demonstrated that protein kinase D (PKD) exerts a protective function during oxidative stress-induced intestinal epithelial cell injury; however, the exact role of DAG kinase (DGK)ζ, an isoform expressed in intestine, during this process is unknown. We sought to determine the role of DGK during oxidative stress-induced intestinal cell injury and whether DGK acts as an upstream regulator of PKD. Inhibition of DGK with R59022 compound or DGKζ siRNA transfection decreased H2O2-induced RIE-1 cell apoptosis as measured by DNA fragmentation and increased PKD phosphorylation. Overexpression of kinase-dead DGKζ also significantly increased PKD phosphorylation. Additionally, endogenous nuclear DGKζ rapidly translocated to the cytoplasm following H2O2 treatment. Our findings demonstrate that DGK is involved in the regulation of oxidative stress-induced intestinal cell injury. PKD activation is induced by DGKζ, suggesting DGK is an upstream regulator of oxidative stress-induced activation of the PKD signaling pathway in intestinal epithelial cells.
|Number of pages||5|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Oct 17 2008|
Bibliographical noteFunding Information:
The authors thank Karen Martin for manuscript preparation and Tatsuo Uchida for assistance with statistical analyses. This work was supported by the Grants RO1 DK61470, RO1 DK48498, RO1 CA104748, PO1 DK 35608 from the National Institutes of Health and a Grant #8580 from the Shriners Hospital for Children.
- Intestinal epithelial cells
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology