Details

Autor(en) / Beteiligte

• Usatyuk, Peter V.
• Gorshkova, Irina A.
• He, Donghong
• Zhao, Yutong
• Kalari, Satish K.
• Garcia, Joe G.N.
• Natarajan, Viswanathan

Titel

Phospholipase D-mediated Activation of IQGAP1 through Rac1 Regulates Hyperoxia-induced p47phox Translocation and Reactive Oxygen Species Generation in Lung Endothelial Cells

Ist Teil von

• The Journal of biological chemistry, 2009-05, Vol.284 (22), p.15339-15352

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2009

Link zum Volltext

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Phosphatidic acid generated by the activation of phospholipase D (PLD) functions as a second messenger and plays a vital role in cell signaling. Here we demonstrate that PLD-dependent generation of phosphatidic acid is critical for Rac1/IQGAP1 signal transduction, translocation of p47phox to cell periphery, and ROS production. Exposure of [32P]orthophosphate-labeled human pulmonary artery endothelial cells (HPAECs) to hyperoxia (95% O2 and 5% CO2) in the presence of 0.05% 1-butanol, but not tertiary-butanol, stimulated PLD as evidenced by accumulation of [32P]phosphatidylbutanol. Infection of HPAECs with adenoviral constructs of PLD1 and PLD2 wild-type potentiated hyperoxia-induced PLD activation and accumulation of O2⋅−/reactive oxygen species (ROS). Conversely, overexpression of catalytically inactive mutants of PLD (hPLD1-K898R or mPLD2-K758R) or down-regulation of expression of PLD with PLD1 or PLD2 siRNA did not augment hyperoxia-induced [32P]phosphatidylbutanol accumulation and ROS generation. Hyperoxia caused rapid activation and redistribution of Rac1, and IQGAP1 to cell periphery, and down-regulation of Rac1, and IQGAP1 attenuated hyperoxia-induced tyrosine phosphorylation of Src and cortactin and ROS generation. Further, hyperoxia-mediated redistribution of Rac1, and IQGAP1 to membrane ruffles, was attenuated by PLD1 or PLD2 small interference RNA, suggesting that PLD is upstream of the Rac1/IQGAP1 signaling cascade. Finally, small interference RNA for PLD1 or PLD2 attenuated hyperoxia-induced cortactin tyrosine phosphorylation and abolished Src, cortactin, and p47phox redistribution to cell periphery. These results demonstrate a role of PLD in hyperoxia-mediated IQGAP1 activation through Rac1 in tyrosine phosphorylation of Src and cortactin, as well as in p47phox translocation and ROS formation in human lung endothelial cells.