Abstract
Although treatment of myocytes with the reactive oxygen species (ROS) H 2 O 2 activates the heterotrimeric GTP-binding proteins G i and G o in a receptor-independent manner, the mechanismic detail of this effect has not been clear. Nishida et al. report that H 2 O 2 is converted to a more reactive hydroxyl radical in the presence of Fe 2+ . Myocytes treated with a cell-permeable Fe 2+ chelator inhibited the effect of H 2 O 2 and subsequent activation of mitogen-activated protein kinase. This highly reactive ROS modified two specific cyteine resideus present only in Gα i and Gα o in vitro. The modification caused dissociation of Gα i from the Gβ γ subunit and increased GTP binding. Mutation of the cysteines in Gα i inhibited subunit dissociation and the activating effect of the ROS radical. Treatment of Gα i with UV light in vitro, which generates ROS from O 2 dissolved in solution, also required the presence of the critical cysteines, suggesting that such cellular stress can activate G proteins through ROS generation. M. Nishida, K. L. Schey, S. Takagahara, K. Kontani, T. Katada, Y. Urano, T. Nagano, T. Nagao, H. Kurose, Activation mechanism of G i and G o by reactive oxygen species. J. Biol. Chem . 277 , 9036-9042 (2002). [Abstract] [Full Text]
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
