TY - JOUR
T1 - In vitro evidence for the recognition of 8-oxoGTP by Ras, a small GTP-binding protein
AU - Yoon, Sun Hee
AU - Hyun, Jin Won
AU - Choi, Jinhee
AU - Choi, Eun Young
AU - Kim, Hee Joon
AU - Lee, Su Jae
AU - Chung, Myung Hee
PY - 2005/2/4
Y1 - 2005/2/4
N2 - Oxygen radicals attack guanine bases in DNA but they also attack cytoplasmic GTP forming 8-oxoGTP. The presence of 8-oxoGTP in cytoplasm is evidenced by the fact that cells contain MutT/MTH1 which hydrolyze 8-oxoGTP into 8-oxoGMP. In this study, the interaction between 8-oxoGTP and Ras, a small GTP-binding protein, was tested in vitro, and the action of 8-oxoGTP was compared to that of GTP. When purified Ras was treated with 8-oxoGTPγS, Ras was activated, as indicated by the enhanced binding of Ras with Raf-1. GTPγS also activated Ras but 8-oxoGTPγS had a much more potent effect. In lysates of human embryo kidney 293 cells, 8-oxoGTPγS activated not only Ras but also the downstream effectors of the Ras-ERK pathway, i.e., Raf-1 and ERK1/2. In contrast to Ras, other small GTP-binding proteins, Rac1 and Cdc42, were inactivated by 8-oxoGTPγS, whereas both of these proteins were activated by GTPγS, indicating that the biological natures of 8-oxoGTP and GTP differ. These results suggest the possibility that 8-oxoGTP is not a simple by-product but a functional molecule transmitting an oxidative signal to small GTP-binding proteins like Ras.
AB - Oxygen radicals attack guanine bases in DNA but they also attack cytoplasmic GTP forming 8-oxoGTP. The presence of 8-oxoGTP in cytoplasm is evidenced by the fact that cells contain MutT/MTH1 which hydrolyze 8-oxoGTP into 8-oxoGMP. In this study, the interaction between 8-oxoGTP and Ras, a small GTP-binding protein, was tested in vitro, and the action of 8-oxoGTP was compared to that of GTP. When purified Ras was treated with 8-oxoGTPγS, Ras was activated, as indicated by the enhanced binding of Ras with Raf-1. GTPγS also activated Ras but 8-oxoGTPγS had a much more potent effect. In lysates of human embryo kidney 293 cells, 8-oxoGTPγS activated not only Ras but also the downstream effectors of the Ras-ERK pathway, i.e., Raf-1 and ERK1/2. In contrast to Ras, other small GTP-binding proteins, Rac1 and Cdc42, were inactivated by 8-oxoGTPγS, whereas both of these proteins were activated by GTPγS, indicating that the biological natures of 8-oxoGTP and GTP differ. These results suggest the possibility that 8-oxoGTP is not a simple by-product but a functional molecule transmitting an oxidative signal to small GTP-binding proteins like Ras.
KW - 8-oxoGTP
KW - Oxidative stress
KW - Ras
KW - Small GTP-binding protein
UR - http://www.scopus.com/inward/record.url?scp=11144235215&partnerID=8YFLogxK
U2 - 10.1016/j.bbrc.2004.12.013
DO - 10.1016/j.bbrc.2004.12.013
M3 - Article
C2 - 15629468
AN - SCOPUS:11144235215
SN - 0006-291X
VL - 327
SP - 342
EP - 348
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 1
ER -