Copper Ions Strongly Activate the Phosphoinositide-3-Kinase/Akt Pathway Independent of the Generation of Reactive Oxygen Species

2002 ◽  
Vol 397 (2) ◽  
pp. 232-239 ◽  
Author(s):  
Elena A. Ostrakhovitch ◽  
Mohammad Reza Lordnejad ◽  
Freimut Schliess ◽  
Helmut Sies ◽  
Lars-Oliver Klotz
Keyword(s):  
Reactive Oxygen Species ◽  
Copper Ions ◽  
Reactive Oxygen ◽  
Akt Pathway ◽  
Oxygen Species ◽  
Phosphoinositide 3 Kinase

scholarly journals The Major Target of the Endogenously Generated Reactive Oxygen Species in Response to Insulin Stimulation Is Phosphatase and Tensin Homolog and Not Phosphoinositide-3 Kinase (PI-3 Kinase) in the PI-3 Kinase/Akt Pathway

2005 ◽  
Vol 16 (1) ◽  
pp. 348-357 ◽  
Author(s):  
Ji Hae Seo ◽  
Younghee Ahn ◽  
Seung-Rock Lee ◽  
Chang Yeol Yeo ◽  
Kyu Chung Hur
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Lines ◽  
Membrane Fraction ◽  
Akt Pathway ◽  
Oxygen Species ◽  
Insulin Stimulation ◽  
Phosphatase And Tensin Homolog ◽  
Downstream Signaling ◽  
Tensin Homolog ◽  
Phosphoinositide 3 Kinase

Phosphoinositide-3 kinase (PI-3 kinase) and its downstream signaling molecules PDK-1 and Akt were analyzed in SK-N-SH and SK-N-BE(2) human neuroblastoma cell lines. When cells were stimulated with insulin, PI-3 kinase was activated in both cell lines, whereas the translocation of PDK-1 to the membrane fraction and phosphorylated Akt were observed only in SK-N-SH cells. Analyses of the insulin-mediated reactive oxygen species (ROS) generation and Phosphatase and Tensin homolog (PTEN) oxidation indicate that PTEN oxidation occurred in SK-N-SH cells, which can produce ROS, but not in SK-N-BE(2) cells, which cannot increase ROS in response to insulin stimulation. When SK-N-SH cells were pretreated with the NADPH oxidase inhibitor diphenyleneiodonium chloride before insulin stimulation, insulin-mediated translocation of PDK-1 to the membrane fraction and phosphorylation of Akt were remarkably reduced, whereas PI-3 kinase activity was not changed significantly. These results indicate that not only PI-3 kinase activation but also inhibition of PTEN by ROS is needed to increase cellular level of phosphatidylinositol 3,4,5-trisphosphate for recruiting downstream signaling molecules such as PDK-1 and Akt in insulin-mediated signaling. Moreover, the ROS generated by insulin stimulation mainly contributes to the inactivation of PTEN and not to the activation of PI-3 kinase in the PI-3 kinase/Akt pathway.

scholarly journals β-Amyloid Fibrils in Alzheimer Disease Are Not Inert When Bound to Copper Ions but Can Degrade Hydrogen Peroxide and Generate Reactive Oxygen Species

2014 ◽  
Vol 289 (17) ◽  
pp. 12052-12062 ◽  
Author(s):  
Jennifer Mayes ◽  
Claire Tinker-Mill ◽  
Oleg Kolosov ◽  
Hao Zhang ◽  
Brian J. Tabner ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Alzheimer Disease ◽  
Amyloid Fibrils ◽  
Copper Ions ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Β Amyloid

scholarly journals Reactive Oxygen Species Regulate Oxygen-Sensitive Potassium Flux in Rainbow Trout Erythrocytes

2001 ◽  
Vol 117 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Anna Yu Bogdanova ◽  
Mikko Nikinmaa
Keyword(s):  
Reactive Oxygen Species ◽  
Hydroxyl Radicals ◽  
Fenton Reaction ◽  
Copper Ions ◽  
Reactive Oxygen ◽  
Potassium Transport ◽  
Oxygen Species ◽  
Hypoxic Conditions ◽  
Potassium Flux ◽  
Oxygen Sensitive

In the present study, we have investigated if reactive oxygen species are involved in the oxygen-dependent regulation of potassium-chloride cotransport activity in trout erythrocyte membrane. An increase in the oxygen level caused an increase in chloride-sensitive potassium transport (K+-Cl− cotransport). 5 mM hydrogen peroxide caused an increase in K+-Cl− cotransport at 5% oxygen. The increase in flux could be inhibited by adding extracellular catalase in the incubation. Pretreatment of the cells with mercaptopropionyl glycine (MPG), a scavenger of reactive oxygen species showing preference for hydroxyl radicals, abolished the activation of the K+-Cl− cotransporter by increased oxygen levels. The inhibition by MPG was reversible, and MPG could not inhibit the activation of transporter by the sulfhydryl reagent, N-ethylmaleimide, indicating that the effect of MPG was due to the scavenging of reactive oxygen species and not to the reaction of MPG with the cotransporter. Copper ions, which catalyze the production of hydroxyl radicals in the Fenton reaction, activated K+-Cl− cotransport significantly at hypoxic conditions (1% O2). These data suggest that hydroxyl radicals, formed from O2 in close vicinity to the cell membrane, play an important role in the oxygen-dependent activation of the K+-Cl− cotransporter.

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