H-Ras is well known as one of the essential components of Ras/Raf/MEK/ERK cascade, which is a critical prosurvival signaling mechanism in most eukaryotic cells. Ras targets Raf/MEK/ERK cascade by integrating and trans...H-Ras is well known as one of the essential components of Ras/Raf/MEK/ERK cascade, which is a critical prosurvival signaling mechanism in most eukaryotic cells. Ras targets Raf/MEK/ERK cascade by integrating and transmitting extracellular signals from growth factor receptors to Raf, leading to the propagation of signals to modulate a serious of cellular survival events. Apoptosis signal-regulating kinasel (ASK1) serves as a general mediator of cell death because it is responsive to a variety of death signals. In this study, we found that H-Ras interacted with ASK1 to cause the inhibition of both ASK1 activity and ASK1-induced apoptosis in vivo, which was reversed only partially by addition of RafS621A, an antagonist of Raf, whereas MEK inhibitor, PD98059, and PI3K inhibitor, LY294002, did not disturb the inhibitory effect of H-Ras on ASK-1-induced apoptosis. Furthermore, by means of immunoprecipitate and kinase assays, we demonstrated that the interaction between H-Ras and ASK1 as well as the inhibition of ASK1 activity were dependent on the binding activity of H-Ras. These results suggest that a novel mechanism may be involved in H-Rasmediated cell survival in addition to the well established MEK/ERK and PI3K/Akt kinase-dependent enhancement of cell survival.展开更多
Objective: To demonstrate the relation sh ip between actin phosphorylation and actin sequestration in ATP-depleted rabbi t renal proximal tubules. Methods: Using two-dimensional electr ophoreses and Western blotting t...Objective: To demonstrate the relation sh ip between actin phosphorylation and actin sequestration in ATP-depleted rabbi t renal proximal tubules. Methods: Using two-dimensional electr ophoreses and Western blotting to analyze the phosphorylation state of the seque stered actin in rabbit renal proximal tubules. Results: The anal ytical result of the sequestered actin indicated that nearly half of the actin w as phosphorylated on serine residue(s). Conclusion: Result sugge sted a close correlation between actin sequestration and actin phosphorylation i n ATP-depleted rabbit renal proximal tubules.展开更多
文摘H-Ras is well known as one of the essential components of Ras/Raf/MEK/ERK cascade, which is a critical prosurvival signaling mechanism in most eukaryotic cells. Ras targets Raf/MEK/ERK cascade by integrating and transmitting extracellular signals from growth factor receptors to Raf, leading to the propagation of signals to modulate a serious of cellular survival events. Apoptosis signal-regulating kinasel (ASK1) serves as a general mediator of cell death because it is responsive to a variety of death signals. In this study, we found that H-Ras interacted with ASK1 to cause the inhibition of both ASK1 activity and ASK1-induced apoptosis in vivo, which was reversed only partially by addition of RafS621A, an antagonist of Raf, whereas MEK inhibitor, PD98059, and PI3K inhibitor, LY294002, did not disturb the inhibitory effect of H-Ras on ASK-1-induced apoptosis. Furthermore, by means of immunoprecipitate and kinase assays, we demonstrated that the interaction between H-Ras and ASK1 as well as the inhibition of ASK1 activity were dependent on the binding activity of H-Ras. These results suggest that a novel mechanism may be involved in H-Rasmediated cell survival in addition to the well established MEK/ERK and PI3K/Akt kinase-dependent enhancement of cell survival.
基金National Institute of Diabetes and Digestive and Kidney Diseases (R15DK56599 01)(USA) to Dr. Jing Chen
文摘Objective: To demonstrate the relation sh ip between actin phosphorylation and actin sequestration in ATP-depleted rabbi t renal proximal tubules. Methods: Using two-dimensional electr ophoreses and Western blotting to analyze the phosphorylation state of the seque stered actin in rabbit renal proximal tubules. Results: The anal ytical result of the sequestered actin indicated that nearly half of the actin w as phosphorylated on serine residue(s). Conclusion: Result sugge sted a close correlation between actin sequestration and actin phosphorylation i n ATP-depleted rabbit renal proximal tubules.
