Activation of Akt is induced by heat shock and involved in suppression of heat-shock-induced apoptosis of NIH3T3 cells.
Heat shock exposure to NIH3T3 cells for 15 min at 45 degrees C activated Akt, which is mediated by PI3-kinase, as evidenced by the significant inhibition of heat-shock-induced phosphorylation by specific inhibitors of PI3-kinase. The phosphorylated Akt was gradually decreased to the basal level within 9 h after heat shock. This resulted in growth arrest, but cell growth could be recovered within 24 h accompanied with a high rate of proliferation. However, heat shock for 60 min failed to activate Akt, resulting in apoptosis. The recovery of cell growth after heat-shock-inducing activation of Akt was completely blocked by wortmannin. Moreover, overexpression of a dominant-negative Akt mutant significantly inhibited the apoptosis-suppressive effect of heat shock, indicating the direct involvement of heat-shock-induced Akt activation in the apoptosis suppression. The results indicate that a signal transduction pathway, namely, PI3-kinase/Akt, may contribute to an apoptosis-suppressive function after heat shock in NIH3T3 cells.
Bang
O S
OS
Department of Biology, College of Natural Sciences, Kyungpook National University, Taegu, 702-701, Korea.
Ha
B G
BG
Park
E K
EK
Kang
S S
SS
D016475:3T3 Cells; D000818:Animals; D017209:Apoptosis; D002453:Cell Cycle; D002455:Cell Division; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018869:Heat-Shock Response; D051379:Mice; D016716:PC12 Cells; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats
D004791:Enzyme Inhibitors; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; C494920:Akt1 protein, rat; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt