Jeon Byeong Wook, Kim Kee Tae, Chang Soo-Ik, Kim Hak Yong
Division of Life Sciences, College of Natural Sciences, and Institute for Basic Science, Chungbuk National University, Cheongju 361-763, Korea.
J Biochem. 2002 May;131(5):693-9. doi: 10.1093/oxfordjournals.jbchem.a003153.
Apoptosis is a common mode of programmed cell death in multicellular organisms. However, the recent observation of yeast cell death displaying the morphology of apoptosis has suggested the presence of an ancestral cell death machinery. Here we examined apoptotic features induced by reactive oxygen species (ROS) in yeast. Saccharomyces cerevisiae show typical apoptotic features upon exposure to ROS: membrane staining with annexin V and DNA fragmentation by the TUNEL assay. The detection of apoptotic features in yeast strongly support the existence of molecular machinery performing the basic pathways of apoptosis. The phosphoinositide 3-OH kinase (PI3K)/protein kinase B (PKB) signaling pathway has been shown to prevent apoptosis in a variety of cells. It is therefore of interest to determine whether the PI3K/PKB signaling pathway is capable of protecting yeast from apoptosis induced by ROS. We determined that PI3K/PKB is capable of significantly inhibiting ROS-evoked apoptosis in yeast. These results suggest that yeast may provide a suitable model system in which to study the apoptotic signaling pathway elicited by a variety of stimuli.
细胞凋亡是多细胞生物体中一种常见的程序性细胞死亡方式。然而，最近对呈现细胞凋亡形态的酵母细胞死亡的观察表明，存在一种原始的细胞死亡机制。在此，我们研究了酵母中活性氧（ROS）诱导的凋亡特征。酿酒酵母在暴露于ROS时表现出典型的凋亡特征：通过膜联蛋白V进行膜染色以及通过TUNEL检测法检测DNA片段化。在酵母中检测到凋亡特征有力地支持了执行凋亡基本途径的分子机制的存在。磷酸肌醇3-羟基激酶（PI3K）/蛋白激酶B（PKB）信号通路已被证明可防止多种细胞发生凋亡。因此，确定PI3K/PKB信号通路是否能够保护酵母免受ROS诱导的凋亡是很有意义的。我们确定PI3K/PKB能够显著抑制酵母中ROS诱发的凋亡。这些结果表明，酵母可能提供一个合适的模型系统，用于研究由多种刺激引发的凋亡信号通路。
