铈诱导细胞凋亡过程中O_2^-·对ERK-like激酶的调控

ERK-like MAP kinase regulated by O_2^-·during Ce ^(4+)-induced apoptois of cultured Taxus cuspidata cells

对1mmol·L-1Ce4+诱导东北红豆杉细胞凋亡中ERKlike和O-2·的变化规律及其信号调控进行了分析和研究.结果表明,一相对分子质量约为46×103的ERKlike激酶在诱导5min时被快速激活,60min时达到对照水平的2.1倍,并在120min内持续激活,诱导240min后ERKlike下调到对照水平的43%,到48h下调到对照的25%.Ce4+诱导O-2·迅速产生,并有两次迸发峰分别出现在3.7～4h和7h.在Ce4+诱导前2h分别加入5μmol·L-1和10μmol·L-1DPI有效抑制了O-2·迸发,并且显著提高和延长了ERKlike磷酸化水平,诱导60min时ERKlike达到对照水平的7.3和18.8倍,240min时达到对照的9.6和10.5倍.这些结果揭示ERKlike的激活和O-2·迸发在诱导早期应是相互独立的信号事件,诱导约4h后O-2·大量迸发对ERKlike的激活有明显信号负调控作用,并通过ERKlike的下调介导了凋亡信号传递.

Ce^4＋ at 1 mmol ·L^-1 induces apop however, the underlying signal regulation of s kinase （ERK） -like MAP kinase is unknown. It kinase appeared to be activated in 5 min, and reaching 2.1-fold higher than that of the control tosis of suspension cultures of Taxus cuspidata cells; uperoxide anions （O2^-·） and extracellularly-responsive was shown that an approximately 46 ×10^3 ERK-like MAP a significant activity increase was detected in 60 min, cells. ERK-like activity remained at this high level until 120 min, and started to diminish within 240 min. By the 240th minute the activity reached about 43% of control value, and in 48 h declined to 25%. Ce^4＋-induced O2^-· transient burst, and the first peak appeared in about 3.7-4 h, the second peak appeared in about 7 h. The burst of O2^-· was effectively suppressed by the application of diphenyl iodonium （DPI） at 5 μmol·L^-1 or 10 μmol·L^-1. The inhibition of O2^-· production increased and prolonged ERK-like activity. ERK-like activity increased by about 7.3 and 18.8-fold of control value in 60 min, and reached about 9.6 and 10. 5-fold in 240 min. These results suggested that it was possible that ERK-like activation and O2^-· burst were separate signal events in early times. O2^-· burst formed signal negative regulation to ERK-like activity. Down-regulation of ERK-like partly participated in mediating apoptotie signal transduetion.