Reactive oxygen species (ROS), including the hydroxyl radical ( · OH), are known to be potential modulators of apoptosis. However, the biochemical mechanisms underlying apoptosis induced by ...Reactive oxygen species (ROS), including the hydroxyl radical ( · OH), are known to be potential modulators of apoptosis. However, the biochemical mechanisms underlying apoptosis induced by ·OH, namely how the radical induces a cell to die, are poorly understood. The present work highlights the changes of the energy/redox status during apoptosis by exogenous ·OH treatment. HeLa cells were induced to undergo typical apoptosis by ·OH generated directly via the Fe 2+ mediated Fenton reaction. The thermodynamics study indicated that the ·OH treatment increased the cellular heat output in the first hours, and then the cellular thermodynamics shifted to endothermic. The data demonstrates that the mitochondria are actively involved in ·OH treatment induced apoptosis, with the cellular oxygen consumption rapidly decreasing after the ·OH treatment for only 0.5 h. But DNA fragmentation, which is the major characteristic of apoptosis, took place 16 h after ·OH treatment. The results suggest that alteration of the energy/redox metabolism and the energy/redox status may be the primary causes among the early events of ·OH induced apoptosis.展开更多
Synaptotagmin Ⅰ(sytⅠ) is an abundant integral membrane protein of the synaptic vesicle and the C2A domain is an important functional domain in the cytoplasmic part of sytⅠ. C2A prefers to interact with plasmic me...Synaptotagmin Ⅰ(sytⅠ) is an abundant integral membrane protein of the synaptic vesicle and the C2A domain is an important functional domain in the cytoplasmic part of sytⅠ. C2A prefers to interact with plasmic membranes of neuron cells in vivo and such interaction is closely related to the sytⅠ physiological function as a Ca 2+ sensor in the Ca 2+ regulated neurotransmitter release. However, the interaction nature between C2A and phospholipids is not well understood. Monolayers at an air/water interface were used to study the interaction between C2A and a phospholipid membrane. The results show that C2A preferentially inserts into the negatively charged phosphatidylserine monolayer and Ca 2+ ions are required for the interaction. Electrostatic force is mostly responsible for the insertion of C2A into dipalmitoyl phosphatidylserine monolayers.展开更多
文摘Reactive oxygen species (ROS), including the hydroxyl radical ( · OH), are known to be potential modulators of apoptosis. However, the biochemical mechanisms underlying apoptosis induced by ·OH, namely how the radical induces a cell to die, are poorly understood. The present work highlights the changes of the energy/redox status during apoptosis by exogenous ·OH treatment. HeLa cells were induced to undergo typical apoptosis by ·OH generated directly via the Fe 2+ mediated Fenton reaction. The thermodynamics study indicated that the ·OH treatment increased the cellular heat output in the first hours, and then the cellular thermodynamics shifted to endothermic. The data demonstrates that the mitochondria are actively involved in ·OH treatment induced apoptosis, with the cellular oxygen consumption rapidly decreasing after the ·OH treatment for only 0.5 h. But DNA fragmentation, which is the major characteristic of apoptosis, took place 16 h after ·OH treatment. The results suggest that alteration of the energy/redox metabolism and the energy/redox status may be the primary causes among the early events of ·OH induced apoptosis.
文摘Synaptotagmin Ⅰ(sytⅠ) is an abundant integral membrane protein of the synaptic vesicle and the C2A domain is an important functional domain in the cytoplasmic part of sytⅠ. C2A prefers to interact with plasmic membranes of neuron cells in vivo and such interaction is closely related to the sytⅠ physiological function as a Ca 2+ sensor in the Ca 2+ regulated neurotransmitter release. However, the interaction nature between C2A and phospholipids is not well understood. Monolayers at an air/water interface were used to study the interaction between C2A and a phospholipid membrane. The results show that C2A preferentially inserts into the negatively charged phosphatidylserine monolayer and Ca 2+ ions are required for the interaction. Electrostatic force is mostly responsible for the insertion of C2A into dipalmitoyl phosphatidylserine monolayers.
