细胞凋亡与衰老 Cell apoptosis.ppt

Cell apoptosis PRIZED Horvitz, and Sulston share Physiology or Medicine Nobel （2002） “for their discoveries concerning genetic regulation of organ development and programmed cell death” 1090 –131= 959(cells) 机体结构 细胞增殖 细胞分化 细胞凋亡 细胞信号转导 染色体 （DNA与蛋白质的相互作用） 衰老 ?A simplified model of one way that mitogens stimulate cell division Human cells have a built-in limitation on the number of times they can divide The cell division is cotrolled not only by extracellular mitogens but also by intracellular mechanisms that can limit cell proliferation. Cell-cycle arrest or apoptosis induced by excessive stimulation of mitogenic pathways. Extracellular growth factors stimulate cell growth Activation of cell-surface receptors Activation of PI 3-kinase Activation of elF4E (translation initiation factor) and S6 kinase(phosphorylates ribosomal protein S6) Increasing protein synthesis and cell growth 2.Apoptosis, Programmed cell death Biological functions of apoptosis ? In development, homeostasis, tumor surveillance, and the function of the immune system. ?细胞凋亡是多细胞生物在发育过程中，一种由基因控制的主动的细胞生理性自杀行为。 Morphological and biochemical characteristics of apoptosis ? Morphologi changes: Early : Chromosome condensation, cell body shrink Later : Blebbing and Nucleus and cytoplasm fragment— Apoptotic bodies At last: Phagocytosed A、Normal cell B、Apoptosis: Apoptotic bodies ? Biochemical characteristics of apoptosis : Apoptosis induced by Cyto C Lane 1．0 h 2．1 h 3．2 h 4．3 h 5．4 h 6．Control 7．Marker 2.0kbp 1.0 0.5 0.2 180~200bp DNA ladder, Accumulation of tTG, PS flip-flop Contrast ofApoptosis and necrosis Apoptosis Necrosis Death by apoptosis is a neat, orderly process 3.Molecular mechanisms of apoptosis Early researches (MIT: Robert Horrid , 1986) C. elegans:1090 cells, The Finding of CED3 mutant Without losing any of their cells to apoptosis. CED3 gene play a cr