1、Chapter 13Cell apoptosis 1.Extracellular cotrol of cell division, cell growth, and apoptosisMitogens stimulate G1-Cdk and G1/S-Cdk activitiesPRIZED Horvitz, and Sulston share Physiology or Medicine Nobel （ 2002） “ for their discoveries concerning genetic regulation of organ development and programme
2、d 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 divisionHuman cells have a built-in limitation on the number of times they can divideThe cell division is cotrolled not only by extracellular mitogens but also by i
3、ntracellular mechanisms that can limit cell proliferation.Cell-cycle arrest or apoptosis induced by excessive stimulation of mitogenic pathways.Extracellular growth factors stimulate cell growthActivation of cell-surface receptorsActivation of PI 3-kinaseActivation of elF4E (translation initiation f
4、actor) and S6 kinase(phosphorylates ribosomal protein S6)Increasing protein synthesis and cell growth2.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 fragmentApoptotic bodiesAt last: Phagocytosed
