2009 sinauer associates inc uncorrected page proofs

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Unformatted text preview: from caspase-8 cleavage of the proapoptotic BH3-only protein Bid, leading to Bid activation, permeabilization of mitochondria, and activation of caspase-9, thus amplifying the caspase cascade initiated by direct activation of caspase-8 at cell death receptors. Alternative Pathways of Programmed Cell Death Although apoptosis is the most common form of regulated or programmed cell death, recent research has shown that programmed cell death can also occur by alternative, non-apoptotic mechanisms. One of these alternative pathways of regulated cell death is autophagy. As discussed in Chapter 8, autophagy provides a mechanism for the gradual turnover of the cell’s components by the uptake of proteins or organelles into vesicles (autophagosomes) that fuse with lysosomes (see Figure 8.45). In addition, autophagy promotes cell survival under conditions of nutrient deprivation. Under conditions of starvation, activation of autophagy serves to increase the degradation of cellular proteins and organelles, generating energy and allowing their components to be reutilized for essential functions. In other circumstances, however, autophagy provides an alternative to apoptosis as a pathw...
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This note was uploaded on 08/25/2009 for the course BIO 315 taught by Professor Steiner during the Spring '08 term at Kentucky.

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