Neurons and other cells express a conserved death program

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Neurons and other cells express a conserved death program Neurons and other cells express a conserved death program. Different cellular insults trigger a genetic cascade that involves a series of death effector genes. These death genes and pathways have been conserved in the evolution of species from worms to humans. The target of the core death pathway is the activation of a set of proteolytic enzymes, the caspases. Caspases cleave many downstream and essential protein substrates (see Figure 53–19), resulting in the death of cells by a process termed apoptosis. Genetic analysis of the worm Caenorhabditis elegans indicates that the Ced-9 protein acts upstream and inhibits the activity of Ced-4 and Ced-3, two proteins that promote cell death. Many vertebrate homologs of Ced-9, the Bcl-2 family of proteins, have been identified. Some of these proteins, such as Bcl-2 itself, inhibit cell death, but others promote cell death by antagonizing the actions of the Bcl-2. The Bcl-2 class proteins act upstream of Apaf-1 (a vertebrate homolog of Ced-4) and the caspases (vertebrate homologs of Ced-3). Source: Differentiation and Survival of Nerve Cells, Principles of Neural Science, Fifth Editon Citation: Kandel ER, Schwartz JH, Jessell TM, Siegelbaum SA, Hudspeth AJ, Mack S. Principles of Neural Science, Fifth Editon; 2012 Available at: http://neurology.mhmedical.com/DownloadImage.aspx?image=/data/books/1049/kan_ch53_f018.png&sec=59146129&BookID=1049&ChapterSecID=59138687&imagename= Accessed: November 09, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved