Molecular steps of death receptor and mitochondrial pathways of apoptosis

In almost all multicellular organisms, cell suicide or apoptosis appears to play an important role in the maintenance of cellular homeostasis, Apoptosis is tightly regulated by a set of genes that either promote apoptosis or promote cell survival. Although a number of stimuli appear to trigger the process of apoptosis, there are two major signaling pathways of apoptosis; the death receptor pathway and the death receptor-independent or mitochondrial pathway. There is evidence to suggest that, under certain conditions and in some cell types; these two pathways may cross talk. During the past 5 years, rapid progress has been made in understanding the molecular basis of apoptosis. In this brief review, I will summarize the various molecular steps of apoptosis. (C) 2001 Elsevier Science Inc. All rights reserved.