Apoptotic protease-activating factor 1 <p>Apoptosis, or programmed cell death (PCD), is a common and evolutionarily conserved property of all metazoans [<cite idref="PUB00017281"/>]. In many biological processes, apoptosis is required to eliminate supernumerary or dangerous (such as pre-cancerous) cells and to promote normal development. Dysregulation of apoptosis can, therefore, contribute to the development of many major diseases including cancer, autoimmunity and neurodegenerative disorders. In most cases, proteins of the caspase family execute the genetic programme that leads to cell death.</p><p>Apoptotic death can occur via a caspase-dependent mechanism, involving cytochrome c, apoptosis protease-activating factor-1 (Apaf-1), and caspase-9, or by a caspase-independent mechanism involving apoptosis-inducing factor (AIF) [<cite idref="PUB00043546"/>].</p><p>During apoptosis, cytochrome c is released from mitochondria to the cytosol and binds Apaf-1. The Apaf-1/cytochrome c complex oligomerises into either heptameric caspase-9-activating apoptosome (which activates caspase-3 and caspase-7) or bigger inactive aggregates, depending on the availability ATP [<cite idref="PUB00043547"/>]. Pro-apoptotic protein (Parcs) is required for cell survival since it is involved in both cell cycle progression and apoptosis. Parcs interacts with Apaf-1 by binding to the oligomerisation domain of Apaf-1 [<cite idref="PUB00043548"/>].This group represents an apoptotic protease-activating factor 1.</p>