, 2010a). However, AZD4547 clinical trial most often the plasma membrane changes observed during necrotic cell injury are a late consequence of the cell death process ( Lemasters et al., 1987), but early membrane events may also be involved in necrosis
signaling pathway. Cell death linked to autophagy involves transfer of cytosolic material for degradation in lysosomes, which may be associated with the formation of double-membrane autophagic vacuoles, called autophagosomes (Baehrecke, 2002 and Reggiori and Klionsky, 2005). The double-membrane cytoplasmic vacuoles will further merge with lysosomes to form autolysosomes (Eskelinen, 2005 and Levine and Klionsky, 2004). Polyubiquitinylated EPZ015666 proteins can be addressed to autophagosomes through recognition by specific adaptor proteins (Kirkin et al., 2009). When stress conditions are excessive, autophagy becomes a cellular suicide pathway operating by digestion of essential cellular proteins and structures (Gozuacik and Kimchi, 2004). Autophagic cell death seems to involve proteins such as VPS34, Ambra-1, Atg5, Atg2 and beclin-1 (Levine et al., 2008). A biochemical marker of autophagy is the lipidation of microtubule-associated protein 1 Light Chain 3 (LC3/Atg8).
Moreover, recent studies have shown that cytoskeleton-related positioning of lysosomes play an important role in the execution of autophagy (Korolchuk and Rubinsztein, 2011). Besides its role in degradation of proteins and organelles, autophagy plays a critical role in cellular survival by CYTH4 providing energy during periods of starvation. Although this duality was
reported as contradictory in the literature in the past (Kroemer et al., 2010), autophagy may be seen as either a survival mechanism during starvation or a cell death pathway when other cell death mechanisms, such as apoptosis, are deficient. A complex crosstalk between autophagy and apoptosis has recently been described (Maiuri et al., 2007). Indeed it has become clear that apoptosis and autophagy share common molecular effectors (Orrenius et al., 2012); interestingly, it has been recently shown that Ambra-1 (Fimia et al., 2012), but also sphingolipids (Young et al., 2012), might play a critical role in the inter-connection between autophagy and apoptosis. Autophagic vacuoles are also often found to be a part of the regulated necrosis called necroptosis (Ye et al., 2011). In addition to extrinsic and intrinsic apoptosis, autophagy and necrosis, other caspase-dependent or -independent modes of cell death have been described (Galluzzi et al., 2012), including pyroptosis, mitotic catastrophe, parthanatos, netosis, entosis, cornification and anoikis (Brennan and Cookson, 2000 and Frisch and Francis, 1994).