molecular similarities to that of animal apoptosis, but it also has differences, notable ones being the presence of a cell wall and the lack of an immune system that removes the pieces of the dead cell. Instead of an immune response, the dying cell synthesizes substances to break itself down and places them in a vacuole that ruptures as the cell dies. Additionally, plants do not contain phagocytic cells, which are essential in the process of breaking down and removing apoptotic bodies. Whether this whole process resembles animal apoptosis closely enough to warrant using the name apoptosis (as opposed to the more general programmed cell death) is unclear. Caspase-independent apoptosis The characterization of the caspases allowed the development of caspase inhibitors, which can be used to determine whether a cellular process involves active caspases. Using these inhibitors it was discovered that cells can die while displaying a morphology similar to apoptosis without caspase activation. Later studies linked this phenomenon to the release of AIF (apoptosis-inducing factor) from the mitochondria and its translocation into the nucleus mediated by its NLS (nuclear localization signal). Inside the mitochondria, AIF is anchored to the inner membrane. In order to be released, the protein is cleaved by a calcium-dependent calpain protease. See also Anoikis Apaf-1 Apo2.7 Apoptotic DNA fragmentation Atromentin induces apoptosis in human leukemia U937 cells. Autolysis Autophagy Cisplatin Cytotoxicity Entosis Ferroptosis Homeostasis Immunology Necrobiosis Necrosis Necrotaxis Nemosis Mitotic catastrophe p53 Paraptosis Pseudoapoptosis PI3K/AKT/mTOR pathway Explanatory footnotes Citations General bibliography External links Apoptosis & cell surface Apoptosis & Caspase 3, The Proteolysis Map – animation Apoptosis & Caspase 8, The Proteolysis Map – animation Apoptosis & Caspase 7, The Proteolysis Map – animation Apoptosis MiniCOPE Dictionary – list of apoptosis terms and acronyms Apoptosis (Programmed Cell Death) – The Virtual Library of Biochemistry, Molecular Biology and Cell Biology Apoptosis Research Portal Apoptosis Info Apoptosis protocols, articles, news, and recent publications. Database of proteins involved in apoptosis Apoptosis Video Apoptosis Video (WEHI on YouTube ) The Mechanisms of Apoptosis Kimball's Biology Pages. Simple explanation of the mechanisms of apoptosis triggered by internal signals (bcl-2), along the caspase-9, caspase-3 and caspase-7 pathway; and by external signals (FAS and TNF), along the caspase 8 pathway. Accessed 25 March 2007. WikiPathways – Apoptosis pathway "Finding Cancer's Self-Destruct Button". CR magazine (Spring 2007). Article on apoptosis and cancer. Xiaodong Wang's lecture: Introduction to Apoptosis Robert Horvitz's Short Clip: Discovering