Programmed cell death: Encyclopedia II - Programmed cell death - Types of programmed cell death

Programmed cell death - Types of programmed cell death

Programmed cell death has been classified into two main types:

• Apoptosis (or Type I cell death), is a particular form of programmed cell death and is described in that article.
• Autophagic (a.k.a. cytoplasmic, or Type II) cell death, characterized by the formation of large vacuoles that eat away organelles in a specific sequence before the nucleus is destroyed. (See Lawrence M. Schwartz et al.: "Do All Programmed Cell Deaths Occur Via Apoptosis?", PNAS 90(3) p. 980, 1 February. 1993[1]; and, for a more recent view, see W. Bursch et al.: "Programmed Cell Death (PCD): Apoptosis, Autophagic PCD, or Others?", Annals of the New York Academy of Sciences 926 p.1, 2000)[2].

Plant cells undergo particular processes of programmed cell death, much more similar to autophagic cell death. However, some common features of PCD are highly conserved in both plants and metazoa.

The concept of "programmed cell death" was used in 1964 in relation to insect tissue development, around eight years before "apoptosis" was coined. Since then, PCD has become the more general of these terms. In other words, it refers to both apoptotic and nonapoptotic cell death pathways. Thus, it would not be correct to consider all forms of regulated cell death as "apoptosis".

"Physiological cell death" has also been used as a general term to cover different sequences and morphologies (see Richard Lockshin and Zahra Zakeri: "Programmed cell death and apoptosis: origins of the theory", Nature Reviews Molecular Cell Biology 2 p. 545, 1 January. 2001[3]).

The fact that programmed cell death has been the subject of increasing attention and research efforts was highlighted by the award of the 2002 Nobel Prize in Physiology or Medicine to Sydney Brenner (United Kingdom), H. Robert Horvitz (US) and John E. Sulston (UK) "for their discoveries concerning genetic regulation of organ development and programmed cell death" (see [4] ).

Adapted from the Wikipedia article "Types of programmed cell death", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki