The role of major apoptotic proteins in Ca2+ dependent cell homeostasis

The key role of Bcl-2 (B-cell lymphoma) family proteins in programmed cell death (apoptosis) is reliably established, but particular molecular mechanisms of downregulation involving these anti- and pro-apoptotic proteins are still insufficiently clear. There are several hypotheses explaining the cell-protective (Bcl-2, Bcl-XL) and pro-apoptotic (Bcl-x, Bak) functions of Bcl-2 family proteins. This paper briefly summarizes the available information concerning the molecular mechanisms of action of the pro- and anti-apoptotic proteins of Bcl-2 family. In particular, an original hypothesis is put forward according to which homo- and heterodimerization of these proteins are the key events in the mechanism of Ca2+ ion dependent homeostasis regulation. © 2005 Springer Science+Business Media, Inc.