Apoptosis anchors

The anti-apoptotic proteins Bcl-2 and Bcl-xL protect against mitochondrial dysfunction by inhibiting pro-apoptotic proteins and preventing mitochondrial permeability transition. The mitochondrial localization of Bcl-2 and Bcl-xL seems to be crucial for their function, but the molecular mechanisms involved have been unclear. In the December 23 online Nature Cell Biology, Michiko Shirane and Keiichi Nakayama at Kyushu University, Fukuoka, Japan, show that FKBP38 — a member of the FKBP family of immunophilins — anchors Bcl-2 to mitochondria and inhibits apoptosis (Nature Cell Biology, DOI: 10.1038/ncb894, December 23, 2002).

Shirane and Nakayama used a yeast two-hybrid system toscreen proteins interacting with Bcl-2. They observed that FKBP38 is a natural calcineurin inhibitor which interacts both with Bcl-2 and Bcl-xL. In addition, they showed that FKBP38 anchors Bcl-2 and Bcl-xL to the mitochondrial membrane and that the FKBP38-mediated mitochondrial localization of these proteins was important for the inhibition of apoptosis....