Antiapoptotic function of Bcl-2 in mast cells is dependent on its association with heat shock protein 90β

In the present study, we demonstrated that the antiapoptotic function of Bcl-2 in mast cells is significantly dependent on its association with the heat shock protein 90β (Hsp90β). Dissociation of these 2 proteins inhibits the antiapoptotic activity of Bcl-2 by initiating the release of cytochrome c from mitochondria into cytosol and increasing the activity of caspase 3 and caspase 7, resulting in mast-cell apoptosis. The antiapoptotic activity of Bcl-2 was greatly affected by knocking-out specifically Hsp90β using the RNA interference approach. Thus, for the first time, it has been shown that Hsp90β might modulate the antiapoptotic activity of Bcl-2 at least in mast cells. These findings could have implications for a novel strategy of regulating apoptosis in patients with mastocytosis and other mast cell–associated diseases.