BAG5 is a member of the BAG1 related protein family. BAG1 is an anti apoptotic protein that functions through interactions with a variety of cell apoptosis and growth related proteins including BCL 2, Raf protein kinase, steroid hormone receptors, growth factor receptors and members of the heat shock protein 70 kDa family. A BAG domain near the C terminus, may bind and inhibit the chaperone activity of Hsc70/Hsp70. It has been hypothesized that the BAG5 protein will induce the death of nigral neurons through its predicted interaction with hsp70, which will cause increased protein aggregation and cell death by disinhibition of hsp70’s anti apoptotic function. It is believed that BAG5 will play an important role in the mechanisms of neuronal death. BAG5 may also be of interest due to its possible role as a modulator of the hsp70/hsp40 chaperone axis or its possible interaction and coordination of localization/modulation of other BAG containing proteins via BAG-BAG heterodimerization.