Expression profile of Bag 1 in the postmortem brain

Bag 1 is a protein intimately involved in signaling pathways that regulate cell survival. Here we examined the expression profile of Bag 1 in the brain to consider issues associated with the sampling of anti-apoptotic proteins in a rat model of the human postmortem process. Following a 4 h postmortem interval, we analyzed the hippocampus of rats maintained at 24 or 4 °C storage temperatures using immunocytochemical and Western blotting techniques. Remarkably, postmortem tissue (up to 4 h) showed a significant and prominent up-regulation of Bag 1 in CA1 and CA3 subfields of the hippocampal formation. Over-expression of Bag 1, however, could only be traced down to a storage temperature of 24 °C. These data suggest that storage temperatures, but not postmortem intervals, significantly affect the expression profile and cellular stability of Bag 1 proteins.