YB-1 mediates TNF-induced pro-survival signaling by regulating NF-κB-activation and thereby influences cell death decisions.

The aim of this proposal is to characterize the roles of the cold shock proteins YB-1 and DbpA within the TNFR-signaling complex. The role of signaling adaptor is new to these proteins, which are presently best
known for their activities in regulating transcription, translation, and mRNA splicing. Here we shall characterize the protein-protein interactions as well as post-translational modifications required for recruitment of both proteins to the receptor complex. Additionally, we shall determine if the loss of either protein influences receptor function, as TNF receptors can signal cell survival as well as cell death, depending upon the circumstances. The longterm goal is to determine whether selective targeting of YB-1-dependent NF-kB-activitation is a therapeutic option in cancer. Preliminary data from the Ybx1 knockout mice are encouraging. First, longterm survival of the whole body Ybx1 knockout mice appears to be unaffected by the loss of YB-1. Secondly, stem cell proliferation and hematopoietic reconstitution are normal in knockouts. Therefore, we should be able to therapeutically targeted YB-1 without adverse side effects .