Identifying Novel CReP-Binding Proteins

A variety of cellular stress responses are linked to the phosphorylation of eukaryotic initiation factor 2 alpha. Kinases phosphorylate eIF2a, resulting in lowered rates of translation, and phosphatases dephosphorylate eIF2a, resulting in increased rates of translation and ultimately induces apoptosis. GADD34 (growth arrest DNA damage 34) and CReP (constitutive repressor of eIF2a phosphorylation) form a complex with PP1 (protein phosphatase 1) to dephosphorylate eIF2a. Yeast two-hybrid was done to find potential protein-binding partners to CReP. CReP was bound to the DNA binding domain and used as bait in search of any proteins from the HeLa cell cDNA library. Of all the hits found from yeast two-hybrid, SNAPIN and COP9 were most common. SNAPIN and COP9 have never been studied in collaboration with CReP. However, what is known of COP9 is that it is involved in protein degradation, and SNAPIN has a role in mediating BACE1 retrograde transport. In this experiment, we will be preparing the test for what the functions of COP9 and SNAPIN are when bound to CReP in vivo. This work can help us understand the responses of cells when undergoing stress