Hypoxia is a primary factor in ischemic diseases such as stroke and traumatic brain disease. PC-12 cells have been widely used as a model to study signaling pathways of neuronal sensitivity to hypoxia, notably the PI3K/Akt survival pathway. Hypoxia induces heat shock protein response in ischemic brain as well as in PC- 12 cells, and HspQO has been implicated in the regulation of Akt activity. Thus hypoxia-induced HspQO may modulate PC-12 cell survival via protein binding, regulated by phosphorylation. Proteomic techniques, SDS-PAGE and MALDI-MS, as well as site-directed mutagenesis, translation, co-immunoprecipitation, and GST pull-down methods will be used to: (i) identify HspQO binding proteins in normoxic and hypoxic cells and determine their role in PC-12 survival to hypoxia; (ii) determine whether Akt and Akt-mediated phosphorylation events regulate HspQO protein binding and cell survival to hypoxia; (iii) determine whether HspQO regulation of cell survival to hypoxia involves shuttling its binding proteins to various subcellular compartments in an Akt dependent or independent manner. These studies will provide the groundwork for future intervention strategies aiming to prevent neuronal cell loss in diseases associated hypoxia.
|Clark, Christina B; Rane, Madhavi J; El Mehdi, Delphine et al. (2009) Role of oxidative stress in geldanamycin-induced cytotoxicity and disruption of Hsp90 signaling complex. Free Radic Biol Med 47:1440-9|