Ser/Thr protein kinase Akt is a central mediator of insulin metabolic action. Impairment in Akt activity results in type II diabetes, a globe pandemic that will remain major challenges to public health in foreseeable future. A primary mechanism under which Akt to participate in metabolic action is to promote glucose transport in adipose and muscle cells, a process that is requires Akt membrane compartmentalization. Our studies is to understand how Akt membrane compartmentalization is regulated. To such goal, we identified ClipR-59 as a regulator of Akt membrane compartmentalization and demonstrated that, by modulating Akt membrane compartmentalization, ClipR-59 regulates insulin dependent Glut4 membrane translocation and that ClipR-59 plays a role in the regulation of glucose and energy metabolism as transgenic expression of ClipR-59 in mouse adipose tissue lowered blood glucose level, increased glucose tolerance and led the mice against diet induced obesity. The current proposal is our continued effort to define the role of ClipR-59 in the regulation of whole body glucose homeostasis and the mechanism under which ClipR-59 regulates Akt signaling. Our hypothesis is that inactivation of ClipR-59 will lead to dysregulation of body glucose and energy metabolism, and Elmo2 and DHHC17, via their regulations of the interaction of Akt with ClipR-59 and ClipR-59 association with detergent resistant membrane, are the new regulators of Akt membrane compartmentalization. Specifically, we will determine a) how inducible inactivation of ClipR-59 in adipose tissue affects glucose homeostasis and the development of obesity; b) how scaffold protein Elmo2, through its insulin regulated interaction with ClipR-59, regulates Akt membrane compartmentalization and insulin dependent Glut4 membrane translocation and c) how cysteine palmitoyl acyltransferase DHHC17, through modulating ClipR-59 palmitoylation and detergent resistant membrane (DRM) association, regulates Akt membrane compartmentalization. Overall, our application will allow us further define the role of ClipR-59 in the regulation of Akt signaling and whole body glucose homeostasis and the molecular mechanism under which ClipR-59 regulates these processes. We believe successful conducting our proposal will undoubtedly advance our understanding of the regulation of insulin signaling and the development of type II diabetes.
ClipR-59 specifies Akt signaling in fat cell to regulate fat cell glucose transport and body glucose homeostasis. Our studies are to determine how Specification of Akt signaling by ClipR-59 is modulated by scaffold protein Elmo2 and cysteine palmitoyltransferase DHHC17 insulin regulated manner. This research will provide invaluable knowledge to understand the development of adipocyte insulin resistance and identify a novel drug target for treatment of type II diabetes.
