ARRA: Administrative Supplement for Histone Acetylation and Insulin Gene Expression

Production and secretion of insulin in response to changing blood glucose levels is essential for maintaining normoglycemia and defects in this process result in hyperglycemia, which is the major cause of the secondary complications associated with diabetes, including blindness, nerve damage, kidney failure, and cardiovascular complications. The major focus of the parent grant is to understand how changes in blood glucose levels regulate insulin production via modulation of the beta-cell specific transcription factors Pdx- 1, MafA and NeuroD 1. Specific aim 1 of the parent grant proposes to study the role of acetylation in regulation of Pdx- I DNA binding. To identify glucose-regulated acetylation sites within Pdx- I, we have recently carried out a tandem affinity purification of Pdx-l from low and high glucose-incubated pancreatic beta cells. The purified Pdx-l protein was used to identify glucose-regulated post-tranlational modifications and novel Pdx-1 interacting proteins utilizing the multidimensional protein identification technology (MudPIT). Our group is the first one to use this unique proteomics approach with beta-cell specific transcription factors to identify high-glucose induced post- translational modifications. This approach led to the identification of one phosphorylation and two acetylation sites within Pdx-l, that are modified only in response to high concentrations of glucose. We are currently studying the role of the identifed modifications in regulation of Pdx- 1 function as part of the parent grant. In addition, we have identified several Pdx-1 interacting proteins that associate with Pdx-l in a glucose- dependent manner. We are the first ones to identi~' proteins that associate with Pdx- 1 in a glucose-regulated manner using proteomics. The requested administrative supplement will be used: 1) to characterize the role of the novel Pdx- I associated proteins identified by proteomies in insulin production and secretion, which will accelerate and advance scientific research and may lead to novel treatments of diabetes associated with insulin insufficiency; 2) to hire a postdoctoral fellow and a graduate student, which will contribute to job creation and stimulation of the economy; 3) to purchase additional needed equipment, which will also help to stimulate the economy.