The unprecedented rise in worldwide diabetes prevalence is made even more alarming by our inability to halt the progression of this insidious disease. My career goal is to direct a basic research program focused on developing new diabetes therapies. Using an RNA interference (RNAi) screen, I have identified a novel G- protein coupled receptor (GPCR) that is important for insulin production and secretion. My aims are as follows: Aim I. Define the molecular mechanism of this novel GPCR's action on the insulin promoter and insulin secretion. I will identify what G protein signaling pathway(s) are required for this GPCR's effect on the insulin promoter and insulin secretion. I will also identify the transcription factors and the regulatory sites in the insulin promoter that are regulated by this GPCR. A parallel approach using a Gq/11-coupled engineered GPCR will also be undertaken. Aim II. Determine the role of this GPCR in beta cell development and insulin production in vivo. I will study a knockout mouse for this GPCR focusing on beta cell development and adult beta cell function. Aim III. Identify novel genes required for insulin promoter activity. Expanding on the RNAi screen used to identify the candidate identified in Aim I, I will use a high throughput system to screen siRNAs targeting all known genes to find additional regulators of the insulin promoter. These aims will provide the training and independent research direction necessary for my first R01 application. Specifically, I will learn to use mouse models of diabetes and the design and performance of whole genome RNAi screens. To gain this experience, I have joined the laboratory of Dr. Michael McManus, an expert on RNA interference screening and non-coding RNAs, and the immediately adjacent laboratory of Dr. Michael German, a physician scientist who studies the pancreatic beta cell both in vitro and in vivo. I also have two excellent collaborators -- Dr. Bruce Conklin, an expert in GPCR signaling, and Dr. Michelle Arkin, the leader of the UCSF High Throughput Screening facility. UCSF and the UCSF Diabetes Center are excellent training environments for young investigators. I will capitalize on their rich resources. To assist with Aim III, I will enroll in the UCSF Biomedical Informatics Program's class on the statistical analysis of large data sets. For career development, I will also participate in classes and workshops on the responsible conduct of research, grant writing, and scientific writing. I will attend and present my research in several seminar series and joint lab meetings focused on diabetes, RNAi or non- coding RNAs. Importantly, my position at UCSF allows 100% of my effort to be devoted to my training. In summary, I propose to study the mechanism of a novel GPCR in insulin production and to identify other novel genes important in beta cell function. This grant will not only allow the completion of these studies but will also allow me to transition into an independent diabetes investigator.