This application encompasses a 5-year training program designed for the development of a clinician scientist. The principal investigator is an Assistant Professor in the Department of Pediatrics at the Dartmouth Medical School with an interest in the role of oxidants in the pathogenesis of bronchopulmonary dysplasia. This program will advance the candidate's knowledge of molecular biology and cell signaling and develop technical skills necessary for success as an independent researcher. Dr. Aaron Barchowsky, an Associate Professor in the Department of Pharmacology and Toxicology, will serve as the mentor. He is well recognized as an authority in oxidant-mediated cell signaling in the lung and vasculature. Dr. Barchowsky has trained numerous graduate level students and several post-doctoral fellows. Additional expertise in protein synthetic mechanisms will be garnered from Dr. Stephen G. Zimmer, Associate Professor of Immunology and Microbiology at the University of Kentucky. Dr. Zimmer is well known as a leader in the investigation of translational regulation and cell growth. Lastly, an advisory committee composed of highly regarded researchers in pharmacology and physiology will provide further guidance and career direction. The goal of this proposal is to establish the role of eIF4E activity in the regulation of cell growth and protein synthesis following oxidant exposure. Preliminary evidence indicates that oxidants slow pulmonary epithelial cell growth and alter the phosphorylation of key translational regulatory proteins. The specific aims entail: 1) determining that oxidants increase eIF4E activity; 2) establishing that increased eIF4E activity protects cells from oxidant-mediated growth arrest and cell death; and 3) determining that activation of eIF4E is mediated through CaZ+/CaMK. Experimental design includes establishing growth arrest in A549 cells with H202, analyzing eIF4E activity through analysis of phosphorylation state, expression, cleavage, and binding; altering eIF4E activity by cellular transformation and site-directed mutagenesis; and determining kinase and phosphatase activities integral to the changes in eIF4E activity. These studies will generate new information concerning the inter-dependence of translation and cell growth and form a novel basis for pharmacological intervention to minimize oxidative injury.