Using immunosuppressants, FK506 and rapamycin, to block critical pathways in the activation of T cells, as well as other known inhibitors of signaling pathways, the pathways linking upstream signals to downstream events at the level of translation have been determined. Signal transduction and the control of translation in T cells. Identification of signaling pathways important for the global regulation of the overall increase in translation during T cell is in progress. We are in the process of identifying which translation initiation factors are regulated by each signaling pathway, so that a total picture of the signaling pathways and events controlling the increase in translation during T cell activation can be constructed. Biological relevance based upon identification of these proteins is also being pursued by in situ immunofluorescence. Development of protein isolation methods for peptide sequencing and protein identification. These procedures enabled the isolation of the gene products from in vitro synthesis of PAmRNAs. Identification of these proteins was then possible by mass spectrometry. Mass spectrometry was performed using MALDI-TOF and electrospray LCQ.