Dimorphism is directly related to fungal pathogenicity. The long term goal of this project is to determine the nature of the signal transduction mechanism(s) involved in the regulation of dimorphism in fungi using Sporothrix schenckii as a model system. In order to understand the relationship between dimorphism and the signal transduction pathways it is essential that we initiate the analysis of the molecular constituents of these pathways and study their expression throughout the yeast to mycelium transition and the yeast cell cycle. Thr proteins involved in signal transduction are many, but at the present, our experimental objectives are concerned primarily with protein kinase C (PKC) and protein kinase p34, cdc2. Our studies will be concern mainly with establishing their presence in the fungus through various experimental approaches, a characterization of the role of these proteins in the regulation of dimorphism through the study of their expression during the development of alternate forms of the fungus, their association to other proteins and the study of protein phosphorylation during development of alternate forms of the fungus.