The recent discovery of conserved domains (called SH2) in proteins of mammalian cells and nematodes, which appear to mediate their interaction with tyrosine kinases, has underscored the fact that protein-protein interactions are critical during many stages of signal transduction. Dictyostelium discoideam has proven to be an excellent model system for studying signal transduction, especially because a well characterized signal transduction pathway is being investigated and it is possible to perform reverse genetics -- using cloned genes to disrupt their endogenous homologues. Our hypothesis is that SH2-like domains also function in proteins involved in the signal transduction responses in Dictyostelium. The goal of this project is to test the hypothesis by identifying genes that encode such domains and to elucidate their roles in the response. The strategies are proposed to achieve these goals: First, PCR will be used to aid the cloning of Dictyostelium genes encoding sequences that are homologous to the SH2 domains in other organisms. Alternatively conserved domains of tyrosine kinases (or whole polypeptides) that interact with SH2 domains will be used to screen for proteins and their encoding genes that contain SH2-like domains. These approaches should identify genes encoding novel proteins important in signal transduction. Second, to discern their function some of these genes will then be inactivated using reverse genetics. The """"""""parent"""""""" lab is studying the role of serine kinases and the DNA - protein interactions involved in signal transduction. This proposal is revised to meet the objection that the previous proposal was too close to the parent project and beyond the expertise of the Prague lab. These concerns have been addressed.
