Toward Determining the Role of PKA in Controlling TORC2 Function and Chemotaxis in Dictyostelium Discoideum

Abstract

Chemotaxis is a process whereby single- and multi-cellular organisms migrate in response to external chemical stimuli. This directed cell movement is regulated by complex signaling pathways and is implicated in embryonic development, immune response, and the metastasis of cancer cells. Dictyostelium discoideum, social amoebae with the ability to migrate and aggregate in response to chemoattractants such as cAMP, have been used as a model system to study chemotaxis. Preliminary research suggests that protein kinase (PKA) is involved in some of the signaling pathways that regulate chemotaxis. The role of PKA in chemotaxis was investigated, first, by characterizing the phenotype of PKA null cells using established cell biological and biochemical assays. Furthermore, spatiotemporal regulation of critical cytoskeletal proteins was probed in wild-type and PKA null cells using confocal fluorescence microscopy, indicating misregulation of both F-actin and Myosin II in pkaC- and pkaR- cells. Finally, preliminary work was done to lay the groundwork for experiments exploring possible PKA targets mediating TORC2 function in chemotaxis.