TRANSMEMBRANE SIGNAL TRANSDUCTION PATHWAYS IN DICTYOSTELIUM

Can investigators working with mammalian cells learn new concepts on transmembrane signal transduction from the work with Dictyostelium? Essentially all transduction pathways that operate in mammalian cells are presented in this primitive eukaryotic organism, including surface receptors, G-proteins, adenylate cyclase, and an inositol cycle. This is remarkable, because it is thought that Dictyostelium originated during evolution at the beginning of the eukaryotic cell, some two billion years ago, and has evolved largely independent from many other eukaryotic cells. The notion that signal transduction is so similar in many organisms suggests that we may not learn new concepts from Dictyostelium, but instead, the old principle could be recognized. Aspects of signal transduction that are unique for Dictyostelium may then show how specific demands have been solved during evolution. This may provide insight into the phenomena by which differentiated cells are unique.In this chapter I want to summarized some data that have been obtained in the Dictyostelium field since the last review in this series by Devroetes (22). Several related reviews have been published recently that focus on the biochemistry of signal transduction (56), the genetics (63), the function of the cytoskeleton (95), and chemotaxis (24). The recent work of many groups working on Dictyostelium was collected in a recent issue of Developmental Genetics (64).