1. Genetics of RAS Signaling in Drosophila -- I. Introduction -- II. Background to the Experimental Systems -- III. Protein Tyrosine Kinase Receptors -- IV. Linking RAS with Tyrosine Kinase Receptors -- V. A Kinase Cascade Downstream of RAS -- VI. Nuclear Events -- VII. Concluding Remarks -- 2. RAS-Mediated Signal Transduction in C. elegans -- I. Introduction -- II. Genetic Approaches Used to Study Vulval Signal Transduction -- III. Genetic and Molecular Analysis of the let-60 RAS Gene -- IV. Genes Acting Upstream of RAS -- V. Genes Acting Downstream of RAS -- VI. Multiple Functions of the let-60 RAS-mediated Signal Transduction Pathway During C elegans Development -- 3. Mammals I: Regulation of RAS Activation -- I. Introduction -- II. Growth Factor/Cytokine Signaling -- III. Growth Factor Cascades: Autocrine Stimulation -- 4. Prenylation of RAS and Inhibitors of Prenyltransferases -- I. Introduction -- II. C-Terminal Modification of RAS Proteins -- III. Farnesyltransferase and Geranylgeranyltransferases -- IV. Mutational Analyses of Prenyltransferases -- V. Inhibitors of Prenylation -- VI. Biological Effects of Prenyltransferase Inhibitors -- 5. Mammals II: Downstream of RAS and Actin-Cytoskeleton -- I. RAS GAPs -- II. Oncogenic Mutations of RAS -- III. Effectors of RAS -- IV. Actin-Cytoskeleton -- V. G Proteins in the Rho Family (Rho, Rac and CDC42) -- VI. RAS-Activated or -Repressed Genes -- 6. From RAS to MAPK: Cell-Free Assay System for RAS- and Rap 1-Dependent B-Raf Activation -- I. Introduction -- II. Cell-free Assay System for the RAS-dependent Activation of the MAP Kinase Cascade in Xenopus Oocyte Cytosol -- III. REKS -- IV. Raf Activation -- V. Conclusion.