ABSTRACT
The ras gene family has been the focus of intensive research since 1982, when their transforming versions were first identified in human tumors. 1 In addition to their role in cancer, this family of genes has been implicated in the regulation of key steps of cell proliferation and differentiation, suggesting that ras proteins may function as pivotal elements in signal transduction mechanisms. Despite a vivid research of both the biological and the biochemical properties of the ras gene products, there is not yet a precise knowledge about their real functions and the nature of the alterations that follow ras-mediated cell transformation. However, there is abundant information that locates ras proteins as essential switches involved in regulating processes as diverse as cell growth, cell differentiation, and cell fate during development. In this chapter, we will discuss the most relevant contributions aimed at the deciphering of the function of ras proteins in the signaling pathways that regulate proliferation, differentiation, and development as well as their implications in neoplastic transformation.
