The Structure and Regulation of Mammalian Initiation Factor eIF2

The process of protein synthesis on ribosomes is promoted by soluble protein factors that act during the initiation, elongation and termination phases of translation (for reviews, see Moldave, 1985; Pain, 1986). A striking characteristic of these factors is that most of them bind GTP or GDP. Since the structure and mechanism of action of these proteins have been studied extensively for the past 20 years, considerable knowledge of their mechanisms of action has accummulated which may be relevant to understanding how G-proteins function in general. We are concerned here with one of the mammalian factors, initiation factor eIF2.