GTP-binding proteins: One molecular machine can transduce diverse signals
GTP-binding proteins: One molecular machine can transduce diverse signals
复制标题
GTP 结合蛋白：一台分子机器可以转导多种信号
作者：
H. Bourne
ARGUMENT by analogy, like gambling, was once practised behind closed doors. But the increasing recognition of duplicated and diverged genes has elevated it into respectability; it is still a gambler's strategy but, often enough, it works. A prime example of a rich payoff is the understanding of the single molecular machine that mediates vision, olfaction, control of cell proliferation, ribosomal protein synthesis and cellular regulation by a host of hormones and neurotransmitters. In each of its many forms, the machine is a guanine nucleotide-binding protein that mediates signal transduction through the following sequence of events. On stimulation by a receptor protein, it releases GDP and binds GTP. In its GTP-bound conformation, it regulates the function of an effector, usually an enzyme or ion channel. Hydrolysis of bound GTP to GDP terminates the regulatory effect of the G protein.As was clear from a recent meeting" the power of molecular cloning and sitedirected mutagenesis, combined with painstaking biochemistry and considerable luck, is revealing a rapidly expanding list of members of the three related fami-lies of GTP binding proteins: the G proteins; the ras proteins; and elongation factors (such as bacterial EF-Tu) and related
