Reed R R
Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
New Biol. 1990 Nov;2(11):957-60.
The subunits of the heterotrimeric guanine nucleotide-binding (G) proteins mediate the transfer of information from receptor to effector molecules. Biochemical studies and recent molecular cloning efforts have revealed a rich but largely unexpected diversity in G protein subunit structure and function. Extreme specificity in signaling pathways could be accommodated by the combinatorial association of individual subunits. Alternatively, this wealth of diversity may allow for the simultaneous activation of related G alpha subunits and the modulation of several effector systems. In tissues where the subunits are expressed at different levels, activation of receptors could stimulate distinct effector pathways. Mutations in individual subunits as well as alterations in their level of expression can lead to profound physiological changes. The mechanisms that underlie these changes are being elucidated and will provide insight into the complex regulatory processes associated with the large G protein subunit family.
异三聚体鸟嘌呤核苷酸结合（G）蛋白的亚基介导信息从受体传递至效应分子。生化研究及近期的分子克隆工作揭示了G蛋白亚基在结构和功能上存在丰富但大多出人意料的多样性。信号通路中的极端特异性可通过单个亚基的组合关联来实现。或者，这种丰富的多样性可能允许相关Gα亚基的同时激活以及多个效应系统的调节。在亚基表达水平不同的组织中，受体的激活可刺激不同的效应途径。单个亚基的突变及其表达水平的改变可导致深刻的生理变化。这些变化背后的机制正在被阐明，这将有助于深入了解与庞大的G蛋白亚基家族相关的复杂调控过程。
