GUANINE NUCLEOTIDE BINDING PROTEIN BETA-GAMMA DIMERS--STRUCTURE AND FUNCTION

鸟嘌呤核苷酸结合调节蛋白(G蛋白)是 作为跨膜信号的α1β1伽马1异三聚体 通过将细胞外刺激受体偶联到 细胞内效应物(酶、离子通道)。G蛋白构成 以特定受体和效应器区分的不同家族 相互作用又由三者的结构决定 组成亚单位。α亚基与鸟嘌呤核苷酸结合， 在效应器调节中起到了很好的作用。贝塔和伽马 亚基由一个Betagamma复合体紧密联系在一起，包括一个 单个功能实体，就像阿尔法亚单位一样，绝对是 G蛋白与受体相互作用所必需的。效应器调节器 贝塔格玛复合体的作用在#年日益明显 几个系统。本研究强调了 G蛋白介导的信号转导中的β-淀粉复合体。我们有 使用亚单位特异性多肽抗体来探测 Betagamma复合体在与α功能相互作用中的重要作用 并监测重组亚基的表达。站点定向 诱变技术已被用于研究分子的组装、加工和效应。 Betagamma复合体在瞬变和稳定中的作用 转基因细胞系统。这些研究可能会阐明这一贡献 β-淀粉样亚单位复合体对受体和效应器的选择性 G-蛋白的特性和对根据 激动剂刺激。

The guanine-nucleotide binding regulatory proteins (G-proteins) are alpha1beta1gamma1 heterotrimers which function as transmembrane signal transducers by coupling receptor for extracellular stimuli to intracellular effectors (enzymes, ion channels). G-proteins constitute a diverse family distinguished by specific receptor and effector interactions which in turn are determined by the structure of the three constituent subunits. The alpha subunit binds guanine nucleotides and has a well established role in effector modulation. The beta and gamma subunits are tightly associated by a betagamma complex, comprising a single functional entity which, like the alpha subunit, is absolutely required for G-protein interaction with receptor. An effector modulatory role for the betagamma complex is becoming increasingly apparent in several systems. The present research emphasized the role of the betagamma complex in G-protein-mediated signal transduction. We have used subunit specific peptide antibodies to probe regions of the betagamma complex important for functional interaction with the alpha subunit and to monitor expression of recombinant subunits. Site-directed mutagenesis has been used to study the assembly, processing and effector function of the betagamma complex in both transient and stable transfected cell systems. These studies may elucidate the contribution of the betagamma subunit complex to the receptor and effector selectivity characteristic of G-proteins and to the adaptive responses pursuant to agonist stimulation.