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α 1 β 1 γ 1异源三聚体 通过将细胞外刺激的受体偶联到 细胞内效应物（酶、离子通道）。 G蛋白组成 一个以特异性受体和效应子为特征的多样化家族 相互作用，这反过来又取决于三个结构 组成亚单位。 α亚基结合鸟嘌呤核苷酸， 在效应物调节中具有公认的作用。 β和γ 亚基紧密结合为β-γ复合物，包括 单个功能实体，就像α亚基一样， G蛋白与受体相互作用所必需的。 效应子 β-γ复合体的调节作用越来越重要 在几个系统中很明显。 目前的研究强调的作用 在G蛋白介导的信号转导中的作用。 我们已经使用亚单位特异性肽抗体来探测 β-γ复合物对与α-γ复合物的功能相互作用很重要 亚基和监测重组亚基的表达。 网站 定向诱变已被用于研究组装、加工和 β-γ复合物在瞬时和稳定的 转染的细胞系统。 这些研究可以阐明 β-γ亚单位复合物与受体和效应物的结合 G蛋白的选择性特征和适应性反应 根据激动剂刺激。 补助金= Z01DK59005 肾源性尿崩症（NDI）是一种遗传性X线疾病 其中受影响的受试者对加压素的作用有抗性 (AVP)肾脏髓质细胞负责水的浓缩。 临床表现包括严重的多饮和多尿， 由此产生的严重脱水可导致脑肿胀和死亡。 用有效的AVP类似物（DDAVP，可用于其他形式的DI， 由于终末器官对tahe激素的抵抗，NDI无效。 AVP的肾脏作用是通过V2型受体介导的， 通过Gs蛋白刺激第二信使cAMP。 从理论上讲， 遗传基因缺陷可以位于信号沿着的任何地方 转导途径，但间接证据表明，可能的受体 缺损 最近克隆的人V2受体允许染色体 定位研究表明，受体定位于 Xq28，由家族连锁确定的基因缺陷位点 问题研究 这有力地表明，但并没有证明受体基因 突变是NDI的潜在缺陷。 我们已经获得了 多个NDI家庭的样本，迄今为止已有三个家庭 已经确定了预测会破坏正常V2形成的突变， 受体的 这些发现对我们的下- NDI的发病机制和正常V2受体结构 和功能，用于识别受影响的受试者和携带者， 最终用于疾病的基因治疗。

The quanine-nucleotide binding regulatory proteins (G-proteins) are alpha1beta1gamma1 heterotrimers which function as transmembrane signal transducers by coupling receptors 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 quanine nucleotides and has a well established role in effector modulation. The beta and gamma subunits are tightly associated as a beta gamma 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 beta gamma complex is becoming increasingly apparent in several systems. The present research emphasizes the role of the beta gamma complex in G-protein-mediated signal transduction. We have used subunit specific peptide antibodies to probe regions of the beta gamma 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 beta gamma complex in both transient and stable transfected cell systems. These studies may elucidate the contribution of the beta gamma subunit complex to the receptor and effector selectivity characteristic of G-proteins and to the adaptive responses pursuant to agonist stimulation. GRANTS=Z01DK59005 Nephrogenic diabetes insipidus (NDI) is an inherited X-lined disorder in which affected subjects are resistant ot the actions of vasopressin (AVP) on renal medullary cells responsible for water concentration. Clinical manifestations include severe polydipsia and polyuria, and resultant severe dehydration can lead to cerebral swelling and death. Treatment with a potent AVP analog (DDAVP, useful in other forms of DI, is in-effective in NDI because of end-organ resistance to tahe hormone. The renal actions of AVP are mediated through a V2 type receptor linked via the Gs protein to stimulation of the 2nd messenger CAMP. In theory, the inherited gene defect could be located anywhere along the signal transduction path, but indirect evidence suggested a likely receptor defect. The recent cloning of a human V2 receptor permitted chromosomal localization studies which showed that the receptor is localized to Xq28, the site of the gene defect as determined by family linkage studies. This strongly suggested but did not prove that a receptor gene mutation is the underlying defect in NDI. We have obtained genomic DNA samples on multiple families with NDI, and in three families thus far have identified mutations predicted to disrupt formation of a normal V2 receptor. These findings have important implications for our under- standing of the pathogenesis of NDI and of normal V2 receptor structure and function, for identification of affected subjects and carriers, and eventually for gene therapy of the disease.