Research on Distribution and Function of Two Subtypes of G Protein Go

GO是G蛋白家族中的一员，G蛋白是已知的信号转导蛋白，在大脑中占主导地位。编码两种形式的GO亚单位的cDNA被分离出来，命名为GoApha和GoBalpha。在这项研究中，我们首先研究了GoAlpha的两个亚型的分布，然后确定了它们的功能差异。获得了以下结果：制备了针对GoApha和GoBalpha的特异性抗体，并利用这些抗体研究了GoA和GoB的分布。GoApha和GoApha均存在于多种组织中，但在周围组织中的分布不同。GoApha似乎主要与神经组织有关。另一方面，GoBalpha在许多组织中分布，两种亚型在脑内的浓度在个体发育过程中都有所增加，但在发育后期观察到GOb的增加。A1腺苷受体是从牛脑中部分纯化的，而M受体则是从表达人m2亚型的Sf9细胞中纯化出来的。A1腺苷受体与GoA结合更有效，而M受体与GoB结合更有效。这些结果表明，该受体能够区分GoA和GOB。

Go is a member of the family of G proteins which are known to function as signal transducers, and was dominant in the brain. The cDNAs encoding two forms of a subunit of Go were isolated and designated GoAalpha and GoBalpha. In this study, we first examined the distribution of two subtypes of Goalpha and then determined their functional difference. Following results were obtained.Specific antibodies against GoAalpha and GoBalpha were developed and the distribution of GoA and GoB was studied by the use of these antibodies. Both GoAalpha and GoAalpha were present in many tissues, but their distribution in peripheral tissues was distince. GoAalpha seemed to be associate mainly with neural tissues. On the other hand, GoBalpha distributed in many tissues, The concentrations of both subtypes in the brain increased during ontogenic development, but the increase in GoB was observed at a later age.The coupling of both subtypes of Go with A1 adenosine and muscarinic acetylcholine receptors were investigated by reconstitution experiments. A1 adenosine receptors were partially purified from bovine brain, whereas muscarinic receptors were purified from Sf9 cells expressing human m2 subtypes. A1 adenosine receptors coupled more efficiently with GoA, while muscarinic receptors coupled more efficiently with GoB.These results suggest that the receptor is able to distinguish between GoA and GoB.