Nairn A C, Greengard P
Fed Proc. 1983 Nov;42(14):3107-13.
Many of the actions of cyclic AMP (cAMP) and cyclic GMP (cGMP) are believed to be mediated via the phosphorylation of specific substrate proteins by cAMP-dependent and cGMP-dependent protein kinases. cGMP-regulated protein phosphorylation systems are less widely distributed than cAMP-regulated systems. This conclusion is supported by studies of the distribution, within the mammalian brain, of cGMP-dependent protein kinase and of G substrate, the only specific substrate protein for this enzyme yet found in the nervous system. cGMP-dependent protein kinase and G substrate are both highly enriched in the cerebellum. Within the cerebellum both proteins are concentrated in Purkinje cells. The localization of these and other components of the cGMP-dependent protein phosphorylation system in Purkinje cells suggests an important and selective role for cGMP in this neuron. The functional significance of cGMP-dependent protein kinase and G substrate in the Purkinje cell is currently being investigated. That study should be greatly facilitated by the recent preparation and characterization of serum antibodies highly selective for either the phospho or dephospho form of G substrate.
许多环磷酸腺苷（cAMP）和环磷酸鸟苷（cGMP）的作用被认为是通过cAMP依赖性蛋白激酶和cGMP依赖性蛋白激酶对特定底物蛋白的磷酸化来介导的。与cAMP调节系统相比，cGMP调节的蛋白磷酸化系统分布没那么广泛。对哺乳动物大脑中cGMP依赖性蛋白激酶和G底物（神经系统中目前发现的该酶唯一的特异性底物蛋白）分布的研究支持了这一结论。cGMP依赖性蛋白激酶和G底物在小脑中都高度富集。在小脑中，这两种蛋白都集中在浦肯野细胞中。cGMP依赖性蛋白磷酸化系统的这些及其他组分在浦肯野细胞中的定位表明cGMP在这种神经元中具有重要且选择性的作用。目前正在研究cGMP依赖性蛋白激酶和G底物在浦肯野细胞中的功能意义。最近制备并鉴定了对G底物的磷酸化或去磷酸化形式具有高度选择性的血清抗体，这将极大地促进该项研究。
