Garcia M M, Cusick C G, Harlan R E
Department of Anatomy, Tulane University School of Medicine, New Orleans, Louisiana 70112.
J Comp Neurol. 1993 May 15;331(3):375-88. doi: 10.1002/cne.903310307.
Originally characterized as the calcium- and phospholipid-dependent protein kinases, the protein kinases C include at least eight separate isoforms, some of which are calcium-independent and all of which are highly enriched in brain. Of the calcium-independent isoforms, the delta subspecies of protein kinase C has the most restricted complement of lipid activators and substrate specificity, suggesting that it may have a unique role in cell signalling pathways. Using immunocytochemistry, we report that the distribution of protein kinase C-delta immunoreactivity in rat brain is also restricted, being present in all sensory systems. Moreover, it is found in alternating hierarchies of sensory pathways: in all sensory systems except auditory, it is found in first- and third-order neurons, while in the auditory system, it is found in second- and fourth-order neurons. Thalamocortical systems are intensely immunoreactive, including barrel fields of the rat parietal cortex. Outside of sensory systems, protein kinase C-delta is present in cerebellum within longitudinal stripes in Purkinje neurons, and in the caudate-putamen, it appears to be associated with the striosome (patch) compartment. In contrast to all other protein kinase C isoforms, protein kinase C-delta is absent from hippocampus. These findings suggest that protein kinase C-delta may have a unique role in signal transduction in the central nervous system (CNS), especially in sensory systems.
蛋白激酶C最初被表征为钙和磷脂依赖性蛋白激酶，它至少包括八种不同的亚型，其中一些亚型不依赖钙，并且所有亚型在脑中都高度富集。在不依赖钙的亚型中，蛋白激酶C的δ亚型具有最有限的脂质激活剂互补物和底物特异性，这表明它可能在细胞信号通路中具有独特作用。通过免疫细胞化学方法，我们报告了蛋白激酶C-δ免疫反应性在大鼠脑中的分布也是受限的，存在于所有感觉系统中。此外，它在感觉通路的交替层级中被发现：在除听觉系统外的所有感觉系统中，它存在于一级和三级神经元中，而在听觉系统中，它存在于二级和四级神经元中。丘脑皮质系统具有强烈的免疫反应性，包括大鼠顶叶皮质的桶状区。在感觉系统之外，蛋白激酶C-δ存在于浦肯野神经元的纵向条纹内的小脑中，并且在尾状核-壳核中，它似乎与纹状体（斑块）区室相关。与所有其他蛋白激酶C亚型相反，海马中不存在蛋白激酶C-δ。这些发现表明蛋白激酶C-δ可能在中枢神经系统（CNS）的信号转导中，特别是在感觉系统中具有独特作用。
