Muly E Chris, Allen Patrick, Mazloom Maney, Aranbayeva Zina, Greenfield Audrey T, Greengard Paul
Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA 30329, USA.
Cereb Cortex. 2004 Dec;14(12):1398-407. doi: 10.1093/cercor/bhh101. Epub 2004 Jun 24.
Prefrontal cortical functioning depends on dopaminergic neurotransmission, which in turn depends on a complex signal transduction pathway including protein phosphatase-1 (PP1). Targeted localization of PP1 by the scaffolding proteins, spinophilin and neurabin, is critical for dopaminergic modulation of glutamate neurotransmission. In this study, we report the preparation of an antiserum to neurabin, use it to study the subcellular localization of neurabin and compare that to our previous study of spinophilin, a closely related PP1 scaffold. Neurabin is found predominately in dendritic spines, but is also found in other compartments, including dendrites, axons, terminals and glia. This distribution contrasts with that of spinophilin in that neurabin is found in axon terminals where spinophilin is absent, and in parvalbumin-containing interneuron dendrites there is no significant neurabin though these dendrites contain substantial spinophilin. Within the dendritic spine compartment, however, the two proteins are similarly distributed. Both neurabin and spinophilin are concentrated in spines, and double-labeling reveals that they co-localize in most spines. Furthermore, post-embedding immunogold labeling demonstrates that within a spine, neurabin is distributed in the same pattern as spinophilin, concentrated in the postsynaptic density and the 100 nm just below. These results indicate that neurabin and spinophilin share important similarities and differences in their patterns of distribution. Varying patterns of scaffold localization may play an important role in determining the content and action of signal transduction pathways in different neuronal populations or compartments.
前额叶皮质功能依赖于多巴胺能神经传递，而多巴胺能神经传递又依赖于包括蛋白磷酸酶-1（PP1）在内的复杂信号转导途径。支架蛋白亲环蛋白和神经突素对PP1的靶向定位，对于谷氨酸能神经传递的多巴胺能调节至关重要。在本研究中，我们报告了一种针对神经突素抗血清的制备，用它来研究神经突素的亚细胞定位，并将其与我们之前对密切相关的PP1支架亲环蛋白的研究进行比较。神经突素主要存在于树突棘中，但也存在于其他区域，包括树突、轴突、终末和神经胶质细胞。这种分布与亲环蛋白的分布形成对比，因为在没有亲环蛋白的轴突终末发现了神经突素，而在含有小白蛋白的中间神经元树突中，虽然这些树突含有大量亲环蛋白，但神经突素含量并不显著。然而，在树突棘区域内，这两种蛋白的分布相似。神经突素和亲环蛋白都集中在树突棘中，双重标记显示它们在大多数树突棘中共定位。此外，包埋后免疫金标记显示，在一个树突棘内，神经突素的分布模式与亲环蛋白相同，集中在突触后致密区和其下方100纳米处。这些结果表明，神经突素和亲环蛋白在分布模式上既有重要的相似之处，也有差异。支架定位的不同模式可能在决定不同神经元群体或区域中信号转导途径的内容和作用方面发挥重要作用。
