Ouimet Charles C, Katona István, Allen Patrick, Freund Tamás F, Greengard Paul
Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32303, USA.
J Comp Neurol. 2004 Nov 22;479(4):374-88. doi: 10.1002/cne.20313.
Spinophilin is an actin binding protein that positions protein phosphatase 1 next to its substrates in dendritic spines. It contains a single PDZ domain and has the biochemical characteristics of a cytoskeletal scaffolding protein. Previous studies suggest that spinophilin is present in most spines, but the concentration of spinophilin varies from brain region to region in a manner that does not simply reflect differences in spine density. Here, we show that spinophilin is enriched in the great majority of dendritic spines in cerebral cortex, caudatoputamen, hippocampal formation, and cerebellum, irrespective of regional differences in spinophilin concentration. In addition, spinophilin is present postsynaptic to asymmetrical contacts on interneuronal dendritic shafts. We further show that, in hippocampus and ventral pallidum, spinophilin is occasionally present in dendritic shafts adjacent to gamma-aminobutyric acid-containing contacts. Thus, the functional role of spinophilin may not be exclusively restricted to excitatory synapses and may be significant at a small fraction of inhibitory contacts. These data also suggest that the concentration of spinophilin per spine is variable and is likely regulated by local physiological factors and/or regional influences.
亲嗜素是一种肌动蛋白结合蛋白，可将蛋白磷酸酶1定位在树突棘中其底物旁边。它含有一个单一的PDZ结构域，具有细胞骨架支架蛋白的生化特性。先前的研究表明，亲嗜素存在于大多数棘中，但亲嗜素的浓度在不同脑区有所不同，其方式并非简单地反映棘密度的差异。在这里，我们表明，无论亲嗜素浓度的区域差异如何，亲嗜素在大脑皮层、尾状核壳核、海马结构和小脑中的绝大多数树突棘中都有富集。此外，亲嗜素存在于中间神经元树突轴上不对称接触的突触后。我们进一步表明，在海马体和腹侧苍白球中，亲嗜素偶尔存在于与含γ-氨基丁酸接触相邻的树突轴中。因此，亲嗜素的功能作用可能并不完全局限于兴奋性突触，在一小部分抑制性接触中可能也很重要。这些数据还表明，每个棘中亲嗜素的浓度是可变的，可能受局部生理因素和/或区域影响的调节。
