Morales M, Fifkova E
Department of Psychology, University of Colorado, Boulder 80309.
Cell Tissue Res. 1989 Jun;256(3):447-56. doi: 10.1007/BF00225592.
The distribution of MAP2 and actin in dendritic spines of the visual and cerebellar cortices, dentate fascia, and hippocampus was determined by using immunogold electron microscopy. By this approach, we have confirmed the presence of MAP2 in dendritic spines and identified substructures within the spine compartment showing MAP2 immunoreactivity. MAP2 immunolabeling was mainly associated associated with filaments which reacted with a monoclonal anti-actin antibody. Also, by immunogold double-labeling we colocalized MAP2 with actin on the endomembranes of the spine apparatus, smooth endoplasmic reticulum, and in the postsynaptic density. Labeling was nearly absent in axons and axonal terminals. These results indicate that MAP2 is an actin-associated protein in dendritic spines. Thus, MAP2 may organize actin filaments in the spine and endow the actin network of the spine with dynamic properties that are necessary for synaptic plasticity.
采用免疫金电子显微镜技术确定了微管相关蛋白2（MAP2）和肌动蛋白在视觉皮质、小脑皮质、齿状筋膜和海马树突棘中的分布。通过这种方法，我们证实了树突棘中存在MAP2，并鉴定出了棘区内显示MAP2免疫反应性的亚结构。MAP2免疫标记主要与能与单克隆抗肌动蛋白抗体发生反应的细丝相关。此外，通过免疫金双标记，我们使MAP2与肌动蛋白在棘器、滑面内质网的内膜以及突触后致密物中共定位。轴突和轴突终末几乎没有标记。这些结果表明，MAP2是树突棘中一种与肌动蛋白相关的蛋白质。因此，MAP2可能在棘中组织肌动蛋白丝，并赋予棘的肌动蛋白网络以突触可塑性所需的动态特性。
