Errante L D, Wiche G, Shaw G
Department of Neuroscience, University of Florida College of Medicine, Gainesville 32610-0244.
J Neurosci Res. 1994 Mar 1;37(4):515-28. doi: 10.1002/jnr.490370411.
Plectin is a high molecular weight protein originally identified and characterized as a major cytoskeletal component of the C6 rat glioma cell. Here we demonstrate by immunoblotting of crude intermediate filament (IF) protein preparations that plectin is a cytoskeleton-associated component of the rat spinal cord. We then used avidin-biotin peroxidase immunocytochemistry and indirect immunofluorescence to localize plectin within the adult rat central nervous system (CNS) and examine its distribution with respect to IF proteins. Plectin immunoreactivity is localized to all ependymal cells including the choroidal epithelial cells and tanycytes, Bergmann glial processes, radially oriented glial cells in the spinal cord, astrocytes in white matter, a subset of astrocytes in gray matter, a subset of motoneurons in the brainstem and spinal cord, and certain endothelial cells. Colocalization studies with neural IF proteins show that plectin has a unique distribution pattern which most closely resembles, but is distinct from, that of vimentin. The few plectin positive neurons invariably also contain the neurofilament triplet proteins and peripherin, so that the ability of plectin to bind to the triplet proteins in vitro may reflect an in vivo interaction. The predominance of plectin at the inner ventricular boundaries of the nervous system as well as at the blood-brain barrier is in line with the pattern of plectin expression in other tissues and suggests a general role for plectin in the maintenance of such junctional regions.
网蛋白是一种高分子量蛋白质，最初被鉴定并表征为C6大鼠胶质瘤细胞的主要细胞骨架成分。在此，我们通过对粗制中间丝（IF）蛋白制剂进行免疫印迹证明，网蛋白是大鼠脊髓的一种细胞骨架相关成分。然后，我们使用抗生物素蛋白-生物素过氧化物酶免疫细胞化学和间接免疫荧光来定位成年大鼠中枢神经系统（CNS）中的网蛋白，并检查其相对于IF蛋白的分布。网蛋白免疫反应性定位于所有室管膜细胞，包括脉络丛上皮细胞和伸展细胞、伯格曼胶质细胞突起、脊髓中呈放射状排列的胶质细胞、白质中的星形胶质细胞、灰质中一部分星形胶质细胞、脑干和脊髓中一部分运动神经元以及某些内皮细胞。与神经IF蛋白的共定位研究表明，网蛋白具有独特的分布模式，与波形蛋白的分布模式最为相似，但又有所不同。少数网蛋白阳性神经元始终也含有神经丝三联体蛋白和外周蛋白，因此网蛋白在体外与三联体蛋白结合的能力可能反映了体内的相互作用。网蛋白在神经系统的脑室内边界以及血脑屏障处占优势，这与网蛋白在其他组织中的表达模式一致，并表明网蛋白在维持此类连接区域中具有普遍作用。
