BIOCHEMICAL-CHARACTERIZATION OF THE SOLUBLE FORM OF THE JUNCTIONAL PLAQUE PROTEIN, PLAKOGLOBIN, FROM DIFFERENT CELL-TYPES
BIOCHEMICAL-CHARACTERIZATION OF THE SOLUBLE FORM OF THE JUNCTIONAL PLAQUE PROTEIN, PLAKOGLOBIN, FROM DIFFERENT CELL-TYPES
复制标题
DOI：
10.1111/j.1432-1033.1987.tb13543.x
复制
发表时间：
1987-08-03
期刊：
影响因子：
--
通讯作者：
FRANKE, WW
中科院分区：
文献类型：
--
作者：
KAPPRELL, HP;COWIN, P;FRANKE, WW
从不同哺乳动物种属的不同组织和细胞，包括缺乏桥粒的细胞和组织（如内皮细胞、视网膜细胞、晶状体细胞、成纤维细胞）的可溶性颗粒组分中，鉴定出分子量（Mr 83 000）和来自牛鼻表皮的桥粒斑珠蛋白电荷相同的多肽。然而，在红细胞、血小板、骨髓瘤细胞和平滑肌组织中均未检测到该蛋白。在所有检查的细胞中，发现在接近生理pH和离子强度的缓冲液中细胞裂解时可溶的斑珠蛋白（在不同细胞类型中占总斑珠蛋白的21 - 31%）以独特的分子形式存在。在蔗糖梯度离心中，它出现在约7S处，凝胶过滤色谱显示Stokes半径约为5.0nm，由此估计Mr约为170 000。通过在非变性条件下使用等电聚焦，可溶性。7-S斑珠蛋白的等电点约为pH 5.3。斑珠蛋白的斑块结合和可溶形式是无法区分的电荷和分子量，无论来源，表明分子身份。可溶性蛋白质与二价铜1，10-菲咯啉的交联导致形成具有与天然斑珠蛋白类似的物理性质的斑珠蛋白的交联产物。7-S颗粒，这与可溶性斑珠蛋白颗粒是二聚体的解释一致。虽然桥粒斑块中的斑珠蛋白的主要比例是耐各种提取程序，斑珠蛋白存在于斑块中的非含桥粒的细胞和组织是容易提取的低盐和高盐条件下。这表明斑珠蛋白与桥粒斑和非桥粒连接斑的结合存在差异。
A polypeptide of identical molecular mass (Mr 83 000) and charge to desmosomal plakoglobin from bovine snout epidermis was identified in soluble pelletable fractions from diverse tissues and cells of different mammalian species, including cells and tissues devoid of desmosomes (e.g. endothelial, retinal, lenticular cells, fibroblast). The protein, however, was not detected in erythrocytes and platelets and in myeloma cells, nor in smooth muscle tissue. In all cells examined, the plakoglobin soluble upon cell lysis in buffers of near-physiological pH and ionic strenght (21 - 31% of the total plakoglobin in the different cell types) was found to exist in a distinct molecular form. On sucrose gradient contrifugation it appeared at about 7 S and gel filtration chromatography revealed a Stokes radius of about 5.0 nm, from which an Mr of about 170 000 was estimated. By using isoelectric focusing under non-denaturing conditions, soluble .apprxeq. 7-S plakoglobin had an isoelectric point at about pH 5.3. The plaque-bound and the soluble form of plakoglobin were indistinguishable by electrical charge and molecular mass, regardless of the source, indicating molecular identity. Cross-linking of soluble proteins with cupric 1,10-phenanthroline resulted in the formation of a cross-linked product of plakoglobin with similar physical properties as the native .apprxeq. 7-S particle, which is compatible with the interpretation that the soluble plakoglobin particle is a dimer. While a major proportion of the plakoglobin in the desmosomal plaque was resistant to various extraction procedures, plakoglobin present in the plaques of non-desmosome-containing cells and tissues was readily extractable under low and high salt conditions. This indicates that differences exist in the binding of plakoglobin to desmosomal plaques and the plaques of non-desmosomal junctions.