CELLULAR-DISTRIBUTION OF P68, A NEW CALCIUM-BINDING PROTEIN FROM LYMPHOCYTES
CELLULAR-DISTRIBUTION OF P68, A NEW CALCIUM-BINDING PROTEIN FROM LYMPHOCYTES
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DOI：
10.1002/j.1460-2075.1984.tb01912.x
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发表时间：
1984-01-01
期刊：
影响因子：
11.4
通讯作者：
CRUMPTON, MJ
中科院分区：
文献类型：
--
作者：
OWENS, RJ;GALLAGHER, CJ;CRUMPTON, MJ
分子量为 68,000 的 Ca2+ 结合蛋白 (p68) 是人和猪淋巴细胞质膜 Nonidet P-40 不溶部分的主要成分。已经生产出针对 p68 的亲和纯化兔抗体，并用于研究其细胞分布。该抗体对固定并透化的人 B 类淋巴母细胞、外周血淋巴细胞和人扁桃体切片进行染色。整个细胞没有被染色，表明蛋白质没有出现在细胞表面。这一分配与生物合成细胞而非表面标记细胞的免疫沉淀物中 p68 的检测结果一致。 p68 位于质膜的细胞质面上。亚细胞分离实验证实p68在淋巴细胞中主要是膜结合的，尽管检测到了少量可溶部分（约占总数的10%）。淋巴细胞膜的细分显示 p68 不仅与质膜相关，而且与其他内膜系统相关。根据免疫沉淀法判断，p68 存在于多种淋巴和非淋巴来源的培养细胞系中。 p68 在固定和透化的成纤维细胞中表现出弥漫性分布，其与微丝或中间丝的分布不对应。在去污剂提取的细胞中，蛋白质定位于层状网络中。最近在成纤维细胞的去污剂抗性细胞骨架中观察到血影蛋白相关蛋白具有类似的免疫荧光染色模式。有人认为，p68 不仅是淋巴细胞中的膜下细胞骨架复合体的一部分，而且也是其他细胞类型中的膜下细胞骨架复合体的一部分。
A Ca2+-binding protein of MW 68,000 (p68) is a major component of a Nonidet P-40 insoluble fraction of human and pig lymphocyte plasma membrane. An affinity-purified rabbit antibody has been produced against p68 and used to study its cellular distribution. The antibody stained fixed and permeabilized human B lymphoblastoid cells, peripheral blood lymphocytes and sections of human tonsil. Whole cells were not stained, indicating that the protein was not represented at the cell surface. This assignment was consistent with the detection of p68 in immunoprecipitates from biosynthetically- but not surface-labeled cells. p68 is located on the cytoplasmic face of the plasma membrane. Subcellular fractionation experiments confirmed that p68 was largely membrane-bound in lymphocytes, although a small soluble fraction (.apprx. 10% of the total) was detected. Sub-fractionation of lymphocyte membranes revealed that p68 was associated not only with the plasma membrane but also with other endomembrane systems. As judged by immunoprecipitation, p68 was present in a variety of cultured cell lines of both lymphoid and non-lymphoid origin. p68 demonstrated a diffuse distribution in fixed and permeabilized fibroblasts which did not correspond to the distribution of either microfilaments or intermediate filaments. In detergent-extracted cells the protein was localized in a lamina-like network. A similar immunofluorescent staining pattern was recently observed for spectrin-related proteins in the detergent-resistant cytoskeleton of fibroblasts. It is suggested that p68 is part of a sub-membranous cytoskeletal complex not only in lymphocytes but also in other cell types.