Identification of metallothionein receptors in human astrocytes.
Identification of metallothionein receptors in human astrocytes.
复制标题
人星形胶质细胞中金属硫蛋白受体的鉴定。
DOI：
10.1016/s0304-3940(97)00548-x
复制
发表时间：
1997
影响因子：
2.5
通讯作者：
Hamed,A
中科院分区：
文献类型：
--
作者：
ElRefaey,H;Ebadi,M;Kuszynski,CA;Sweeney,J;Hamada,FM;Hamed,A
金属硫蛋白（MT）亚型是低分子量（6000-7000 Da）锌结合蛋白，含有60-68个氨基酸残基，25-30%半胱氨酸，无芳香族氨基酸，结合5-7 g锌/mol蛋白质。由于MT的合成是由内毒素、细胞因子和糖皮质激素诱导的，MT现在被认为是一种急性时相蛋白，可以保护中枢神经系统免受炎症、组织损伤和应激引起的氧自由基和氧化损伤。通过假设必须存在特定的机制来促进多种不同因素对MT I和II的诱导，我们首次通过使用荧光标记的MT I亚型探针来寻找和鉴定U373 MG细胞膜制备物上的MT受体;并通过使用半胱氨酸、谷胱甘肽和四种MT亚型来确定高亲和力和特异性结合。MT受体的Kd值为0.84 nM，Bmax为99.82 fmol/mg蛋白。此外，MT受体被发现在聚集的星形胶质细胞的表面上的更大的密度。我们推测产生活性氧的条件或试剂可能会影响MT受体的表达。
Metallothionein (MT) isoforms are low molecular weight (6000–7000 Da) zinc binding proteins containing 60–68 amino acid residues, 25–30% cysteine, no aromatic amino acids, and binding between 5–7 g zinc/mol of protein. Since the synthesis of MT is induced by endotoxin, cytokines, and glucocorticoids, MT is now considered to be an acute phase protein protecting against oxygen radicals and oxidative damages caused by inflammation, tissue injury, and stress to the central nervous system. By postulating that a specific mechanism must exist to foster the induction of MTs I and II by numerous and diversified factors, we searched for and identified for the first time, MT receptors on U373MG cell membrane preparations, by using fluoresceinated MT I isoform probe; and by employing cysteine, glutathione, and four MT isoforms to determine high affinity and specific binding. MT receptors revealed a Kdvalue of 0.84 nM and a Bmaxof 99.82 fmol/mg protein. Moreover, MT receptors were found in greater density on the surface of aggregated astrocytes. We postulate that conditions or agents generating reactive oxygen species may influence the expression of MT receptors.