S100A6 and S100A11 are specific targets of the calcium- and zinc-binding S100B protein in vivo
S100A6 and S100A11 are specific targets of the calcium- and zinc-binding S100B protein in vivo
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DOI：
10.1074/jbc.m003943200
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发表时间：
2000-11-10
影响因子：
4.8
通讯作者：
Baudier, J
中科院分区：
文献类型：
--
作者：
Deloulme, JC;Assard, N;Baudier, J
在溶液中，S100 B蛋白是由两个亚基以反平行方式缔合的非共价同源二聚体。在钙离子结合后，S100 B的构象发生显著变化，导致S100 B表面疏水残基的暴露。S100 B的C-末端结构域中包含Phe（87）和Phe（88）的残基已经涉及与靶蛋白的相互作用。本研究利用双杂交技术对S100 B特异性靶蛋白进行了鉴定。以S100 B为诱饵，我们确定S100 A6和S100 A11为S100 B的特异性靶标。S100 A1是S100 B的最接近的同源物，能够与S100 B相互作用，但不与S100 A6或S100 A11相互作用。S100 B、S100 A6和S100 A11亚型在星形细胞瘤U373细胞中共调节和共定位。此外，免疫共沉淀实验表明，Ca 2 +/Zn 2+稳定S100 B-S100 A6和S100 B-S100 A11杂复合物。C-末端结构域的缺失或Phe（87）和Phe（88）残基的突变对S100 B同源二聚化和与S100 A1的异源二聚化没有影响，但显著降低了S100 B与S100 A6或S100 A11之间的相互作用。我们的数据表明，S100 B和S100 A6或S100 A11之间的相互作用不应被视为典型的S100异源二聚化，而应被视为S100 B和靶蛋白之间相互作用的模型。
In solution, S100B protein is a noncovalent homodimer composed of two subunits associated in an antiparallel manner. Upon calcium binding, the conformation of S100B changes dramatically, leading to the exposure of hydrophobic residues at the surface of S100B. The residues in the C-terminal domain of S100B encompassing Phe(87) and Phe(88) have been implicated in interaction with target proteins. In this study, we used two-hybrid technology to identify specific S100B target proteins. Using S100B as bait, we identify S100A6 and S100A11 as specific targets for S100B. S100A1, the closest homologue of S100B, is capable of interaction with S100B but does not interact with S100A6 or S100A11. S100B, S100A6, and S100A11 isoforms are co-regulated and,co-localized in astrocytoma U373 cells. Furthermore, co-immunoprecipitation experiments demonstrated that Ca2+/Zn2+ stabilizes S100B-S100A6 and S100B-S100A11 heterocomplexes. Deletion of the C-terminal domain or mutation of Phe(87) and Phe(88) residues has-no effect on S100B homodimerization and heterodimerization with S100A1 but drastically decreases interaction between S100B and S100A6 or S100A11. Our data, suggest that the interaction between S100B and S100A6 or S100A11 should not be viewed as a typical S100 heterodimerization but rather as a model of interaction between S100B and target proteins.