Bianchi R, Garbuglia M, Verzini M, Giambanco I, Ivanenkov V V, Dimlich R V, Jamieson G A, Donato R
Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Italy.
Biochim Biophys Acta. 1996 Oct 11;1313(3):258-67. doi: 10.1016/0167-4889(96)00098-5.
Alignment of previously characterized S-100 (alpha and beta)-binding peptides (J. Biol. Chem. 270, 14651-14658) has enabled the identification of a putative S-100 target epitope within the head domain of glial fibrillary acidic protein (GFAP). The capacity of a known peptide inhibitor of S-100 protein (TRTK-12), homologous to this region, to perturb the interaction of S-100 (alpha and beta) and GFAP (J. Biol. Chem 268, 12669-12674) was investigated. Fluorescence spectrophotometry and chemical cross-linking analyses determined TRTK-12 to disrupt S-100:GFAP interaction in a dose- and Ca(2+_dependent manner. TRTK-12 also inhibited S-100's ability to block GFAP assembly and to mediate disassembly of preformed glial filaments. Each of these events was strictly dependent upon the presence of calcium and inhibitory peptide, maximal inhibition occurring at a concentration of TRTK-12 equivalent to the molar amount of S-100 monomer present. Together with our recent report demonstrating TRTK-12 also blocks the interaction of S-100 protein with the actin capping protein, CapZ, these results suggest TRTK-12 functions as a pleiotropic inhibitor of S-100 function. Availability of a functional inhibitor of S-100 will assist the further characterization of S-100 protein function in vitro and in vivo. Moreover, this report provides additional evidence supportive of a role for S-100 as a multi-faceted regulator of cytoskeletal integrity.
对先前已鉴定的S-100（α和β）结合肽（《生物化学杂志》第270卷，第14651 - 14658页）进行比对，使得能够在胶质纤维酸性蛋白（GFAP）的头部结构域内鉴定出一个假定的S-100靶表位。研究了与该区域同源的一种已知S-100蛋白肽抑制剂（TRTK-12）干扰S-100（α和β）与GFAP相互作用的能力（《生物化学杂志》第268卷，第12669 - 12674页）。荧光分光光度法和化学交联分析确定TRTK-12以剂量和Ca²⁺依赖的方式破坏S-100：GFAP相互作用。TRTK-12还抑制S-100阻止GFAP组装以及介导预先形成的胶质细丝解聚的能力。这些事件中的每一个都严格依赖于钙和抑制性肽的存在，在TRTK-12浓度等同于存在的S-100单体摩尔量时发生最大抑制。连同我们最近的报告表明TRTK-12也阻断S-100蛋白与肌动蛋白封端蛋白CapZ的相互作用，这些结果表明TRTK-12作为S-100功能的多效性抑制剂发挥作用。一种S-100的功能性抑制剂的可得性将有助于在体外和体内进一步鉴定S-100蛋白的功能。此外，本报告提供了额外的证据支持S-100作为细胞骨架完整性的多方面调节因子的作用。
