UNDERSTANDING AND REDEFNING NEUREGULIN SPECIFICITY

人神经调节素与ErbB-3的高亲和力结合 受体将用于分析受体配体相互作用， EGF受体（ErbB-1）相关受体家族， 与多种人类癌症有关我会用一个组合 计算序列分析，定向突变和噬菌体 显示选择以构建所述配体的基于功能的图谱， 受体界面该分析将产生两个库，每个库 它代表了两个假定的 神经调节蛋白和它的受体之间的接触表面。这些库 将分别和组合用于噬菌体展示 选择显示特异性结合的神经调节蛋白同种型 ErbB-2受体与ErbB-3高度同源。目前为止还没有 特异性结合ErbB-2的天然配体已被完全 表征了这种受体在许多细胞上过表达， 侵袭性乳腺癌细胞系。选择的ErbB-2特异性配体 可以作为瞄准ErbB-2的“魔法子弹”的目标载体 过度表达乳腺癌细胞。选择ErbB-2的有用性 神经谷蛋白的特异性亚型将通过融合 与白喉毒素的催化和易位结构域， 产生ErbB-2特异性定向毒素。EGF的60种氨基酸 类似于神经调节蛋白同种型heregulin β的结构域， 用作诱变的起始点，也将被结晶化， 用于结构测定。这一结构将补充 EGF中相应结构域的现有NMR结构， 神经调节蛋白HRG-alpha以及辅助配体受体分析 互动

The highly affinity binding of human neuregulin to the ErbB-3 receptor will be used to analyze the receptor ligand interaction in this family of EGF receptor (ErbB-1) related receptors which is implicated in various forms of human cancer. I will use a combination of computational sequence analysis, directed mutagenesis and phage display selection to construct a function based map of the ligand- receptor interface. This analysis will result in two libraries, each of which represents ten randomized residues on one of the two putative contact surfaces between neuregulin and its receptor. These libraries will be used separately and in combination for the phage display selection of neuregulin isoforms which show specific binding to the ErbB-2 receptor that is highly homologous to ErbB-3. So far, no natural ligand that binds specifically to ErbB-2 has been fully characterized. This receptor is overexpressed on a number of aggressive breast cancer cell lines. Selected ErbB-2-specific ligands can serve as targeting vehicles for "magic bullets" aimed at ErbB-2 overexpressing breast cancer cells. The usefulness of selected ErbB-2 specific isoforms of neurogulin will be demonstrated through fusion with the catalytic and translocation domains of diphtheria toxin, to generate an ErbB-2 specific directed toxin. The sixty amino acid EGF like domain of the neuregulin isoform heregulin beta, that will be used as the starting point for mutagenesis, will also be crystallized for structure determination. This structure will complement the existing NMR structures of the corresponding domain in EGF and neuregulin hrg-alpha as well as aid in the analysis of ligand receptor interaction.