Unusual binding properties of the SH3 domain of the yeast actin-binding protein Abp1 - Structural and functional analysis
Unusual binding properties of the SH3 domain of the yeast actin-binding protein Abp1 - Structural and functional analysis
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DOI：
10.1074/jbc.m109848200
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发表时间：
2002-02-15
影响因子：
4.8
通讯作者：
Castagnoli, L
中科院分区：
文献类型：
--
作者：
Fazi, B;Cope, MJTV;Castagnoli, L
ABP1p是一种肌动蛋白结合蛋白，在酿酒酵母肌动蛋白细胞骨架的组织中起着核心作用。通过结合双杂交和噬菌体展示的方法，我们已经确定了六个新的配体的Abp1-SH3结构域。在最近的全基因组高通量蛋白质相互作用项目中没有检测到这些SH3介导的新的相互作用。在这里，我们表明，SH3介导的协会的ABP 1P与丝氨酸/苏氨酸激酶Prk1P和Ark1P是必不可少的本地化肌动蛋白皮质补丁。Abp1-SH3结构域具有相当不寻常的结合特异性，因为其靶肽含有在两侧的聚脯氨酸核心侧翼带正电荷的四肽+XXXPXXPX + PXXL。在这里，我们提出了在1.3-A分辨率下解决的Abp1-SH3结构域的结构。SH3结构域中的肽结合口袋两侧是两个酸性残基，这在SH3结构域家族中的那些位置是不常见的。我们已经表明，通过定点诱变，这些带负电荷的侧链之一可能是非经典配体的偏好的关键决定因素。
Abp1p is an actin-binding protein that plays a central role in the organization of Saccharomyces cerevisiae actin cytoskeleton. By a combination of two-hybrid and phage-display approaches, we have identified six new ligands of the Abp1-SH3 domain. None of these SH3-mediated novel interactions was detected in recent all genome high throughput protein interaction projects. Here we show that the SH3-mediated association of Abp1p with the Ser/Thr kinases Prk1p and Ark1p is essential for their localization to actin cortical patches. The Abp1-SH3 domain has a rather unusual binding specificity, because its target peptides contain the tetrapentapeptide +XXXPXXPX+PXXL with positive charges flanking the polyproline core on both sides. Here we present the structure of the Abp1-SH3 domain solved at 1.3-A resolution. The peptide-binding pockets in the SH3 domain are flanked by two acidic residues that are uncommon at those positions in the SH3 domain family. We have shown by site-directed mutagenesis that one of these negatively charged side chains may be the key determinant for the preference for non-classical ligands.