Identification of Xin-repeat proteins as novel ligands of the SH3 domains of nebulin and nebulette and analysis of their interaction during myofibril formation and remodeling.
Identification of Xin-repeat proteins as novel ligands of the SH3 domains of nebulin and nebulette and analysis of their interaction during myofibril formation and remodeling.
复制标题
将XIN重复蛋白鉴定为Nebulin和Nebulette的SH3结构域的新型配体，并分析其在肌纤维形成和重塑过程中的相互作用。
DOI：
10.1091/mbc.e13-04-0202
复制
发表时间：
2013-10
影响因子：
3.3
通讯作者：
Fürst DO
中科院分区：
文献类型：
--
作者：
Eulitz S;Sauer F;Pelissier MC;Boisguerin P;Molt S;Schuld J;Orfanos Z;Kley RA;Volkmer R;Wilmanns M;Kirfel G;van der Ven PF;Fürst DO
横纹肌特异性肌动蛋白结合蛋白Xin和Xirp2被鉴定为细丝标尺、星云蛋白和星云蛋白SH3结构域的新配体。这种相互作用在空间上仅限于与肌原纤维发育或重塑相关的结构，表明这些蛋白在肌原纤维的组装和修复中发挥了作用。Xin肌动蛋白结合重复序列蛋白Xin和XIRP2仅在横纹肌细胞中表达，它们被认为在发育过程中发挥着重要作用。在成人肌肉中，这两种蛋白质都集中在肌原纤维与膜的附着位置。相反，在发育过程中，它们与其结合伙伴细丝C一起定位于未成熟的肌原纤维，这表明这两种蛋白都参与了肌原纤维的组装。我们确定星云蛋白和星云蛋白的SH3结构域是XIN和XIRP2富含脯氨酸区的新配体。精确的结合基序被映射并显示以微摩尔亲和力结合两个SH3结构域。星云SH3结构域与相互作用的XIRP2肽PPPTLPKLPKH的共结晶显示了符合第二类SH3结构域结合肽的选择性相互作用。在培养的肌肉细胞中的双分子荧光互补实验表明，在肌原纤维发育的早期阶段，Xin-Repeat蛋白与星云蛋白/星云的相互作用受到时间的限制，随着进一步的成熟，这种相互作用会消失。在成熟的肌原纤维中，这种相互作用仅限于与肌原纤维的发育和重塑相关的纵向结构。这些数据为Xin肌动蛋白结合重复序列蛋白(及其相互作用伙伴)在肌原纤维组装和肌肉损伤后的作用提供了新的见解。
The striated muscle–specific actin-binding proteins Xin and Xirp2 are identified as novel ligands of the SH3 domains of the thin filament ruler nebulin and nebulette. The interaction is spatially restricted to structures associated with myofibril development or remodeling, indicating a role for these proteins in myofibril assembly and repair. The Xin actin-binding repeat–containing proteins Xin and XIRP2 are exclusively expressed in striated muscle cells, where they are believed to play an important role in development. In adult muscle, both proteins are concentrated at attachment sites of myofibrils to the membrane. In contrast, during development they are localized to immature myofibrils together with their binding partner, filamin C, indicating an involvement of both proteins in myofibril assembly. We identify the SH3 domains of nebulin and nebulette as novel ligands of proline-rich regions of Xin and XIRP2. Precise binding motifs are mapped and shown to bind both SH3 domains with micromolar affinity. Cocrystallization of the nebulette SH3 domain with the interacting XIRP2 peptide PPPTLPKPKLPKH reveals selective interactions that conform to class II SH3 domain–binding peptides. Bimolecular fluorescence complementation experiments in cultured muscle cells indicate a temporally restricted interaction of Xin-repeat proteins with nebulin/nebulette during early stages of myofibril development that is lost upon further maturation. In mature myofibrils, this interaction is limited to longitudinally oriented structures associated with myofibril development and remodeling. These data provide new insights into the role of Xin actin-binding repeat–containing proteins (together with their interaction partners) in myofibril assembly and after muscle damage.