The coiled-coil domain is required for HS1 to bind to F-actin and activate Arp2/3 complex
The coiled-coil domain is required for HS1 to bind to F-actin and activate Arp2/3 complex
复制标题
DOI：
10.1074/jbc.m504552200
复制
发表时间：
2005-11-11
影响因子：
4.8
通讯作者：
Zhan, X
中科院分区：
文献类型：
--
作者：
Hao, JJ;Zhu, JW;Zhan, X
HS 1（hematopoietic lineage cell-specific protein 1，造血细胞特异性蛋白1）是淋巴细胞中蛋白酪氨酸激酶的底物，与F-肌动蛋白结合，促进Arp 2/3复合物介导的肌动蛋白聚合。然而，HS 1和F-肌动蛋白之间的相互作用的机制尚未得到充分的表征。HS 1含有3.5个串联重复序列、卷曲螺旋区和C末端的SH 3结构域。与与HS 1密切相关并且绝对需要重复结构域用于F-肌动蛋白结合的cornein不同，缺失重复结构域的HS 1突变体保持显著的F-肌动蛋白结合活性。另一方面，卷曲螺旋区的删除废除HS 1的能力，结合肌动蛋白丝和激活Arp 2/3复合体的肌动蛋白成核和肌动蛋白分支。此外，仅含有卷曲螺旋序列的肽足以用于F-肌动蛋白结合。在过表达绿色荧光蛋白标记的HS 1蛋白的细胞内，野生型HS 1与皮质F-肌动蛋白在细胞前缘共定位，而缺失卷曲螺旋区域或重复结构域的突变体在细胞质中扩散。免疫沉淀分析表明，卷曲螺旋缺失突变体与F-肌动蛋白的结合较差，而没有重复结构域的突变体则无法与Arp 2/3复合物和F-肌动蛋白结合。这些数据表明，HS 1卷曲螺旋区协同作用的重复结构域的Arp 2/3复合物介导的肌动蛋白聚合的调制。
HS1 ( hematopoietic lineage cell-specific protein 1), a substrate of protein tyrosine kinases in lymphocytes, binds to F-actin, and promotes Arp2/3 complex-mediated actin polymerization. However, the mechanism for the interaction between HS1 and F-actin has not yet been fully characterized. HS1 contains 3.5 tandem repeats, a coiled-coil region, and an SH3 domain at the C terminus. Unlike cortactin, which is closely related to HS1 and requires absolutely the repeat domain for F-actin binding, an HS1 mutant with deletion of the repeat domain maintains a significant F-actin binding activity. On the other hand, deletion of the coiled-coil region abolished the ability of HS1 to bind to actin filaments and to activate the Arp2/3 complex for actin nucleation and actin branching. Furthermore, a peptide containing the coiled-coil sequence only was sufficient for F-actin binding. Within cells overexpressing green fluorescent protein-tagged HS1 proteins, wild type HS1 co-localizes with cortical F-actin at the cell leading edge, whereas mutants with deletion of either the coiled-coil region or the repeat domain diffuse in the cytoplasm. Immunoprecipitation analysis reveals that the coiled-coil deletion mutant binds poorly to F-actin, whereas the mutant without the repeat domain fails to bind to both Arp2/3 complex and F-actin. These data suggest that the HS1 coiled-coil region acts synergistically with the repeat domain in the modulation of the Arp2/3 complex-mediated actin polymerization.