A central helical hairpin in SPD-5 enables centrosome strength and assembly.
A central helical hairpin in SPD-5 enables centrosome strength and assembly.
复制标题
SPD-5 中的中央螺旋发夹可增强中心体强度和组装。
DOI：
10.1101/2023.05.16.540868
复制
发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Woodruff,JeffreyB
中科院分区：
文献类型：
--
作者：
Rios,ManoloU;Ryder,BryanD;Familiari,Nicole;Joachimiak,ŁukaszA;Woodruff,JeffreyB
中心体组织微管进行有丝分裂纺锤体的组装和定位。由这些微管介导的力在中心粒周围物质（PCM）上产生拉伸应力，中心粒的最外层。PCM如何抵抗这些应力在分子水平上尚不清楚。在这里，我们使用交联质谱法（XL-MS）来映射SPD-5（C中一种重要的PCM支架成分）多聚化的相互作用。优雅的我们鉴定了SPD-5中α螺旋发夹基序中的相互作用热点（a.a. 541-677）。XL-MS数据，ab initiostructural预测，和质量测光表明，该区域二聚形成一个四聚体卷曲的线圈。使螺旋区段（a.a. 610-640）或单个残基（R592）抑制PCM在胚胎中的组装。通过消除微管拉力来挽救这种表型，揭示了PCM组装和材料强度是相互关联的。我们提出，由螺旋发夹介导的相互作用强烈地将SPD-5分子彼此结合，从而使PCM能够完全组装并承受微管产生的应力。
Centrosomes organize microtubules for mitotic spindle assembly and positioning. Forces mediated by these microtubules create tensile stresses on pericentriolar material (PCM), the outermost layer of centrosomes. How PCM resists these stresses is unclear at the molecular level. Here, we use cross-linking mass spectrometry (XL-MS) to map interactions underlying multimerization of SPD-5, an essential PCM scaffold component inC. elegans. We identified an interaction hotspot in an alpha helical hairpin motif in SPD-5 (a.a. 541-677). XL-MS data,ab initiostructural predictions, and mass photometry suggest that this region dimerizes to form a tetrameric coiled-coil. Mutating a helical section (a.a. 610-640) or a single residue (R592) inhibited PCM assembly in embryos. This phenotype was rescued by eliminating microtubule pulling forces, revealing that PCM assembly and material strength are interrelated. We propose that interactions mediated by the helical hairpin strongly bond SPD-5 molecules to each other, thus enabling PCM to assemble fully and withstand stresses generated by microtubules.