Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge, UK.
EMBO J. 2018 Apr 13;37(8). doi: 10.15252/embj.201797902. Epub 2018 Mar 6.
Aurora-A regulates the recruitment of TACC3 to the mitotic spindle through a phospho-dependent interaction with clathrin heavy chain (CHC). Here, we describe the structural basis of these interactions, mediated by three motifs in a disordered region of TACC3. A hydrophobic docking motif binds to a previously uncharacterized pocket on Aurora-A that is blocked in most kinases. Abrogation of the docking motif causes a delay in late mitosis, consistent with the cellular distribution of Aurora-A complexes. Phosphorylation of Ser558 engages a conformational switch in a second motif from a disordered state, needed to bind the kinase active site, into a helical conformation. The helix extends into a third, adjacent motif that is recognized by a helical-repeat region of CHC, not a recognized phospho-reader domain. This potentially widespread mechanism of phospho-recognition provides greater flexibility to tune the molecular details of the interaction than canonical recognition motifs that are dominated by phosphate binding.
极光激酶 A 通过与网格蛋白重链(CHC)的磷酸依赖性相互作用,调节 TACC3 向有丝分裂纺锤体的募集。在这里,我们描述了由 TACC3 无规卷曲区域中的三个模体介导的这些相互作用的结构基础。一个疏水性对接模体与极光激酶 A 上的一个以前未被表征的口袋结合,该口袋在大多数激酶中被阻断。对接模体的缺失会导致后期有丝分裂延迟,这与极光激酶 A 复合物的细胞分布一致。Ser558 的磷酸化使第二个模体从无序状态到一个构象开关发生转变,该构象开关需要与激酶活性位点结合,形成一个螺旋构象。该螺旋延伸到第三个相邻的模体,该模体被 CHC 的螺旋重复区域识别,而不是被公认的磷酸化读码域识别。这种潜在的广泛的磷酸化识别机制比以磷酸结合为主导的典型识别模体提供了更大的灵活性,可以调节相互作用的分子细节。