Zelter Alex, Bonomi Massimiliano, Kim Jae Ook, Umbreit Neil T, Hoopmann Michael R, Johnson Richard, Riffle Michael, Jaschob Daniel, MacCoss Michael J, Moritz Robert L, Davis Trisha N
Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA.
Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK.
Nat Commun. 2015 Nov 12;6:8673. doi: 10.1038/ncomms9673.
Accurate segregation of chromosomes during cell division is essential. The Dam1 complex binds kinetochores to microtubules and its oligomerization is required to form strong attachments. It is a key target of Aurora B kinase, which destabilizes erroneous attachments allowing subsequent correction. Understanding the roles and regulation of the Dam1 complex requires structural information. Here we apply cross-linking/mass spectrometry and structural modelling to determine the molecular architecture of the Dam1 complex. We find microtubule attachment is accompanied by substantial conformational changes, with direct binding mediated by the carboxy termini of Dam1p and Duo1p. Aurora B phosphorylation of Dam1p C terminus weakens direct interaction with the microtubule. Furthermore, the Dam1p amino terminus forms an interaction interface between Dam1 complexes, which is also disrupted by phosphorylation. Our results demonstrate that Aurora B inhibits both direct interaction with the microtubule and oligomerization of the Dam1 complex to drive error correction during mitosis.
细胞分裂过程中染色体的准确分离至关重要。Dam1复合物将动粒与微管结合，其寡聚化是形成牢固连接所必需的。它是Aurora B激酶的关键靶点，Aurora B激酶会破坏错误连接，以便随后进行校正。了解Dam1复合物的作用和调控需要结构信息。在此，我们应用交联/质谱分析和结构建模来确定Dam1复合物的分子结构。我们发现微管附着伴随着大量构象变化，由Dam1p和Duo1p的羧基末端介导直接结合。Dam1p C末端的Aurora B磷酸化削弱了与微管的直接相互作用。此外，Dam1p氨基末端在Dam1复合物之间形成相互作用界面，该界面也会因磷酸化而被破坏。我们的结果表明，Aurora B在有丝分裂过程中抑制与微管的直接相互作用以及Dam1复合物的寡聚化，从而推动错误校正。
