Astrin-SKAP complex reconstitution reveals its kinetochore interaction with microtubule-bound Ndc80

• Published in: eLife Vol. 6
• Main Authors: Kern, David M, Monda, Julie K, Su, Kuan-Chung, Wilson-Kubalek, Elizabeth M, Cheeseman, Iain M
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 25.08.2017; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: Analysis; Anaphase; Binding Sites; Biochemistry; Biochemistry and Chemical Biology; Cell Biology; Cell Cycle Proteins - metabolism; Cell Line; Cells (Biology); Chromosome Segregation; Chromosomes; Cytoskeletal Proteins; Humans; kinetochore; Kinetochores; Kinetochores - metabolism; Localization; Macromolecules; Mass spectrometry; Microscopy; microtubule; Microtubule-Associated Proteins - metabolism; Microtubules; Microtubules - metabolism; mitosis; Models, Biological; Novels; Nuclear Proteins - metabolism; Polymer industry; Polymers; Protein Binding; Proteins; Scientific imaging; microtubule; cell biology; chromosome segregation; biochemistry; kinetochore; mitosis; human
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.26866

Chromosome segregation requires robust interactions between the macromolecular kinetochore structure and dynamic microtubule polymers. A key outstanding question is how kinetochore-microtubule attachments are modulated to ensure that bi-oriented attachments are selectively stabilized and maintained. The Astrin-SKAP complex localizes preferentially to properly bi-oriented sister kinetochores, representing the final outer kinetochore component recruited prior to anaphase onset. Here, we reconstitute the 4-subunit Astrin-SKAP complex, including a novel MYCBP subunit. Our work demonstrates that the Astrin-SKAP complex contains separable kinetochore localization and microtubule binding domains. In addition, through cross-linking analysis in human cells and biochemical reconstitution, we show that the Astrin-SKAP complex binds synergistically to microtubules with the Ndc80 complex to form an integrated interface. We propose a model in which the Astrin-SKAP complex acts together with the Ndc80 complex to stabilize correctly formed kinetochore-microtubule interactions.