Abstract
Mitosis is a highly regulated process that allows the equal distribution of the genetic material to the daughter cells. Chromosome segregation requires the formation of a bipolar mitotic spindle and assembly of a multi-protein structure termed the kinetochore to mediate attachments between condensed chromosomes and spindle microtubules. In budding yeast, a single microtubule attaches to each kinetochore, necessitating robustness and processivity of this kinetochore–microtubule attachment. The yeast kinetochore-localized Dam1 complex forms a direct interaction with the spindle microtubule. In vitro, the Dam1 complex assembles as a ring around microtubules and couples microtubule depolymerization with cargo movement. However, the subunit organization within the Dam1 complex, its higher-order oligomerization and how it interacts with microtubules remain under debate. Here, we used chemical cross-linking and mass spectrometry to define the architecture and subunit organization of the Dam1 complex. This work reveals that both the C termini of Duo1 and Dam1 subunits interact with the microtubule and are critical for microtubule binding of the Dam1 complex, placing Duo1 and Dam1 on the inside of the ring structure. Integrating this information with available structural data, we provide a coherent model for how the Dam1 complex self-assembles around microtubules.
Highlights
Chromosomes must form bioriented attachments to the mitotic spindle to ensure equal partitioning of the genetic material during mitosis
The outer kinetochore must harness the chemical energy released by depolymerizing microtubules and convert it to mechanical energy to move chromosomes
The 10-subunit Dam1 complex localizes to the outer kinetochore where it attaches to the single incoming microtubule to facilitate chromosome segregation [1]
Summary
Chromosomes must form bioriented attachments to the mitotic spindle to ensure equal partitioning of the genetic material during mitosis. The 10-subunit Dam complex localizes to the outer kinetochore where it attaches to the single incoming microtubule to facilitate chromosome segregation [1]. In vitro studies have shown that the Dam complex assembles as a ring around microtubules [3,4]. Structures of the Dam complex have provided conflicting models for its self-assembly and organization around microtubules, depending on the fitting of the monomeric Dam complex [11,12,13]. In the absence of high-resolution information, it is not possible to define the structural organization of the Dam complex alone, its selfassembly, or its interaction with microtubules. Our data provide a map of the subunit arrangement of the Dam complex. Our data provide key information on the organization of the Dam complex around microtubules
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
