Architecture of the Dam1 kinetochore ring complex and implications for microtubule-driven assembly and force-coupling mechanisms

作者：Wang Hong Wei; Ramey Vincent H; Westermann Stefan; Leschziner Andres E; Welburn Julie P I; Nakajima Yuko; Drubin David G; Barnes Georjana; Nogales Eva^*

来源：Nature Structural & Molecular Biology, 2007, 14(8): 721-726.

DOI：10.1038/nsmb1274

The Dam1 kinetochore complex is essential for chromosome segregation in budding yeast. This ten-protein complex self-assembles around microtubules, forming ring-like structures that move with depolymerizing microtubule ends, a mechanism with implications for cellular function. Here we used EM-based single-particle and helical analyses to define the architecture of the Dam1 complex at 30-A resolution and the self-assembly mechanism. Ring oligomerization seems to be facilitated by a conformational change upon binding to microtubules, suggesting that the Dam1 ring is not preformed, but self-assembles around kinetochore microtubules. The C terminus of the Dam1p protein, where most of the Aurora kinase Ipl1 phosphorylation sites reside, is in a strategic location to affect oligomerization and interactions with the microtubule. One of Ipl1';s roles might be to fine-tune the coupling of the microtubule interaction with the conformational change required for oligomerization, with phosphorylation resulting in ring breakdown.

• 出版日期2007-8