Aurora B switches relative strength of kinetochore–microtubule attachment modes for error correction

Abstract

To establish chromosome biorientation, aberrant kinetochore–microtubule interaction must be resolved (error correction) by Aurora B kinase. Aurora B differentially regulates kinetochore attachment to the microtubule plus end and its lateral side (end-on and lateral attachment, respectively). However, it is still unclear how kinetochore–microtubule interactions are exchanged during error correction. Here, we reconstituted the budding yeast kinetochore–microtubule interface in vitro by attaching the Ndc80 complexes to nanobeads. These Ndc80C nanobeads recapitulated in vitro the lateral and end-on attachments of authentic kinetochores on dynamic microtubules loaded with the Dam1 complex. This in vitro assay enabled the direct comparison of lateral and end-on attachment strength and showed that Dam1 phosphorylation by Aurora B makes the end-on attachment weaker than the lateral attachment. Similar reconstitutions with purified kinetochore particles were used for comparison. We suggest the Dam1 phosphorylation weakens interaction with the Ndc80 complex, disrupts the end-on attachment, and promotes the exchange to a new lateral attachment, leading to error correction.

Swap and stop – Kinetochores play error correction with microtubules

“…In addition, the behaviors of Ndc80C-nanobeads were investigated with Ndc80 wild-type and Ndc80 phosphomimic mutants (Ndc80-7D), but their behaviors were very similar in these two conditions. [41] Whether a Ndc80C-nanobead is transferred or not from the MT end to the lateral side of another MT would reflect the relative strength of end-on and lateral attachments. .…”

“…However, Dam1‐4D rarely led to detachment of either Ndc80C‐nanobeads or purified kinetochore particles from a MT end in the absence of a crossing MT, even if the end‐on attachment was weakened by Dam1‐4D. [ 41 ] In addition, Dam1‐4D led to only slow kinetochore detachment from the MT end (over 30 min or longer) in cells. [26] How can we explain these observations?…”

“…[41] Dam1-WT represents nonphosphorylated Dam1 as Aurora B kinase is not present in the systems. This figure was taken from Doodhi et al [41] after modification attachment by interacting with Ndc80Cs. [15,[23][24][25][26]45] Dam1 C-terminus phosphorylation would weaken the interaction with Ndc80C, thus leading to disruption of the end-on attachment.…”

“…Steps 1-4 represent "Swap' and step 5 represents "Stop" in regulation of kinetochore-MT interactions by Aurora B. This figure was taken from Doodhi et al [41] were clearly distinguished. Intriguingly, Dam1 phospho-mimic mutants at four Aurora B phosphorylation sites (at the Dam1 C-terminus; Dam1-4D) weakened end-on attachment, but did not affect the lateral attachment.…”

Highway to hell‐thy meiotic divisions: Chromosome passenger complex functions driven by microtubules

“…The central spindle, or midzone, is usually enhanced during anaphase where it establishes the midzone, but during prometaphase, these microtubules could have a role in chromosome bi-orientation. And while the central spindle predominantly forms lateral attachments with the kinetochores and are insensitive to Aurora B activity, [114,115] these interactions could have a role in regulating end-on attachments.…”