Research paper: The ndc80 loop region facilitates formation of kinetochore attachment to the dynamic microtubule plus end
Tanaka Lab paper provides insight into essential KT-MT mechanism
The mechanism for the conversion of kinetochore-microtubule KT-MT interactions from lateral to end-on attachment is still elusive. And yet this interaction is crucial because end-on attachment is more robust and believed to be necessary to sustain KT-MT attachment when tension is applied across sister KTs upon their biorientation. This is essential as proper chromosome segregation in mitosis relies on correct kinetochore-microtubule (KT-MT) interactions. Tomo Tanaka’s research paper in Current Biology, "The ndc80 loop region facilitates formation of kinetochore attachment to the dynamic microtubule plus end," (8 February, 2011ÿVolume 21, Issue 3) shows how the Ndc80 loop region of the Ndc80 complex, itself an essential component of the KT-MT interface has an important role in the conversion from lateral to end-on attachment, and therefore to the crucial maturation step of KT-MT interaction.
The Tanaka lab studied a role of the Ndc80 loop region, a distinct motif looping out from the coiled-coil shaft of the complex, in Saccharomyces cerevisiae. With deletions or mutations of the loop region, the lateral KT-MT attachment occurred normally; however, subsequent conversion to end-on attachment was defective, leading to failure in sister KT biorientation. The Ndc80 loop region was required for Ndc80-Dam1 interaction and KT loading of the Dam1 complex, which in turn supported KT tethering to the dynamic MT plus end.
Authors: Maure, J.F., Komoto, S., Oku, Y., Mino, A., Pasqualato, S., Natsume, K., Clayton, L., Musacchio, A. and Tanaka, T.U.