Spindle microtubules generate tension-dependent changes in the distribution of inner kinetochore proteins.
Aussie Suzuki, Tetsuya Hori, Tatsuya Nishino, Jiro Usukura, Atsushi Miyagi, Kosuke Morikawa, and Tatsuo Fukagawa
J. Cell Biol. , Vol.193, 125-140 (2011) www.jcb.org/cgi/doi/10.1083/jcb.201012050
The kinetochore forms a dynamic interface with microtubules from the mitotic spindle. Live cell light microscopy-based observations on the dynamic structural changes within the kinetochore suggests that molecular rearrangements within the kinetochore occur upon microtubule interaction. However, the source of these rearrangements is still unclear. Here, we analyzed vertebrate kinetochore ultra-structure by immuno-EM in the presence or absence of tension from spindle microtubules. We found that the inner kinetochore region defined by CENP-A, CENP-C, CENP-R, and the C-terminal domain of CENP-T is deformed in the presence of tension, while the outer kinetochore region defined by Ndc80, Mis12, and CENP-E is not stretched even under tension. Importantly, based on EM, fluorescence microscopy, and in vitro analyses, we demonstrated that the N- and C-termini of CENP-T undergo a tension-dependent separation, suggesting that CENP-T elongation is at least partly responsible for changes in the shape of the inner kinetochore.
|
|
|
Immuno-EM images of the inner kinetochore stained with anti-CENP-T in the presence or absence of microtubules. In the presence of microtubules inner kinetochore structure is deformed.
|
|
