Cutting edge science: Laser surgery illuminates viscoelasticity of merotelic kinetochores

Abstract

Increasing evidence in eukaryotic cells suggests that mechanical forces are essential for building a robust mitotic apparatus and correcting inappropriate chromosome attachments. In this issue, Cojoc et al. (2016. J. Cell Biol., http://dx.doi.org/10.1083/jcb.201506011) use laser microsurgery in vivo to measure and study the viscoelastic properties of kinetochores.

Figure 1.

The viscoelastic responses of merotelic KTs to laser surgery. (left) Schematic description of a stretched merotelic KT in vivo. Both the inner and outer KT structures undergo stretching through the pulling forces produced by MTs. Laser ablation leads to the relaxation of the merotelic KT. (right) In silico, merotelic KT relaxation can be modeled through a combination of a spring and dashpot and reveals the viscoelastic properties of this structure. Note that in PtK1 cells, as opposed to fission yeast, the spring relaxes but the dashpot remains stretched (i.e., the KT does not regain its initial length).