Editors' ChoiceCell Biology

How cells sense connected chromosomes

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Sci. Signal.  16 Jun 2015:
Vol. 8, Issue 381, pp. ec164
DOI: 10.1126/scisignal.aac7822

Cells have a “checkpoint” that pauses cell division until all chromosomes are properly arranged on the mitotic spindle to allow precise distribution of one copy of each chromosome to each daughter cell. Hiruma et al. and Ji et al. explain the molecular mechanism by which cells sense that they are ready to divide. The protein kinase MPS1 associates with a protein complex at the kinetochore of the chromosome. Its activity produces signals that pause the cell cycle. When the chromosome becomes properly attached to the mitotic spindle, microtubules of the spindle physically compete for binding to the same site on the kinetochore where MPS1 is bound. Thus, once the kinetochore is properly attached, MPS1 dissociates, the inhibitory signal is lost, and cell division is allowed to proceed.

Y. Hiruma, C. Sacristan, S. T. Pachis, A. Adamopoulos, T. Kuijt, M. Ubbink, E. von Castelmur, A. Perrakis, G. J. P. L. Kops, Competition between MPS1 and microtubules at kinetochores regulates spindle checkpoint signaling. Science 348, 1264–1267 (2015). [Abstract] [Full Text]

Z. Ji, H. Gao, H. Yu, Kinetochore attachment sensed by competitive Mps1 and microtubule binding to Ndc80C. Science 348, 1260–1264 (2015). [Summary] [Full Text]