Journal article
Adaptation to the spindle checkpoint is regulated by the interplay between Cdc28/Clbs and PP2A(Cdc55)



Publication Details
Authors:
Vernieri, C.; Chiroli, E.; Francia, V.; Gross, F.; Ciliberto, A.
Publisher:
ROCKEFELLER UNIV PRESS
Publication year:
2013
Journal:
Journal of Cell Biology
Pages range:
765-778
Volume number:
202
Issue number:
5
Start page:
765
End page:
778
Number of pages:
14
ISSN:
0021-9525

Abstract
The spindle checkpoint arrests cells in metaphase until all chromosomes are properly attached to the chromosome segregation machinery. Thereafter, the anaphase promoting complex (APC/C) is activated and chromosome segregation can take place. Cells remain arrested in mitosis for hours in response to checkpoint activation, but not indefinitely. Eventually, they adapt to the checkpoint and proceed along the cell cycle. In yeast, adaptation requires the phosphorylation of APC/C. Here, we show that the protein phosphatase PP2A(Cdc55) dephosphorylates APC/C, thereby counteracting the activity of the mitotic kinase Cdc28. We also observe that the key regulator of Cdc28, the mitotic cyclin Clb2, increases before cells adapt and is then abruptly degraded at adaptation. Adaptation is highly asynchronous and takes place over a range of several hours. Our data suggest the presence of a double negative loop between PP2A(Cdc55) and APC/C-Cdc20 (i.e., a positive feedback loop) that controls APC/C-Cdc20 activity. The circuit could guarantee sustained APC/C-Cdc20 activity after Clb2 starts to be degraded.

Last updated on 2019-25-07 at 18:16