SciCombinator

Discover the most talked about and latest scientific content & concepts.

V SiliĆ³, AD McAinsh and JB Millar
Abstract
The spindle assembly checkpoint (SAC) ensures the accurate segregation of sister chromatids during mitosis. Activation of the SAC occurs through a series of ordered molecular events that result in recruitment of Mad1:Mad2 complexes to improperly attached kinetochores. The current model involves sequential phospho-dependent recruitment of Bub3:Bub1 to KNL1 followed by binding of Mad1:Mad2 to Bub1. Here, we show in non-transformed diploid human cells that the KNL1-Bub3-Bub1 (KBB) pathway is required during normal mitotic progression when kinetochores are misaligned but is nonessential for SAC activation and Mad2 loading when kinetochores are unattached from microtubules. We provide evidence that the Rod-ZW10-Zwilch (RZZ) complex is necessary to recruit Mad1:Mad2 to, and delay anaphase onset in response to, unattached kinetochores independently of the KBB pathway. These data suggest that the KBB and RZZ complexes provide two distinct kinetochore receptors for Mad1:Mad2 and reveal mechanistic differences between SAC activation by unattached and improperly attached kinetochores.
Tweets*
2
Facebook likes*
0
Reddit*
0
News coverage*
0
Blogs*
0
SC clicks
1
Concepts
Chromatid, Spindle apparatus, Centromere, Spindle checkpoint, Meiosis, Cell cycle, Kinetochore, Mitosis
MeSH headings
-
comments powered by Disqus

* Data courtesy of Altmetric.com