TRIP13 Functions in the Establishment of the Spindle Assembly Checkpoint by Replenishing O-MAD2

TRIP13 Functions in the Establishment of the Spindle Assembly Checkpoint by Replenishing O-MAD2

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Summary: The spindle assembly checkpoint (SAC) prevents premature segregation of chromosomes during mitosis.This process requires structural remodeling of MAD2 from O-MAD2 to C-MAD2 conformation.After the checkpoint is satisfied, C-MAD2 is reverted to O-MAD2 to allow anaphase-promoting complex/cyclosome (APC/C) to trigger anaphase.Recently, red pygmy dogwood the AAA+-ATPase TRIP13 was shown to act in concert with p31comet to catalyze C- to O-MAD2.Paradoxically, although C-MAD2 is present in TRIP13-deficient cells, the SAC cannot be sawgrass virtuoso sg500 complete sublijet sublimation printer kit activated.

Using a degron-mediated system to uncouple TRIP13 from O- and C-MAD2 equilibrium, we demonstrated that the loss of TRIP13 did not immediately abolish the SAC, but the resulting C-MAD2-only environment was insufficient to enable the SAC.These results favor a model in which MAD2-CDC20 interaction is coupled directly to the conversion of O- to C-MAD2 instead of one that involves unliganded C-MAD2.TRIP13 replenishes the O-MAD2 pool for activation by unattached kinetochores.