Rey-Huei Chen

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The spindle assembly checkpoint delays anaphase until all chromosomes are attached to a mitotic spindle. The mad (mitotic arrest-deficient) and bub (budding uninhibited by benzimidazole) mutants of budding yeast lack this checkpoint and fail to arrest the cell cycle when microtubules are depolymerized. A frog homolog of MAD2 (XMAD2) was isolated and found(More)
The spindle checkpoint prevents the metaphase to anaphase transition in cells containing defects in the mitotic spindle or in chromosome attachment to the spindle. When the checkpoint protein Xmad2 is depleted from Xenopus egg extracts, adding Xmad2 to its endogenous concentration fails to restore the checkpoint, suggesting that other checkpoint(More)
A single unattached kinetochore can delay anaphase onset in mitotic tissue culture cells (Rieder, C.L., A. Schultz, R. Cole, G. Sluder. 1994. J. Cell Biol. 127:1301-1310). Kinetochores in vertebrate cells contain multiple binding sites, and tension is generated at kinetochores after attachment to the plus ends of spindle microtubules. Checkpoint component(More)
We demonstrate that members of the erk-encoded family of mitogen-activated protein (MAP) kinases (pp44/42mapk/erk) and members of the rsk-encoded protein kinases (RSKs or pp90rsk) are present in the cytoplasm and nucleus of HeLa cells. Addition of growth factors to serum-deprived cells results in increased tyrosine and threonine phosphorylation and in the(More)
In yeast, the Mad2 protein is required for the M phase arrest induced by microtubule inhibitors, but the protein is not essential under normal culture conditions. We tested whether the Mad2 protein participates in regulating the timing of anaphase onset in mammalian cells in the absence of microtubule drugs. When microinjected into living prophase or(More)
The duration of intracellular signalling is associated with distinct biological responses, but how cells interpret differences in signal duration are unknown. We show that the immediate early gene product c-Fos functions as a sensor for ERK1 (extracellular-signal-regulated kinase 1) and ERK2 signal duration. When ERK activation is transient, its activity(More)
The spindle checkpoint inhibits the metaphase to anaphase transition until all the chromosomes are properly attached to the mitotic spindle. We have isolated a Xenopus homologue of the spindle checkpoint component Bub1, and investigated its role in the spindle checkpoint in Xenopus egg extracts. Antibodies raised against Bub1 recognize a 150-kD(More)
The spindle checkpoint delays anaphase onset until all chromosomes have attached properly to the mitotic spindle. Checkpoint signal is generated at kinetochores that are not bound with spindle microtubules or not under tension. Unattached kinetochores associate with several checkpoint proteins, including BubR1, Bub1, Bub3, Mad1, Mad2, and CENP-E. I herein(More)
The spindle checkpoint delays anaphase until all chromosomes are properly attached to spindle microtubules. When the spindle checkpoint is activated at unattached kinetochores, the checkpoint proteins BubR1, Bub3 and Mad2 bind and inhibit Cdc20, an activator of the anaphase-promoting complex (APC). Here, we show that Xenopus laevis Cdc20 is phosphorylated(More)
The spindle checkpoint arrests cells at the metaphase-to-anaphase transition until all chromosomes have properly attached to the mitotic spindle. Checkpoint proteins Mad2p and Mad3p/BubR1p bind and inhibit Cdc20p, an activator for the anaphase-promoting complex (APC). We find that upon spindle checkpoint activation by microtubule inhibitors benomyl or(More)