Related Experiment Videos
Deregulation of Cdc2 kinase induces caspase-3 activation and apoptosis
Ling Gu1, Hongwu Zheng, Stephen A Murray
1Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA.
Abstract:
Progression of the cell cycle and control of apoptosis are tightly linked processes. It has been reported that manifestation of apoptosis requires cdc2 kinase activity yet the mechanism(s) of which is largely unclear. In an attempt to study the role of human MDM2 (HDM2) in interphase and mitosis, we employed the Xenopus cell-free system to study HDM2 protein stability. Interestingly, HDM2 is specifically cleaved in Xenopus mitotic extracts but not in the interphase extracts. We demonstrate that HDM2 cleavage is dependent on caspase-3 and that activation of cdc2 kinase results in caspase-3 activation in the Xenopus cell-free system. Furthermore, expression of cdc2 kinase in mammalian cells leads to activation of caspase-3 and apoptosis. Taken together, these data indicate that deregulation of cdc2 kinase activity can trigger apoptotic machinery that leads to caspase-3 activation and apoptosis.
Insights
Deregulation of cdc2 kinase activity triggers apoptosis by activating caspase-3, leading to human MDM2 (HDM2) cleavage during mitosis. This study reveals a novel link between cell cycle control and programmed cell death.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Cell cycle progression and apoptosis are interconnected processes.
- The precise mechanisms linking cdc2 kinase activity to apoptosis are not fully understood.
- The role of human MDM2 (HDM2) in cell cycle regulation requires further investigation.
Purpose of the Study:
- To investigate the role of HDM2 in interphase and mitosis.
- To elucidate the mechanisms by which cdc2 kinase activity influences apoptosis.
- To determine the relationship between HDM2 cleavage, caspase-3 activation, and cdc2 kinase activity.
Main Methods:
- Utilized the Xenopus cell-free system to study HDM2 protein stability.
- Analyzed HDM2 cleavage in interphase and mitotic extracts.
- Investigated the dependence of HDM2 cleavage on caspase-3.
- Examined the effect of cdc2 kinase activation on caspase-3 in Xenopus and mammalian systems.
Main Results:
- HDM2 undergoes specific cleavage in Xenopus mitotic extracts, but not in interphase extracts.
- HDM2 cleavage is dependent on caspase-3 activity.
- Activation of cdc2 kinase leads to caspase-3 activation in the Xenopus cell-free system.
- Expression of cdc2 kinase in mammalian cells induces caspase-3 activation and apoptosis.
Conclusions:
- Deregulation of cdc2 kinase activity can initiate the apoptotic pathway.
- Caspase-3 activation is a key mediator in the process linking cdc2 kinase to apoptosis and HDM2 cleavage.
- These findings provide new insights into the intricate regulation of apoptosis by cell cycle machinery.