Related Experiment Videos
Caspase-dependent activation of cyclin-dependent kinases during Fas-induced apoptosis in Jurkat cells
Abstract:
The activation of cyclin-dependent kinases (cdks) has been implicated in apoptosis induced by various stimuli. We find that the Fas-induced activation of cdc2 and cdk2 in Jurkat cells is not dependent on protein synthesis, which is shut down very early during apoptosis before caspase-3 activation. Instead, activation of these kinases seems to result from both a rapid cleavage of Wee1 (an inhibitory kinase of cdc2 and cdk2) and inactivation of anaphase-promoting complex (the specific system for cyclin degradation), in which CDC27 homolog is cleaved during apoptosis. Both Wee1 and CDC27 are shown to be substrates of the caspase-3-like protease. Although cdk activities are elevated during Fas-induced apoptosis in Jurkat cells, general activation of the mitotic processes does not occur. Our results do not support the idea that apoptosis is simply an aberrant mitosis but, instead, suggest that a subset of mitotic mechanisms plays an important role in apoptosis through elevated cdk activities.
Insights
Fas-induced apoptosis involves cyclin-dependent kinases (cdks) activation, independent of protein synthesis. Key regulators like Wee1 and CDC27 are cleaved by caspase-3-like proteases, suggesting mitotic mechanisms contribute to programmed cell death.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Cyclin-dependent kinases (cdks) play a role in apoptosis.
- Protein synthesis is inhibited early in apoptosis.
- Caspase-3 activation precedes the inactivation of key cell cycle regulators.
Purpose of the Study:
- To investigate the role of cdks in Fas-induced apoptosis.
- To determine the mechanisms underlying cdk activation during apoptosis.
- To explore the relationship between apoptosis and mitotic processes.
Main Methods:
- Studied Fas-induced apoptosis in Jurkat cells.
- Assessed cdk activation and protein synthesis.
- Investigated cleavage of Wee1 and CDC27.
- Examined the role of caspase-3-like proteases.
Main Results:
- Fas-induced activation of cdc2 and cdk2 is protein synthesis-independent.
- Wee1 cleavage and anaphase-promoting complex inactivation occur early in apoptosis.
- Wee1 and CDC27 are substrates of caspase-3-like proteases.
- Elevated cdk activity during apoptosis does not lead to general mitotic activation.
Conclusions:
- Apoptosis is not simply aberrant mitosis.
- Elevated cdk activities, through mechanisms like Wee1 cleavage, are integral to apoptosis.
- Caspase-mediated cleavage of cell cycle regulators is a key event in programmed cell death.