An optimized activity-based probe for the study of caspase-6 activation

Area of Science:

• Cell Biology
• Biochemistry
• Molecular Biology

Background:

• Apoptosis is a crucial cellular process regulated by caspases.
• Understanding the precise activation mechanisms of executioner caspases (caspase-3, -6, and -7) remains a significant challenge in cell death research.

Purpose of the Study:

• To design and synthesize a novel activity-based probe for simultaneous monitoring of executioner caspases.
• To investigate the activation mechanism of caspase-6 in vivo.

Main Methods:

• Development of a new activity-based probe targeting caspase-3/-6/-7.
• In vivo characterization of the probe's properties, including enhanced performance and reduced cross-reactivity compared to previous probes.
• Utilizing the probe to study caspase-6 activation and substrate binding.

Main Results:

• The new probe enables simultaneous detection of all executioner caspases with improved in vivo characteristics.
• Caspase-6 exhibits a conformational change and can bind substrates before proenzyme cleavage.
• Caspase-6 activation was observed to be independent of active caspase-3/-7, indicating potential autoactivation or cleavage by alternative proteases.

Conclusions:

• The developed activity-based probe is a valuable tool for studying executioner caspase activity.
• Caspase-6 activation follows a distinct pathway, potentially involving autoactivation or non-caspase proteases.
• These findings shed light on the unique biological functions and regulation of caspase-6 in apoptosis.