Small-molecule activators of a proenzyme.

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Most human proteases exist as inactive proenzymes, requiring strict regulation.
• Proenzyme activation is a critical step in many biological processes, including apoptosis and differentiation.

Purpose of the Study:

• To identify and characterize the first small molecules capable of directly activating proenzymes.
• To investigate the mechanism by which these small molecules activate procaspases-3 and -6.
• To explore the potential of these activators in controlling apoptosis and cellular differentiation.

Main Methods:

• Small-molecule screening and characterization.
• Biochemical and biophysical analyses of proenzyme activation.
• Cell-based assays to assess apoptosis induction.
• Mutation analysis to identify resistance mechanisms.

Main Results:

• Identification of the first small molecules that directly activate apoptotic procaspases-3 and -6.
• Demonstration that these activators induce autoproteolytic activation by stabilizing a specific conformation.
• Procaspase activators bypass upstream signaling, leading to rapid apoptosis in various cell lines.
• Identification of mutations conferring resistance to small-molecule activation.

Conclusions:

• Small molecules can directly activate proenzymes, offering a novel approach to biological control.
• These activators provide a tool for direct manipulation of executioner caspases in apoptosis and differentiation.
• The findings open avenues for discovering other proenzyme activators and understanding their fundamental roles.