Caspases from scleractinian coral show unique regulatory features

Area of Science:

• Marine Biology
• Molecular Biology
• Biochemistry

Background:

• Coral reefs face global decline due to disease and bleaching.
• Apoptotic cell death regulation is crucial for coral stress response.
• Coral apoptotic pathways are complex but largely unexplored.

Purpose of the Study:

• To identify and characterize caspases in two reef-building coral species.
• To investigate the mechanisms of caspase activation and function in corals.
• To explore the evolutionary relationship between coral and human caspases.

Main Methods:

• Identification and characterization of coral caspases.
• Biochemical analyses of caspase activity and interactions.
• X-ray crystallography to determine the structure of a coral caspase.

Main Results:

• Two distinct caspases were identified in *Orbicella faveolata* and *Porites astreoides*.
• Coral caspases exhibit unique activation mechanisms differing from human counterparts.
• The crystal structure of *Porites astreoides* caspase-7a revealed conserved features and potential regulatory elements.

Conclusions:

• Coral caspases play a role in stress response and cell death.
• Distinct activation pathways suggest unique evolutionary trajectories for coral apoptosis.
• Structural insights into coral caspases provide a basis for understanding substrate selection and evolution.