Question

Which of these are executioner caspases?
A. Caspase 3
B. Caspase 6
C. Caspase 8
D. Caspase 5
Choose the most appropriate answer from the options given below:

• A. A and B only
• B. B and C only
• C. C and D only
• D. A and D only

Hint:

A simple way to remember the main caspases:

\textbf{Initiators}: Caspase-8 (Extrinsic path), Caspase-9 (Intrinsic path). Think of them as the "generals" giving the order.
\textbf{Executioners}: Caspase-3, -6, -7. Think of them as the "soldiers" carrying out the order. Caspase-3 is the main soldier. \end{itemize}

Answer 1

The Correct Option is A

Step 1: Caspase Fundamentals:
Caspases, or cysteine-aspartic proteases, are crucial enzymes in apoptosis (programmed cell death). They are divided into initiator and executioner (effector) caspases based on their role in the apoptotic pathway.

Step 2: Caspase Types Explained:
- Initiator Caspases: These caspases (e.g., Caspase-2, -8, -9, -10) are activated by apoptotic signals and subsequently activate executioner caspases.
- Executioner Caspases: Activated by initiator caspases, these caspases (e.g., Caspase-3, -6, -7) execute apoptosis by cleaving cellular substrates, resulting in characteristic changes like DNA fragmentation and membrane blebbing.

Step 3: Caspase Classification:
- A. Caspase 3: A key executioner caspase, often considered the primary executioner.
- B. Caspase 6: An executioner caspase.
- C. Caspase 8: A primary initiator caspase, activated via the extrinsic (death receptor-mediated) apoptotic pathway.
- D. Caspase 5: An inflammatory caspase (along with Caspase-1 and -4 in humans), primarily activating pro-inflammatory cytokines, not directly involved in apoptosis execution.

Step 4: Conclusion:
Caspase 3 (A) and Caspase 6 (B) are identified as executioner caspases from the given options. Therefore, the correct answer is (A).