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1. For each of the following proteins that are proteolytically cleaved in apopto

ID: 70754 • Letter: 1

Question

1. For each of the following proteins that are proteolytically cleaved in apoptosis, indicate which cleavage is first carried out by an executioner caspase

a. The initiator caspase-2

b. The executioner caspase-3

c. The BH3-only protein Bid

d. The endonuclease inhibitor iCAD

2. Which Bcl-2 family member links intrinsic apoptotic signals (cellular stress), such as DNA damage, infections, to mito-mediated cell death?

pro-apoptotic bcl2 proteins

BH3-only proteins.

Anti-apoptotic bcl2 proteins

Anti-apoptotic BH3-only proteins.

3. The apoptosome ....

Releases cytochrome c to the cytosol

Activates caspase 9

Is a wheel-like heptamer of Apaf2

Is an intracellular regulator

a.

pro-apoptotic bcl2 proteins

b.

BH3-only proteins.

c.

Anti-apoptotic bcl2 proteins

d.

Anti-apoptotic BH3-only proteins.

Explanation / Answer

Ans1. The executioner caspase 3 is first activated by initiator caspase which then triggers further apoptosis process.

2. BH3 only proteins links intrinsic apoptic signals such as DNA damage, infection,to and mito mediated cell death. A cascade of different BH3 only proteins lead to the apoptosis in order to overcome damage and to restrt the process correctly.

3. The apoptosome activated caspase 9 in response to the release of cytochrome c to the cytosol.