Cell Death

Question 1

What is the purpose of apoptosis?

Answer 1

A defence mechanism to destroy cells that represent a threat to the integrity of the organism

Question 2

Morphological hallmarks of apoptosis

Answer 2

Blebbing
Cell shrinkage
Nuclear fragmentation
Chromatin condensation
Chromosomal DNA fragmentation
Global mRNA decay

Question 3

Biochemical hallmarks of apoptosis

Answer 3

Protein cleavage
DNA fragmentation
Cell surface markers for phagocytosis

Question 4

Initiator caspases

Answer 4

Caspase 2, 8, 9, 10

Question 5

Executioner caspases

Answer 5

Caspase 3, 6, 7

Question 6

What is caspase?

Answer 6

Family of specialised intracellular proteases, used in apoptosis

Question 7

Negative stimuli of intrinsic pathway of apoptosis

Answer 7

Absence of growth factors/hormones (failure to suppress death programs)

Question 8

Positive stimuli of intrinsic pathway of apoptosis

Answer 8

Radiation
Toxins
Hypoxia
Hyperthermia
Viral infections
Free radicals

Question 9

The intrinsic pathway of apoptosis is triggered by…

Answer 9

Cytochrome C release from mitochondria

Question 10

What proteins inhibit apoptosis by blocking Cytochrome C release?

Answer 10

Anti-apoptotic Bcl2 family proteins

e.g. Bcl2, BclX(L)

Question 11

What proteins promote apoptosis by enhancing the Cytochrome C release?

Answer 11

Pro-apoptotic effect Bcl2 family: Bax, Bak

Pro-apoptotic BH3-only protein: Bad, Bim, Bid Puma, Noxa

Question 12

What are IAPs?

Answer 12

Inhibitors of Apoptosis

Inactivate caspases