Apoptosis

Question 1

What is apoptosis?

Answer 1

Routine controlled cell death that minimizes spread of damage or inflammation

“Cells shrink and condense but never spill content”

Question 2

What are some instances when apoptosis is normal?

Answer 2

• Abnormal, non-functional and potentially dangerous cells like in cancer
• Elimination of lymphocytes after destroying and ingesting microbes
• Organs to maintain certain size such as a liver
• Elimination of damaged DNA cells

Question 3

What is a biochemical marker for apoptosis?

Answer 3

Cytochrome C release from mitochondria

Question 4

What is a key protease involves in apoptosis?

Answer 4

Caspases

Has a cysteine in the active site

Question 5

What are the two classes of caspases?

Answer 5

Initiator and Executioner

Question 6

What the two pathways for apoptosis and illustrate some details.

Answer 6

Internal: in situations where there are abnormalities in DNA and it mito. dependent. Often in response to injury.

External: IN situations like removal of survival factors and proteins of tumor necrosis factor family and is mito. INDEPENDENT

Question 7

The extrinsic factors has a transmembrane protein with 3 domains:

Answer 7

Extracellular binding domains
Single transmembrane domain
Intracellular death domain

Question 8

What are the two inhibitor proteins for extrinsic pathways?

Answer 8

FLIp and Decoy receptors

Question 9

Decoy receptors act by

Answer 9

Don’t have death domains to activate apoptosis

Question 10

Flip proteins act by

Answer 10

Functioning as a competitive inhibitor against procaspase 8 or 10

Question 11

Intrinsic pathway

Answer 11

involves translocation of cytochrome C from intermediate space. This causes cytochrome C release to cytosol, binding to adaptor protein to activate proscapases.

Question 12

Note the steps involved in activating the intrinsic pathway

Answer 12

Cytochrome C released from mito., binds to Apaf1.

Apaf1 forms apoptosome and activates caspase 9 and that activates caspase 3

Question 13

Extrinsic pathway involves activation of caspases _ and _ while Intrinsic pathways involves activation of caspase__. Both commonly activate caspase__

Answer 13

8,10
9
3

Question 14

What is an enemy or inhibitor causing pro-apoptotic function by inhibiting anti-apoptotic bcl2

Answer 14

BH3-only

Question 15

IAPS

Answer 15

Inhibitor of apoptosis bind and inhibit caspases

Question 16

IAPs can be countered by

Answer 16

Anti-IAPs

They neutralize IAPs and liberate caspases

Question 17

___ promotes development of cancer by inhibiting apoptosis

Answer 17

Excess Bcl2

Question 18

Release of cytochrome C out of mito. leads to

Answer 18

Signals for apoptosis