7. Apoptosis

Question 1

Phosphatidyl serine

Answer 1

Increase of outwards-facing PS in plasma membrane are a indicator of apoptosis as well.

Question 2

BH3-only proteins

Answer 2

Pro-apoptotic proteins eg. Bad, Bim, Bid, Puma, Noxa.

Question 3

Caspase 3 cleavage

Answer 3

Catalyzed by caspase 9, facilitated by apoptosome assembly.

Question 4

Granzyme B

Answer 4

Protease capable of truncating Bid, causing it to inhibit Bcl2 proteins.

Question 5

BH123

Answer 5

Bax, Bak

Question 6

Caspase cascade

Answer 6

Initiator caspases cleaves executioner caspases that cleaves cytosolic proteins and nuclear lamins.

Question 7

Ced-3

Answer 7

Caspase. Cleaves after aspartic acid residues.

Question 8

Bcl-xl, Bik function regulation

Answer 8

Bcl-xl sequesters Apaf-1 on the mitochondric surface. Bik binds and displaces Apaf-1, releasing it to form the apoptosome.

Question 9

Bcl2 regulation

Answer 9

Bax, Bak (BH123 induces intrinsic apoptosis. Are inhibited by Bcl-2 proteins. BH3-only proteins inhibits Bcl2 proteins.

Question 10

Asaptor proteins

Answer 10

Mediates dimerization of initiator caspases, which facilitates cleavage in trans of the inactive monomers.

Question 11

Binding of cyt c to Apaf-1 results in…

Answer 11

ADP exchange for dATP and following oligomerization.

Question 12

CARD domains

Answer 12

Dimerization domains found on eg. Apaf-1 and caspase 9.

Question 13

What does cell do without trophic factors?

Answer 13

Undergo apoptosis.

Question 14

p53 regulation of Bax and Bak function

Answer 14

Presumes to help Bax and Bak into an active conformation. Induces expression of Fas and Bax. (and IFGBP-3)

Question 15

Death domain

Answer 15

Oligomerization domain between Fas death receptor, FADD adaptor protein and procaspase 8 or 10.

Question 16

Apoptosome consists of

Answer 16

Apaf-1, Cyt C and caspase 9

Question 17

BH3 only

Answer 17

Bim, Bik, Bid, Puma, Noxa, Bad

Question 18

Bcl-2 proteins

Answer 18

Anti-apoptotic proteins. Eg. Bcl2, Bcl-Xl. Have BH4, 3, 2 and 1.

Question 19

Bax, Bak function

Answer 19

Bax and Bak make up the channel through which Cyt C is releases. Gets sequestered and inhibited by Bax or Bak.

Question 20

Procaspase activation

Answer 20

Caspases are activated by cleavage of the inactive procaspase into the active caspase.

Question 21

Initiator caspases

Answer 21

Caspase 8,9

Question 22

Bcl2 proteins

Answer 22

Family consist of Bcl2, BH123 and BH3-only proteins.

Question 23

Apoptosis characteristics

Answer 23

Individual cells, decreased cell volume, condensed chromatin. No inflammation

Question 24

Necrosis characteristics

Answer 24

Multiple cells, increased cell volume, inflammatory resonse.

Question 25

TUNEL

Answer 25

dUTP nick end labeling: labels bare DNA ends - sign of apoptosis

Question 26

Two major types of cell death

Answer 26

Apoptosis and necrosis

Question 27

Diablo/SMAC

Answer 27

Released from mitochondrion with Cyt C. Inhibits IAPs

Question 28

Bcl2 proteins (subgroup)

Answer 28

Bcl2, Bcl-Xl

Question 29

IAPs

Answer 29

Inhibitor of apoptosis proteins. Presumely binds active caspase as eg. XIAP, blocking caspase function

Question 30

Cyt C release

Answer 30

Release of Cyt C from mitochondria are a sign of apoptosis.

Question 31

3 strategies to avoid apoptosis:

Answer 31

Increased production of Bcl2 protein, inactivation of BH3-only Bcl2 proteins by active Akt, inactivation of anti-IAPs with MAPK-mediated phosphorylation

Question 32

Fas ligand

Answer 32

Binds Fas death receptor. Induces apoptosis in target cell.

Question 33

DNA fragmentation

Answer 33

In apoptosis, DNA fragments, creating af DNA ladder cause of fragmenting of linker regions between nucleosomes.

Question 34

Executioner caspases

Answer 34

Caspase 3,6,7

Question 35

Extrinsic pathway activation

Answer 35

Through cell death receptors. Binding induces DISC formation in which procaspase 8 is cleaved into caspase 8, initiating apoptosis.

Question 36

FADD

Answer 36

Fas-associated protein with death domain.

Question 37

Two ways Death receptor can induce apoptosis

Answer 37

Direct cleavage of procaspase 3 by caspase 8 or truncation of Bid, causing release of Cyt C.

Question 38

Roles of apoptosis

Answer 38

Morphogenesis, synaptogenesis, tissue turnover, removal of stressed cells

Question 39

BH123

Answer 39

Pro-apoptotic proteins. Eg. Bax, Bak.