Cell death

Question 1

What is (are) the executioner caspase(s) in apoptosis?

Answer 1

Caspase 3 and 6

Question 2

What is necroptosis?

Answer 2

A regulated, pro-inflammatory, and caspase-independent form of necrotic cell death.
Death receptors (DRs), toll-like receptors (TLRs), and nucleic acid sensing protein ZBP1 (Z-DNA binding protein 1) are prototypic inducer of necroptosis whose stimulation converges on the activation of RIP3 (receptor-interacting protein 3) (Newton & Manning, 2016).

2021 EMBO J. https://doi.org/10.15252/embj.2020106700

Question 3

Which of the following is caspase-independent?

1) Fas-mediated apoptosis
2) mitochondrial apoptosis
3) Pyroptosis
4) Necroptosis

Answer 3

Necroptosis is a regulated, pro-inflammatory, and caspase-independent form of necrotic cell death.

Question 4

What is granzyme-mediated apoptosis?

Answer 4

Cytotoxic lymphoid cells (predominantly NK cells and cytotoxic T cells) can induce cell death via death receptor ligands (see above) or the granzyme/perforin system.

2021 EMBO J. https://doi.org/10.15252/embj.2020106700

Question 5

What does granzyme B (a protease) do to induce apoptosis?

Answer 5

Cleave caspase 3/7; cleave BID; cleave ICAD, a known caspase-3 target, to induce DNA fragmentation

Question 6

How do cytotoxic T lymphocytes/NK cells initiate granzyme B-mediated apoptosis?

Answer 6

After recognition of transformed or infected cells, cytotoxic cells release secretory granules that contain perforin and granzyme B (Fig 1). These secreted factors are taken up by endocytosis and released to the cytosol by the perforin-dependent or -independent pathways

Question 7

In extrinsic apoptosis, what is death inducing signaling complex (DISC) composed of?

Answer 7

FADD contains a DD and also a death effector domain (DED), which allows the recruitment of caspase-8 via homotopic domain interaction, forming the death inducing signaling complex— DISC.
2021 EMBO J. https://doi.org/10.15252/embj.2020106700

Question 8

How do cytotoxic T lymphocytes/NK cell initiate cell apoptosis?

Answer 8

Via cell death receptor ligand (ex: FasL, extrinsic apoptosis) or via releasing granzyme/perforin into virus-infected cells, which the cell picks up the granzyme/perforin by endocytosis.

Question 9

What are apoptosis initiator-regulators?

Answer 9

BAD, BIM, Puma, Noxa, BH-3-only proteins

Question 10

What are apoptosis initiator-regulators?

Answer 10

BAD, BIM, Puma, Noxa

Question 11

What is the component that flip from inner leaflet to outer leaflet of the membrane to induce apoptosis?

Answer 11

Phosphatidylserine

Question 12

What is the molecule which cytochrome C would bind to form apoptosome?

Answer 12

APAF-1 (apoptosis-activating factor-1)

Question 13

Where does Smac come from?

Answer 13

mitrochondria

Question 14

Which of the following is pro-apoptotic?

1) BAX and BAK
2) Bcl-2, Bcl-x

Answer 14

BAX and BAK

Question 15

Which of the following is anti-apoptotic?

1) BAX and BAK
2) Bcl-2, Bcl-x

Answer 15

Bcl-2, Bcl-x

Question 16

What are pyroptosis markers (in IHC)?

Answer 16

Active form of IL1b and IL18, cleaved caspase 1

Question 17

What is terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) detecting?

1) DNA breaks
2) cleaved caspase
3) inner membrane (phosphatidylserine)
4) disrupted mitochondria

Answer 17

1) DNA breaks

Question 18

What is the target of Annexin V staining?

1) DNA breaks
2) cleaved caspase
3) inner membrane (phosphatidylserine)
4) disrupted mitochondria

Answer 18

3) phosphatidylserine

Question 19

Which of the following is gasdermin D-mediated cell lysis?

1) Mitochondrial apoptosis
2) Ferroptosis
3) Necroptosis
4) Pyroptosis

Answer 19

4) Pyroptosis

2021 EMBO J

Question 20

Which caspase is part of DISC (death inducing signaling complex)?

1) caspase 7
2) caspase 8
3) caspase 9
4) caspase 10

Answer 20

2) caspase 8

2021 EMBO J

Question 21

What molecule can directly regulate (antagonize) Bcl-2?

1) BAX and BAK
2) BID
3) BH3-only proteins
4) cytochrome c

Answer 21

3) BH3-only proteins

2021 EMBO J

Question 22

What drug can edit the gene of adult mice?

Answer 22

Tamoxin–> cleave and edit DNA in adult mice (cited from Dr. Webster’s seminar “cell death” 2021 April)

Question 23

What is MAC (membrane attack complex)?

Answer 23

A membranous complex composed of components of complement and form pores on the membrane. This structure is triggered by bacterial cytolysins and molecules from NK cells.

Question 24

Which component is NOT the element of membrane attack complex (MAC)?

1) complement 3 (C3)
2) complement 5 (C5)
3) complement 7 (C7)
4) complement 9 (C9)

Answer 24

1) complement 3

Only cleaved C5b is part of the MAC.

Question 25

Which molecule can block the function/formation of MAC (membrane attack complex)?

1) CD59
2) CD95
3) CD86
4) CD68

Answer 25

1) CD59

Question 26

Which molecule is one of the components of membrane attack complex (MAC)?

1) complement C3a
2) complement C3b
3) complement C5a
4) complement C5b

Answer 26

4) complement C5b