Biochemistry - Apoptosis

Front 1

what is the major difference between apoptosis and necrosis?

Back 1

apoptosis is planned cell death and does not release any of the cellular contents into the cytoplasm and elicit an immune response. Necrosis releases cellular components into the extracellular space and does elicit an immune response

Front 2

what are the 6 steps in apoptosis?

Back 2

signaling, integrating the signals, commitment to cell death, cell-death execution, phagocytosis, and degradation

Front 3

the activation of which enzymes irreversibly commits a cell to cell death?

Back 3

caspases

Front 4

where do caspases cleave?

Back 4

After 4-residue sequences ending in aspartate

Front 5

an active caspase has how many subunits? What is the composition?

Back 5

4; 2 heterodimers

Front 6

what are the two types of caspases?

Back 6

initiator caspases and effector caspases

Front 7

how are initiator caspases processed and activated?

Back 7

autocatalytically with the help of specific adaptor proteins such as Apaf-1 or FADD/MORT1

Front 8

how are effector caspases processed and activated?

Back 8

by initiator caspases

Front 9

which type of caspases are activated by adaptor proteins?

Back 9

initiator caspases

Front 10

what are the two pathways by which apoptosis pathways can be distinguished?

Back 10

extrinsic and intrinsic

Front 11

what is another name for the extrinsic pathway of apoptosis? Intrinsic?

Back 11

death receptor; mitochondria-dependent

Front 12

in which types of cells is the extrinsic pathway of apoptosis active? The intrinsic pathway?

Back 12

cells of the immune system; many cells of different types

Front 13

what is the name of the adaptor protein involved in extrinsic apoptosis? Intrinsic apoptosis?

Back 13

FADD/MORT1; Apaf-1

Front 14

to which caspase does FADD/MORT1 bind? Apaf-1? Which effector caspase does each initiator caspase activate, in turn?

Back 14

Casp8; Casp9; Casp3

Front 15

the activity of Apaf-1 is controlled by which type of protein? FADD/MORT1?

Back 15

death receptors; Bcl2-like proteins

Front 16

what is an example of a death receptor? Where are the death receptors located?

Back 16

TNFR; plasma membrane

Front 17

where do the ligands of the death receptors bind? What is the name of the complex formed by the intra-cellular domain of the death receptor upon activation by receptor ligands?

Back 17

to the extra-cellular domain of the death receptors; DISC complex

Front 18

what associates with the DISC complex to activate apoptosis?

Back 18

FADD/MORT1 molecules

Front 19

what do Bcl2-like proteins regulate?

Back 19

permeability of the outer mitochondrial membrane and release of cytochrome c into the cytosol.

Front 20

what happens when cytochrome c is released into the cytosol?

Back 20

it binds to Apaf-1 which induces the assembly of the apoptosome

Front 21

what is the composition of the apoptosome?

Back 21

seven Apaf-1-cytochrome c dimers

Front 22

Apaf-1 associated with the apoptosome can recruit which molecule?

Back 22

Casp9

Front 23

Are Bcl2-like proteins anti- or pro-apoptotic? The Bax- and BH3-only proteisn

Back 23

anti; pro

Front 24

in healthy cells, does the activity of Bcl2 domain or the activity of Bax2 and BH3 dominate? What effect does this have on the other death ligands?

Back 24

Bcl2; inactivates

Front 25

which proteins, upon activation, block the activity of anti-apoptotic Bcl2-like proteins?

Back 25

BH3-only proteins

Front 26

what is the action of BH3-only proteins?

Back 26

Block Bcl2-like proteins and promote activation of Bax-like proteins

Front 27

what do Bax-like proteins do?

Back 27

permeabilize OMM, release cytochrome c, assemble the apoptosome and activate caspases

Front 28

by which cells are death cell receptor ligands produced?

Back 28

neighboring cells

Front 29

upstream of BH3-only cells, what controls the activation of the intrinsic pathway of apoptosis?

Back 29

transcriptional or post-transcriptional level regulation of BH3 activity

Front 30

which three types of proteins have been shown to be cleaved by caspases?

Back 30

1) anti-apoptotic proteins, 2) dormant pro-apoptotic proteins, and 3) structural proteins

Front 31

upon what is phagocytosis dependent?

Back 31

activation of caspases

Front 32

which molecule is responsible for fragmentation of DNA into DNA ladders? By what is this inhibited? How is the inhibitor inactivated?

Back 32

DNAse CAD; ICAD; caspases

Front 33

what is the name for the fragmented DNA seen in apoptotic cells?

Back 33

DNA ladder

Front 34

what is the identity of the 'eat-me' signal seen in apoptotic cells?

Back 34

phosphatidyl serine in the PM