31_Apoptosis Flashcards

1
Q

What results in inflammation due to necrosis?

A

cells die and release intracellular contents into tissue/bloodstream; releases antigens not seen as “self” and activates immune response

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2
Q

What are two diseases that can involve inappropriate (excessive) apoptosis?

A

AD & PD

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3
Q

How is apoptosis required in mammary glands?

A

plays a role in the formation of epithelial ducts of mammary gland
required for elimination of secretory cells @ weaning

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4
Q

How is an apoptotic cell characterized on EM?

A

blebs (cellular contents not released, but maintained in apoptotic bodies)

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5
Q

What provides a phagocytosis signal in an apoptotic cell?

A

movement of phosphatidylserine from the inner leaflet to the outer leaflet of the PM

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6
Q

Briefly describe the morphological changes in an apoptotic cells (sequential order).

A

1) shrinkage of cell & nuclear volume
2) loss of adhesion to neighbouring cells
3) bleb formation
4) DNA, chromatin, nuclear, cellular fragmentation
5) phagocytosis

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7
Q

What protein kinases do caspases cleave?

A

> 12 of them, including FAK, PKC, Raf 1 (MAPKKK)

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8
Q

What is the consequence of lamin cleavage by caspases?

A

disassembly of nuclear envelope

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9
Q

What proteins do caspases activate? What are their functions?

A

endonuclease (cuts between nucleosomes)

DNAse (cleaves DNA)

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10
Q

What groups of proteins do caspases inactivate (through cleavage)?

A

protein kinases, lamins, intermediate filaments & actin, DNA repair enzymes

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11
Q

In a DNA ladder apoptosis assay, a DNA ladder of ______ bp steps is observed.

A

180

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12
Q

What are some general cases in which an extrinsic, receptor-mediated apoptosis pathway could be observed?

A

viral infection, toxic agents

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13
Q

How many subunits does the TNF receptor have?

A

3 (trimer)

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14
Q

What does the TNFR1 death domain recruit?

A

FADD (Fas-associated death domain)

TRADD (TNFR-associated death domain)

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15
Q

Which caspase is the initiator caspase? How does it activate itself?

A

Procaspase 8 (2 subunits) proteolytically cleaves itself into initiator caspase 8 (4 subunits).

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16
Q

What does initiator caspase 8 cleave?

A

executioner caspases

17
Q

What are some situations that can induce intrinsic, mitochondria-mediated apoptosis?

A

excessive Ca2+, starvation from GFs, irreparable DNA damage

18
Q

What family of proteins does Bax belong to?

A

Bcl-2

19
Q

Once translated, where does Bax integrate? What is released as a result

A

integrated into OMM; cytochrome c released

20
Q

What is the apoptosome composed of?

A

7 each of: cytochrome c, pro-caspase 9, and cytoplasmic factors (e.g. Apaf-1)

21
Q

What do the apoptosomes cleave?

A

executioner caspases

22
Q

What are two ways by which executioner caspases can be cleaved?

A

initiator caspase-8

initiator caspase-9 complex (apoptosome)