Term
| What are the two ways that cells die? |
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Definition
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Term
| What are the key differences between necrosis and apoptosis? |
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Definition
Necrosis: break down of the membrane, causes inflammation
Apoptosis: programmed cell death. Cell will shrink due to membrane blebbing. Requires ATP |
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Term
| What big role does apoptosis perform during development? |
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Definition
Apoptosis performs 2 key roles in development: Sculpting and Deleting vestigial organs
Sculpting: forming of fingers and toes
deleting: destroying the organs that existed solely for development (such as the allantois) |
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Term
| What is the result of the failure of sculpting during development? |
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Definition
| Syndactyly (fused digits) results from a failure of apoptosis |
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Term
| What role does apoptosis perform in developed humans? |
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Definition
| Maintaining homeostasis and eliminating abnormal, misplaced, nonfunctional, or harmful cells |
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Term
| What are the four main signals that initiate apoptosis? |
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Definition
Loss of survival signals
Loss of contact signals
Irreperable internal damage
Instructive apoptosis |
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Term
| What is instructive apoptosis? |
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Definition
| Apoptosis after an immune response to lower levels of immune cells |
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Term
| What are the two major pathways of apoptosis? |
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Definition
Membrane receptor pathway
and
Mitochondrial pathway |
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Term
| What is the TNF superfamily? |
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Definition
This is the family of receptors on cell membranes that initiate apoptosis.
Stands for Tumor Necrosis Factor. Called Death Receptors |
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Term
| What is the general pathway of apoptosis in membrane receptor pathway? |
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Definition
1) Signalling ligand binds to membrane receptors
2) Trimerization of receptor, Death domains in cell come together
3) Adapter protein (FADD) joins death domains
4) Adapter protein recruits procaspase through use of a death effector domain [DED, CARD]
5) Oligomerization and proteolytic activation of of initiator caspase
6) Further recruitment of effector caspases through cleavage by initiator caspases |
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Term
| What caspases are initiator caspases? |
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Definition
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Term
| What caspases are effector caspases? |
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Definition
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Term
| Caspases only cleave when they recognize which compound? |
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Definition
| Aspartic acid, highly specific |
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Term
| Caspases have what on their active site? |
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Definition
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Term
| Due to the proteolytic function of caspases, what checks are put in place to tightly regulate caspase function? |
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Definition
1) Synthesized as inactive precursors
2) inhibitors exist |
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Term
| What do the inactive caspase precursors look like? |
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Definition
Have three segments: predomain, large domain, and small domain.
Dimerize to form active caspase |
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Term
| What is the mechanism of mitochondrial initiated pathway for apoptosis? |
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Definition
1) Pro-apoptotic Bcl-2 family perforates the mitonchondrial membrane
2) Cytochrome C leaks out of mitochondrial membrane and binds to Apaf-1
3) Procaspase 9 binds to complex
4) Procaspase 3 binds to complex forming Apoptosome
5) Cleavage and subsequent activation |
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Term
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Definition
| Protein complex formed by Procaspase 3, Procaspase 9, and Apaf-1 during mitochondrial initiated apoptosis |
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Term
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Definition
| Apoptotic protease activating factor |
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Term
| What are the Proapoptotic factors of mitochondrial initiated apoptosis? |
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Definition
In cytosol:
Bax, Bak, Bad, Bim, Bid, Noxa, Puma
In mitochondria:
AIF
SMAC/Diablo
Cytochrome C |
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Term
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Definition
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Term
| What does SMAC/Diablo do? |
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Definition
| binds pro-caspase 3 inhibitors (IAPs) |
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Term
| What are the anti-apoptotic factors in mitochondrial initiated apoptosis? |
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Definition
| Bcl-2, Bcl-Xl, Mcl-1, Al/Bfl-1 and IAPs |
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Term
| What do anti-apoptotic factors such as BCL-2 and Mcl-1 do? |
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Definition
| Insert into the mitochondrial membrane and inhibit the release of Cytochrome C and other pro-apoptotic factors |
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Term
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Definition
IAPs = Inhibitors of Apoptosis
Bind to caspases and keep them inactive |
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