Apoptosis Flashcards
Membrane blebbing
Pockets of cellular material created
Eaten by phagocytes
TNF
Tumor necrosis factor (ligand)
Extrinsic pathway
Binds to TNFR1
TNFR1
Tumor necrosis factor receptor
Trimeric “death receptor”
Has death domains (intercellular)
TRADD
TNFR-associated death domain protein
Adapter protein
One death domain for TNFR1, one for FADD
FADD
Fas associated death domain protein
Death domain and death effector domain
Procaspase 8
“Pro” caspase = inactive, uncleaved
Becomes initiator caspase 8
Cysteine protease, cysteine in catalytic site
Initiator caspase-8
Cleaves executioner procaspase into caspase 3 and 7
Executioner caspases
Cleave:
- kinases (FAK, PKB, PKC, Raf1)
- lamins - nuclear envelope breakdown
- cytoskeleton - ifs, MFs, MTs -> shape changes, blebbing
- caspase activated dnase (CAD), endonuclease
Anti-apoptotic factors
Bcl-2, Bcl-xL, Bcl-w
Prevent cell death
Restrain pro-apoptosis factors
Pro-apoptotic factors
Bax, Bak
Promote cell death
BH3 only proteins
Bid, Bad, Puma, Bim
Can inhibit anti-apoptotic factors or activate pro-apoptotic factors
In healthy cells, absent or inhibited
Activated when stressed or damaged
Bcl-2
Anti-apoptotic
In healthy cell, binds to bax to prevent it making holes in mitochondria
Bax
Pro-apoptotic
Normally restrained by being bound to bcl-2
Bid
BH3 only protein
Binds to bcl-2, releasing bax
Bax forms homodimer with self or heterodimer with bak to form pores in mitochondria
