Apoptosis Flashcards
(20 cards)
what is apoptosis
regulated cell death, very tidy process
what are the physiologic reasons
remove cells, involution following hormone withdraw , cell turnover in prolif cell populations , eliminate potential harmful lymph , death of host cell
what are the pathologic causes
DNA damage,
accumulation of misfolded proteins,
infections
patho. atrophy
what are the two pathways for apoptosis
intrinsic and extrinsic
what are three players in apoptosis
anti-apoptopic
apoptic inhibitors
pro-apoptotic
what are the key factors in anti-apoptic and what is the function
- BCL2, BCL-X2, MCL-1
- prevents leakage of cytochrome c
what are the key factors in apoptosis initiators and function
-BH3 proteins
- initiate apoptosis
what are the key factors in pro-apoptotic and function
-BAK and BAX
- enhance mitochondrial membrane permeable
what is present in the intrinsict pathway that intiatites it
BCL2
what are the steps of the intrinsic pathway
decrease in survival signal/damage
antagonism of BCL
activaiton of BAX/BAK
leakage of cytochrome c
activation og capsase-9 and apoptosis
what initiates the extrinsic pathway
engagement of plasma membrane death receptors
what is the death receptor
Fas
What binds to the Fas
FasL
where are Fasl expressed
- on t-cells that recognize self antigens
- on cytotoxic t-cells
what are the steps of the extrinsic pathway
Fasl binds to Fas
3 death domains act as binding sites for FADD
FADD binds initiating inactive capsases
activated Caspases ( 8 &10) activates executioner caspase sequence
capsases contain
cysteine that cleave aspartic residues
what are the two phases of capases
initiation: become active
execution: terminal capases cause fragmentation
removal of dead cells cause
decrease in inflammation
what is the key signal for cell death
phosphatidyl serine on outer membrane
