Cell Death Flashcards
apoptosis
falling off
Difference between apoptosis and necrosis
necrosis: bursting causes an inflammatory response
caspases
cysteine containing proteases that cleave sequences on proteins during apoptosis.
How do initiator caspases work?
inacitve soluble monomers group together, pair up into a dimer to stabilize and activate each other.
How do executioner caspases work?
After paired and activated, catalyze the protein cleavage events.
death receptors
extrinsic pathway triggers: homotrimers of the TNF superfamily.
DISC
Death inducing signal complex: Fas ligand on a killer activates Fas on cell surface, cytolic tails of Fas bind to adaptor proteins which bind to the initiator caspases.
cytochrome c
intrinsic pathway trigger: binds to Apaf1 which become apoptomose which activates the proteins that initiate downstream initiator caspases.
Bcl2 family
suppress/regulates apoptosis
Bax/ Bak
main effector proteins in the Bcl2 family, one is required for the intrinsic pathway to operate.
Bcl2/ BclXl
anti-apoptotoc Bcl family proteins
p53
a tumor suppression protein that accumulates and activates the intrinsic pathway
Bid
the protein that links the two apoptotic pathways.
IAPs
Inhibitors of apoptosis - ensure the proteases only activate when appropriate.
survival factors
cells require continuous signalling from other cells or they die
phosphatidylserine
flips to the outer membrane in apoptotic cells to signal phagocytosis
apoptosis
clean death..ideal for cancer. necrosis (chemo) will cause the return
