Flashcards in Week 5 Apoptosis Deck (17):
Contrast Necrosis and Apoptosis: stimuli, morphology, host response, insult severity, nucleus dissolution
Necrosis: pathologic, cell swelling and lysis, inflammation, greater insults
Apoptosis: physiologic or pahtologic, cell shrinking, no inflammation, lesser insult
Nucleus dissolves in both!
what is the general/morphological progresssion of a cell undergoing apoptosis
nucleus condenses and fragments-->part of the cell Bleb and form apopotic bodies that are eaten by phagocytes
name three diseases in which we see excessive apoptosis?
AIDs (excessive loss of lymphocytes), Alzheimers disease (neuron loss), stroke
name a disease associated with suppression of apoptosis
what are the pro-apoptotic and anti-apoptotic Bcl-2 subgroups
Pro: Bax family (Bax/Bak), BH2-only family (Bid)
Anti: Bcl-2 family
what is the role of Bcl-2
when there is not cell stress Bcl-2 binds and inhibits Bax/Bik preventing them from inducing apoptosis
what is the role of Bid? activated?
under cell stress Bid is cleaved (caspase -8 or granzyme-B) and inhibits Bcl-2 binding and thus frees Bax/Bak
what is the role of Bax/Bak
when not sequestered Bax/bak create a pore in the mitochondrial membrane and release Cyt C, AIF, and Smac/Diablo
what is the role of Smac/Diablo
inhibits IAB which normally inhibits the caspase cascade
what is the role of AIF
causes nuclear condensation and DNA fragmentation
what is the role of Cyt C?
complexes with Apaf-1 to form an apatosome that activates procaspase-9
Activated pro-caspase-9 (caspase-9) does what
initiates caspase cascade which eventually activates execution caspases that degrade cellular components and lead to apoptosis
what is the extrinsic pathway of apoptosis?
death receptors at cell surface are sensitive to external signals that mediate apoptosis.
which caspase is seen in the extrinsic pathway? significance?
caspase-8 (this is the same caspase that activates Bid of the intrinsic pathway, crosstalk!)
what is Granzyme B? what is it released by?
a Ser protease that is released by cytotoxic T cells and NK cells
how does granzyme B function?
granzyme-B is released with perforin which enables it to enter cells. once in the cell granzyme-B activates Bid, Caspase 3 and 8.