apoptosis, programmed cell death Flashcards
how do you control your organs sizes?
cell growth, cell division, cell death
examples of apoptosis during development?
sculpting, deleting structures, adjusting cell numbers
what disease if there is too much apoptosis?
alzheimers
disease if too little apoptosis?
cancer and autoimmune disorders
example ff apoptosis bing hijacked?
virus, bacteria
to get cancer, what two things have to be present
deregulated cell proliferation ALONG WITH suppressed apoptosis
what is necrosis
degeneration of all cellular organelles, and spewing contents by rupturing the plasma membrane into the environment
apoptosis vs necrosis
apoptosis condenses the chromatin and is controlled. the mitochondria in apoptosis are also not swelling and popping, unlike necrosis
early look of an apoptosing cell
it “rounds up” because the cytoskeleton is broken down by proteolysis
ie. it used to be a flat and happy fibroblast, and now it looks round and has condensed chromatin
what is blebbing? what does it do?
blebbing is breaking apart of the cell in a CONTROLLED manner. it allows a phagocyte or neutrocyte to recognize death and eat the cells
what regulates effectors? example of effector
sensors signal things like protease “capsase”
__are the things that keep a cell in its happy place
trophic growth factors (PDGJ,NGF,IGF,IL). if these are MISSING then apoptosis is initiated
what signals a cell to murder another cell?
presence of fas ligand or TNF stimulates apoptosis
so there are two ways to signal death. do the different signals have different results.
nope. death, by same mechanism
famous cancer related gene?
p53. it is a tumor supressor. if you don’t have it, you can’t trap the cell in G0 phase
4 things that cause cell death
DNA damage, signal imbalance, lack of survival factor, hypoxia
what are capsases
downstream effectors of cell death that destroy lamins, cytoskeletons
how are capsases stored
stored in an inactive state and are activated by something before they work
most upstream capsase? activated by?
procaspase 9 which needs proteolysis by two things that associate
- Cytochrome C (normally in mito)
- Apaf-I
what is the general organization of capsase action
caspase cascade
wheel of death is? made of ? does?
apoptosome. its made of lots of cytC it brings in capsase 9
what is the signal for capsase 9
cyt C
what signals the cyt C to come out of the cell?
BCL-2 family of protein. but this family is “YING/YANG” some of them are antipoptotic, some are proapoptotic
what are the proapoptotic BCLS?
baX or baK. they letthe cytC out (of the mitochondria)
what are the antiapoptotic BCLS?
BCL-2 or BCL-XL; it binds bak or bax to keep it from coming together and making a pore that lets Cyt C out
what does Bad do?
he is bad and he prevents the BCL-2 and BCL-XL to come together to prevent cell death…. (inhibits the inhibitor) so it apoptoses
what prevents Bad from doing its job
phosphorylation
what does bim do.
it prevents bcl-2 binding and is released by disruption of microtubule cytoskeleton. it stimulates cell death
how does a growth factor affect Bad?
the cell makes a 14-3-3 protein and phosphorylates Bad
where does puma come from?
it comes out of the nucleus when there is DNA damage to stimulate bak and bax
what upregulates BCL-XL? how does this work in hemopoeisis?
epo. keeps the cells from dying even though the nucleus is destroyed
if you upregulate BCL-2?
keeps the cell alive…. even if it shouldn’t be
