14 - Cell Death Flashcards
What are the 2 types of cell death?
apoptosis | necrosis
What is apoptosis?
a signal is what causes cell death | everything condenses = cell blebbing = apoptotic bodies
What is necrosis?
injury causes cell death (ie: lack of O2) | lose integrity of cell = membrane stops working = water rushes in = cell lysis
What is the difference between apoptosis and necrosis?
apoptosis = cell membrane remains intact | necrosis = membrane is broken
How can necrosis lead to inflammation?
cell lysis = genetic material escapes = immune system sees that and induces inflammation
How are the apoptotic bodies removed?
macrophages phagocytose them
What are the 2 pathways to induce apoptosis?
intrinsic and extrinsic
What is the intrinsic pathway of apoptosis?
mitochondrial pathway
What are the 2 sides to the Bcl-2 family? Who is the main player of each family and who has the bigger family?
pro-survival side = Bcl-2 | pro-apoptotic side = Cax (bigger family)
What is the function of the pro-apoptotic proteins?
pro-apoptotic proteins inhibit Bcl-2-like proteins and its activities | form an octamer complex on mitochondrial membrane
What is displacement in the mitochondrial pathway (intrinsic)?
originally Bax is sequestered by Bcl-2 | Bim displaces Bax = Bcl-2+Bim so Bax can oligomerize = octamer complex on mitochondrial membrane
What is an octamer complex?
pore on mitochondrial membrane = stuff inside leaks out into cytoplasm
What is the main reason why octamer complex happens on the mitochondrial reason? Why do you want stuff from mitochondria to leak out?
release cytochrome c into cytoplasm
What is the role of cytochrome c in the intrinsic apoptosis pathway?
to complete the apoptosome formation
What are the 3 proteins that form the apoptosome?
cytochrome c | Apaf-1 | procaspase-9
What is the main function of the apoptosome?
to cleave procaspase-9 into caspase-9 = initiates caspase cascade
What are caspases?
proteases | inactive unless prodomain is cleaved into smaller subunits which associate = active caspase
What is the executioner caspase?
caspase 3
What is the role of caspase 3?
to proteolytically cleave the other inactive caspase = speeds up apoptosis
Until when can apoptosis be paused and reversed? What is the point of no return?
until the DNA is chopped up
In apoptosis, what chops up the DNA and what is the nature of this molecule?
CAD = DNase
What inhibits CAD?
ICAD
How is CAD activated?
caspase 3 cuts ICAD from CAD = activates CAD
What is PARP?
a detector of DNA damage like ATM and ATR = tells p53 of the damage