Cell Death Flashcards
What is apoptosis?
Programmed cell death
-controlled, no inflammation!
What are the 6 hallmarks of apoptosis?
1: cell SHRINKAGE and ROUNDING bc of breakdown of the cytoskeleton by caspases
2: the cytoplasm is dense and organelles are TIGHTLY PACKed
3: CHROMATIN is CONDENSED and packed against the NUCLEAR ENVELOPE
4: the NUCLEAR envelope is broken down and DNA is fragmented
5: the cell MEMBRANE shows irregular buds known as BLEBS
6: the cell breaks apart into APOPTOTIC BODIES which are then phagocytosed
Does apoptosis require energy?
Yes! It requires the last of the cells energy
What are Annexins?
-calcium dependent phospholipid binding proteins
-bind to PS and identify apoptotic cells
What is Necrosis?
A cell death as a result of trauma, it’s messy, the PM breaks, contents leak out, and adjacent tissues become inflamed
Does necrosis require energy?
No it doesn’t! Its passive the cell just bursts open, causing inflammation!
Who does the dirty work of the apoptotic pathway?
Caspases!
What is the chemical makeup of Caspases?
Cysteine in the active site plus ASPartic acid and it’s an enzyme!
What is the extrinsic pathway?
1: Fas Ligand (immune cell) activates Fas receptor on the PM,
2: Death Domains are activated and recruit FADD
3: FADD makes Procaspase 8 become active Caspase 8
4: Caspase 8 then activates “executioner Caspases” 3 and 7
What is DISC?
The Death Inducing Signaling Complex
-a part of the extrinsic pathway
-made up of Fas, Death Domains, FADD, and inactive procaspase 8
What triggers the intrinsic pathway of apoptosis?
the release of Cytochrome C from the mitochondria
What are the anti-apoptotic signals trying to defend against apoptosis?
Bcl-2, BCL-XL, and IAPs
(They block cytochrome C from being released)
What are Pro-Apoptotic signals?
-BAX, BID, BAD, BIM, Puma, Noxa, SMAC/DIABLO
-they help cytochrome C get released from the mitochondria to try to initiate apoptosis!
What is the pathway of the intrinsic pathway of apoptosis?
1: BID/BAD/etc cause cytochrome C to be released from the mitochondria
2: Cyt C. bind with APAF1 and procaspase 9 to make an APOPTOSOME
3: Caspase 9 is activated and calls in excutioner caspases 3,6, and 7 to kill stuff
What makes up an APOPTOSOME?
APAF1, Cytochrome C, Procaspase 9
