Part 6 Flashcards
(5 cards)
What are the alternative pathways of programmed cell death?
What are the mechanisms that lead to cell death for these alternative pathways?
What role do caspases have during the process of apoptosis?
Autophagy: Mechanism for the gradual turnover of the cells components by the uptake of proteins or organelles into vesicles that phuse with lysosomes. Provides mechanism for cell survival Durning nutrients deprivation.
Necroptosis: Results in release of intracellular substances into the extracellular space - triggering an immune response. Triggered by specific stimuli.
Proptosis: Induced by specific stimuli such as microbial infection, executed by specific pyroptotic machinery and involved activation and oligomerization of gardermin into pore complex.
What role do caspases have during the process of apoptosis?
Cleave over 100 cellular proteins to induce the morphological alterations characteristic of apoptosis. DNA fragmentation, fragmentation of the nucleus, cytoskeleton disruption.
Focus on figure 18.24.
What are the roles of effector proteins in the mitochondrial pathway of apoptosis? Focus on the role of Bax and Bak.
What steps lead to cytochrome C release?
Caspase activation in response to apoptotic signals
When caspase active, pro apoptic effector proteins Bax and Bak form oligomeric pores in outer membrane of mitochondria, which cytochrome C is releases from intermediate space.
What role does p53 have in DNA damage-induced apoptosis.
What are the main molecules involved in this apoptotic pathway (see figure 18.25)?
1) DNA damage leads to activation of the ATM and chk2 protein kinases
2) Phosphorylates and stabilize p35
3) Results in rapid increase in p53 levels
4) p53 protein activates transcription of genes encoding the pro apoptic regulatory proteins PUMA and NOXA leading to cell death
What role does Caspase-8 have in the mitochondrial pathway of apoptosis?
What type of enzyme is Caspase-8?
Capase-8 cleaves the pro-apoptotic regulatory Bid, which activates the mitochondrial pathway of apoptosis
Capase-8 cysteine protease
Initiates apoptotic signaling via the extrinsic pathway.
