Lecture 10 - Mitochondria 4 Flashcards
What are the differences between apoptosis and necrosis?
Apoptosis: Active requires energy and RNA and protein synthesis Characteristic morphological features DNA cleaved and chromatin condenses Formation of apoptotic body. Cleared by phagocytosis No inflammation
Necrosis: Passive cell death cells swell up and burst (conents leak out.) Nucleus disintegrates Cell ghosts Inflammation
What is the effect of UV light on cyt c?
Cytochrome C shown to disperse through cell in response to UV light
What causes cyt c release? (in general terms)
Cytochrome C released in response to a range of pro-death stimuli.
What anchors cyt c in the inner membrane?
A lipid anchor known as cardiolipin is believed to promote the localisation of cyt c to the inner membrane
What are the types of Bcl-2 family proteins?
Anti-apoptotic (Bcl-2, Bcl-w, Bcl-xL)
Pro-apoptotic (Bax, Bak, Bok)
BH3-only (Bid, Bim, Bad)
What kind of proteins are the pro and anti apoptotic Bcl-2 proteins?
C-tail anchored proteins in outer membrane of mitochondria.
What domains do anti apoptotic Bcl-2 proteins have?
Anti-apoptotic Bcl-2 proteins have 4 BH domains and a transmembrane domain. They are C-tail anchored proteins.
What domains do pro apoptotic Bcl-2 proteins have?
Pro-apoptotic Bcl-2 proteins have 3 BH domains and a transmembrane domain. These are C-tail anchored proteins
What are the domains found in BH3 proteins?
BH3 proteins have 1 BH3 domain. These proteins regulate function of anti and pro apoptotic pathway.
What are the pathways for apoptosis?
Intrinsic: from within the cell apoptosis is induced
Extrinsic: From outside of the cell apoptosis is induced
What happens when BH3 is activated?
activation of BH3 results in either inhibition of anti-apoptotic proteins or inhibition of pro-apoptotic proteins
What is the point of no return of apoptosis?
Mitochondrial Outer Membrane Permeabilization
What happens during MOMP?
Cytochrome C is released from the mitochondria, apoptosome is formed and caspase 3 is released resulting in cell death
Where do the Bcl-2 proteins perform their function?
Efforts of the Bcl-2 family converge at the level of the mitochondrial outer membrane. where they protect against or initiate MOMP
What is the function of Bax? Where is it localized when inactive?
During apoptosis Bax changes conformation and enters the mirochondrial outer membrane by exposing a mitochondrial targetting signal. This induces cyt c release. This signal is at the C-terminus and is an alpha helix.
