Apoptosis Flashcards
What is necrosis?
“dirty way of dying” for example: carrying Petri dish of cells; spill and step on them, accidental cell death
What is apoptosis?
“clean way of dying” cell death under physiological conditions, programmed cell death that minimizes spread of damage and/or inflammation
What is the phenotype of apoptosis?
overall shrinkage in volume of cell loss of adhesion to neighboring cells formation of blebs on surface DNA fragmentation cytoskeleton collapses nuclear envelope disassembles rapid engulfment of dying cell by phagocytosis
What is caspase?
cysteine aspartyl specific protease
What is an active site on caspase?
cysteine
What does caspase?
targets proteins and cleaves them in their sequence where an aspartic amino acid residue occurs
What is the inactive precursor of caspases? how does it become active?
procaspase; by protease cleavage
What is initiator caspase?
initiates apoptosis
What is executioner caspase?
destroys actual targets- executes apoptosis
What are examples of internal stimuli?
abnormalities in DNA
What are examples of external stimuli?
removal of survival factors and proteins of tumor necrosis factor family
Intrinsic pathway is mitochondrial ________
dependent
Extrinsic pathway is mitochondrial _______
independent
Extracellular signals bind to cell surface ________ receptors and trigger extrinsic pathway
death
What are the three domains of death receptors?
extracellular binding domain
single transmembrane domain
intracellular death domain
Extrinsic pathway activates downstream _______ _____
executioner caspases
What are decoy receptors?
have ligand binding domain but no death domain
What is FLIP?
protein resembling initiator procaspase with no proteolytic domain
FLIP is a ______ inhibitor against procaspase 8 and procaspase 10; prevents apoptosis
competitive
Decoy proteins and FLIP act as ______
sponges
When cytochrome C is release from mitochondria, it binds to procaspase activating adaptor protein called ______
Apaf1
Apaf1 forms ____ which activates _____
apoptosome; capase-9
What does the Bcl2 family of proteins regulate what?
intrinsic pathway
What are the two types of Bcl2 protein?
anti apoptotic
pro apoptotic
What does anti apoptotic protein do?
blocks release of cytochrome C
What does pro apoptotic protein do?
promotes release of cytochrome C
