Compare and Contrasting Apoptosis/ Necrosis
Programmed cell death and cell death by lysis and rupture.
What are the definitions of apoptosis and necrosis?
DNA damage
What initiates the intrinsic pathway?
both act to activate executioner procaspase 3 by cleavage, resulting in activated caspase 3
What is activated in both caspase 9 & 8?
Bak, Bax and Puma
What are proapoptotic proteins?
Promote cell survival and growth
What are signaling molecules?
During embryonic development, B and T cell development, normal cellular turnover, and due to DNA damage or infection
When does apoptosis occur?
Ligand binding to a death receptor on the cell surface
What initiates the extrinsic pathway?
The initiator procaspase 9 by cleavage, forming activated caspase 9
What are activated in intrinsic pathways?
Bcl2
what is a anti-poptotic protein?
suppresses apoptosis to promote cell survival.
What are survival factors?
cellular injury, disease, or failure of blood supply
What causes necrosis?
Cytochrome C is released and associates with APAF1 (apoptotic protease-activating Factor 1). Which then activates an initiator procaspase 9 by cleavage. Which then activates executioner procaspase 3 by cleavage.
What is the intrinsic pathway?
The initiator procaspase 8 by cleavage, forming activated caspase 8.
What is activated in extrinsic pathways?
Regulates apoptosis, primarily through their control over the release of cytochrome C from the mitochondria in the intrinsic pathway
What do the family of Bcl2 proteins do?
Stimulates cell division by accelerating the passage through cell cycle checkpoints
What are mitogens?
Fragmentation of DNA and cell contents, the formation of blebs, and the release of apoptotic bodies. These apoptotic bodies are then phagocytized by immune cells.
What is the general process of apoptosis?
adaptor protein, which then activates an initiator procaspase 8 by cleavage4 . Activated caspase 8 can then directly activate executioner procaspase 3 by cleavage
What is the extrinsic pathway?
Executioner procaspase 6 is also activated by cleavage into activated caspase 6.
What is the activation of caspase 3?
Forms pores in the outer mitochondrial membrane, facilitating the release of cytochrome C
How does Bak and Bax proapototic work?
Small daughter cells
What happens if mitogen is active but growth factors are absent?
The cell membrane loses integrity and contents spill out, leading to loss of functional tissue and impaired organ function
What is the general process of necrosis?
Has the death receptor ligand in extrinsic pathways
What are NK and T cells?
cleave DNA, proteins, and other cellular contents, leading to the morphological changes characteristic of apoptosis, such as DNA fragmentation and bleb formation
What is the result of the activated executioner caspases, caspase 3, and caspase 6?
Prevents the release of cytochrome C and blocks the intrinsic apoptotic pathway
How does Bcl2 function?
Promotes an increase in cell size through enhanced synthesis of proteins and other biomolecules
What are growth factors?