MODULE 8: Chapter 8.4 Flashcards
What is the role of tumor necrosis factor-α (TNF-α) in cell signaling?
TNF-α initiates programmed cell death (apoptosis) and stimulates a cell survival pathway.
What determines the downstream cellular response in TNF receptor signaling?
The relative levels of downstream pro-apoptotic and anti-apoptotic proteins.
What is the function of the death domain (DD) in TNF receptors?
It acts as a protein-protein interaction module for assembling adaptor signaling complexes.
Fill in the blank: The two types of pathways regulated by TNF receptor signaling are ______ and ______.
[cell death pathway] and [cell survival pathway]
What is the primary function of caspases in the apoptosis pathway?
They are enzymes that degrade cellular proteins and kill the cell.
What is the role of the adaptor protein TRADD in TNF receptor signaling?
TRADD binds to the TNF receptor and facilitates the assembly of downstream signaling complexes.
True or False: The Fas receptor is a member of the TNF receptor family.
True
What complex is formed in the apoptosis pathway when TRADD binds to FADD?
The TRADD–FADD complex.
What does the activation of caspase 8 lead to in the apoptosis pathway?
The cleavage and activation of caspase 3.
What is the outcome of the TNF receptor signaling pathway when levels of TRAF2 and RIP are higher than FADD?
The cell stimulated by TNF-α will survive.
What is the role of IκBα in the TNF receptor signaling pathway?
IκBα inhibits NFκB by retaining it in the cytosol until degraded.
Fill in the blank: The proteolytic processing of TNF-α releases a ______ signaling molecule.
[185-amino-acid]
What type of proteins do caspases cleave during apoptosis?
Cysteine–aspartate proteases.
What is the function of the protein receptor interacting protein (RIP) in the survival pathway?
It binds to TRADD and participates in the phosphorylation cascade.
What is a potential therapeutic target for cancer treatment regarding apoptotic signaling?
Blocking the function of anti-apoptotic proteins.
What is the significance of the death-inducing signaling complex (DISC)?
It activates caspase 8, which then activates executioner caspase 3.
True or False: The TNF receptor signaling pathway includes only pathways leading to cell death.
False
What is the consequence of the phosphorylation of IκB by IKK?
The degradation of IκBα, leading to NFκB activation.
Fill in the blank: The mature form of caspase 3 is a ______ complex.
[p17p12]2 heterotetramer
What is the role of the Fas receptor in the immune system?
It regulates apoptosis in B and T lymphocytes.
What happens when procaspase 8 is activated?
It initiates a proteolytic cascade leading to cell death.
How do neurodegenerative diseases relate to apoptotic pathways?
They may be caused by increased activation of apoptotic pathways leading to cell death.
What is the primary function of NFκB in cell survival signaling?
To activate transcription of anti-apoptotic genes.
What is apoptosis?
Programmed cell death in which a cell causes its own death and lysis.
Apoptosis is a crucial process for maintaining cellular homeostasis and preventing the survival of damaged cells.
What is the role of the death domain (DD) in TNF receptors?
A region in the cytoplasmic tail of TNF receptors that functions as a protein–protein interaction module.
The death domain is essential for signaling pathways that lead to apoptosis.
What are cysteine–aspartate proteases (caspases)?
A class of proteins that initiates a proteolytic cascade leading to protein degradation and cell death.
Caspases are key executors of the apoptotic process.
What does TNF receptor–associated death domain (TRADD) do?
A downstream signaling protein that binds to TNF receptors in the absence of SODD proteins, regulating apoptosis.
TRADD is crucial for the transmission of apoptotic signals.
What is the function of the Fas-associated death domain (FADD)?
A protein complex that binds with TRADD as part of the cell death signaling pathway.
FADD acts as an adaptor protein in the apoptotic signaling cascade.
What is the death effector domain (DED)?
A protein–protein interaction module that enables the TRADD–FADD complex to bind with procaspase 8 as part of the cell death pathway.
DED is essential for the activation of initiator caspases.
What role does TNF receptor–associated factor 2 (TRAF2) play?
A protein complex that binds with TRADD as part of the cell survival pathway alternative to apoptosis.
TRAF2 helps promote cell survival under certain conditions.
What is the function of receptor interacting protein (RIP)?
A protein recruited to the TNF receptor complex to bind with the TRADD–TRAF2 complex as part of the cell survival pathway.
RIP is involved in signaling pathways that prevent apoptosis.
Why do cells have both apoptotic and survival pathways?
To provide a ‘toggle switch’ to kill or rescue the cell quickly, depending on stimuli.
This mechanism allows cells to adapt to changing conditions and maintain homeostasis.
True or False: Apoptosis is beneficial to the organism as a whole.
True.
Apoptosis prevents damaged or inappropriate cells from surviving, contributing to overall health.
Fill in the blank: The key activating signal in the TNF receptor signaling pathway occurs downstream of _______ binding.
[TNF-α]
TNF-α binding initiates the signaling cascade that can lead to either cell survival or apoptosis.
What is the purpose of having opposing cell death and survival pathways in the same cell?
To quickly adapt to the quantity and quality of stimuli, allowing for rapid decisions about cell fate.
This flexibility is crucial in responding to environmental changes.
