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22 Cards in this Set
- Front
- Back
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DAMPs vs PAMPs |
DAMPs: danger associated molecular patterns that are endogenous molecules that create an immune response by being somewhere they are not supposed to be (DNA in cytoplasm) PAMPs: pathogen associated molecular patterns that are distinct markers on foreign invaders |
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What recognize and bind DAMPs and/or PAMPs? |
Pattern Recognition Receptors |
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What is the result of ligand binding to a PRR? |
It induces signalling pathways that can modulate the expression of important genes (cytokine genes) |
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DAMP Binding |
DAMPs are often intracellular proteins that are released from the cell entering the extracellular space and enabling them to bind to PRR initiating a signalling pathway |
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What sort of gene expression is induced by DAMP binding? |
Inflammatory cytokine genes (IL-6, Il-1, and TNF-a) |
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Where were toll like receptors initially discovered and how? |
They were initially discovered in fruit flies, insects without these receptors quickly succumbed to fungal infections |
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What amino acid is important for ligand binding in TLRs? |
A series of leucine repeats allows for ligand binding in the TLRs |
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What is the PAMP recognized by TLR4? |
LPS or lipopolysaccharide a component of bacterial cell membranes |
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What four proteins are required for the binding of LPS and signal transduction? |
A homodimer of TLR4, LPS binding protein, and CD14 |
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What is the result of LPS binding with the TLR4 complex? |
Binding activates a protein called MyD88, which activates the transcription factor NF-kB which will in turn lead to transcription of cytokine genes |
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In addition to cytokine gene expression what other genes are expressed upon TLR4 activation? |
Activation will also cause the expression of cell surface protein responsible for antigen presentation |
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Where is TLR7 found? |
TLR7 is found in endosomes that form is cell during the entrance of viruses |
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What PAMP does TLR7 primarily recognize? |
TLR7 primarily recognizes ssRNA in endosomes as ssRNA is considered foreign in these structures (should only be found in nucleus or cytoplasm) |
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What is the result of ssRNA binding to TLR7? |
Binding results in the activation of a signalling pathway that results in IFN (type 1) gene expression |
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What is the role of IFN? |
It is an anti-viral protein that blocks viral replication and further infection |
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How do viruses propagate with interferon? |
Viruses produce proteins that interfere with interferon signalling pathways |
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NOD-Like receptor ligand |
Are similar to TLRs, but they bind peptidoglycan fragments |
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Why bind peptidoglycan fragments? |
Peptidoglycan fragment in the intracellular space are indication of pathogen phagocytosis and therefore this may likely be carried out by macrophages |
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Transcription factor activated by NOD-like receptors? |
NF-kB |
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What is RIG-1? |
Retinoic Acid inducible gene 1 |
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Where might one find RIG-1 like helicases and what do they bind and how do they recognize it? |
These enzymes are found in the cytoplasm where they bind viral RNA because it doesn't have a poly a tail or guanosine cap |
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What is the result of RIG-1 helicase binding? |
Activation of interferon gene expression similar to with NOD-like receptors |
