Intracellular Sensing Mechanisms PDF
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Summary
This document details various intracellular sensing mechanisms, focusing on NOD receptors, inflammasomes, and RIG-I/MDA5 pathways. The pathways function in detecting cytoplasmic bacteria, viral RNA, or cellular damage and activating downstream inflammatory responses mediated by NF-κB. The content likely discusses immune signaling pathways in detail.
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## Intracellular Sensing ### NOD Receptors - Cytoplasmic NOD proteins reside in the cytoplasm in an inactive form. - Binding of bacterial ligands to NOD proteins induces recruitment of RIPK2, which activates TAK1, leading to NFKB activation. ### Inflammasome - A specific case of NOD is the inflamm...
## Intracellular Sensing ### NOD Receptors - Cytoplasmic NOD proteins reside in the cytoplasm in an inactive form. - Binding of bacterial ligands to NOD proteins induces recruitment of RIPK2, which activates TAK1, leading to NFKB activation. ### Inflammasome - A specific case of NOD is the inflammasome. - It is a complex of proteins whose function is to activate inflammation. - It is made up of three main proteins. - NLRP, ASC and 1 ProCaspase - The inflammasome is activated by the recognition of a microbe. - It can also be activated by tissue damage. - It is a positive feedback loop. - The activating portion of the inflammasome is NLRP which contains the LRR region. - ASC is a crucial adaptor protein which acts as a linker between the detection portion and the effector portion. - Caspase 1 is a long inactive protein that needs to be cleaved to become active. - The inflammasome cleaves procaspase 1 when it detects a foreign microbe. - This results in the activation of inflammatory mediators and the subsequent inflammatory response. ### RIG-I / MDA5 - There is another group of receptors that are found in the cytoplasm, RIG and 5-MDA. - They are soluble and bind to uncapped RNA. - When this occurs, it leads to the recruitment of adaptor proteins and eventually the activation of NFKB. - This mechanism prevents the replication of viruses in the cytoplasm. - Many of these mechanisms are based on the same principles: the activation of adaptor proteins to ultimately activate NFKB. ## Image Description - The image on the first page shows a diagram of the intracellular signalling pathway of NOD receptors. - The image on the second page shows a diagram of how an inflammasome is formed and signals for inflammation.
