Related Experiment Video
Updated: Aug 12, 2025
13:02
Production, Crystallization, and Structure Determination of the IKK-binding Domain of NEMO
Published on: December 28, 2019
7.6K
Linear ubiquitination induces NEMO phase separation to activate NF-κB signaling
Simran Goel1, Rosario Oliva2,3, Sadasivam Jeganathan1
1Department Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany.
Life Science Alliance
|January 31, 2023
Summary
Linear ubiquitin chains drive the phase separation of NF-κB essential modulator (NEMO), forming critical assemblies for immune signaling. This phase separation is essential for activating NF-κB pathways in response to stimuli like IL-1β.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- NEMO (NF-κB essential modulator) is central to the IKK complex and canonical NF-κB signaling.
- NEMO interacts with linear (M1-linked) ubiquitin chains generated by LUBAC upon immune receptor stimulation.
- This interaction is crucial for kinase activation and downstream signaling.
Purpose of the Study:
- To investigate the role of M1-ubiquitin chains in NEMO regulation.
- To determine if NEMO undergoes phase separation and its functional significance in NF-κB activation.
Main Methods:
- Cellular assays to observe NEMO assembly formation.
- Analysis of NEMO binding and linkage to M1-ubiquitin chains.
- Utilizing a pathogenic NEMO mutant to assess functional defects.
Main Results:
- M1-ubiquitin chains induce phase separation of NEMO, forming cellular assemblies after IL-1β exposure.
- Both NEMO binding to and covalent linkage of M1-ubiquitin chains promote phase separation.
- A NEMO mutant deficient in M1-ubiquitin interactions fails to phase separate and shows impaired IL-1β-induced NF-κB activation.
Conclusions:
- M1-ubiquitin-induced phase separation of NEMO is a key mechanism in innate and adaptive immune signaling.
- NEMO phase separation is essential, though not sufficient, for NF-κB pathway activation.
- Disruption of NEMO phase separation impairs immune responses, highlighting its critical role.
Related Concept Videos
02:26NF-κB-dependent Signaling Pathway
7.8K
The transcription factor NF-κB was discovered in 1986 in the lab of Nobel laureate Professor David Baltimore, for its interaction with the immunoglobulin light chain enhancer in B-cells. After more than three decades of study, it is now evident that NF-κB regulates the expression of over 100 genes. Most of these genes play an essential role in the innate and adaptive immune responses as well as the inflammatory responses of animals.
NF-κB-dependent Signaling Mechanism
The...
NF-κB-dependent Signaling Mechanism
The...
7.8K
01:45Regulation of Nuclear Protein Sorting
2.4K
Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
2.4K
01:31Regulation of the Unfolded Protein Response
2.5K
Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...
2.5K
01:15Receptor Downregulation in MVBs
2.1K
Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR...
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR...
2.1K
01:37The Unfolded Protein Response
4.9K
The ER is the hub of protein synthesis in a cell. It has robust systems to quality control protein folding and also for degradation of terminally misfolded proteins. Under normal conditions, a small proportion of misfolded proteins that cannot be salvaged need to be transported to the cytoplasm by the ER-associated degradation or ERAD pathways. However, if the ERAD cannot handle the misfolded proteins, the cell activates the unfolded protein response or UPR to adjust the protein folding...
4.9K
01:07MAPK Signaling Cascades
5.8K
Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
5.8K