TNFR1 mediates heterogeneity in single-cell NF-κB activation

Area of Science:

• Immunology
• Cell Biology
• Molecular Biology

Background:

• Nuclear factor kappa B (NF-κB) is crucial for immune responses and exhibits digital activation.
• The molecular mechanisms behind NF-κB's single-cell activation variability remain unclear.

Purpose of the Study:

• To investigate the molecular basis of heterogeneous NF-κB activation at the single-cell level.
• To elucidate the role of the tumor necrosis factor receptor 1 (TNFR1) in regulating NF-κB dynamics.

Main Methods:

• Utilized genome editing and time-lapse imaging to track endogenous TNFR1 and NF-κB in single cells.
• Employed Total Internal Reflection Fluorescence (TIRF) microscopy to analyze TNFR1 clustering and dynamics.
• Applied multi-color cell imaging to assess information processing in NF-κB activation.

Main Results:

• Endogenous TNFR1 forms pre-ligand clusters in resting cells.
• TNF stimulation decreases TNFR1 diffusion and promotes oligomerization into trimers and hexamers.
• Both digital and graded signaling pathways contribute to NF-κB activation, influenced by TNFR1 expression levels.

Conclusions:

• Single-cell NF-κB activation is significantly influenced by intrinsic TNFR1 characteristics.
• TNFR1 dynamics, including clustering and oligomerization, are key determinants of NF-κB activation potential.