Phospho-SXXE/D motif mediated TNF receptor 1-TRADD death domain complex formation for T cell activation and migration

Area of Science:

• Immunology
• Molecular Biology
• Cell Signaling

Background:

• Tumor Necrosis Factor Receptor 1 (TNFR1) and its associated proteins, including TRADD, Fas-associated death domain protein, and receptor-interacting protein kinase, assemble into signaling complexes via death domain interactions.
• These interactions are critical for initiating downstream signaling pathways.

Purpose of the Study:

• To investigate the role of phosphorylation in the SXXE/D motifs within the death domains of TNFR1 and TRADD.
• To determine the impact of this phosphorylation on TNFR1-TRADD complex formation, NF-κB activation, and T cell recruitment in inflammatory processes.

Main Methods:

• Analysis of protein-protein interactions within TNF-treated cells.
• Investigation of phosphorylation events on specific death domain motifs (S381 in TNFR1, S215 and S296 in TRADD).
• Examination of T cell accumulation and TNFR1 phosphorylation in inflammatory bowel disease (IBD) patient samples.

Main Results:

• Phosphorylation of SXXE/D motifs in TNFR1 and TRADD is required for stable TNFR1-TRADD complex formation and NF-κB activation.
• Phosphorylated TRADD motifs are critical for recruiting Fas-associated death domain protein and receptor-interacting protein kinase.
• IκB kinase β mediates TNFR1 phosphorylation at S381, promoting T cell migration and accumulation.
• Constitutive TNFR1 S381 phosphorylation was observed in inflammatory T cells within IBD mucosa.

Conclusions:

• Phosphorylation of SXXE/D motifs acts as a key regulatory mechanism for TNFR1 signaling complex assembly and function.
• These motifs are crucial for T cell recruitment and accumulation in inflammatory diseases.
• The findings highlight a potential therapeutic target for modulating inflammatory responses.