Time-resolved interactome profiling deconvolutes secretory protein quality control dynamics.

Area of Science:

• Cellular Biology
• Biochemistry
• Molecular Medicine

Background:

• Protein-protein interactions are crucial for cellular functions and disease pathogenesis.
• Understanding the dynamics of these interactions is essential for comprehending cellular processes and disease states.
• Aberrant protein interactions contribute to various pathological conditions, including protein misfolding diseases.

Purpose of the Study:

• To develop a quantitative mass spectrometry method for mapping protein-protein interactions with time resolution at an organelle-wide scale.
• To apply this method, termed time-resolved interactome profiling (TRIP), to investigate aberrant protein interaction dynamics in congenital hypothyroidism.
• To identify novel therapeutic targets by elucidating the temporal coordination of protein homeostasis in disease.

Main Methods:

• Development of time-resolved interactome profiling (TRIP), a quantitative mass spectrometry-based approach.
• Application of TRIP to map de novo protein-protein interactions in the context of congenital hypothyroidism.
• Functional siRNA screening to identify key protein degradation components involved in disease pathophysiology.

Main Results:

• TRIP successfully mapped de novo protein-protein interactions with temporal resolution.
• Altered temporal interactions of thyroglobulin with folding, redox, and glycosylation pathways were identified in congenital hypothyroidism.
• VCP and TEX264 were identified as critical protein degradation factors, and their inhibition rescued mutant prohormone secretion.

Conclusions:

• The study provides novel insights into the temporal coordination of protein homeostasis.
• The TRIP method offers a powerful tool for investigating protein-folding diseases and other cellular processes.
• Findings highlight VCP and TEX264 as potential therapeutic targets for congenital hypothyroidism.