Time-Resolved Interactome Profiling Deconvolutes Secretory Protein Quality Control Dynamics

Abstract

SUMMARYMany cellular processes are governed by protein-protein interactions that require tight spatial and temporal regulation. Accordingly, it is necessary to understand the dynamics of protein interactions to fully comprehend and elucidate cellular processes and pathological disease states. To map de novo protein-protein interactions with time-resolution at an organelle-wide scale, we developed a quantitative mass-spectrometry method, time-resolved interactome profiling (TRIP). We apply TRIP to elucidate aberrant protein interaction dynamics that lead to the protein misfolding disease congenital hypothyroidism. We deconvolute altered temporal interactions of the thyroid hormone precursor thyroglobulin with pathways associated with hypothyroidism pathophysiology such as Hsp70/90 assisted folding, disulfide/redox processing, and N-glycosylation. Functional siRNA screening identified VCP and TEX264 as key protein degradation components whose inhibition selectively rescues mutant prohormone secretion. Ultimately, our results provide insight into the temporal coordination of protein homeostasis, and our TRIP method can have broad application in investigating protein folding diseases and cellular processes.HIGHLIGHTSMethod to map de novo protein-protein interactions with temporal resolutionCharacterization of the time-resolved interactome of a protein folding disease statesiRNA screening identifies VCP and TEX264 as major regulators of thyroglobulin processingVCP pharmacological inhibition rescues mutant thyroglobulin secretion

The glycoprotein quality control factor Malectin promotes coronavirus replication and viral protein biogenesis

“…The proteostasis network maintains the cellular proteome, from protein folding, addition of post-translational modifications, and trafficking to degrading old or misfolded proteins (15). Key to this network is the coordination of PPIs between quality control factors and client proteins to surveil the state of proteome, which is particularly important in the biogenesis and secretion of glycosylated proteins (glycoproteins) (16)(17)(18)(19). CoVs encode several N-linked glycoproteins with critical roles in replication, including nsp3, nsp4, spike (S), and membrane (M) proteins, while MHV encodes an additional structural glycoprotein, hemagglutinin-esterase (HE) (20).…”