Rawat 2019 J Mol Biol
|Rawat S, Anusha V, Jha M, Sreedurgalakshmi K, Raychaudhuri S (2019) Aggregation of respiratory complex subunits marks the onset of proteotoxicity in proteasome inhibited cells. J Mol Biol [Epub ahead of print].|
Abstract: Proteostasis is maintained by optimal expression, folding, transport, and clearance of proteins. Deregulation of any of these processes triggers protein aggregation and is implicated in many age-related pathologies. In this study, using quantitative proteomics and microscopy, we show that aggregation of many nuclear-encoded mitochondrial proteins is an early protein-destabilization event during short-term proteasome inhibition. Among these, Respiratory Chain Complex (RCC) subunits represent a group of functionally related proteins consistently forming aggregates under multiple proteostasis-stresses with varying aggregation-propensities. Sequence analysis reveals that several RCC subunits, irrespective of the cleavable mitochondrial targeting sequence (MTS), contain low complexity regions (LCR) at the N-terminus. Using different chimeric and mutant constructs, we show that these low complexity regions partially contribute to the intrinsic instability of multiple RCC subunits. Taken together, we propose that physicochemically driven aggregation of unassembled RCC subunits destabilizes their functional assembly inside mitochondria. This eventually deregulates the biogenesis of respiratory complexes and marks the onset of mitochondrial dysfunction.
Copyright © 2019. Published by Elsevier Ltd.
• Keywords: Low complexity region, Mitochondria, Mitochondrial respiratory chain complex, Protein aggregation, Protein misfolding, Protein turnover, Proteomics, Proteostasis • Bioblast editor: Plangger M • O2k-Network Lab: IN Hyderabad Thangaraj K
Labels: MiParea: Respiration
Organism: Mouse Tissue;cell: Nervous system Preparation: Permeabilized cells
Coupling state: OXPHOS Pathway: N, S, CIV, ROX HRR: Oxygraph-2k