scholarly journals Proteomic analysis reveals the recruitment of intrinsically disordered regions to stress granules

2019 ◽  
Author(s):  
Mang Zhu ◽  
Erich R. Kuechler ◽  
Joyce Zhang ◽  
Or Matalon ◽  
Benjamin Dubreuil ◽  
...  
Keyword(s):  
Heat Stress ◽  
Stress Granules ◽  
Vital Role ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Proteomic Study ◽  
As Stress ◽  
Cellular Compartmentalization ◽  
Diffusive Exchange ◽  
Disordered Regions

AbstractHeat-stress triggers the formation of condensates known as stress granules (SGs), which store non-translating mRNA and stalled translation initiation complexes. To gain a better understanding of SGs, we identified yeast proteins that sediment after heat-shock by mass spectrometry. Heat-regulated proteins are biased toward a subset of abundant proteins that are significantly enriched in intrinsically disordered regions (IDRs). SG localization of over 80 heat-regulated proteins was confirmed using microscopy, including 32 proteins that were not known previously to localize to SGs. We find that several IDRs are sufficient to mediate SG recruitment. Moreover, the diffusive exchange of IDRs within SGs, observed via FRAP, can be highly dynamic while other components remain immobile. Lastly, we showed that the IDR of the Ubp3 deubiquitinase is critical for SG formation. This work confirms that IDRs play an important role in cellular compartmentalization upon stress, can be sufficient for SG incorporation, can remain dynamic in vitrified SGs, and play a vital role during heat-stress.SummaryThe authors provide an in-depth proteomic study of yeast heat stress granule (SG) proteins. They identified intrinsic disordered regions (IDRs) as one of the main features shared by these proteins and demonstrated IDRs can be sufficient for SG recruitment.

scholarly journals Proteomic analysis reveals the direct recruitment of intrinsically disordered regions to stress granules in S. cerevisiae

2020 ◽  
Vol 133 (13) ◽  
pp. jcs244657 ◽  
Author(s):  
Mang Zhu ◽  
Erich R. Kuechler ◽  
Joyce Zhang ◽  
Or Matalon ◽  
Benjamin Dubreuil ◽  
...  
Keyword(s):  
Proteomic Analysis ◽  
Stress Granules ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Disordered Regions

scholarly journals Aggregation and Disaggregation Features of the Human Proteome

2020 ◽  
Author(s):  
Tomi A Määttä ◽  
Mandy Rettel ◽  
Dominic Helm ◽  
Frank Stein ◽  
Mikhail M Savitski
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Protein Quality ◽  
Protein Solubility ◽  
Protection Mechanism ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Aggregation Processes ◽  
Aggregation And Disaggregation ◽  
Disordered Regions

ABSTRACTProtein aggregates have negative implications in disease. While reductionist experiments have increased our understanding of aggregation processes, the systemic view in biological context is still limited. To extend this understanding, we used mass spectrometry-based proteomics to characterize aggregation and disaggregation in human cells after non-lethal heat shock. Aggregation-prone proteins were enriched in nuclear proteins, high proportion of intrinsically disordered regions, high molecular mass, high isoelectric point and hydrophilic amino acids. During recovery, most aggregating proteins disaggregated with a rate proportional to the aggregation propensity: larger loss in solubility was counteracted by faster disaggregation. High amount of intrinsically disordered regions also resulted in faster disaggregation. However, other characteristics enriched in aggregating proteins did not correlate with the disaggregation rates. In addition, we analyzed changes in protein thermal stability after heat shock. Soluble remnants of aggregated proteins were more thermally stable compared to control condition. Our results provide a rich resource of heat stress-related protein solubility data, propose novel roles for intrinsically disordered regions in protein quality control and reveal a protection mechanism to repress protein aggregation in heat stress.

scholarly journals Musashi-1: An Example of How Polyalanine Tracts Contribute to Self-Association in the Intrinsically Disordered Regions of RNA-Binding Proteins

2020 ◽  
Vol 21 (7) ◽  
pp. 2289 ◽  
Author(s):  
Tsai-Chen Chen ◽  
Jie-rong Huang
Keyword(s):  
Nmr Spectroscopy ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Structural Heterogeneity ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Self Association ◽  
As Stress ◽  
Disordered Regions

RNA-binding proteins (RBPs) have intrinsically disordered regions (IDRs) whose biophysical properties have yet to be explored to the same extent as those of the folded RNA interacting domains. These IDRs are essential to the formation of biomolecular condensates, such as stress and RNA granules, but dysregulated assembly can be pathological. Because of their structural heterogeneity, IDRs are best studied by NMR spectroscopy. In this study, we used NMR spectroscopy to investigate the structural propensity and self-association of the IDR of the RBP Musashi-1. We identified two transient α-helical regions (residues ~208–218 and ~270–284 in the IDR, the latter with a polyalanine tract). Strong NMR line broadening in these regions and circular dichroism and micrography data suggest that the two α-helical elements and the hydrophobic residues in between may contribute to the formation of oligomers found in stress granules and implicated in Alzheimer’s disease. Bioinformatics analysis suggests that polyalanine stretches in the IDRs of RBPs may have evolved to promote RBP assembly.

scholarly journals Cavin1 intrinsically disordered domains are essential for fuzzy electrostatic interactions and caveola formation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Vikas A. Tillu ◽  
James Rae ◽  
Ya Gao ◽  
Nicholas Ariotti ◽  
Matthias Floetenmeyer ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Membrane Lipid ◽  
Membrane Curvature ◽  
Caveolin 1 ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Solution Generation ◽  
Endosomal System ◽  
Disordered Regions

AbstractCaveolae are spherically shaped nanodomains of the plasma membrane, generated by cooperative assembly of caveolin and cavin proteins. Cavins are cytosolic peripheral membrane proteins with negatively charged intrinsically disordered regions that flank positively charged α-helical regions. Here, we show that the three disordered domains of Cavin1 are essential for caveola formation and dynamic trafficking of caveolae. Electrostatic interactions between disordered regions and α-helical regions promote liquid-liquid phase separation behaviour of Cavin1 in vitro, assembly of Cavin1 oligomers in solution, generation of membrane curvature, association with caveolin-1, and Cavin1 recruitment to caveolae in cells. Removal of the first disordered region causes irreversible gel formation in vitro and results in aberrant caveola trafficking through the endosomal system. We propose a model for caveola assembly whereby fuzzy electrostatic interactions between Cavin1 and caveolin-1 proteins, combined with membrane lipid interactions, are required to generate membrane curvature and a metastable caveola coat.

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