scholarly journals Determinants for Intrinsically Disordered Protein Recruitment into Phase-Separated Protein Condensates

2022 ◽  
Author(s):  
Yongsang Jo ◽  
Jinyoung Jang ◽  
Daesun Song ◽  
Hyoin Park ◽  
Yongwon Jung
Keyword(s):  
Phase Separation ◽  
Amino Acid ◽  
Intrinsically Disordered Proteins ◽  
Intrinsically Disordered Protein ◽  
Disordered Proteins ◽  
Amino Acid Residues ◽  
Intrinsically Disordered ◽  
Disordered Protein ◽  
Protein Recruitment ◽  
In Cells

Multivalent interactions between amino acid residues of intrinsically disordered proteins (IDPs) drive phase separation of these proteins into liquid condensates, forming various membrane-less organelles in cells. These interactions between often...

scholarly journals Sequence fingerprints distinguish erroneous from correct predictions of Intrinsically Disordered Protein Regions

2017 ◽  
Author(s):  
Konda Mani Saravanan ◽  
A Keith Dunker ◽  
Sankaran Krishnaswamy
Keyword(s):  
Amino Acid ◽  
False Positive ◽  
Intrinsically Disordered Proteins ◽  
Intrinsically Disordered Protein ◽  
Disordered Proteins ◽  
Prediction Algorithm ◽  
Amino Acid Residues ◽  
Intrinsically Disordered ◽  
Distinguishing Features

ABSTRACTMore than sixty prediction methods for intrinsically disordered proteins (IDPs) have been developed over the years, many of which are accessible on the world-wide web. Nearly, all of these predictors give balanced accuracies in the ~65% to ~80% range. Since predictors are not perfect, further studies are required to uncover the role of amino acid residues in native IDP as compared to predicted IDP regions. In the present work, we make use of sequences of 100% predicted IDP regions, false positive disorder predictions, and experimentally determined IDP regions to distinguish the characteristics of native versus predicted IDP regions. A higher occurrence of asparagine is observed in sequences of native IDP regions but not in sequences of false positive predictions of IDP regions. The occurrences of certain combinations of amino acids at the pentapeptide level provide a distinguishing feature in the IDPs with respect to globular proteins. The distinguishing features presented in this paper provide insights into the sequence fingerprints of amino acid residues in experimentally-determined as compared to predicted IDP regions. These observations and additional work along these lines should enable the development of improvements in the accuracy of disorder prediction algorithm.

scholarly journals NSP 11 of SARS-CoV-2 is an Intrinsically Disordered Protein

2020 ◽  
Author(s):  
Kundlik Gadhave ◽  
Prateek Kumar ◽  
Ankur Kumar ◽  
Taniya Bhardwaj ◽  
Neha Garg ◽  
...  
Keyword(s):  
Amino Acid ◽  
Intrinsically Disordered Proteins ◽  
Conformational Dynamics ◽  
Alpha Helix ◽  
Intrinsically Disordered Protein ◽  
Disordered Proteins ◽  
Helical Conformation ◽  
Structural Protein ◽  
Intrinsically Disordered ◽  
Protein Size

AbstractThe intrinsically disordered proteins/regions (IDPs/IDPRs) are known to be responsible for multiple cellular processes and are associated with many chronic diseases. In viruses, the existence of disordered proteome is also proven and are related with its conformational dynamics inside the host. The SARS-CoV-2 virus has a large proteome, in which, structure and functions of many proteins are not known as of yet. Previously, we have investigated the dark proteome of SARS-CoV-2. However, the disorder status of non-structural protein 11 (nsp11) was not possible because of very small in size, just 13 amino acid long, and for most of the IDP predictors, the protein size should be at least 30 amino acid long. Also, the structural dynamics and function status of nsp11 was not known. Hence, we have performed extensive experimentation on nsp11. Our results, based on the Circular dichroism spectroscopy gives characteristic disordered spectrum for IDPs. Further, we investigated the conformational behaviour of nsp11 in the presence of membrane mimetic environment, alpha helix inducer, and natural osmolyte. In the presence of negatively charged and neutral liposomes, nsp11 remains disordered. However, with SDS micelle, it adopted an α-helical conformation, suggesting the helical propensity of nsp11. At the end, we again confirmed the IDP behaviour of nsp11 using molecular dynamics simulations.

scholarly journals New technologies to analyse protein function: an intrinsic disorder perspective

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 101 ◽  
Author(s):  
Vladimir N. Uversky
Keyword(s):  
Protein Function ◽  
Intrinsically Disordered Proteins ◽  
New Technologies ◽  
Intrinsically Disordered Protein ◽  
Intrinsic Disorder ◽  
Disordered Proteins ◽  
Intrinsically Disordered ◽  
Disordered Protein ◽  
Protein Functions ◽  
Require Structure

Functions of intrinsically disordered proteins do not require structure. Such structure-independent functionality has melted away the classic rigid “lock and key” representation of structure–function relationships in proteins, opening a new page in protein science, where molten keys operate on melted locks and where conformational flexibility and intrinsic disorder, structural plasticity and extreme malleability, multifunctionality and binding promiscuity represent a new-fangled reality. Analysis and understanding of this new reality require novel tools, and some of the techniques elaborated for the examination of intrinsically disordered protein functions are outlined in this review.

scholarly journals Phosphorylation regulates the binding of intrinsically disordered proteins via a flexible conformation selection mechanism

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Na Liu ◽  
Yue Guo ◽  
Shangbo Ning ◽  
Mojie Duan
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Hydrophobic Interactions ◽  
Intrinsically Disordered Protein ◽  
Disordered Proteins ◽  
Regulation Mechanism ◽  
Enhanced Sampling ◽  
Dynamic Interactions ◽  
Post Translational Modifications ◽  
Intrinsically Disordered ◽  
Disordered Protein

Abstract Phosphorylation is one of the most common post-translational modifications. The phosphorylation of the kinase-inducible domain (KID), which is an intrinsically disordered protein (IDP), promotes the folding of KID and binding with the KID-interacting domain (KIX). However, the regulation mechanism of the phosphorylation on KID is still elusive. In this study, the structural ensembles and binding process of pKID and KIX are studied by all-atom enhanced sampling technologies. The results show that more hydrophobic interactions are formed in pKID, which promote the formation of the special hydrophobic residue cluster (HRC). The pre-formed HRC promotes binding to the correct sites of KIX and further lead the folding of pKID. Consequently, a flexible conformational selection model is proposed to describe the binding and folding process of intrinsically disordered proteins. The binding mechanism revealed in this work provides new insights into the dynamic interactions and phosphorylation regulation of proteins.

scholarly journals The intrinsically disordered protein SPE-18 promotes localized assembly of the major sperm protein in C. elegans spermatocytes

2020 ◽  
Author(s):  
Kari L. Price ◽  
Marc Presler ◽  
Christopher M. Uyehara ◽  
Diane C. Shakes
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Intrinsically Disordered Protein ◽  
Disordered Proteins ◽  
Major Sperm Protein ◽  
Sperm Protein ◽  
C Elegans ◽  
Intrinsically Disordered ◽  
Disordered Protein ◽  
Changing Patterns ◽  
Cytoskeletal Elements

ABSTRACTMany specialized cells use unconventional strategies of cytoskeletal control. Nematode spermatocytes discard their actin and tubulin following meiosis, and instead employ the regulated assembly/disassembly of the Major Sperm Protein (MSP) to drive sperm motility. However prior to the meiotic divisions, MSP is effectively sequestered as it exclusively assembles into paracrystalline structures called fibrous bodies (FBs). The accessory proteins that direct this sequestration process have remained mysterious. This study reveals SPE-18 as an intrinsically disordered protein that that is essential for MSP assembly within FBs. In spe-18 mutant spermatocytes, MSP remains cytosolic, and the cells arrest in meiosis. In wildtype spermatocytes, SPE-18 localizes to pre-FB complexes and functions with the kinase SPE-6 to recruit MSP. Changing patterns of SPE-18 localization revealed unappreciated complexities in FB maturation. Later, within newly individualized spermatids, SPE −18 is rapidly lost, yet SPE-18 loss alone is insufficient for MSP disassembly. Our findings reveal an alternative strategy for sequestering cytoskeletal elements, not as monomers but in localized, bundled polymers. Additionally, these studies provide an important example of disordered proteins promoting ordered cellular structures.Summary StatementIntrinsically disordered proteins are increasingly recognized as key regulators of localized cytoskeletal assembly. Expanding that paradigm, SPE-18 localizes MSP assembly within C. elegans spermatocytes.

scholarly journals Degradation of Intrinsically Disordered Proteins by the NADH 26S Proteasome

Biomolecules ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1642
Author(s):  
Peter Tsvetkov ◽  
Nadav Myers ◽  
Julia Adler ◽  
Yosef Shaul
Keyword(s):  
Substrate Specificity ◽  
Structural Integrity ◽  
Intrinsically Disordered Proteins ◽  
Intrinsically Disordered Protein ◽  
Degradation Pathway ◽  
26S Proteasome ◽  
Disordered Proteins ◽  
Intrinsically Disordered ◽  
Disordered Protein

The 26S proteasome is the endpoint of the ubiquitin- and ATP-dependent degradation pathway. Over the years, ATP was regarded as completely essential for 26S proteasome function due to its role in ubiquitin-signaling, substrate unfolding and ensuring its structural integrity. We have previously reported that physiological concentrations of NADH are efficient in replacing ATP to maintain the integrity of an enzymatically functional 26S PC. However, the substrate specificity of the NADH-stabilized 26S proteasome complex (26S PC) was never assessed. Here, we show that the binding of NADH to the 26S PC inhibits the ATP-dependent and ubiquitin-independent degradation of the structured ODC enzyme. Moreover, the NADH-stabilized 26S PC is efficient in degrading intrinsically disordered protein (IDP) substrates that might not require ATP-dependent unfolding, such as p27, Tau, c-Fos and more. In some cases, NADH-26S proteasomes were more efficient in processing IDPs than the ATP-26S PC. These results indicate that in vitro, physiological concentrations of NADH can alter the processivity of ATP-dependent 26S PC substrates such as ODC and, more importantly, the NADH-stabilized 26S PCs promote the efficient degradation of many IDPs. Thus, ATP-independent, NADH-dependent 26S proteasome activity exemplifies a new principle of how mitochondria might directly regulate 26S proteasome substrate specificity.

scholarly journals Liquid-Liquid Phase Separation is Driven by Large-Scale Conformational Unwinding and Fluctuations of Intrinsically Disordered Protein Molecules

2019 ◽  
Author(s):  
Anupa Majumdar ◽  
Priyanka Dogra ◽  
Shiny Maity ◽  
Samrat Mukhopadhyay
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Large Scale ◽  
Intrinsically Disordered Proteins ◽  
Intrinsically Disordered Protein ◽  
Liquid Phase Separation ◽  
Disordered Proteins ◽  
Fluorescence Depolarization ◽  
Intrinsically Disordered ◽  
Liquid Liquid Phase Separation

ABSTRACTLiquid-liquid phase separation occurs via a multitude of transient, non-covalent, intermolecular interactions resulting in phase transition of intrinsically disordered proteins/regions (IDPs/IDRs) and other biopolymers into mesoscopic, dynamic, non-stoichiometric, supramolecular condensates. IDPs resemble associative polymers possessing stereospecific “stickers” and flexible “spacers” that govern the transient chain-chain interactions and fluidity in phase-separated liquid droplets. However, the fundamental molecular origin of phase separation remains elusive. Here we present a unique case to demonstrate that unusual conformational expansion events coupled with solvation and fluctuations drive phase separation of tau, an IDP associated with Alzheimer’s disease. Using intramolecular excimer emission as a powerful proximity readout, we show the unraveling of polypeptide chains within the protein-rich interior environment that can promote critical interchain contacts. Using highly-sensitive picosecond time-resolved fluorescence depolarization measurements, we directly capture rapid large-amplitude torsional fluctuations in the extended chains that can control the relay of making-and-breaking of noncovalent intermolecular contacts maintaining the internal fluidity. Our observations, together with the existing polymer theories, suggest that such an orchestra of concerted molecular shapeshifting events involving chain expansion, solvation, and fluctuations can provide additional favorable free energies to overcome the entropy of mixing term during phase separation. The interplay of these key molecular parameters can also be of prime importance in modulating the mesoscale material property of liquid-like condensates and their maturation of into pathological gel-like and solid-like aggregates.

scholarly journals Proteasomal degradation of the intrinsically disordered protein tau at single-residue resolution

2020 ◽  
Vol 6 (30) ◽  
pp. eaba3916 ◽  
Author(s):  
T. Ukmar-Godec ◽  
P. Fang ◽  
A. Ibáñez de Opakua ◽  
F. Henneberg ◽  
A. Godec ◽  
...  
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Degradation Products ◽  
Degradation Kinetics ◽  
Intrinsically Disordered Protein ◽  
Disordered Proteins ◽  
Dependent Protein Kinase ◽  
Intrinsically Disordered ◽  
Disordered Protein ◽  
Dependent Protein ◽  
Independent Process

Intrinsically disordered proteins (IDPs) can be degraded in a ubiquitin-independent process by the 20S proteasome. Decline in 20S activity characterizes neurodegenerative diseases. Here, we examine 20S degradation of IDP tau, a protein that aggregates into insoluble deposits in Alzheimer’s disease. We show that cleavage of tau by the 20S proteasome is most efficient within the aggregation-prone repeat region of tau and generates both short, aggregation-deficient peptides and two long fragments containing residues 1 to 251 and 1 to 218. Phosphorylation of tau by the non-proline–directed Ca2+/calmodulin-dependent protein kinase II inhibits degradation by the 20S proteasome. Phosphorylation of tau by GSK3β, a major proline-directed tau kinase, modulates tau degradation kinetics in a residue-specific manner. The study provides detailed insights into the degradation products of tau generated by the 20S proteasome, the residue specificity of degradation, single-residue degradation kinetics, and their regulation by posttranslational modification.

scholarly journals Modelling Intrinsically Disordered Protein Dynamics as Networks of Transient Secondary Structure

2018 ◽  
Author(s):  
Hannah K. Wayment-Steele ◽  
Carlos X. Hernández ◽  
Vijay S. Pande
Keyword(s):  
Secondary Structure ◽  
Intrinsically Disordered Proteins ◽  
Model Building ◽  
Intrinsically Disordered Protein ◽  
Dynamics Simulation ◽  
Disordered Proteins ◽  
Intrinsically Disordered ◽  
Disordered Protein ◽  
State Models ◽  
Transient Secondary Structure

ABSTRACTDescribing the dynamics and conformational landscapes of Intrinsically Disordered Proteins (IDPs) is of paramount importance to understanding their functions. Markov State Models (MSMs) are often used to characterize the dynamics of more structured proteins, but models of IDPs built using conventional MSM modelling protocols can be difficult to interpret due to the inherent nature of IDPs, which exhibit fast transitions between disordered microstates. We propose a new method of determining MSM states from all-atom molecular dynamics simulation data of IDPs by using per-residue secondary structure assignments as input features in a MSM model. Because such secondary structure algorithms use a select set of features for assignment (dihedral angles, contact distances, etc.), they represent a knowledge-based refinement of feature sets used for model-building. This method adds interpretability to IDP conformational landscapes, which are increasingly viewed as composed of transient secondary structure, and allows us to readily use MSM analysis tools in this paradigm. We demonstrate the use of our method with the transcription factor p53 c-terminal domain (p53-CTD), a commonly-studied IDP. We are able to characterize the full secondary structure phase space observed for p53-CTD, and describe characteristics of p53-CTD as a network of transient helical and beta-hairpin structures with different network behaviors in different domains of secondary structure. This analysis provides a novel example of how IDPs can be studied and how researchers might better understand a disordered protein conformational landscape.

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