scholarly journals Ubiquitylation of ABA Receptors and Protein Phosphatase 2C Coreceptors to Modulate ABA Signaling and Stress Response

2021 ◽  
Vol 22 (13) ◽  
pp. 7103
Author(s):  
Alberto Coego ◽  
Jose Julian ◽  
Jorge Lozano-Juste ◽  
Gaston A. Pizzio ◽  
Abdulwahed F. Alrefaei ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Protein Function ◽  
Degradation Pathway ◽  
26S Proteasome ◽  
Aba Signaling ◽  
Post Translational Modifications ◽  
Core Components ◽  
Regulate Protein ◽  
Branched Chains ◽  
Aba Receptors

Post-translational modifications play a fundamental role in regulating protein function and stability. In particular, protein ubiquitylation is a multifaceted modification involved in numerous aspects of plant biology. Landmark studies connected the ATP-dependent ubiquitylation of substrates to their degradation by the 26S proteasome; however, nonproteolytic functions of the ubiquitin (Ub) code are also crucial to regulate protein interactions, activity, and localization. Regarding proteolytic functions of Ub, Lys-48-linked branched chains are the most common chain type for proteasomal degradation, whereas promotion of endocytosis and vacuolar degradation is triggered through monoubiquitylation or Lys63-linked chains introduced in integral or peripheral plasma membrane proteins. Hormone signaling relies on regulated protein turnover, and specifically the half-life of ABA signaling components is regulated both through the ubiquitin-26S proteasome system and the endocytic/vacuolar degradation pathway. E3 Ub ligases have been reported that target different ABA signaling core components, i.e., ABA receptors, PP2Cs, SnRK2s, and ABFs/ABI5 transcription factors. In this review, we focused specifically on the ubiquitylation of ABA receptors and PP2C coreceptors, as well as other post-translational modifications of ABA receptors (nitration and phosphorylation) that result in their ubiquitination and degradation.

scholarly journals iProteinDB: an integrative database of Drosophila post-translational modifications

2018 ◽  
Author(s):  
Yanhui Hu ◽  
Richelle Sopko ◽  
Verena Chung ◽  
Romain A. Studer ◽  
Sean D. Landry ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Protein Function ◽  
Large Scale ◽  
Model Organisms ◽  
General Strategy ◽  
Post Translational Modification ◽  
Post Translational Modifications ◽  
Functional Sites ◽  
Evolutionarily Conserved ◽  
And Function

AbstractPost-translational modification (PTM) serves as a regulatory mechanism for protein function, influencing stability, protein interactions, activity and localization, and is critical in many signaling pathways. The best characterized PTM is phosphorylation, whereby a phosphate is added to an acceptor residue, commonly serine, threonine and tyrosine. As proteins are often phosphorylated at multiple sites, identifying those sites that are important for function is a challenging problem. Considering that many phosphorylation sites may be non-functional, prioritizing evolutionarily conserved phosphosites provides a general strategy to identify the putative functional sites with regards to regulation and function. To facilitate the identification of conserved phosphosites, we generated a large-scale phosphoproteomics dataset from Drosophila embryos collected from six closely-related species. We built iProteinDB (https://www.flyrnai.org/tools/iproteindb/), a resource integrating these data with other high-throughput PTM datasets, including vertebrates, and manually curated information for Drosophila. At iProteinDB, scientists can view the PTM landscape for any Drosophila protein and identify predicted functional phosphosites based on a comparative analysis of data from closely-related Drosophila species. Further, iProteinDB enables comparison of PTM data from Drosophila to that of orthologous proteins from other model organisms, including human, mouse, rat, Xenopus laevis, Danio rerio, and Caenorhabditis elegans.

scholarly journals Jasmonate and auxin perception: how plants keep F-boxes in check

2019 ◽  
Vol 70 (13) ◽  
pp. 3401-3414 ◽  
Author(s):  
Clara Williams ◽  
Patricia Fernández-Calvo ◽  
Maite Colinas ◽  
Laurens Pauwels ◽  
Alain Goossens
Keyword(s):  
Protein Interactions ◽  
26S Proteasome ◽  
Protein Protein Interactions ◽  
Biotic And Abiotic Stresses ◽  
Post Translational Modifications ◽  
Receptor Complexes ◽  
Subsequent Degradation ◽  
Selective Agonists ◽  
Multiple Levels ◽  
Type Receptor

Abstract Phytohormones regulate the plasticity of plant growth and development, and responses to biotic and abiotic stresses. Many hormone signal transduction cascades involve ubiquitination and subsequent degradation of proteins by the 26S proteasome. The conjugation of ubiquitin to a substrate is facilitated by the E1 activating, E2 conjugating, and the substrate-specifying E3 ligating enzymes. The most prevalent type of E3 ligase in plants is the Cullin–RING ligase (CRL)-type, with F-box proteins (FBPs) as the substrate recognition component. The activity of these SKP–Cullin–F-box (SCF) complexes needs to be tightly regulated in time and place. Here, we review the regulation of SCF function in plants on multiple levels, with a focus on the auxin and jasmonate SCF-type receptor complexes. We discuss in particular the relevance of protein–protein interactions and post-translational modifications as mechanisms to keep SCF functioning under control. Additionally, we highlight the unique property of SCFTIR1/AFB and SCFCOI1 to recognize substrates by forming co-receptor complexes. Finally, we explore how engineered selective agonists can be used to study and uncouple the outcomes of the complex auxin and jasmonate signaling networks that are governed by these FBPs.

scholarly journals Transient exposure of a buried phosphorylation site in an autoinhibited protein

2021 ◽  
Author(s):  
Simone Orioli ◽  
Kresten Lindorff-Larsen
Keyword(s):  
Protein Function ◽  
Molten Globule ◽  
Phosphorylation Site ◽  
Structural Disorder ◽  
Helical Structures ◽  
Post Translational Modifications ◽  
Cis Acting ◽  
Functional Sites ◽  
Inhibitory Domain ◽  
Regulate Protein

Autoinhibition is a mechanism used to regulate protein function, often by making functional sites inaccessible through the interaction with a cis-acting inhibitory domain. Such autoinhibitory domains often display a substantial degree of structural disorder when unbound, and only become structured in the inhibited state. This structural dynamics makes it difficult to study the structural origin of regulation, including effects of regulatory post-translational modifications. Here, we study the autoinhibition of the Dbl Homology domain in the protein Vav1 by the so-called acidic inhibitory domain. We use molecular simulations to study the process by which a mostly unstructured inhibitory domain folds upon binding and how transient exposure of a key buried tyrosine residue makes it accessible for phosphorylation. We show that the inhibitory domain, which forms a helix in the bound and inhibited stated, samples helical structures already before binding and that binding occurs via a molten-globule-like intermediate state. Together, our results shed light on key interactions that enable the inhibitory domain to sample a finely-tuned equilibrium between an inhibited and a kinase-accessible state.

scholarly journals Tau Post-translational Modifications: Dynamic Transformers of Tau Function, Degradation, and Aggregation

2021 ◽  
Vol 11 ◽  
Author(s):  
Carolina Alquezar ◽  
Shruti Arya ◽  
Aimee W. Kao
Keyword(s):  
Protein Interactions ◽  
Protein Function ◽  
Protein Localization ◽  
Critical Role ◽  
Protein Protein Interactions ◽  
Post Translational Modification ◽  
Post Translational Modifications ◽  
Tau Function ◽  
Potential Impact ◽  
Important Position

Post-translational modifications (PTMs) on tau have long been recognized as affecting protein function and contributing to neurodegeneration. The explosion of information on potential and observed PTMs on tau provides an opportunity to better understand these modifications in the context of tau homeostasis, which becomes perturbed with aging and disease. Prevailing views regard tau as a protein that undergoes abnormal phosphorylation prior to its accumulation into the toxic aggregates implicated in Alzheimer's disease (AD) and other tauopathies. However, the phosphorylation of tau may, in fact, represent part of the normal but interrupted function and catabolism of the protein. In addition to phosphorylation, tau undergoes another forms of post-translational modification including (but not limited to), acetylation, ubiquitination, glycation, glycosylation, SUMOylation, methylation, oxidation, and nitration. A holistic appreciation of how these PTMs regulate tau during health and are potentially hijacked in disease remains elusive. Recent studies have reinforced the idea that PTMs play a critical role in tau localization, protein-protein interactions, maintenance of levels, and modifying aggregate structure. These studies also provide tantalizing clues into the possibility that neurons actively choose how tau is post-translationally modified, in potentially competitive and combinatorial ways, to achieve broad, cellular programs commensurate with the distinctive environmental conditions found during development, aging, stress, and disease. Here, we review tau PTMs and describe what is currently known about their functional impacts. In addition, we classify these PTMs from the perspectives of protein localization, electrostatics, and stability, which all contribute to normal tau function and homeostasis. Finally, we assess the potential impact of tau PTMs on tau solubility and aggregation. Tau occupies an undoubtedly important position in the biology of neurodegenerative diseases. This review aims to provide an integrated perspective of how post-translational modifications actively, purposefully, and dynamically remodel tau function, clearance, and aggregation. In doing so, we hope to enable a more comprehensive understanding of tau PTMs that will positively impact future studies.

scholarly journals The Function of FEN1 is Regulated by Post-Translational Modification

2021 ◽  
Author(s):  
Zhenxing Wu ◽  
Xiaofen Mo ◽  
Chengbo Lang ◽  
Jinjing Luo
Keyword(s):  
Protein Interactions ◽  
Cellular Localization ◽  
Genome Instability ◽  
Nuclease Activity ◽  
Protein Protein Interactions ◽  
Post Translational Modification ◽  
Post Translational Modifications ◽  
Dna Structures ◽  
Effective Role ◽  
Regulate Protein

Flap endonuclease 1 (FEN1) is a multifunctional DNA branching nuclease. Post-translational modifications (PTMs) exist in this protein widely, including phosphorylation, methylation, acetylation, ubiquitination and small ubiquitination modification (SUMO). Here, we make a summary for those PTMs studies on FEN1, to illustrate relationships between mutations of those amino acids and their functions alteration of FEN1. Numerous evidences have confirmed that dysfunction of FEN1 would lead to genome instability, and then induce a variety of chromosome-related diseases ultimately, including tumors. On one hand, interaction partner also stimulates FEN1 nuclease activity, to further ensure an effective role in the processing of different DNA structures; on the other hand, PTMs may regulate protein-protein interactions and FEN1’s cellular localization.

Do F-box proteins with a C-terminal domain homologous with the tobacco lectin play a role in protein degradation in plants?

2008 ◽  
Vol 36 (5) ◽  
pp. 843-847 ◽  
Author(s):  
Nausicaä Lannoo ◽  
Willy J. Peumans ◽  
Els J.M. Van Damme
Keyword(s):  
Protein Degradation ◽  
Protein Interactions ◽  
Degradation Pathway ◽  
26S Proteasome ◽  
Protein Protein Interactions ◽  
Target Proteins ◽  
Sugar Binding ◽  
Terminal Domain ◽  
High Mannose ◽  
Genome Analyses

Protein turnover is a key post-translational event that regulates numerous cellular processes. It enables cells to respond rapidly to intracellular signals and changing environmental conditions by adjusting the levels of pivotal proteins. A major proteolytic pathway involves the ubiquitination of target proteins and subsequent targeting to the 26S proteasome for degradation. Many F-box proteins play a determining role in the substrate specificity of this degradation pathway. In most cases, selective recognition of the target proteins relies on protein–protein interactions mediated by the C-terminal domain of the F-box proteins. In mammals, the occurrence of F-box proteins with a C-terminal SBD (sugar-binding domain) that specifically interacts with high-mannose N-glycans on target glycoproteins has been documented. The identification and characterization of these sugar-binding F-box proteins demonstrated that F-box proteins do not exclusively use protein–protein interactions but also protein–carbohydrate interactions in the Ub (ubiquitin)/proteasome pathway. Recently, putative sugar-binding F-box proteins have been identified in plants. Genome analyses in Arabidopsis and rice revealed the presence of F-box proteins with a C-terminal lectin-related domain homologous with Nictaba, a jasmonate-inducible lectin from tobacco that was shown to interact with the core structure of high-mannose and complex N-glycans. Owing to the high similarity in structure and specificity between Nictaba and the SBD of the mammalian Fbs proteins, a similar role for the plant F-box proteins with a Nictaba domain in nucleocytoplasmic protein degradation in plant cells is suggested.

Reading the phosphorylation code: binding of the 14-3-3 protein to multivalent client phosphoproteins

2020 ◽  
Vol 477 (7) ◽  
pp. 1219-1225 ◽  
Author(s):  
Nikolai N. Sluchanko
Keyword(s):  
Protein Function ◽  
Intrinsically Disordered Protein ◽  
Structural Basis ◽  
Major Protein ◽  
Post Translational Modifications ◽  
Protein Protein Interaction ◽  
Intrinsically Disordered ◽  
Biochemical Journal ◽  
Multiple Binding ◽  
And Control

Many major protein–protein interaction networks are maintained by ‘hub’ proteins with multiple binding partners, where interactions are often facilitated by intrinsically disordered protein regions that undergo post-translational modifications, such as phosphorylation. Phosphorylation can directly affect protein function and control recognition by proteins that ‘read’ the phosphorylation code, re-wiring the interactome. The eukaryotic 14-3-3 proteins recognizing multiple phosphoproteins nicely exemplify these concepts. Although recent studies established the biochemical and structural basis for the interaction of the 14-3-3 dimers with several phosphorylated clients, understanding their assembly with partners phosphorylated at multiple sites represents a challenge. Suboptimal sequence context around the phosphorylated residue may reduce binding affinity, resulting in quantitative differences for distinct phosphorylation sites, making hierarchy and priority in their binding rather uncertain. Recently, Stevers et al. [Biochemical Journal (2017) 474: 1273–1287] undertook a remarkable attempt to untangle the mechanism of 14-3-3 dimer binding to leucine-rich repeat kinase 2 (LRRK2) that contains multiple candidate 14-3-3-binding sites and is mutated in Parkinson's disease. By using the protein-peptide binding approach, the authors systematically analyzed affinities for a set of LRRK2 phosphopeptides, alone or in combination, to a 14-3-3 protein and determined crystal structures for 14-3-3 complexes with selected phosphopeptides. This study addresses a long-standing question in the 14-3-3 biology, unearthing a range of important details that are relevant for understanding binding mechanisms of other polyvalent proteins.

The challenge of detecting modifications on proteins

2020 ◽  
Vol 64 (1) ◽  
pp. 135-153 ◽  
Author(s):  
Lauren Elizabeth Smith ◽  
Adelina Rogowska-Wrzesinska
Keyword(s):  
Mass Spectrometry ◽  
Protein Function ◽  
Chemical Properties ◽  
Lysine Acetylation ◽  
Mass Determination ◽  
Post Translational Modifications ◽  
Site Specific ◽  
The Common

Abstract Post-translational modifications (PTMs) are integral to the regulation of protein function, characterising their role in this process is vital to understanding how cells work in both healthy and diseased states. Mass spectrometry (MS) facilitates the mass determination and sequencing of peptides, and thereby also the detection of site-specific PTMs. However, numerous challenges in this field continue to persist. The diverse chemical properties, low abundance, labile nature and instability of many PTMs, in combination with the more practical issues of compatibility with MS and bioinformatics challenges, contribute to the arduous nature of their analysis. In this review, we present an overview of the established MS-based approaches for analysing PTMs and the common complications associated with their investigation, including examples of specific challenges focusing on phosphorylation, lysine acetylation and redox modifications.

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