scholarly journals Structural and functional consequences of NEDD8 phosphorylation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Katrin Stuber ◽  
Tobias Schneider ◽  
Jill Werner ◽  
Michael Kovermann ◽  
Andreas Marx ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Structural Dynamics ◽  
Family Members ◽  
Covalent Attachment ◽  
Post Translational Modifications ◽  
Hsp70 Family ◽  
General Importance ◽  
Functional Consequences

AbstractUbiquitin (Ub) and Ub-like proteins (Ubls) such as NEDD8 are best known for their function as covalent modifiers of other proteins but they are also themselves subject to post-translational modifications including phosphorylation. While functions of phosphorylated Ub (pUb) have been characterized, the consequences of Ubl phosphorylation remain unclear. Here we report that NEDD8 can be phosphorylated at S65 - the same site as Ub - and that S65 phosphorylation affects the structural dynamics of NEDD8 and Ub in a similar manner. While both pUb and phosphorylated NEDD8 (pNEDD8) can allosterically activate the Ub ligase Parkin, they have different protein interactomes that in turn are distinct from those of unmodified Ub and NEDD8. Among the preferential pNEDD8 interactors are HSP70 family members and we show that pNEDD8 stimulates HSP70 ATPase activity more pronouncedly than unmodified NEDD8. Our findings highlight the general importance of Ub/NEDD8 phosphorylation and support the notion that the function of pUb/pNEDD8 does not require their covalent attachment to other proteins.

scholarly journals Functional role of J domain of cysteine string protein in Ca2+-dependent secretion from acinar cells

2009 ◽  
Vol 296 (5) ◽  
pp. G1030-G1039 ◽  
Author(s):  
Ning Weng ◽  
Megan D. Baumler ◽  
Diana D. H. Thomas ◽  
Michelle A. Falkowski ◽  
Leigh Anne Swayne ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Secretory Pathway ◽  
Digestive Enzyme ◽  
Family Members ◽  
Protective Role ◽  
Amylase Secretion ◽  
Zymogen Granule ◽  
Hsp70 Family ◽  
Cysteine String Protein ◽  
J Domain

The heat shock protein 70 family members Hsc70 and Hsp70 are known to play a protective role against the onset of experimental pancreatitis, yet their molecular function in acini is unclear. Cysteine string protein (CSP-α) is a zymogen granule (ZG) membrane protein characterized by an NH2-terminal “J domain” and a central palmitoylated string of cysteine residues. The J domain functions as a cochaperone by modulating the activity of Hsc70/Hsp70 family members. A role for CSP-α in regulating digestive enzyme exocytosis from pancreas was investigated by introducing CSP-α truncations into isolated acini following their permeabilization with Perfringolysin O. Incubation of acini with CSP-α1-82, containing the J domain, significantly augmented Ca2+-stimulated amylase secretion. Effects of CSP-α1-82 were concentration dependent, with a maximum 80% increase occurring at 200 μg/ml of protein. Although CSP-α1-82 had no effects on basal secretion measured in the presence of ≤10 nM free Ca2+, it did significantly augment GTP-γS-induced secretion under basal Ca2+ conditions by ∼25%. Mutation of the J domain to abolish its cochaperone activity failed to augment Ca2+-stimulated secretion, implicating the CSP-α/Hsc70 cochaperone system as a regulatory component of the secretory pathway. CSP-α physically associates with vesicle-associated membrane protein 8 (VAMP 8) on ZGs, and the CSP-α-VAMP 8 interaction was dependent on amino acids 83-112 of CSP-α. Immunofluorescence analysis of acinar lobules or purified ZGs confirmed the CSP-α colocalization with VAMP 8. These data establish a role for CSP-α in regulating digestive enzyme secretion and suggest that CSP-α and Hsc70 modulate specific soluble N-ethylmaleimide-sensitive attachment receptor interactions necessary for exocytosis.

The new world of inorganic polyphosphates

2016 ◽  
Vol 44 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Cristina Azevedo ◽  
Adolfo Saiardi
Keyword(s):  
Protein Modification ◽  
Biochemical Characterization ◽  
Covalent Attachment ◽  
Detection Methods ◽  
Inorganic Polyphosphate ◽  
Post Translational Modifications ◽  
Topoisomerase 1 ◽  
Lysine Residues ◽  
Acidic Conditions

Post-translational modifications (PTMs) add regulatory features to proteins that help establish the complex functional networks that make up higher organisms. Advances in analytical detection methods have led to the identification of more than 200 types of PTMs. However, some modifications are unstable under the present detection methods, anticipating the existence of further modifications and a much more complex map of PTMs. An example is the recently discovered protein modification polyphosphorylation. Polyphosphorylation is mediated by inorganic polyphosphate (polyP) and represents the covalent attachment of this linear polymer of orthophosphate to lysine residues in target proteins. This modification has eluded MS analysis as both polyP itself and the phosphoramidate bonds created upon its reaction with lysine residues are highly unstable in acidic conditions. Polyphosphorylation detection was only possible through extensive biochemical characterization. Two targets have been identified: nuclear signal recognition 1 (Nsr1) and its interacting partner, topoisomerase 1 (Top1). Polyphosphorylation occurs within a conserved N-terminal polyacidic serine (S) and lysine (K) rich (PASK) cluster. It negatively regulates Nsr1–Top1 interaction and impairs Top1 enzymatic activity, namely relaxing supercoiled DNA. Modulation of cellular levels of polyP regulates Top1 activity by modifying its polyphosphorylation status. Here we discuss the significance of the recently identified new role of inorganic polyP.

scholarly journals Structural and Functional Consequences Induced by Post-Translational Modifications in α-Defensins

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Enrico Balducci ◽  
Alessio Bonucci ◽  
Monica Picchianti ◽  
Rebecca Pogni ◽  
Eleonora Talluri
Keyword(s):  
Antimicrobial Peptide ◽  
Marked Change ◽  
Antibacterial Activities ◽  
Post Translational Modification ◽  
Post Translational Modifications ◽  
Adp Ribosylation ◽  
Functional Consequences ◽  
Adp Ribosyltransferase ◽  
Guanidino Group ◽  
Ribose Moiety

HNP-1 is an antimicrobial peptide that undergoes proteolytic cleavage to become a mature peptide. This process represents the mechanism commonly used by the cells to obtain a fully active antimicrobial peptide. In addition, it has been recently described that HNP-1 is recognized as substrate by the arginine-specific ADP-ribosyltransferase-1. Arginine-specific mono-ADP-ribosylation is an enzyme-catalyzed post-translational modification in which NAD+ serves as donor of the ADP-ribose moiety, which is transferred to the guanidino group of arginines in target proteins. While the arginine carries one positive charge, the ADP-ribose is negatively charged at the phosphate moieties at physiological pH. Therefore, the attachment of one or more ADP-ribose units results in a marked change of cationicity. ADP-ribosylation of HNP-1 drastically reduces its cytotoxic and antibacterial activities. While the chemotactic activity of HNP-1 remains unaltered, its ability to induce interleukin-8 production is enhanced. The arginine 14 of HNP-1 modified by the ADP-ribose is in some cases processed into ornithine, perhaps representing a different modality in the regulation of HNP-1 activities.

scholarly journals Two Hsp70 family members expressed in atherosclerotic lesions

2003 ◽  
Vol 100 (3) ◽  
pp. 1256-1261 ◽  
Author(s):  
Z. Han ◽  
Q. A. Truong ◽  
S. Park ◽  
J. L. Breslow
Keyword(s):  
Family Members ◽  
Hsp70 Family ◽  
Atherosclerotic Lesions

scholarly journals Post-Translational Modifications of FXR; Implications for Cholestasis and Obesity-Related Disorders

2021 ◽  
Vol 12 ◽  
Author(s):  
Monique D. Appelman ◽  
Suzanne W. van der Veen ◽  
Saskia W. C. van Mil
Keyword(s):  
Bile Acids ◽  
Posttranslational Modifications ◽  
Metabolic Disorders ◽  
Target Genes ◽  
Farnesoid X Receptor ◽  
Dietary Fats ◽  
Transcriptional Level ◽  
Alcoholic Fatty Liver ◽  
Post Translational Modifications ◽  
Functional Consequences

The Farnesoid X receptor (FXR) is a nuclear receptor which is activated by bile acids. Bile acids function in solubilization of dietary fats and vitamins in the intestine. In addition, bile acids have been increasingly recognized to act as signaling molecules involved in energy metabolism pathways, amongst others via activating FXR. Upon activation by bile acids, FXR controls the expression of many genes involved in bile acid, lipid, glucose and amino acid metabolism. An inability to properly use and store energy substrates may predispose to metabolic disorders, such as obesity, diabetes, cholestasis and non-alcoholic fatty liver disease. These diseases arise through a complex interplay between genetics, environment and nutrition. Due to its function in metabolism, FXR is an attractive treatment target for these disorders. The regulation of FXR expression and activity occurs both at the transcriptional and at the post-transcriptional level. It has been shown that FXR can be phosphorylated, SUMOylated and acetylated, amongst other modifications, and that these modifications have functional consequences for DNA and ligand binding, heterodimerization and subcellular localization of FXR. In addition, these post-translational modifications may selectively increase or decrease transcription of certain target genes. In this review, we provide an overview of the posttranslational modifications of FXR and discuss their potential involvement in cholestatic and metabolic disorders.

scholarly journals Distinct Gene Expression Patterns of Two Heat Shock Protein 70 Members During Development, Diapause, and Temperature Stress in the Freshwater Crustacean Daphnia magna

2021 ◽  
Vol 9 ◽  
Author(s):  
Luxi Chen ◽  
Rocío Gómez ◽  
Linda C. Weiss
Keyword(s):  
Heat Shock ◽  
Family Member ◽  
Daphnia Magna ◽  
Nuclear Translocation ◽  
Protein Localization ◽  
Expression Patterns ◽  
Family Members ◽  
Hsp70 Family ◽  
Before And After ◽  
Shock Proteins

Dormancy is a lifecycle delay that allows organisms to escape suboptimal environmental conditions. As a genetically programmed type of dormancy, diapause is usually accompanied by metabolic depression and enhanced tolerance toward adverse environmental factors. However, the drivers and regulators that steer an organism’s development into a state of suspended animation to survive environmental stress have not been fully uncovered. Heat shock proteins 70 (HSP70s), which are often produced in response to various types of stress, have been suggested to play a role in diapause. Considering the diversity of the Hsp70 family, different family members may have different functions during diapause. In the present study, we demonstrate the expression of two hsp70 genes (A and B together with protein localization of B) throughout continuous and diapause interrupted development of Daphnia magna. Before and after diapause, the expression of Dmhsp70-A is low. Only shortly before diapause and during diapause, Dmhsp70-A is significantly upregulated and may therefore be involved in diapause preparation and maintenance. In contrast, Dmhsp70-B is expressed only in developing embryos but not in diapausing embryos. During continuous development, the protein of this Hsp70 family member is localized in the cytosol. When we expose both embryo types to heat stress, expression of both hsp70 genes increases only in developing embryos, and the protein of family member B is translocated to the nucleus. In this stress formation, this protein provides effective protection of nucleoplasmic DNA. As we also see this localization in diapausing embryos, it seems that Daphnia embryo types share a common subcellular strategy when facing dormancy or heat shock, i.e., they protect their DNA by HSP70B nuclear translocation. Our study underlines the distinctive roles that different Hsp70 family members play throughout continuous and diapause interrupted development.

scholarly journals Crystal structures of adenylylated and unadenylylated PII protein GlnK from Corynebacterium glutamicum

2021 ◽  
Vol 77 (3) ◽  
pp. 325-335
Author(s):  
Florian C. Grau ◽  
Andreas Burkovski ◽  
Yves A. Muller
Keyword(s):  
Corynebacterium Glutamicum ◽  
Crystal Structures ◽  
Bound State ◽  
Covalent Attachment ◽  
Signaling Proteins ◽  
Post Translational Modification ◽  
Conformational Switching ◽  
Post Translational Modifications ◽  
Loop Conformations ◽  
Partner Proteins

PII proteins are ubiquitous signaling proteins that are involved in the regulation of the nitrogen/carbon balance in bacteria, archaea, and some plants and algae. Signal transduction via PII proteins is modulated by effector molecules and post-translational modifications in the PII T-loop. Whereas the binding of ADP, ATP and the concomitant binding of ATP and 2-oxoglutarate (2OG) engender two distinct conformations of the T-loop that either favor or disfavor the interaction with partner proteins, the structural consequences of post-translational modifications such as phosphorylation, uridylylation and adenylylation are far less well understood. In the present study, crystal structures of the PII protein GlnK from Corynebacterium glutamicum have been determined, namely of adenylylated GlnK (adGlnK) and unmodified unadenylylated GlnK (unGlnK). AdGlnK has been proposed to act as an inducer of the transcription repressor AmtR, and the adenylylation of Tyr51 in GlnK has been proposed to be a prerequisite for this function. The structures of unGlnK and adGlnK allow the first atomic insights into the structural implications of the covalent attachment of an AMP moiety to the T-loop. The overall GlnK fold remains unaltered upon adenylylation, and T-loop adenylylation does not appear to interfere with the formation of the two major functionally important T-loop conformations, namely the extended T-loop in the canonical ADP-bound state and the compacted T-loop that is adopted upon the simultaneous binding of Mg-ATP and 2OG. Thus, the PII-typical conformational switching mechanism appears to be preserved in GlnK from C. glutamicum, while at the same time the functional repertoire becomes expanded through the accommodation of a peculiar post-translational modification.

Identification of Lysine Carboxylation Sites in Proteins by Integrating Statistical Moments and Position Relative Features via General PseAAC

2020 ◽  
Vol 15 (5) ◽  
pp. 396-407 ◽  
Author(s):  
Saba Amanat ◽  
Adeel Ashraf ◽  
Waqar Hussain ◽  
Nouman Rasool ◽  
Yaser D. Khan
Keyword(s):  
Prediction Model ◽  
Model Validation ◽  
Cross Validation ◽  
Covalent Attachment ◽  
Side Chain ◽  
Consistency Test ◽  
Post Translational Modifications ◽  
Independent Dataset ◽  
Proposed Model ◽  
Self Consistency

Background: Carboxylation is one of the most biologically important post-translational modifications and occurs on lysine, arginine, and glutamine residues of a protein. Among all these three, the covalent attachment of the carboxyl group with the lysine side chain is the most frequent and biologically important type of carboxylation. For studying such biological functions, it is essential to correctly determine the lysine sites sensitive to carboxylation. Objective: Herein, we present a computational model for the prediction of the carboxylysine site which is based on machine learning. Methods: Various position and composition relative features have been incorporated into the Pse- AAC for construction of feature vectors and a neural network is employed as a classifier. The model is validated by jackknife, cross-validation, self-consistency, and independent testing. Results: The results of the self-consistency test elaborated that model has 99.76% Acc, 99.76% Sp, 99.76% Sp, and 0.99 MCC..Using the jackknife method, prediction model validation gave 97.07% Acc, while for 10-fold cross-validation, prediction model validation gave 95.16% Acc. Conclusion: The results of independent dataset testing were 94.3% which illustrated that the proposed model has better performance as compared to the existing model PreLysCar; however, the accuracy can be improved further, in the future, due to the increasing number of carboxylysine sites in proteins.

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