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1.
Mol Cell ; 82(21): 4080-4098.e12, 2022 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-36272410

RESUMO

Growing evidence suggests prevalence of transcriptional condensates on chromatin, yet their mechanisms of formation and functional significance remain largely unclear. In human cancer, a series of mutations in the histone acetylation reader ENL create gain-of-function mutants with increased transcriptional activation ability. Here, we show that these mutations, clustered in ENL's structured acetyl-reading YEATS domain, trigger aberrant condensates at native genomic targets through multivalent homotypic and heterotypic interactions. Mechanistically, mutation-induced structural changes in the YEATS domain, ENL's two disordered regions of opposing charges, and the incorporation of extrinsic elongation factors are all required for ENL condensate formation. Extensive mutagenesis establishes condensate formation as a driver of oncogenic gene activation. Furthermore, expression of ENL mutants beyond the endogenous level leads to non-functional condensates. Our findings provide new mechanistic and functional insights into cancer-associated condensates and support condensate dysregulation as an oncogenic mechanism.


Assuntos
Neoplasias , Corpos Nucleares , Humanos , Domínios Proteicos , Cromatina/genética , Mutação , Neoplasias/genética
2.
Genes Dev ; 36(17-18): 970-984, 2022 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-36265902

RESUMO

Intrinsically disordered protein regions (IDRs) have been implicated in diverse nuclear and cytoplasmic functions in eukaryotes, but their roles in bacteria are less clear. Here, we report that extracytoplasmic IDRs in Bacillus subtilis are required for cell wall homeostasis. The B. subtilis σI transcription factor is activated in response to envelope stress through regulated intramembrane proteolysis (RIP) of its membrane-anchored anti-σ factor, RsgI. Unlike canonical RIP pathways, we show that ectodomain (site-1) cleavage of RsgI is constitutive, but the two cleavage products remain stably associated, preventing intramembrane (site-2) proteolysis. The regulated step in this pathway is their dissociation, which is triggered by impaired cell wall synthesis and requires RsgI's extracytoplasmic IDR. Intriguingly, the major peptidoglycan polymerase PBP1 also contains an extracytoplasmic IDR, and we show that this region is important for its function. Disparate IDRs can replace the native IDRs on both RsgI and PBP1, arguing that these unstructured regions function similarly. Our data support a model in which the RsgI-σI signaling system and PBP1 represent complementary pathways to repair gaps in the PG meshwork. The IDR on RsgI senses these gaps and activates σI, while the IDR on PBP1 directs the synthase to these sites to fortify them.


Assuntos
Bacillus subtilis , Proteínas Intrinsicamente Desordenadas , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Proteínas Intrinsicamente Desordenadas/genética , Proteínas Intrinsicamente Desordenadas/metabolismo , Regulação Bacteriana da Expressão Gênica , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Parede Celular/metabolismo , Homeostase
3.
Mol Cell ; 81(11): 2332-2348.e9, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-33974912

RESUMO

Meningioma-1 (MN1) overexpression in AML is associated with poor prognosis, and forced expression of MN1 induces leukemia in mice. We sought to determine how MN1 causes AML. We found that overexpression of MN1 can be induced by translocations that result in hijacking of a downstream enhancer. Structure predictions revealed that the entire MN1 coding frame is disordered. We identified the myeloid progenitor-specific BAF complex as the key interaction partner of MN1. MN1 over-stabilizes BAF on enhancer chromatin, a function directly linked to the presence of a long polyQ-stretch within MN1. BAF over-stabilization at binding sites of transcription factors regulating a hematopoietic stem/progenitor program prevents the developmentally appropriate decommissioning of these enhancers and results in impaired myeloid differentiation and leukemia. Beyond AML, our data detail how the overexpression of a polyQ protein, in the absence of any coding sequence mutation, can be sufficient to cause malignant transformation.


Assuntos
Carcinogênese/genética , DNA Helicases/genética , Proteínas Intrinsicamente Desordenadas/genética , Leucemia Mieloide Aguda/genética , Proteínas Nucleares/genética , Transativadores/genética , Fatores de Transcrição/genética , Proteínas Supressoras de Tumor/genética , Animais , Sequência de Bases , Carcinogênese/metabolismo , Carcinogênese/patologia , Linhagem Celular Tumoral , Cromatina/genética , Cromatina/metabolismo , Cromatina/patologia , DNA Helicases/metabolismo , Elementos Facilitadores Genéticos , Feminino , Regulação Leucêmica da Expressão Gênica , Redes Reguladoras de Genes , Humanos , Proteínas Intrinsicamente Desordenadas/metabolismo , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas Nucleares/metabolismo , Peptídeos/genética , Peptídeos/metabolismo , Mapeamento de Interação de Proteínas , Estabilidade Proteica , Transporte Proteico , Transdução de Sinais , Análise de Sobrevida , Transativadores/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismo
4.
Int J Mol Sci ; 24(20)2023 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-37894717

RESUMO

The Atg12 protein in yeast is an indispensable polypeptide in the highly conserved ubiquitin-like conjugation system operating in the macroautophagy/autophagy pathway. Atg12 is covalently conjugated to Atg5 through the action of Atg7 and Atg10; the Atg12-Atg5 conjugate binds Atg16 to form an E3 ligase that functions in a separate conjugation pathway involving Atg8. Atg12 is comprised of a ubiquitin-like (UBL) domain preceded at the N terminus by an intrinsically disordered protein region (IDPR), a domain that comprises a major portion of the protein but remains elusive in its conformation and function. Here, we show that the IDPR in unconjugated Atg12 is positioned in proximity to the UBL domain, a configuration that is important for the functional structure of the protein. A major deletion in the IDPR disrupts intactness of the UBL domain at the unconjugated C terminus, and a mutation in the predicted α0 helix in the IDPR prevents Atg12 from binding to Atg7 and Atg10, which ultimately affects the protein function in the ubiquitin-like conjugation cascade. These findings provide evidence that the IDPR is an indispensable part of the Atg12 protein from yeast.


Assuntos
Proteína 12 Relacionada à Autofagia , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Autofagia , Proteína 5 Relacionada à Autofagia , Proteínas Relacionadas à Autofagia/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Ubiquitina/genética , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases
5.
Trends Biochem Sci ; 43(8): 623-634, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30056837

RESUMO

Mutations of canonical Wnt signaling pathway genes frequently occur in cancer and lead to abnormal accumulation of the key effector ß-catenin. Over the past decades, a number of Wnt inhibitors have been identified through high-throughput screenings, however, very few of them target ß-catenin directly, raising questions regarding its druggability. Here, we review Wnt inhibitors with a focus on small molecules that directly bind ß-catenin, discuss the druggability of ß-catenin, and why it has rarely been targeted, especially in the cellular context. We also propose strategies to develop small molecule binding and depleting cellular ß-catenin, which are generally applicable to other difficult-to-drug or yet-to-be-drugged targets.


Assuntos
Neoplasias/tratamento farmacológico , beta Catenina/efeitos dos fármacos , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Humanos , Proteínas Intrinsicamente Desordenadas/metabolismo , Neoplasias/metabolismo , Via de Sinalização Wnt/efeitos dos fármacos , beta Catenina/metabolismo
6.
J Mol Recognit ; 33(10): e2868, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32573020

RESUMO

In addition to the well-established sense-antisense complementarity abundantly present in the nucleic acid world and serving as a basic principle of the specific double-helical structure of DNA, production of mRNA, and genetic code-based biosynthesis of proteins, sense-antisense complementarity is also present in proteins, where sense and antisense peptides were shown to interact with each other with increased probability. In nucleic acids, sense-antisense complementarity is achieved via the Watson-Crick complementarity of the base pairs or nucleotide pairing. In proteins, the complementarity between sense and antisense peptides depends on a specific hydropathic pattern, where codons for hydrophilic and hydrophobic amino acids in a sense peptide are complemented by the codons for hydrophobic and hydrophilic amino acids in its antisense counterpart. We are showing here that in addition to this pattern of the complementary hydrophobicity, sense and antisense peptides are characterized by the complementary order-disorder patterns and show complementarity in sequence distribution of their disorder-based interaction sites. We also discuss how this order-disorder complementarity can be related to protein evolution.


Assuntos
Proteínas Intrinsicamente Desordenadas/metabolismo , Domínios e Motivos de Interação entre Proteínas , Interações Hidrofóbicas e Hidrofílicas , Proteínas Intrinsicamente Desordenadas/química , Ligação Proteica
7.
Int J Mol Sci ; 21(10)2020 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-32466138

RESUMO

Among the realm of repeat containing proteins that commonly serve as "scaffolds" promoting protein-protein interactions, there is a family of proteins containing between 2 and 20 tetratricopeptide repeats (TPRs), which are functional motifs consisting of 34 amino acids. The most distinguishing feature of TPR domains is their ability to stack continuously one upon the other, with these stacked repeats being able to affect interaction with binding partners either sequentially or in combination. It is known that many repeat-containing proteins are characterized by high levels of intrinsic disorder, and that many protein tandem repeats can be intrinsically disordered. Furthermore, it seems that TPR-containing proteins share many characteristics with hybrid proteins containing ordered domains and intrinsically disordered protein regions. However, there has not been a systematic analysis of the intrinsic disorder status of TPR proteins. To fill this gap, we analyzed 166 human TPR proteins to determine the degree to which proteins containing TPR motifs are affected by intrinsic disorder. Our analysis revealed that these proteins are characterized by different levels of intrinsic disorder and contain functional disordered regions that are utilized for protein-protein interactions and often serve as targets of various posttranslational modifications.


Assuntos
Proteínas Intrinsicamente Desordenadas/química , Repetições de Tetratricopeptídeos , Humanos , Proteínas Intrinsicamente Desordenadas/metabolismo , Ligação Proteica , Processamento de Proteína Pós-Traducional
8.
Cell Mol Life Sci ; 75(21): 3907-3929, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30066087

RESUMO

Effects of macromolecular crowding on structural and functional properties of ordered proteins, their folding, interactability, and aggregation are well documented. Much less is known about how macromolecular crowding might affect structural and functional behaviour of intrinsically disordered proteins (IDPs) or intrinsically disordered protein regions (IDPRs). To fill this gap, this review represents a systematic analysis of the available literature data on the behaviour of IDPs/IDPRs in crowded environment. Although it was hypothesized that, due to the excluded-volume effects present in crowded environments, IDPs/IDPRs would invariantly fold in the presence of high concentrations of crowding agents or in the crowded cellular environment, accumulated data indicate that, based on their response to the presence of crowders, IDPs/IDPRs can be grouped into three major categories, foldable, non-foldable, and unfoldable. This is because natural cellular environment is not simply characterized by the presence of high concentration of "inert" macromolecules, but represents an active milieu, components of which are engaged in direct physical interactions and soft interactions with target proteins. Some of these interactions with cellular components can cause (local) unfolding of query proteins. In other words, since crowding can cause both folding and unfolding of an IDP or its regions, the outputs of the placing of a query protein to the crowded environment would depend on the balance between these two processes. As a result, and because of the spatio-temporal heterogeneity in structural organization of IDPs, macromolecular crowding can differently affect structures of different IDPs. Recent studies indicate that some IDPs are able to undergo liquid-liquid-phase transitions leading to the formation of various proteinaceous membrane-less organelles (PMLOs). Although interiors of such PMLOs are self-crowded, being characterized by locally increased concentrations of phase-separating IDPs, these IDPs are minimally foldable or even non-foldable at all (at least within the physiologically safe time-frame of normal PMLO existence).


Assuntos
Proteínas Intrinsicamente Desordenadas/química , Substâncias Macromoleculares/química , Conformação Proteica , Dobramento de Proteína , Proteínas Intrinsicamente Desordenadas/genética , Modelos Moleculares , Organelas/química , Organelas/genética
9.
Int J Mol Sci ; 20(21)2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31652801

RESUMO

The two-meter-long DNA is compressed into chromatin in the nucleus of every cell, which serves as a significant barrier to transcription. Therefore, for processes such as replication and transcription to occur, the highly compacted chromatin must be relaxed, and the processes required for chromatin reorganization for the aim of replication or transcription are controlled by ATP-dependent nucleosome remodelers. One of the most highly studied remodelers of this kind is the BRG1- or BRM-associated factor complex (BAF complex, also known as SWItch/sucrose non-fermentable (SWI/SNF) complex), which is crucial for the regulation of gene expression and differentiation in eukaryotes. Chromatin remodeling complex BAF is characterized by a highly polymorphic structure, containing from four to 17 subunits encoded by 29 genes. The aim of this paper is to provide an overview of the role of BAF complex in chromatin remodeling and also to use literature mining and a set of computational and bioinformatics tools to analyze structural properties, intrinsic disorder predisposition, and functionalities of its subunits, along with the description of the relations of different BAF complex subunits to the pathogenesis of various human diseases.


Assuntos
Montagem e Desmontagem da Cromatina , Proteínas Cromossômicas não Histona/metabolismo , Proteínas Intrinsicamente Desordenadas/metabolismo , Neoplasias/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Cromossômicas não Histona/genética , Simulação por Computador , Regulação Neoplásica da Expressão Gênica , Humanos , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/genética , Neoplasias/genética , Fatores de Transcrição/genética
10.
Molecules ; 24(18)2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31500307

RESUMO

Cells are inhomogeneously crowded, possessing a wide range of intracellular liquid droplets abundantly present in the cytoplasm of eukaryotic and bacterial cells, in the mitochondrial matrix and nucleoplasm of eukaryotes, and in the chloroplast's stroma of plant cells. These proteinaceous membrane-less organelles (PMLOs) not only represent a natural method of intracellular compartmentalization, which is crucial for successful execution of various biological functions, but also serve as important means for the processing of local information and rapid response to the fluctuations in environmental conditions. Since PMLOs, being complex macromolecular assemblages, possess many characteristic features of liquids, they represent highly dynamic (or fuzzy) protein-protein and/or protein-nucleic acid complexes. The biogenesis of PMLOs is controlled by specific intrinsically disordered proteins (IDPs) and hybrid proteins with ordered domains and intrinsically disordered protein regions (IDPRs), which, due to their highly dynamic structures and ability to facilitate multivalent interactions, serve as indispensable drivers of the biological liquid-liquid phase transitions (LLPTs) giving rise to PMLOs. In this article, the importance of the disorder-based supramolecular fuzziness for LLPTs and PMLO biogenesis is discussed.


Assuntos
Proteínas Intrinsicamente Desordenadas/metabolismo , Ácidos Nucleicos/metabolismo , Organelas/metabolismo , Citoplasma/metabolismo , Lógica Fuzzy , Proteínas Intrinsicamente Desordenadas/química , Biogênese de Organelas , Transição de Fase , Conformação Proteica
11.
Molecules ; 22(12)2017 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-29186753

RESUMO

Intrinsically disordered proteins and proteins with intrinsically disordered regions have been shown to be highly prevalent in disease. Furthermore, disease-causing expansions of the regions containing tandem amino acid repeats often push repetitive proteins towards formation of irreversible aggregates. In fact, in disease-relevant proteins, the increased repeat length often positively correlates with the increased aggregation efficiency and the increased disease severity and penetrance, being negatively correlated with the age of disease onset. The major categories of repeat extensions involved in disease include poly-glutamine and poly-alanine homorepeats, which are often times located in the intrinsically disordered regions, as well as repeats in non-coding regions of genes typically encoding proteins with ordered structures. Repeats in such non-coding regions of genes can be expressed at the mRNA level. Although they can affect the expression levels of encoded proteins, they are not translated as parts of an affected protein and have no effect on its structure. However, in some cases, the repetitive mRNAs can be translated in a non-canonical manner, generating highly repetitive peptides of different length and amino acid composition. The repeat extension-caused aggregation of a repetitive protein may represent a pivotal step for its transformation into a proteotoxic entity that can lead to pathology. The goals of this article are to systematically analyze molecular mechanisms of the proteinopathies caused by the poly-glutamine and poly-alanine homorepeat expansion, as well as by the polypeptides generated as a result of the microsatellite expansions in non-coding gene regions and to examine the related proteins. We also present results of the analysis of the prevalence and functional roles of intrinsic disorder in proteins associated with pathological repeat expansions.


Assuntos
Proteínas Intrinsicamente Desordenadas/metabolismo , Agregação Patológica de Proteínas/metabolismo , Linhagem Celular , Humanos , Proteínas Intrinsicamente Desordenadas/genética , Repetições de Microssatélites , Peptídeos/genética , Peptídeos/metabolismo , Agregados Proteicos , Agregação Patológica de Proteínas/genética , Conformação Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
12.
J Biomol NMR ; 63(2): 201-12, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26282620

RESUMO

A simple triple resonance NMR experiment that leads to the correlation of the backbone amide resonances of each amino acid residue 'i' with that of residues 'i-1' and 'i+1' in ((13)C, (15)N) labelled intrinsically disordered proteins (IDPs) is presented. The experimental scheme, {HN-NCA heteronuclear TOCSY-NH}, exploits the favourable relaxation properties of IDPs and the presence of (1) J CαN and (2) J CαN couplings to transfer the (15)N x magnetisation from amino acid residue 'i' to adjacent residues via the application of a band-selective (15)N-(13)C(α) heteronuclear cross-polarisation sequence of ~100 ms duration. Employing non-uniform sampling in the indirect dimensions, the efficacy of the approach has been demonstrated by the acquisition of 3D HNN chemical shift correlation spectra of α-synuclein. The experimental performance of the RF pulse sequence has been compared with that of the conventional INEPT-based HN(CA)NH pulse scheme. As the availability of data from both the HCCNH and HNN experiments will make it possible to use the information extracted from one experiment to simplify the analysis of the data of the other and lead to a robust approach for unambiguous backbone and side-chain resonance assignments, a time-saving strategy for the simultaneous collection of HCCNH and HNN data is also described.


Assuntos
Proteínas Intrinsicamente Desordenadas/química , Ressonância Magnética Nuclear Biomolecular/métodos
13.
Cell Rep ; 43(7): 114419, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-38985672

RESUMO

The compaction of chromatin into mitotic chromosomes is essential for faithful transmission of the genome during cell division. In eukaryotes, chromosome morphogenesis is regulated by the condensin complex, though the exact mechanism used to target condensin to chromatin and initiate condensation is not understood. Here, we reveal that condensin contains an intrinsically disordered region (IDR) that modulates its association with chromatin in early mitosis and exhibits phase separation. We describe DNA-binding motifs within the IDR that, upon deletion, inflict striking defects in chromosome condensation and segregation, ill-timed condensin turnover on chromatin, and cell death. Importantly, we demonstrate that the condensin IDR can impart cell cycle regulatory functions when transferred to other subunits within the complex, indicating its autonomous nature. Collectively, our study unveils the molecular basis for the initiation of chromosome condensation in early mitosis and how this process ultimately promotes genomic stability and faultless cell division.


Assuntos
Adenosina Trifosfatases , Proteínas de Ligação a DNA , Mitose , Complexos Multiproteicos , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Complexos Multiproteicos/metabolismo , Adenosina Trifosfatases/metabolismo , Cromatina/metabolismo , DNA/metabolismo , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Cromossomos/metabolismo , Ligação Proteica , Segregação de Cromossomos , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética
14.
Bioinformation ; 20(2): 121-135, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38497081

RESUMO

The smallest open reading frame (ORF) encoded protein ORF3 of hepatitis E virus (HEV), recently, has been demonstrated to perform multiple functions besides accessory roles. ORF3 could act as a target for vaccine against HEV infections. The IDR (intrinsically disordered region); IDP (ID protein)/IDPR (ID protein region), plays critical role in various regulatory functions of viruses. The dark proteome of HEV-ORF3 protein including its structure and function was systematically examined by computer predictors to explicate its role in viral pathogenesis and drug resistance beyond its functions as accessory viral protein. Amino acid distribution showed ORF3 enrichment with disorder-promoting residues (Ala, Pro, Ser, Gly) while deficiency in order-promoting residues (Asn, Ile, Phe, Tyr and Trp). Initial investigation revealed ORF3 as IDP (entirely disordered protein) or IDPR (proteins consisting of IDRs with structured globular domains). Structural examination revealed preponderance of disordered regions interpreting ORF3 as moderately/highly disordered protein. Further disorder predictors categorized ORF3 as highly disordered protein/IDP. Identified sites and associated-crucial molecular functions revealed ORF3 involvement in diverse biological processes, substantiating them as targets of regulation. As ORF3 functions are yet to completely explored, thus, data on its disorderness could help in elucidating its disorder related functions.

15.
J Genet Eng Biotechnol ; 21(1): 33, 2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36929465

RESUMO

BACKGROUND: Hepatitis E virus (HEV) is the cause of a liver disease hepatitis E. The translation product of HEV ORF2 has recently been demonstrated as a protein involved in multiple functions besides performing its major role of a viral capsid. As intrinsically disordered regions (IDRs) are linked to various essential roles in the virus's life cycle, we analyzed the disorder pattern distribution of the retrieved ORF2 protein sequences by employing different online predictors. Our findings might provide some clues on the disorder-based functions of ORF2 protein that possibly help us in understanding its behavior other than as a HEV capsid protein. RESULTS: The modeled three dimensional (3D) structures of ORF2 showed the predominance of random coils or unstructured regions in addition to major secondary structure components (alpha helix and beta strand). After initial scrutinization, the predictors VLXT and VSL2 predicted ORF2 as a highly disordered protein while the predictors VL3 and DISOPRED3 predicted ORF2 as a moderately disordered protein, thus categorizing HEV-ORF2 into IDP (intrinsically disordered protein) or IDPR (intrinsically disordered protein region) respectively. Thus, our initial predicted disorderness in ORF2 protein 3D structures was in excellent agreement with their predicted disorder distribution patterns (evaluated through different predictors). The abundance of MoRFs (disorder-based protein binding sites) in ORF2 was observed that signified their interaction with binding partners which might further assist in viral infection. As IDPs/IDPRs are targets of regulation, we carried out the phosphorylation analysis to reveal the presence of post-translationally modified sites. Prevalence of several disordered-based phosphorylation sites further signified the involvement of ORF2 in diverse and significant biological processes. Furthermore, ORF2 structure-associated functions revealed its involvement in several crucial functions and biological processes like binding and catalytic activities. CONCLUSIONS: The results predicted ORF2 as a protein with multiple functions besides its role as a capsid protein. Moreover, the occurrence of IDPR/IDP in ORF2 protein suggests that its disordered region might serve as novel drug targets via functioning as potential interacting domains. Our data collectively might provide significant implication in HEV vaccine search as disorderness in viral proteins is related to mechanisms involved in immune evasion.

16.
Autophagy ; 18(11): 2515-2518, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36041015

RESUMO

Substrates that are selected for degradation by autophagy interact in more complex eukaryotes with Atg8-family proteins via the LC3-interacting region (LIR) that is often preceded by either acidic residues or phosphorylated serine or threonine. These upstream amino acid residues increase the binding affinity of the LIR motif to its binding site on the surface of LC3/GABARAP. It is not fully understood whether or how phosphorylation functionally replaces acidic residues in the LIR-Atg8-family protein interactions. A recent study by Chino et al. discussed in this article analyzed the phosphorylation of two serine residues upstream of the LIR motif in TEX264, a reticulophagy receptor that exhibits a high binding affinity to LC3/GABARAP proteins. The authors found a structural basis for the high-affinity interaction yielded by phosphorylation but not by an acidic residue in place of phosphoserine. Furthermore, finding that phosphorylation of TEX264 generates its high binding affinity to Atg8-family proteins uncovers a mechanistic alternative to that utilized by other reticulophagy receptors when they interact with LC3/GABARAP.Abbreviations: CSNK2: casein kinase 2; ER: endoplasmic reticulum; IDPR: intrinsically disordered protein region; LIR: LC3-interacting region; p-S: phosphorylated serine.


Assuntos
Autofagia , Proteínas Associadas aos Microtúbulos , Fosforilação , Proteínas Associadas aos Microtúbulos/metabolismo , Família da Proteína 8 Relacionada à Autofagia/metabolismo , Proteínas de Transporte/metabolismo , Serina , Ligação Proteica
17.
Virology ; 575: 20-35, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36037701

RESUMO

Zika virus (ZIKV) NS4B protein is a membranotropic multifunctional protein. Despite its versatile functioning, its topology and dynamics are not entirely understood. There is no X-ray or cryo-EM structure available for any flaviviral NS4B full-length protein. In this study, we have investigated the structural dynamics of full-length ZIKV NS4B protein through 3D structure models using molecular dynamics simulations and experimental techniques. Also, we employed a reductionist approach to understand the dynamics of NS4B protein where we studied its N-terminal (residues 1-38), C-terminal (residues 194-251), and cytosolic (residues 131-169) regions in isolation in addition to the full-length protein. Further, using a series of circular dichroism spectroscopic experiments, we validate the cytosolic region as an intrinsically disordered protein region. The microsecond-long all atoms molecular dynamics and replica-exchange simulations complement the experimental observations. Furthermore, we have also studied the NS4B proteins C-terminal regions of four other flaviviruses viz. DENV2, JEV, WNV, and YFV through microsecond simulations to characterize their behaviour in presence and absence of lipid membranes. There are significant differences observed in the conformations of other flavivirus NS4B C-terminal regions in comparison to ZIKV NS4B. Lastly, we have proposed a ZIKV NS4B protein model illustrating its putative topology consisting of various membrane-spanning and non-membranous regions.


Assuntos
Flavivirus , Proteínas Intrinsicamente Desordenadas , Proteínas não Estruturais Virais/química , Infecção por Zika virus , Zika virus , Flavivirus/metabolismo , Humanos , Proteínas Intrinsicamente Desordenadas/metabolismo , Lipídeos , Zika virus/química
18.
Biomolecules ; 12(10)2022 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-36291645

RESUMO

Rabies is a neurological disease that causes between 40,000 and 70,000 deaths every year. Once a rabies patient has become symptomatic, there is no effective treatment for the illness, and in unvaccinated individuals, the case-fatality rate of rabies is close to 100%. French scientists Louis Pasteur and Émile Roux developed the first vaccine for rabies in 1885. If administered before the virus reaches the brain, the modern rabies vaccine imparts long-lasting immunity to the virus and saves more than 250,000 people every year. However, the rabies virus can suppress the host's immune response once it has entered the cells of the brain, making death likely. This study aimed to make use of disorder-based proteomics and bioinformatics to determine the potential impact that intrinsically disordered protein regions (IDPRs) in the proteome of the rabies virus might have on the infectivity and lethality of the disease. This study used the proteome of the Rabies lyssavirus (RABV) strain Pasteur Vaccins (PV), one of the best-understood strains due to its use in the first rabies vaccine, as a model. The data reported in this study are in line with the hypothesis that high levels of intrinsic disorder in the phosphoprotein (P-protein) and nucleoprotein (N-protein) allow them to participate in the creation of Negri bodies and might help this virus to suppress the antiviral immune response in the host cells. Additionally, the study suggests that there could be a link between disorder in the matrix (M) protein and the modulation of viral transcription. The disordered regions in the M-protein might have a possible role in initiating viral budding within the cell. Furthermore, we checked the prevalence of functional disorder in a set of 37 host proteins directly involved in the interaction with the RABV proteins. The hope is that these new insights will aid in the development of treatments for rabies that are effective after infection.


Assuntos
Proteínas Intrinsicamente Desordenadas , Vacina Antirrábica , Vírus da Raiva , Raiva , Humanos , Vírus da Raiva/metabolismo , Raiva/prevenção & controle , Vacina Antirrábica/metabolismo , Biologia Computacional , Proteoma/metabolismo , Proteínas Intrinsicamente Desordenadas/metabolismo , Fosfoproteínas/metabolismo , Antivirais/metabolismo , Nucleoproteínas/metabolismo
19.
Biochim Biophys Acta Mol Cell Res ; 1869(1): 119161, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34655689

RESUMO

Membraneless organelles have emerged during the evolution of eukaryotic cells as intracellular domains in which multiple proteins organize into complex structures to perform specialized functions without the need of a lipid bilayer compartment. Here we describe the perinuclear space of eukaryotic cells as a highly organized network of cytoskeletal filaments that facilitates assembly of biomolecular condensates. Using bioinformatic analyses, we show that the perinuclear proteome is enriched in intrinsic disorder with several proteins predicted to undergo liquid-liquid phase separation. We also analyze immunofluorescence and transmission electron microscopy images showing the association between the nucleus and other organelles, such as mitochondria and lysosomes, or the labeling of specific proteins within the perinuclear region of cells. Altogether our data support the existence of a perinuclear dense sub-micron region formed by a well-organized three-dimensional network of structural and signaling proteins, including several proteins containing intrinsically disordered regions with phase behavior. This network of filamentous cytoskeletal proteins extends a few micrometers from the nucleus, contributes to local crowding, and organizes the movement of molecular complexes within the perinuclear space. Our findings take a key step towards understanding how membraneless regions within eukaryotic cells can serve as hubs for biomolecular condensates assembly, in particular the perinuclear space. Finally, evaluation of the disease context of the perinuclear proteins revealed that alterations in their expression can lead to several pathological conditions, and neurological disorders and cancer are among the most frequent.


Assuntos
Citoesqueleto de Actina/metabolismo , Membrana Nuclear/metabolismo , Citoesqueleto de Actina/genética , Citoesqueleto de Actina/ultraestrutura , Animais , Células Cultivadas , Embrião de Galinha , Proteínas Intrinsicamente Desordenadas/metabolismo , Lisossomos/metabolismo , Lisossomos/ultraestrutura , Microscopia Eletrônica de Transmissão/métodos , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Membrana Nuclear/ultraestrutura , Proteoma/genética , Proteoma/metabolismo , Peixe-Zebra
20.
Membranes (Basel) ; 12(5)2022 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-35629783

RESUMO

Intrinsically disordered proteins and protein regions (IDPs/IDPRs) are mainly involved in signaling pathways, where fast regulation, temporal interactions, promiscuous interactions, and assemblies of structurally diverse components including membranes are essential. The autophagy pathway builds, de novo, a membrane organelle, the autophagosome, using carefully orchestrated interactions between proteins and lipid bilayers. Here, we discuss molecular mechanisms related to the protein disorder-based interactions of the autophagy machinery with membranes. We describe not only membrane binding phenomenon, but also examples of membrane remodeling processes including membrane tethering, bending, curvature sensing, and/or fragmentation of membrane organelles such as the endoplasmic reticulum, which is an important membrane source as well as cargo for autophagy. Summary of the current state of knowledge presented here will hopefully inspire new studies. A profound understanding of the autophagic protein-membrane interface is essential for advancements in therapeutic interventions against major human diseases, in which autophagy is involved including neurodegeneration, cancer as well as cardiovascular, metabolic, infectious, musculoskeletal, and other disorders.

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