Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.093
Filtrar
1.
Nat Commun ; 12(1): 1677, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33723253

RESUMO

The seven 14-3-3 isoforms are highly abundant human proteins encoded by similar yet distinct genes. 14-3-3 proteins recognize phosphorylated motifs within numerous human and viral proteins. Here, we analyze by X-ray crystallography, fluorescence polarization, mutagenesis and fusicoccin-mediated modulation the structural basis and druggability of 14-3-3 binding to four E6 oncoproteins of tumorigenic human papillomaviruses. 14-3-3 isoforms bind variant and mutated phospho-motifs of E6 and unrelated protein RSK1 with different affinities, albeit following an ordered affinity ranking with conserved relative KD ratios. Remarkably, 14-3-3 isoforms obey the same hierarchy when binding to most of their established targets, as supported by literature and a recent human complexome map. This knowledge allows predicting proportions of 14-3-3 isoforms engaged with phosphoproteins in various tissues. Notwithstanding their individual functions, cellular concentrations of 14-3-3 may be collectively adjusted to buffer the strongest phosphorylation outbursts, explaining their expression variations in different tissues and tumors.


Assuntos
Proteínas 14-3-3/química , Isoformas de Proteínas , Proteínas 14-3-3/metabolismo , Sequência de Aminoácidos , Cristalografia por Raios X , Humanos , Papillomaviridae , Fosfoproteínas , Fosforilação , Ligação Proteica , Isoformas de Proteínas/metabolismo
2.
J Mol Biol ; 433(8): 166875, 2021 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-33556408

RESUMO

The coronavirus nucleocapsid protein (N) controls viral genome packaging and contains numerous phosphorylation sites located within unstructured regions. Binding of phosphorylated SARS-CoV N to the host 14-3-3 protein in the cytoplasm was reported to regulate nucleocytoplasmic N shuttling. All seven isoforms of the human 14-3-3 are abundantly present in tissues vulnerable to SARS-CoV-2, where N can constitute up to ~1% of expressed proteins during infection. Although the association between 14-3-3 and SARS-CoV-2 N proteins can represent one of the key host-pathogen interactions, its molecular mechanism and the specific critical phosphosites are unknown. Here, we show that phosphorylated SARS-CoV-2 N protein (pN) dimers, reconstituted via bacterial co-expression with protein kinase A, directly associate, in a phosphorylation-dependent manner, with the dimeric 14-3-3 protein, but not with its monomeric mutant. We demonstrate that pN is recognized by all seven human 14-3-3 isoforms with various efficiencies and deduce the apparent KD to selected isoforms, showing that these are in a low micromolar range. Serial truncations pinpointed a critical phosphorylation site to Ser197, which is conserved among related zoonotic coronaviruses and located within the functionally important, SR-rich region of N. The relatively tight 14-3-3/pN association could regulate nucleocytoplasmic shuttling and other functions of N via occlusion of the SR-rich region, and could also hijack cellular pathways by 14-3-3 sequestration. As such, the assembly may represent a valuable target for therapeutic intervention.


Assuntos
Proteínas 14-3-3/química , Proteínas 14-3-3/metabolismo , /metabolismo , Sequência de Aminoácidos , Sítios de Ligação/genética , Proteínas Quinases Dependentes de AMP Cíclico/genética , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Escherichia coli , Humanos , Mutação , Fosfopeptídeos/química , Fosfopeptídeos/metabolismo , Fosfoproteínas/química , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Fosforilação , Fosfosserina/metabolismo , Ligação Proteica , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , RNA Viral/metabolismo , Especificidade por Substrato
3.
Nat Commun ; 12(1): 476, 2021 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-33473107

RESUMO

Endonuclease G (ENDOG), a mitochondrial nuclease, is known to participate in many cellular processes, including apoptosis and paternal mitochondrial elimination, while its role in autophagy remains unclear. Here, we report that ENDOG released from mitochondria promotes autophagy during starvation, which we find to be evolutionally conserved across species by performing experiments in human cell lines, mice, Drosophila and C. elegans. Under starvation, Glycogen synthase kinase 3 beta-mediated phosphorylation of ENDOG at Thr-128 and Ser-288 enhances its interaction with 14-3-3γ, which leads to the release of Tuberin (TSC2) and Phosphatidylinositol 3-kinase catalytic subunit type 3 (Vps34) from 14-3-3γ, followed by mTOR pathway suppression and autophagy initiation. Alternatively, ENDOG activates DNA damage response and triggers autophagy through its endonuclease activity. Our results demonstrate that ENDOG is a crucial regulator of autophagy, manifested by phosphorylation-mediated interaction with 14-3-3γ, and its endonuclease activity-mediated DNA damage response.


Assuntos
Autofagia/fisiologia , Dano ao DNA/fisiologia , Endodesoxirribonucleases/genética , Endodesoxirribonucleases/metabolismo , Transdução de Sinais/fisiologia , Serina-Treonina Quinases TOR/metabolismo , Proteínas 14-3-3/metabolismo , Animais , Apoptose , Caenorhabditis elegans , Linhagem Celular , Classe III de Fosfatidilinositol 3-Quinases/metabolismo , Drosophila , Técnicas de Inativação de Genes , Células Hep G2 , Humanos , Fígado/metabolismo , Fígado/patologia , Camundongos , Camundongos Knockout , Mitocôndrias/metabolismo , Fosforilação , Transcriptoma , Proteína 2 do Complexo Esclerose Tuberosa/metabolismo
4.
Int J Mol Sci ; 21(24)2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-33339131

RESUMO

The cytoskeleton has a primary role in cardiomyocyte function, including the response to mechanical stimuli and injury. The small heat shock protein 20 (Hsp20) conveys protective effects in cardiac muscle that are linked to serine-16 (Ser16) Hsp20 phosphorylation by stress-induced PKA, but the link between Hsp20 and the cytoskeleton remains poorly understood. Herein, we demonstrate a physical and functional interaction of Hsp20 with the cytoskeletal protein 14-3-3. We show that, upon phosphorylation at Ser16, Hsp20 translocates from the cytosol to the cytoskeleton where it binds to 14-3-3. This leads to dissociation of 14-3-3 from the F-actin depolymerization regulator cofilin-2 (CFL2) and enhanced F-actin depolymerization. Importantly, we demonstrate that the P20L Hsp20 mutation associated with dilated cardiomyopathy exhibits reduced physical interaction with 14-3-3 due to diminished Ser16 phosphorylation, with subsequent failure to translocate to the cytoskeleton and inability to disassemble the 14-3-3/CFL2 complex. The topological sequestration of Hsp20 P20L ultimately results in impaired regulation of F-actin dynamics, an effect implicated in loss of cytoskeletal integrity and amelioration of the cardioprotective functions of Hsp20. These findings underscore the significance of Hsp20 phosphorylation in the regulation of actin cytoskeleton dynamics, with important implications in cardiac muscle physiology and pathophysiology.


Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Citoesqueleto/metabolismo , Proteínas de Choque Térmico HSP20/metabolismo , Miocárdio/metabolismo , Proteínas 14-3-3/metabolismo , Actinas/metabolismo , Animais , Cofilina 2/metabolismo , Células HEK293 , Proteínas de Choque Térmico HSP20/genética , Humanos , Camundongos , Mutação , Fosforilação , Ligação Proteica , Processamento de Proteína Pós-Traducional
5.
Nat Commun ; 11(1): 5436, 2020 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-33116123

RESUMO

Harmful effects of high fructose intake on health have been widely reported. Although fructose is known to promote cancer, little is known about the underlying mechanisms. Here, we found that fructose triggers breast cancer metastasis through the ketohexokinase-A signaling pathway. Molecular experiments showed that ketohexokinase-A, rather than ketohexokinase-C, is necessary and sufficient for fructose-induced cell invasion. Ketohexokinase-A-overexpressing breast cancer was found to be highly metastatic in fructose-fed mice. Mechanistically, cytoplasmic ketohexokinase-A enters into the nucleus during fructose stimulation, which is mediated by LRRC59 and KPNB1. In the nucleus, ketohexokinase-A phosphorylates YWHAH at Ser25 and the YWHAH recruits SLUG to the CDH1 promoter, which triggers cell migration. This study provides the effect of nutrition on breast cancer metastasis. High intake of fructose should be restricted in cancer patients to reduce the risk of metastasis. From a therapeutic perspective, the ketohexokinase-A signaling pathway could be a potential target to prevent cancer metastasis.


Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Frutoquinases/metabolismo , Frutose/administração & dosagem , Frutose/metabolismo , Proteínas 14-3-3/antagonistas & inibidores , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , Animais , Carcinógenos/administração & dosagem , Carcinógenos/metabolismo , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Feminino , Técnicas de Silenciamento de Genes , Humanos , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/patologia , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Invasividade Neoplásica/patologia , Metástase Neoplásica/patologia , Fosforilação , Transdução de Sinais , beta Carioferinas/metabolismo
6.
Nat Commun ; 11(1): 3954, 2020 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-32770072

RESUMO

The systematic stabilization of protein-protein interactions (PPI) has great potential as innovative drug discovery strategy to target novel and hard-to-drug protein classes. The current lack of chemical starting points and focused screening opportunities limits the identification of small molecule stabilizers that engage two proteins simultaneously. Starting from our previously described virtual screening strategy to identify inhibitors of 14-3-3 proteins, we report a conceptual molecular docking approach providing concrete entries for discovery and rational optimization of stabilizers for the interaction of 14-3-3 with the carbohydrate-response element-binding protein (ChREBP). X-ray crystallography reveals a distinct difference in the binding modes between weak and general inhibitors of 14-3-3 complexes and a specific, potent stabilizer of the 14-3-3/ChREBP complex. Structure-guided stabilizer optimization results in selective, up to 26-fold enhancement of the 14-3-3/ChREBP interaction. This study demonstrates the potential of rational design approaches for the development of selective PPI stabilizers starting from weak, promiscuous PPI inhibitors.


Assuntos
Proteínas 14-3-3/metabolismo , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Desenho de Fármacos , Descoberta de Drogas , Proteínas 14-3-3/antagonistas & inibidores , Proteínas 14-3-3/ultraestrutura , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/antagonistas & inibidores , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/ultraestrutura , Cristalografia por Raios X , Simulação de Acoplamento Molecular , Ligação Proteica/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas , Relação Estrutura-Atividade
7.
Biochem Biophys Res Commun ; 532(1): 134-138, 2020 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-32829876

RESUMO

SARS-CoV-2 is the etiologic agent of COVID-19. There is currently no effective means of preventing infections by SARS-CoV-2, except through restriction of population movement and contact. An understanding of the origin, evolution and biochemistry (molecular biology) of SARS-CoV-2 is a prerequisite to its control. Mutations in the phosphorylation sites of SARS-CoV-2 encoded nucleocapsid protein isolated from various populations and locations, are described. Mutations occurred in the phosphorylation sites, all located within a stretch which forms a phosphorylation dependent interaction site, including C-TAK1 phosphorylation sites for 14-3-3. The consequences of these mutations are discussed and a structure-based model for the role of protein 14-3-3 in the sequestration and inhibition of SARS-CoV-2 nucleocapsid protein's function is presented. It is proposed that the phosphorylation of SARS-CoV-2 nucleocapsid protein and its sequestration by Protein 14-3-3 is a cellular response mechanism for the control and inhibition of the replication, transcription and packaging of the SARS-CoV-2 genome.


Assuntos
Proteínas 14-3-3/química , Betacoronavirus/genética , Genoma Viral , Interações Hospedeiro-Patógeno/genética , Proteínas do Nucleocapsídeo/química , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , Sequência de Aminoácidos , Betacoronavirus/metabolismo , Betacoronavirus/patogenicidade , Sítios de Ligação , Infecções por Coronavirus/virologia , Expressão Gênica , Humanos , Simulação de Acoplamento Molecular , Mutação , Proteínas do Nucleocapsídeo/genética , Proteínas do Nucleocapsídeo/metabolismo , Pandemias , Fosfoproteínas , Fosforilação , Pneumonia Viral/virologia , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Termodinâmica
8.
Nat Commun ; 11(1): 3583, 2020 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-32681005

RESUMO

The phosphatases PP1 and PP2A are responsible for the majority of dephosphorylation reactions on phosphoserine (pSer) and phosphothreonine (pThr), and are involved in virtually all cellular processes and numerous diseases. The catalytic subunits exist in cells in form of holoenzymes, which impart substrate specificity. The contribution of the catalytic subunits to the recognition of substrates is unclear. By developing a phosphopeptide library approach and a phosphoproteomic assay, we demonstrate that the specificity of PP1 and PP2A holoenzymes towards pThr and of PP1 for basic motifs adjacent to the phosphorylation site are due to intrinsic properties of the catalytic subunits. Thus, we dissect this amino acid specificity of the catalytic subunits from the contribution of regulatory proteins. Furthermore, our approach enables discovering a role for PP1 as regulator of the GRB-associated-binding protein 2 (GAB2)/14-3-3 complex. Beyond this, we expect that this approach is broadly applicable to detect enzyme-substrate recognition preferences.


Assuntos
Proteína Fosfatase 1/química , Proteína Fosfatase 1/metabolismo , Proteína Fosfatase 2/química , Proteína Fosfatase 2/metabolismo , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Motivos de Aminoácidos , Domínio Catalítico , Holoenzimas/química , Holoenzimas/genética , Holoenzimas/metabolismo , Humanos , Fosforilação , Ligação Proteica , Engenharia de Proteínas , Proteína Fosfatase 1/genética , Proteína Fosfatase 2/genética , Subunidades Proteicas/química , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Especificidade por Substrato
9.
Am J Physiol Gastrointest Liver Physiol ; 319(2): G121-G132, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32567324

RESUMO

Nongenomic glucocorticoid (GC) and serum- and glucocorticoid-inducible kinase 1 (SGK1) signaling regulate ion transport, but CFTR has not been investigated in the intestine. We examined GC, SGK1, and phosphatidylinositol 3-kinase (PI3K) kinase signaling of CFTR ion transport in native intestine and the role of GCs on mRNA, protein, surface expression, and cyclic guanosine monophosphate (cGMP)-elicited diarrhea. Rats were treated with dexamethasone (DEXA; 2 mg/kg ip) or DMSO for 1, 4, and 24 h. Cyclic adenosine monophosphate (cAMP)-activated ion transport was examined in the presence or absence of SGK1 and PI3K inhibitors. Phosphorylation of SGK1, phosphoinositide-dependent kinase 1, and Akt kinases was confirmed by immunoblots using phosphor-specific antibodies. Tissue lysates were analyzed by mass spectrometry. CFTR and SGK1 mRNA were measured by quantitative PCR. Changes in total and surface CFTR protein were determined. The role of GC in cGMP-activated CFTR ion transport was examined. GC synergistically increased CFTR ion transport by SGK1 and PI3K signaling and increased CFTR protein without altering SGK1 or CFTR mRNA. GC induced highest levels of CFTR protein at 4 h that were associated with marked increase in surface CFTR, phosphorylation of the ubiquitin ligase neural precursor cell expressed developmentally downregulated 4-like (Nedd4-2), and 14-3-3ε, supporting their roles in surface retention and stability. Coimmunoprecipitation of CFTR, Nedd4-2, and 14-3-3ε indicated that assembly of this complex is a likely effector of the SGK and Akt pathways. Mass spectrometry identified phosphorylated peptides in relevant proteins. GC-SGK1 potently regulates CFTR in the intestine and is implicated in diarrheal disease.NEW & NOTEWORTHY This is the first study to examine the mechanisms of glucocorticoid, serum- and glucocorticoid-inducible kinase 1, and nongenomic kinase signaling of CFTR in the native intestine. We identified unique and druggable intestine-specific factors of the pathway that are targets for treating stress-induced diarrhea.


Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Dexametasona/toxicidade , Diarreia/etiologia , Dimetil Sulfóxido/toxicidade , Proteínas Imediatamente Precoces/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , Animais , Toxinas Bacterianas/toxicidade , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Diarreia/induzido quimicamente , Enterotoxinas/toxicidade , Proteínas de Escherichia coli/toxicidade , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas Imediatamente Precoces/genética , Masculino , Ubiquitina-Proteína Ligases Nedd4/genética , Ubiquitina-Proteína Ligases Nedd4/metabolismo , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Transporte Proteico , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , /metabolismo , Ratos , Ratos Sprague-Dawley , Trocador 3 de Sódio-Hidrogênio/genética , Trocador 3 de Sódio-Hidrogênio/metabolismo
10.
J Med Chem ; 63(13): 6694-6707, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32501690

RESUMO

Stabilization of protein-protein interactions (PPIs) holds great potential for therapeutic agents, as illustrated by the successful drugs rapamycin and lenalidomide. However, how such interface-binding molecules can be created in a rational, bottom-up manner is a largely unanswered question. We report here how a fragment-based approach can be used to identify chemical starting points for the development of small-molecule stabilizers that differentiate between two different PPI interfaces of the adapter protein 14-3-3. The fragments discriminately bind to the interface of 14-3-3 with the recognition motif of either the tumor suppressor protein p53 or the oncogenic transcription factor TAZ. This X-ray crystallography driven study shows that the rim of the interface of individual 14-3-3 complexes can be targeted in a differential manner with fragments that represent promising starting points for the development of specific 14-3-3 PPI stabilizers.


Assuntos
Proteínas 14-3-3/metabolismo , Bibliotecas de Moléculas Pequenas/farmacologia , Proteínas 14-3-3/química , Desenho de Fármacos , Modelos Moleculares , Ligação Proteica/efeitos dos fármacos , Conformação Proteica
11.
Trends Pharmacol Sci ; 41(7): 431-433, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32402470

RESUMO

14-3-3 Proteins enact a range of cellular functions through protein-protein interactions (PPIs) with client proteins. Kaplan and colleagues recently demonstrated that a semisynthetic compound was able to selectively stabilize or disrupt specific interactions, depending on the binding partner. This finding presents an exciting possibility of designing other 14-3-3 compounds to regulate critical 14-3-3 interactions.


Assuntos
Proteínas 14-3-3 , Crescimento Neuronal , Proteínas 14-3-3/metabolismo
12.
Nucleic Acids Res ; 48(10): 5572-5590, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32365187

RESUMO

RNA decay is a key element of mitochondrial RNA metabolism. To date, the only well-documented machinery that plays a role in mtRNA decay in humans is the complex of polynucleotide phosphorylase (PNPase) and SUV3 helicase, forming the degradosome. REXO2, a homolog of prokaryotic oligoribonucleases present in humans both in mitochondria and the cytoplasm, was earlier shown to be crucial for maintaining mitochondrial homeostasis, but its function in mitochondria has not been fully elucidated. In the present study, we created a cellular model that enables the clear dissection of mitochondrial and non-mitochondrial functions of human REXO2. We identified a novel mitochondrial short RNA, referred to as ncH2, that massively accumulated upon REXO2 silencing. ncH2 degradation occurred independently of the mitochondrial degradosome, strongly supporting the hypothesis that ncH2 is a primary substrate of REXO2. We also investigated the global impact of REXO2 depletion on mtRNA, revealing the importance of the protein for maintaining low steady-state levels of mitochondrial antisense transcripts and double-stranded RNA. Our detailed biochemical and structural studies provide evidence of sequence specificity of the REXO2 oligoribonuclease. We postulate that REXO2 plays dual roles in human mitochondria, 'scavenging' nanoRNAs that are produced by the degradosome and clearing short RNAs that are generated by RNA processing.


Assuntos
Proteínas 14-3-3/metabolismo , Biomarcadores Tumorais/metabolismo , Exorribonucleases/metabolismo , Processamento Pós-Transcricional do RNA , Estabilidade de RNA , RNA de Cadeia Dupla/metabolismo , RNA Mitocondrial/metabolismo , Proteínas 14-3-3/química , Proteínas 14-3-3/fisiologia , Biomarcadores Tumorais/química , Biomarcadores Tumorais/fisiologia , Exorribonucleases/química , Exorribonucleases/fisiologia , Células HeLa , Humanos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Multimerização Proteica , Especificidade por Substrato
13.
Environ Toxicol ; 35(9): 1015-1028, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32420678

RESUMO

Breast cancer (BC) is the leading cause of cancer-related death in women worldwide and one of the most prevalent malignancy. In recent years, increasing evidence had illuminated that long noncoding RNAs (lncRNAs) serve as critical factors in multiple tumor progression, including BC. Emerging references had indicated that the lncRNA H19 acts as significant roles in tumor progression and epithelial-mesenchymal transition (EMT). However, the underlying molecular mechanisms and biological roles of H19 in BC invasion, metastasis and EMT are still unclear. In this study, it was detected that the expression level of H19 was increased in BC paclitaxel-resistant (PR) cells subline (MCF-7/PR) in comparison with MCF-7 parental cells. In vitro, there were demonstrated that H19 overexpression promoted BC cells proliferation, metastasis, invasion and EMT procedures, and suppressed cells apoptosis. Whereas, H19 suppression resulted in the contrary biological effects. Besides, bioinformatics tools and dual-luciferase reporters assays indicated that miR-340-3p could act as a potential target gene of H19, the underlying mechanism studies proved that H19 could act as a competing endogenous RNA (ceRNA) via competitively binding miR-340-3p to promote BC cell proliferation, metastasis and EMT by regulating tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) and potentiate the Wnt/ß-catenin signaling in BC cells. In summary, our findings demonstrated that H19 could act as a ceRNA in BC progression, metastasis and EMT through modulating miR-340-3p/YWHAZ axis and activating the canonical Wnt/ß-catenin signaling pathway, indicating that H19 might act as an underlying therapeutic target and prognostic biomarker for BC therapy.


Assuntos
Proteínas 14-3-3/metabolismo , Antineoplásicos Fitogênicos/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Transição Epitelial-Mesenquimal/efeitos dos fármacos , MicroRNAs/genética , Paclitaxel/farmacologia , RNA Longo não Codificante/genética , Apoptose/efeitos dos fármacos , Apoptose/genética , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Transição Epitelial-Mesenquimal/genética , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Células MCF-7 , MicroRNAs/metabolismo , RNA Longo não Codificante/metabolismo , Via de Sinalização Wnt/efeitos dos fármacos , Via de Sinalização Wnt/genética
15.
Am J Physiol Endocrinol Metab ; 319(1): E117-E132, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32369418

RESUMO

One of the primary metabolic functions of a mature adipocyte is to supply energy via lipolysis, or the catabolism of stored lipids. Adipose triacylglycerol lipase (ATGL) and hormone-sensitive lipase (HSL) are critical lipolytic enzymes, and their phosphorylation generates phospho-binding sites for 14-3-3 proteins, a ubiquitously expressed family of molecular scaffolds. Although we previously identified essential roles of the 14-3-3ζ isoform in murine adipogenesis, the presence of 14-3-3 protein binding sites on ATGL and HSL suggests that 14-3-3ζ could also influence mature adipocyte processes like lipolysis. Here we demonstrate that 14-3-3ζ is necessary for lipolysis in male mice and fully differentiated 3T3-L1 adipocytes, as depletion of 14-3-3ζ significantly impaired glycerol and free fatty acid (FFA) release. Unexpectedly, reducing 14-3-3ζ expression was found to significantly impact adipocyte maturity, as observed by reduced abundance of peroxisome proliferator-activated receptor (PPAR)γ2 protein and expression of mature adipocyte genes and those associated with de novo triglyceride synthesis and lipolysis. The impact of 14-3-3ζ depletion on adipocyte maturity was further examined with untargeted lipidomics, which revealed that reductions in 14-3-3ζ abundance promoted the acquisition of a lipidomic signature that resembled undifferentiated preadipocytes. Collectively, these findings reveal a novel aspect of 14-3-3ζ in adipocytes, as reducing 14-3-3ζ was found to have a negative effect on adipocyte maturity and adipocyte-specific processes like lipolysis.


Assuntos
Proteínas 14-3-3/genética , Adipócitos/metabolismo , Adipogenia/genética , Lipólise/genética , Proteínas 14-3-3/metabolismo , Células 3T3-L1 , Animais , Diferenciação Celular , Ácidos Graxos não Esterificados/metabolismo , Glicerol/metabolismo , Lipase/genética , Lipase/metabolismo , Lipidômica , Masculino , Camundongos , PPAR gama/genética , PPAR gama/metabolismo , RNA Mensageiro/metabolismo , Esterol Esterase/genética , Esterol Esterase/metabolismo
16.
Am J Physiol Renal Physiol ; 319(1): F52-F62, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32463725

RESUMO

14-3-3γ is a small protein regulating its target proteins through binding to phosphorylated serine/threonine residues. Sequence analysis of large-conductance Ca2+-activated K+ (BK) channels revealed a putative 14-3-3 binding site in the COOH-terminal region. Our previous data showed that 14-3-3γ is widely expressed in the mouse kidney. Therefore, we hypothesized that 14-3-3γ has a novel role in the regulation of BK channel activity and protein expression. We used electrophysiology, Western blot analysis, and coimmunoprecipitation to examine the effects of 14-3-3γ on BK channels both in vitro and in vivo. We demonstrated the interaction of 14-3-3γ with BK α-subunits (BKα) by coimmunoprecipitation. In human embryonic kidney-293 cells stably expressing BKα, overexpression of 14-3-3γ significantly decreased BK channel activity and channel open probability. 14-3-3γ inhibited both total and cell surface BKα protein expression while enhancing ERK1/2 phosphorylation in Cos-7 cells cotransfected with flag-14-3-3γ and myc-BK. Knockdown of 14-3-3γ by siRNA transfection markedly increased BKα expression. Blockade of the ERK1/2 pathway by incubation with the MEK-specific inhibitor U0126 partially abolished 14-3-3γ-mediated inhibition of BK protein expression. Similarly, pretreatment of the lysosomal inhibitor bafilomycin A1 reversed the inhibitory effects of 14-3-3γ on BK protein expression. Furthermore, overexpression of 14-3-3γ significantly increased BK protein ubiquitination in embryonic kidney-293 cells stably expressing BKα. Additionally, 3 days of dietary K+ challenge reduced 14-3-3γ expression and ERK1/2 phosphorylation while enhancing renal BK protein expression and K+ excretion. These data suggest that 14-3-3γ modulates BK channel activity and protein expression through an ERK1/2-mediated ubiquitin-lysosomal pathway.


Assuntos
Proteínas 14-3-3/metabolismo , Rim/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Alta/metabolismo , Animais , Butadienos/farmacologia , Células COS , Chlorocebus aethiops , Inibidores Enzimáticos/farmacologia , Células HEK293 , Humanos , Rim/efeitos dos fármacos , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Macrolídeos/farmacologia , Nitrilos/farmacologia , Fosforilação/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
17.
J Virol ; 94(14)2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32321809

RESUMO

Nipah virus (NiV) and Hendra virus (HeV), members of the Henipavirus genus in the Paramyxoviridae family, are recently emerged, highly lethal zoonotic pathogens. The NiV and HeV nonsegmented, negative-sense RNA genomes encode nine proteins, including the W protein. Expressed from the P gene through mRNA editing, W shares a common N-terminus with P and V but has a unique C-terminus. Expressed alone, W modulates innate immune responses by several mechanisms, and elimination of W from NiV alters the course of infection in experimentally infected ferrets. However, the specific host interactions that allow W to modulate innate immunity are incompletely understood. This study demonstrates that the NiV and HeV W proteins interact with all seven isoforms of the 14-3-3 family, regulatory molecules that preferentially bind phosphorylated target proteins to regulate a wide range of cellular functions. The interaction is dependent on the penultimate amino acid residue in the W sequence, a conserved, phosphorylated serine. The cocrystal structure of the W C-terminal binding motif with 14-3-3 provides only the second structure of a complex containing a mode III interactor, which is defined as a 14-3-3 interaction with a phosphoserine/phosphothreonine at the C-termini of the target protein. Transcriptomic analysis of inducible cell lines infected with an RNA virus and expressing either wild-type W or W lacking 14-3-3 binding, identifies new functions for W. These include the regulation of cellular metabolic processes, extracellular matrix organization, and apoptosis.IMPORTANCE Nipah virus (NiV) and Hendra virus (HeV), members of the Henipavirus genus, are recently emerged, highly lethal zoonotic pathogens that cause yearly outbreaks. NiV and HeV each encode a W protein that has roles in regulating host signaling pathways, including antagonism of the innate immune response. However, the mechanisms used by W to regulate these host responses are not clear. Here, characterization of the interaction of NiV and HeV W with 14-3-3 identifies modulation of 14-3-3-regulated host signaling pathways not previously associated with W, suggesting new avenues of research. The cocrystal structure of the NiV W:14-3-3 complex, as only the second structure of a 14-3-3 mode III interactor, provides further insight into this less-well-understood 14-3-3 binding motif.


Assuntos
Proteínas 14-3-3/metabolismo , Regulação da Expressão Gênica , Vírus Hendra/metabolismo , Infecções por Henipavirus/metabolismo , Vírus Nipah/metabolismo , Proteínas Virais/metabolismo , Proteínas 14-3-3/genética , Células HEK293 , Vírus Hendra/genética , Infecções por Henipavirus/genética , Humanos , Vírus Nipah/genética , Proteínas Virais/genética
18.
Biochem J ; 477(7): 1219-1225, 2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32271882

RESUMO

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.


Assuntos
Proteínas 14-3-3/metabolismo , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/metabolismo , Fosfoproteínas/metabolismo , Mapas de Interação de Proteínas , Sítios de Ligação , Humanos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/genética , Mutação , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Fosforilação , Ligação Proteica , Multimerização Proteica , Processamento de Proteína Pós-Traducional
19.
Oncol Rep ; 43(6): 1845-1852, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32236580

RESUMO

The Nemo­like kinase (NLK), a conserved serine/threonine kinase, plays a critical role in the regulation of a variety of transcription factors, with important roles in determining cell fate. Although recent studies have demonstrated decreased expression patterns of NLK in various types of human cancer, the functional mechanism of NLK in cancer development has not been elucidated. Here, in the present study overexpression of NLK was found to inhibit the growth and migration of the non­small cell lung cancer A549 cell line. NLK was subsequently found to interact with 14­3­3ζ (also known as YWHAZ), which is responsible for E­cadherin silencing during epithelial­mesenchymal transition (EMT). Furthermore, NLK overexpression was able to restore the expression of E­cadherin inhibited by 14­3­3ζ. Notably, NLK interacts with 14­3­3ζ and prevents its dimerization, which is essential for 14­3­3ζ stability and function. By fusing two copies of the 14­3­3ζ gene, via a Gly­rich linker, a non­dissociable dimer of 14­3­3ζ was formed. It was found that NLK was unable to restore the expression of E­cadherin inhibited by the overexpression of the fused dimer of 14­3­3ζ. In addition, the increased ability of migration induced by the overexpression of fused 14­3­3ζ dimer could not be altered by NLK overexpression. The results from the present study indicate that NLK is a negative regulator of 14­3­3ζ and plays a tumor suppressive role in the inhibition of cancer cell migration.


Assuntos
Proteínas 14-3-3/metabolismo , Antígenos CD/metabolismo , Caderinas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Neoplasias Pulmonares/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas 14-3-3/química , Células A549 , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Transição Epitelial-Mesenquimal , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Humanos , Estabilidade Proteica
20.
Oxid Med Cell Longev ; 2020: 1750289, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32190168

RESUMO

Reactive oxygen species (ROS) are byproducts of a defective electron transport chain (ETC). The redox couples, GSH/GSSG and NAD+/NADH, play an essential role in physiology as internal defenses against excessive ROS generation by facilitating intracellular/mitochondrial (mt) redox homeostasis. Anoxia alone and anoxia/reoxygenation (A/R) are dissimilar pathological processes. In this study, we measured the impact of capsaicin (Cap) on these pathological processes using a primary cultured neonatal rat cardiomyocyte in vitro model. The results showed that overproduction of ROS was tightly associated with disturbed GSH/GSSG and NAD+/NADH suppressed mt complex I and III activities, decreased oxygen consumption rates, and elevated extracellular acidification rates. During anoxia or A/R period, these indices interact with each other causing the mitochondrial function to worsen. Cap protected cardiomyocytes against the different stages of A/R injury by rescuing NAD+/NADH, GSH/GSSG, and mt complex I/III activities and cellular energy metabolism. Importantly, Cap-mediated upregulation of 14-3-3η, a protective phosphoserine-binding protein in cardiomyocytes, ameliorated mt function caused by a disruptive redox status and an impaired ETC. In conclusion, redox pair, mt complex I/III, and metabolic equilibrium were significantly different in anoxia alone and A/R injury; Cap through upregulating 14-3-3η plays a protection against the above injury in cardiomyocyte.


Assuntos
Proteínas 14-3-3/metabolismo , Capsaicina/farmacologia , Mitocôndrias/metabolismo , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Regulação para Cima , Animais , Apoptose/efeitos dos fármacos , Hipóxia Celular/efeitos dos fármacos , Transporte de Elétrons/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Oxirredução , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Regulação para Cima/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...