Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 13.090
Filtrar
1.
Nat Commun ; 12(1): 4867, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34381029

RESUMO

Circulating tumor cell (CTC) clusters mediate metastasis at a higher efficiency and are associated with lower overall survival in breast cancer compared to single cells. Combining single-cell RNA sequencing and protein analyses, here we report the profiles of primary tumor cells and lung metastases of triple-negative breast cancer (TNBC). ICAM1 expression increases by 200-fold in the lung metastases of three TNBC patient-derived xenografts (PDXs). Depletion of ICAM1 abrogates lung colonization of TNBC cells by inhibiting homotypic tumor cell-tumor cell cluster formation. Machine learning-based algorithms and mutagenesis analyses identify ICAM1 regions responsible for homophilic ICAM1-ICAM1 interactions, thereby directing homotypic tumor cell clustering, as well as heterotypic tumor-endothelial adhesion for trans-endothelial migration. Moreover, ICAM1 promotes metastasis by activating cellular pathways related to cell cycle and stemness. Finally, blocking ICAM1 interactions significantly inhibits CTC cluster formation, tumor cell transendothelial migration, and lung metastasis. Therefore, ICAM1 can serve as a novel therapeutic target for metastasis initiation of TNBC.


Assuntos
Molécula 1 de Adesão Intercelular/metabolismo , Neoplasias Pulmonares/secundário , Células Neoplásicas Circulantes/patologia , Neoplasias de Mama Triplo Negativas/patologia , Animais , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Agregação Celular , Ciclo Celular , Transformação Celular Neoplásica , Humanos , Molécula 1 de Adesão Intercelular/genética , Neoplasias Pulmonares/metabolismo , Camundongos , Células Neoplásicas Circulantes/metabolismo , Domínios e Motivos de Interação entre Proteínas , Transdução de Sinais , Migração Transendotelial e Transepitelial , Neoplasias de Mama Triplo Negativas/metabolismo
2.
Nat Commun ; 12(1): 4709, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34354080

RESUMO

Allostery represents a fundamental mechanism of biological regulation that involves long-range communication between distant protein sites. It also provides a powerful framework for novel therapeutics. NMDA receptors (NMDARs), glutamate-gated ionotropic receptors that play central roles in synapse maturation and plasticity, are prototypical allosteric machines harboring large extracellular N-terminal domains (NTDs) that provide allosteric control of key receptor properties with impact on cognition and behavior. It is commonly thought that GluN2A and GluN2B receptors, the two predominant NMDAR subtypes in the adult brain, share similar allosteric transitions. Here, combining functional and structural interrogation, we reveal that GluN2A and GluN2B receptors utilize different long-distance allosteric mechanisms involving distinct subunit-subunit interfaces and molecular rearrangements. NMDARs have thus evolved multiple levels of subunit-specific allosteric control over their transmembrane ion channel pore. Our results uncover an unsuspected diversity in NMDAR molecular mechanisms with important implications for receptor physiology and precision drug development.


Assuntos
Receptores de N-Metil-D-Aspartato/metabolismo , Regulação Alostérica , Animais , Feminino , Células HEK293 , Humanos , Técnicas In Vitro , Camundongos , Modelos Moleculares , Mutagênese Sítio-Dirigida , Oócitos/metabolismo , Fotoquímica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Subunidades Proteicas , Ratos , Receptores de N-Metil-D-Aspartato/química , Receptores de N-Metil-D-Aspartato/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Xenopus laevis
3.
Nucleic Acids Res ; 49(15): 8961-8973, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34365506

RESUMO

Histone recognition constitutes a key epigenetic mechanism in gene regulation and cell fate decision. PHF14 is a conserved multi-PHD finger protein that has been implicated in organ development, tissue homeostasis, and tumorigenesis. Here we show that PHF14 reads unmodified histone H3(1-34) through an integrated PHD1-ZnK-PHD2 cassette (PHF14PZP). Our binding, structural and HDX-MS analyses revealed a feature of bipartite recognition, in which PHF14PZP utilizes two distinct surfaces for concurrent yet separable engagement of segments H3-Nter (e.g. 1-15) and H3-middle (e.g. 14-34) of H3(1-34). Structural studies revealed a novel histone H3 binding mode by PHD1 of PHF14PZP, in which a PHF14-unique insertion loop but not the core ß-strands of a PHD finger dominates H3K4 readout. Binding studies showed that H3-PHF14PZP engagement is sensitive to modifications occurring to H3 R2, T3, K4, R8 and K23 but not K9 and K27, suggesting multiple layers of modification switch. Collectively, our work calls attention to PHF14 as a 'ground' state (unmodified) H3(1-34) reader that can be negatively regulated by active marks, thus providing molecular insights into a repressive function of PHF14 and its derepression.


Assuntos
Histonas/química , Histonas/metabolismo , Proteínas de Peixe-Zebra/química , Proteínas de Peixe-Zebra/metabolismo , Regulação Alostérica , Animais , Cristalografia por Raios X , Humanos , Modelos Moleculares , Mutagênese , Proteínas Nucleares/química , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Fatores de Transcrição/química , Proteínas de Peixe-Zebra/genética
4.
Nucleic Acids Res ; 49(15): 8699-8713, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34370039

RESUMO

The Bloom syndrome DNA helicase BLM contributes to chromosome stability through its roles in double-strand break repair by homologous recombination and DNA replication fork restart during the replication stress response. Loss of BLM activity leads to Bloom syndrome, which is characterized by extraordinary cancer risk and small stature. Here, we have analyzed the composition of the BLM complex during unperturbed S-phase and identified a direct physical interaction with the Mcm6 subunit of the minichromosome maintenance (MCM) complex. Using distinct binding sites, BLM interacts with the N-terminal domain of Mcm6 in G1 phase and switches to the C-terminal Cdt1-binding domain of Mcm6 in S-phase, with a third site playing a role for Mcm6 binding after DNA damage. Disruption of Mcm6-binding to BLM in S-phase leads to supra-normal DNA replication speed in unperturbed cells, and the helicase activity of BLM is required for this increased replication speed. Upon disruption of BLM/Mcm6 interaction, repair of replication-dependent DNA double-strand breaks is delayed and cells become hypersensitive to DNA damage and replication stress. Our findings reveal that BLM not only plays a role in the response to DNA damage and replication stress, but that its physical interaction with Mcm6 is required in unperturbed cells, most notably in S-phase as a negative regulator of replication speed.


Assuntos
Componente 6 do Complexo de Manutenção de Minicromossomo/metabolismo , RecQ Helicases/metabolismo , Fase S/genética , Sítios de Ligação , Linhagem Celular , Reparo do DNA , Fase G1 , Humanos , Componente 6 do Complexo de Manutenção de Minicromossomo/química , Mutação , Domínios e Motivos de Interação entre Proteínas , RecQ Helicases/química
5.
Biochem Biophys Res Commun ; 573: 158-163, 2021 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-34416436

RESUMO

The angiotensin Converting Enzyme 2 (ACE2) receptor is a key component of the renin-angiotensin-aldesterone system (RAAS) that mediates numerous effects in the cardiovascular system. It is also the cellular point of contact for the coronavirus spike protein. Cleavage of the receptor is both important to its physiological function as well as being necessary for cell entry by the virus. Shedding of ACE2 by the metalloprotease ADAM17 releases a catalytically active soluble form of ACE2, but cleavage by the serine protease TMPRSS2 is necessary for virion internalization. Complicating the issue is the observation that circulating ACE2 can also bind to the virus effectively blocking attachment to the membrane-bound receptor. This work investigates the possibility that the inflammatory response to coronavirus infection can abrogate shedding by ADAM17, thereby favoring cleavage by TMPRSS2 and thus cell entry by the virion.


Assuntos
Proteína ADAM17/química , Proteína ADAM17/metabolismo , Enzima de Conversão de Angiotensina 2/metabolismo , Proteínas de Choque Térmico HSP20/metabolismo , Interações Hospedeiro-Patógeno/fisiologia , SARS-CoV-2/patogenicidade , Enzima de Conversão de Angiotensina 2/química , Sítios de Ligação , Proteínas de Choque Térmico HSP20/química , Resposta ao Choque Térmico/fisiologia , Humanos , Domínios Proteicos , Domínios e Motivos de Interação entre Proteínas , Serina Endopeptidases/metabolismo , Internalização do Vírus
6.
Proc Natl Acad Sci U S A ; 118(36)2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34417349

RESUMO

To investigate the evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the immune population, we coincupi bated the authentic virus with a highly neutralizing plasma from a COVID-19 convalescent patient. The plasma fully neutralized the virus for seven passages, but, after 45 d, the deletion of F140 in the spike N-terminal domain (NTD) N3 loop led to partial breakthrough. At day 73, an E484K substitution in the receptor-binding domain (RBD) occurred, followed, at day 80, by an insertion in the NTD N5 loop containing a new glycan sequon, which generated a variant completely resistant to plasma neutralization. Computational modeling predicts that the deletion and insertion in loops N3 and N5 prevent binding of neutralizing antibodies. The recent emergence in the United Kingdom, South Africa, Brazil, and Japan of natural variants with similar changes suggests that SARS-CoV-2 has the potential to escape an effective immune response and that vaccines and antibodies able to control emerging variants should be developed.


Assuntos
Substituição de Aminoácidos , Enzima de Conversão de Angiotensina 2/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , COVID-19/imunologia , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/genética , Animais , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/genética , Anticorpos Neutralizantes/farmacologia , Anticorpos Antivirais/química , Anticorpos Antivirais/genética , Anticorpos Antivirais/farmacologia , Sítios de Ligação , COVID-19/genética , COVID-19/virologia , Chlorocebus aethiops , Convalescença , Expressão Gênica , Humanos , Evasão da Resposta Imune , Soros Imunes/química , Modelos Moleculares , Mutação , Testes de Neutralização , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/imunologia , SARS-CoV-2/patogenicidade , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Células Vero
7.
Int J Mol Sci ; 22(16)2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-34445310

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite the development of vaccines, the emergence of SARS-CoV-2 variants and the absence of effective therapeutics demand the continual investigation of COVID-19. Natural products containing active ingredients may be good therapeutic candidates. Here, we investigated the effectiveness of geraniin, the main ingredient in medical plants Elaeocarpus sylvestris var. ellipticus and Nephelium lappaceum, for treating COVID-19. The SARS-CoV-2 spike protein binds to the human angiotensin-converting enzyme 2 (hACE2) receptor to initiate virus entry into cells; viral entry may be an important target of COVID-19 therapeutics. Geraniin was found to effectively block the binding between the SARS-CoV-2 spike protein and hACE2 receptor in competitive enzyme-linked immunosorbent assay, suggesting that geraniin might inhibit the entry of SARS-CoV-2 into human epithelial cells. Geraniin also demonstrated a high affinity to both proteins despite a relatively lower equilibrium dissociation constant (KD) for the spike protein (0.63 µM) than hACE2 receptor (1.12 µM), according to biolayer interferometry-based analysis. In silico analysis indicated geraniin's interaction with the residues functionally important in the binding between the two proteins. Thus, geraniin is a promising therapeutic agent for COVID-19 by blocking SARS-CoV-2's entry into human cells.


Assuntos
Enzima de Conversão de Angiotensina 2/metabolismo , Glucosídeos/farmacologia , Taninos Hidrolisáveis/farmacologia , SARS-CoV-2/efeitos dos fármacos , Glicoproteína da Espícula de Coronavírus/metabolismo , Internalização do Vírus/efeitos dos fármacos , Enzima de Conversão de Angiotensina 2/antagonistas & inibidores , Enzima de Conversão de Angiotensina 2/química , Glucosídeos/química , Humanos , Taninos Hidrolisáveis/química , Ligantes , Simulação de Dinâmica Molecular , Domínios e Motivos de Interação entre Proteínas , SARS-CoV-2/fisiologia , Glicoproteína da Espícula de Coronavírus/antagonistas & inibidores , Glicoproteína da Espícula de Coronavírus/química
8.
Nat Commun ; 12(1): 4760, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34362909

RESUMO

The MADS transcription factors (TF) are an ancient eukaryotic protein family. In plants, the family is divided into two main lineages. Here, we demonstrate that DNA binding in both lineages absolutely requires a short amino acid sequence C-terminal to the MADS domain (M domain) called the Intervening domain (I domain) that was previously defined only in type II lineage MADS. Structural elucidation of the MI domains from the floral regulator, SEPALLATA3 (SEP3), shows a conserved fold with the I domain acting to stabilise the M domain. Using the floral organ identity MADS TFs, SEP3, APETALA1 (AP1) and AGAMOUS (AG), domain swapping demonstrate that the I domain alters genome-wide DNA-binding specificity and dimerisation specificity. Introducing AG carrying the I domain of AP1 in the Arabidopsis ap1 mutant resulted in strong complementation and restoration of first and second whorl organs. Taken together, these data demonstrate that the I domain acts as an integral part of the DNA-binding domain and significantly contributes to the functional identity of the MADS TF.


Assuntos
Proteínas de Ligação a DNA/química , Proteínas de Homeodomínio/química , Fatores de Transcrição/química , Proteína AGAMOUS de Arabidopsis/química , Proteína AGAMOUS de Arabidopsis/genética , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Ligação a DNA/metabolismo , Flores , Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Proteínas de Domínio MADS/metabolismo , Fenótipo , Domínios e Motivos de Interação entre Proteínas , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
9.
Molecules ; 26(15)2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34361703

RESUMO

Matrix metalloproteinases (MMPs) are the family of proteases that are mainly responsible for degrading extracellular matrix (ECM) components. In the skin, the overexpression of MMPs as a result of ultraviolet radiation triggers an imbalance in the ECM turnover in a process called photoaging, which ultimately results in skin wrinkling and premature skin ageing. Therefore, the inhibition of different enzymes of the MMP family at a topical level could have positive implications for photoaging. Considering that the MMP catalytic region is mostly conserved across different enzymes of the MMP family, in this study we aimed to design a virtual screening (VS) workflow to identify broad-spectrum MMP inhibitors that can be used to delay the development of photoaging. Our in silico approach was validated in vitro with 20 VS hits from the Specs library that were not only structurally different from one another but also from known MMP inhibitors. In this bioactivity assay, 18 of the 20 compounds inhibit at least one of the assayed MMPs at 100 µM (with 5 of them showing around 50% inhibition in all the tested MMPs at this concentration). Finally, this VS was used to identify natural products that have the potential to act as broad-spectrum MMP inhibitors and be used as a treatment for photoaging.


Assuntos
Inibidores de Metaloproteinases de Matriz/farmacologia , Metaloproteinases da Matriz/química , Pele/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/farmacologia , Produtos Biológicos/química , Domínio Catalítico , Ensaios Enzimáticos , Ensaios de Triagem em Larga Escala , Humanos , Inibidores de Metaloproteinases de Matriz/química , Metaloproteinases da Matriz/metabolismo , Simulação de Acoplamento Molecular , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Sensibilidade e Especificidade , Pele/enzimologia , Pele/patologia , Pele/efeitos da radiação , Envelhecimento da Pele/efeitos dos fármacos , Envelhecimento da Pele/efeitos da radiação , Bibliotecas de Moléculas Pequenas/química , Eletricidade Estática , Relação Estrutura-Atividade , Raios Ultravioleta/efeitos adversos , Interface Usuário-Computador
10.
Molecules ; 26(15)2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34361714

RESUMO

α-glucosidase is a major enzyme that is involved in starch digestion and type 2 diabetes mellitus. In this study, the inhibition of hypericin by α-glucosidase and its mechanism were firstly investigated using enzyme kinetics analysis, real-time interaction analysis between hypericin and α-glucosidase by surface plasmon resonance (SPR), and molecular docking simulation. The results showed that hypericin was a high potential reversible and competitive α-glucosidase inhibitor, with a maximum half inhibitory concentration (IC50) of 4.66 ± 0.27 mg/L. The binding affinities of hypericin with α-glucosidase were assessed using an SPR detection system, which indicated that these were strong and fast, with balances dissociation constant (KD) values of 6.56 × 10-5 M and exhibited a slow dissociation reaction. Analysis by molecular docking further revealed that hydrophobic forces are generated by interactions between hypericin and amino acid residues Arg-315 and Tyr-316. In addition, hydrogen bonding occurred between hypericin and α-glucosidase amino acid residues Lys-156, Ser-157, Gly-160, Ser-240, His-280, Asp-242, and Asp-307. The structure and micro-environment of α-glucosidase enzymes were altered, which led to a decrease in α-glucosidase activity. This research identified that hypericin, an anthracene ketone compound, could be a novel α-glucosidase inhibitor and further applied to the development of potential anti-diabetic drugs.


Assuntos
Antracenos/química , Proteínas Fúngicas/antagonistas & inibidores , Inibidores de Glicosídeo Hidrolases/química , Hipoglicemiantes/química , Perileno/análogos & derivados , alfa-Glucosidases/química , Antracenos/metabolismo , Sítios de Ligação , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Inibidores de Glicosídeo Hidrolases/metabolismo , Humanos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Hipoglicemiantes/metabolismo , Cinética , Simulação de Acoplamento Molecular , Nitrofenilgalactosídeos/química , Nitrofenilgalactosídeos/metabolismo , Perileno/química , Perileno/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Saccharomyces cerevisiae/classificação , Saccharomyces cerevisiae/enzimologia , Ressonância de Plasmônio de Superfície , alfa-Glucosidases/metabolismo
11.
J Plant Physiol ; 264: 153487, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34358944

RESUMO

AtCYP38, a thylakoid lumen localized immunophilin, is found to be essential for photosystem II assembly and maintenance, but how AtCYP38 functions in chloroplast remains unknown. Based on previous functional studies and its crystal structure, we hypothesize that AtCYP38 should function via binding its targets or cofactors in the thylakoid lumen. To identify potential interacting proteins of AtCYP38, we first adopted ATTED-II and STRING web-tools, and found 12 proteins functionally related to AtCYP38. We then screened a yeast two-hybrid library including an Arabidopsis genome wide cDNA with different domain of AtCYP38, and five thylakoid lumen-localized targets were identified. In order to specifically search interacting proteins of AtCYP38 in the thylakoid lumen, we generated a yeast two-hybrid mini library including the thylakoid lumenal proteins and lumenal fractions of thylakoid membrane proteins, and we obtained six thylakoid membrane proteins and nine thylakoid lumenal proteins as interacting proteins of AtCYP38. The interactions between AtCYP38 and several potential targets were further confirmed via pull-down and co-immunoprecipitation assays. Together, a couple of new potential candidate interacting proteins of AtCYP38 were identified, and the results will lay a foundation for unveiling the regulatory mechanisms in photosynthesis by AtCYP38.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Cloroplastos/metabolismo , Ciclofilinas/metabolismo , Proteínas de Arabidopsis/fisiologia , Ciclofilinas/fisiologia , Imunoprecipitação , Complexo de Proteína do Fotossistema II/metabolismo , Domínios e Motivos de Interação entre Proteínas , Técnicas do Sistema de Duplo-Híbrido
12.
Int J Mol Sci ; 22(16)2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34445471

RESUMO

The mammalian/mechanistic target of rapamycin complex 1 (mTORC1) is activated by the small G-protein, Ras homolog enriched in brain (RHEB-GTPase). On lysosome, RHEB activates mTORC1 by binding the domains of N-heat, M-heat, and the focal adhesion targeting (FAT) domain, which allosterically regulates ATP binding in the active site for further phosphorylation. The crucial role of RHEB in regulating growth and survival through mTORC1 makes it a targetable site for anti-cancer therapeutics. However, the binding kinetics of RHEB to mTORC1 is still unknown at the molecular level. Therefore, we studied the kinetics by in vitro and in-cell protein-protein interaction (PPI) assays. To this end, we used the split-luciferase system (NanoBiT®) for in-cell studies and prepared proteins for the in vitro measurements. Consequently, we demonstrated that RHEB binds to the whole mTOR both in the presence or absence of GTPγS, with five-fold weaker affinity in the presence of GTPγS. In addition, RHEB bound to the truncated mTOR fragments of N-heat domain (∆N, aa 60-167) or M-heat domain (∆M, aa 967-1023) with the same affinity in the absence of GTP. The reconstructed binding site of RHEB, ∆N-FAT-M, however, bound to RHEB with the same affinity as ∆N-M, indicating that the FAT domain (∆FAT, aa 1240-1360) is dispensable for RHEB binding. Furthermore, RHEB bound to the truncated kinase domain (∆ATP, aa 2148-2300) with higher affinity than to ∆N-FAT-M. In conclusion, RHEB engages two different binding sites of mTOR, ∆N-FAT-M and ∆ATP, with higher affinity for ∆ATP, which likely regulates the kinase activity of mTOR through multiple different biding modes.


Assuntos
Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Domínios e Motivos de Interação entre Proteínas , Proteína Enriquecida em Homólogo de Ras do Encéfalo/metabolismo , Sítios de Ligação , Células HEK293 , Humanos , Técnicas In Vitro , Cinética , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Fosforilação , Proteína Enriquecida em Homólogo de Ras do Encéfalo/genética
13.
Int J Mol Sci ; 22(16)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34445562

RESUMO

Synaptonemal complex protein 3 (SCP3), a member of the Cor1 family, has been implicated in cancer progression, and therapeutic resistance, as well as cancer stem cell (CSC)-like properties. Previously, we demonstrated that SCP3 promotes these aggressive phenotypes via hyperactivation of the AKT signaling pathway; however, the underlying mechanisms responsible for SCP3-induced AKT activation remain to be elucidated. In this study, we demonstrated that the EGF-EGFR axis is the primary route through which SCP3 acts to activate AKT signaling. SCP3 triggers the EGFR-AKT pathway through transcriptional activation of EGF. Notably, neutralization of secreted EGF by its specific monoclonal antibody reversed SCP3-mediated aggressive phenotypes with a concomitant reversal of EGFR-AKT activation. In an effort to elucidate the molecular mechanisms underlying SCP3-induced transcriptional activation of EGF, we identified Jun activation domain-binding protein 1 (JAB1) as a binding partner of SCP3 using a yeast two-hybrid (Y2H) assay system, and we demonstrated that SCP3 induces EGF transcription through physical interaction with JAB1. Thus, our findings establish a firm molecular link among SCP3, EGFR, and AKT by identifying the novel roles of SCP3 in transcriptional regulation. We believe that these findings hold important implications for controlling SCP3high therapeutic-refractory cancer.


Assuntos
Complexo do Signalossomo COP9/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ligação a DNA/metabolismo , Resistencia a Medicamentos Antineoplásicos , Fator de Crescimento Epidérmico/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Células-Tronco Neoplásicas/efeitos dos fármacos , Peptídeo Hidrolases/metabolismo , Neoplasias do Colo do Útero/tratamento farmacológico , Complexo do Signalossomo COP9/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ligação a DNA/genética , Fator de Crescimento Epidérmico/genética , Receptores ErbB/genética , Receptores ErbB/metabolismo , Feminino , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Mutação , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Peptídeo Hidrolases/genética , Fosforilação , Domínios e Motivos de Interação entre Proteínas , Transdução de Sinais , Células Tumorais Cultivadas , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/metabolismo , Neoplasias do Colo do Útero/patologia
14.
Int J Mol Sci ; 22(16)2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34445335

RESUMO

Protein inhibition is a natural regulatory process to control cellular metabolic fluxes. PII-family signal-transducing effectors are in this matter key regulators of the nitrogen metabolism. Their interaction with their various targets is governed by the cellular nitrogen level and the energy charge. Structural studies on GlnK, a PII-family inhibitor of the ammonium transporters (Amt), showed that the T-loops responsible for channel obstruction are displaced upon the binding of 2-oxoglutarate, magnesium and ATP in a conserved cleft. However, GlnK from Methanocaldococcus jannaschii was shown to bind 2-oxoglutarate on the tip of its T-loop, causing a moderate disruption to GlnK-Amt interaction, raising the question if methanogenic archaea use a singular adaptive strategy. Here we show that membrane fractions of Methanothermococcus thermolithotrophicus released GlnKs only in the presence of Mg-ATP and 2-oxoglutarate. This observation led us to structurally characterize the two GlnK isoforms apo or in complex with ligands. Together, our results show that the 2-oxoglutarate binding interface is conserved in GlnKs from Methanococcales, including Methanocaldococcus jannaschii, emphasizing the importance of a free carboxy-terminal group to facilitate ligand binding and to provoke the shift of the T-loop positions.


Assuntos
Compostos de Amônio/metabolismo , Ácidos Cetoglutáricos/metabolismo , Methanococcales/metabolismo , Proteínas PII Reguladoras de Nitrogênio , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Sequência Conservada , Cristalografia por Raios X , Transporte de Íons , Redes e Vias Metabólicas , Modelos Moleculares , Nitrogênio/metabolismo , Proteínas PII Reguladoras de Nitrogênio/química , Proteínas PII Reguladoras de Nitrogênio/metabolismo , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas/fisiologia , Análise de Sequência de Proteína
15.
Molecules ; 26(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34361778

RESUMO

Protein-ligand interaction analysis is important for drug discovery and rational protein design. The existing online tools adopt only a single conformation of the complex structure for calculating and displaying the interactions, whereas both protein residues and ligand molecules are flexible to some extent. The interactions evolved with time in the trajectories are of greater interest. MolADI is a user-friendly online tool which analyzes the protein-ligand interactions in detail for either a single structure or a trajectory. Interactions can be viewed easily with both 2D graphs and 3D representations. MolADI is available as a web application.


Assuntos
Receptor A2A de Adenosina/química , Bibliotecas de Moléculas Pequenas/química , Software , Sítios de Ligação , Humanos , Cinética , Ligantes , Modelos Moleculares , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Proteínas , Receptor A2A de Adenosina/metabolismo , Bibliotecas de Moléculas Pequenas/metabolismo , Especificidade por Substrato , Termodinâmica
16.
Molecules ; 26(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34361791

RESUMO

As a key enzyme regulating postprandial blood glucose, α-Glucosidase is considered to be an effective target for the treatment of diabetes mellitus. In this study, a simple, rapid, and effective method for enzyme inhibitors screening assay was established based on α-glucosidase catalyzes reactions in a personal glucose meter (PGM). α-glucosidase catalyzes the hydrolysis of maltose to produce glucose, which triggers the reduction of ferricyanide (K3[Fe(CN)6]) to ferrocyanide (K4[Fe(CN)6]) and generates the PGM detectable signals. When the α-glucosidase inhibitor (such as acarbose) is added, the yield of glucose and the readout of PGM decreased accordingly. This method can achieve the direct determination of α-glucosidase activity by the PGM as simple as the blood glucose tests. Under the optimal experimental conditions, the developed method was applied to evaluate the inhibitory activity of thirty-four small-molecule compounds and eighteen medicinal plants extracts on α-glucosidase. The results exhibit that lithospermic acid (52.5 ± 3.0%) and protocatechualdehyde (36.8 ± 2.8%) have higher inhibitory activity than that of positive control acarbose (31.5 ± 2.5%) at the same final concentration of 5.0 mM. Besides, the lemon extract has a good inhibitory effect on α-glucosidase with a percentage of inhibition of 43.3 ± 3.5%. Finally, the binding sites and modes of four active small-molecule compounds to α-glucosidase were investigated by molecular docking analysis. These results indicate that the PGM method is feasible to screening inhibitors from natural products with simple and rapid operations.


Assuntos
Benzaldeídos/farmacologia , Benzofuranos/farmacologia , Glicemia/análise , Catecóis/farmacologia , Depsídeos/farmacologia , Diabetes Mellitus Tipo 2/diagnóstico , Inibidores de Glicosídeo Hidrolases/farmacologia , Monitorização Ambulatorial/métodos , alfa-Glucosidases/sangue , Acarbose/química , Acarbose/farmacologia , Benzaldeídos/química , Benzaldeídos/isolamento & purificação , Benzofuranos/química , Benzofuranos/isolamento & purificação , Sítios de Ligação , Técnicas Biossensoriais/instrumentação , Catecóis/química , Catecóis/isolamento & purificação , Depsídeos/química , Depsídeos/isolamento & purificação , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/tratamento farmacológico , Inibidores de Glicosídeo Hidrolases/química , Humanos , Hidrólise , Cinética , Maltose/metabolismo , Simulação de Acoplamento Molecular , Monitorização Ambulatorial/instrumentação , Extratos Vegetais/química , Plantas Medicinais , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Termodinâmica , Dispositivos Eletrônicos Vestíveis , alfa-Glucosidases/química
17.
Science ; 373(6558): 998-1004, 2021 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-34446601

RESUMO

In eukaryotic cells, half of all proteins function as subunits within multiprotein complexes. Imbalanced synthesis of subunits leads to unassembled intermediates that must be degraded to minimize cellular toxicity. Here, we found that excess PSMC5, a subunit of the proteasome base, was targeted for degradation by the HERC1 ubiquitin ligase in mammalian cells. HERC1 identified unassembled PSMC5 by its cognate assembly chaperone PAAF1. Because PAAF1 only dissociates after assembly, HERC1 could also engage later assembly intermediates such as the PSMC4-PSMC5-PAAF1 complex. A missense mutant of HERC1 that causes neurodegeneration in mice was impaired in the recognition and ubiquitination of the PSMC5-PAAF1 complex. Thus, proteasome assembly factors can serve as adaptors for ubiquitin ligases to facilitate elimination of unassembled intermediates and maintain protein homeostasis.


Assuntos
ATPases Associadas a Diversas Atividades Celulares/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , Calmodulina/metabolismo , Humanos , Células MCF-7 , Camundongos , Mutação , Mutação de Sentido Incorreto , Doenças Neurodegenerativas/genética , Mutação Puntual , Domínios e Motivos de Interação entre Proteínas , Subunidades Proteicas/metabolismo , Proteólise , Proteínas Proto-Oncogênicas/metabolismo , Ubiquitina-Proteína Ligases/química , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
18.
Int J Mol Sci ; 22(15)2021 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-34361094

RESUMO

Protein-protein interactions between G protein-coupled receptors (GPCRs) can augment their functionality and increase the repertoire of signaling pathways they regulate. New therapeutics designed to modulate such interactions may allow for targeting of a specific GPCR activity, thus reducing potential for side effects. Dopamine receptor (DR) heteromers are promising candidates for targeted therapy of neurological conditions such as Parkinson's disease since current treatments can have severe side effects. To facilitate development of such therapies, it is necessary to identify the various DR binding partners. We report here a new interaction partner for DRD2 and DRD3, the orphan receptor G protein-coupled receptor 143 (GPR143), an atypical GPCR that plays multiple roles in pigment cells and is expressed in several regions of the brain. We previously demonstrated that the DRD2/ DRD3 antagonist pimozide also modulates GPR143 activity. Using confocal microscopy and two FRET methods, we observed that the DRs and GPR143 colocalize and interact at intracellular membranes. Furthermore, co-expression of wildtype GPR143 resulted in a 57% and 67% decrease in DRD2 and DRD3 activity, respectively, as determined by ß-Arrestin recruitment assay. GPR143-DR dimerization may negatively modulate DR activity by changing affinity for dopamine or delaying delivery of the DRs to the plasma membrane.


Assuntos
Dopamina/metabolismo , Proteínas do Olho/metabolismo , Glicoproteínas de Membrana/metabolismo , Domínios e Motivos de Interação entre Proteínas , Receptores de Dopamina D2/metabolismo , Receptores de Dopamina D3/metabolismo , beta-Arrestinas/metabolismo , Proteínas do Olho/genética , Humanos , Glicoproteínas de Membrana/genética , Mutação , Ligação Proteica , Receptores de Dopamina D2/genética , Receptores de Dopamina D3/genética , Transdução de Sinais
19.
Nat Commun ; 12(1): 4696, 2021 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-34349113

RESUMO

Productive ribosomal RNA (rRNA) compaction during ribosome assembly necessitates establishing correct tertiary contacts between distant secondary structure elements. Here, we quantify the response of the yeast proteome to low temperature (LT), a condition where aberrant mis-paired RNA folding intermediates accumulate. We show that, at LT, yeast cells globally boost production of their ribosome assembly machinery. We find that the LT-induced assembly factor, Puf6, binds to the nascent catalytic RNA-rich subunit interface within the 60S pre-ribosome, at a site that eventually loads the nuclear export apparatus. Ensemble Förster resonance energy transfer studies show that Puf6 mimics the role of Mg2+ to usher a unique long-range tertiary contact to compact rRNA. At LT, puf6 mutants accumulate 60S pre-ribosomes in the nucleus, thus unveiling Puf6-mediated rRNA compaction as a critical temperature-regulated rescue mechanism that counters rRNA misfolding to prime export competence.


Assuntos
Núcleo Celular/metabolismo , Proteínas de Ligação a RNA/metabolismo , Subunidades Ribossômicas Maiores de Eucariotos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Transporte Ativo do Núcleo Celular , Temperatura Baixa , GTP Fosfo-Hidrolases/metabolismo , Mutação , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Proteoma/metabolismo , Dobramento de RNA , Precursores de RNA/química , Precursores de RNA/metabolismo , RNA Ribossômico/química , RNA Ribossômico/metabolismo , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/genética , Subunidades Ribossômicas Maiores de Eucariotos/química , Ribossomos/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiologia , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética
20.
Int J Lab Hematol ; 43 Suppl 1: 86-95, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34288448

RESUMO

CEBPA-mutant acute myeloid leukemia (AML) encompasses clinically and biologically distinct subtypes of AML in both adults and children. CEBPA-mutant AML may occur with monoallelic (moCEBPA) or biallelic (biCEBPA) mutations, which can be somatic or germline, with each entity impacting prognosis in unique ways. BiCEBPA AML is broadly associated with a favorable prognosis, but differences in the type and location of CEBPA mutations as well as the presence of additional leukemogenic mutations can lead to heterogeneity in survival. Concurrent FLT3-ITD mutations have a well-documented negative effect on survival in adult biCEBPA AML, whereas support for a negative prognostic effect of mutations in TET2, DNMT3A, WT1, CSF3R, ASXL1, and KIT is mixed. NPM1 and GATA2 mutations may have a positive prognostic impact. MoCEBPA AML has similar survival outcomes compared to AML with wild-type CEBPA, and risk stratification is determined by other cytogenetic and molecular findings. Germline CEBPA mutations may lead to familial biCEBPA AML after acquisition of second somatic CEBPA mutation, with variable penetrance and age. BiCEBPA AML in children is likely a favorable-risk diagnosis as it is in adults, but the role of a single CEBPA mutation and the impact of concurrent leukemogenic mutations are not clear in this population. Laboratory evaluation of the CEBPA gene includes PCR-based fragment-length analysis, Sanger sequencing, and next-generation sequencing. Phenotypic analysis using multiparameter flow cytometry can also provide additional data in evaluating CEBPA, helping to assess for the likelihood of mutation presence.


Assuntos
Biomarcadores Tumorais , Proteínas Estimuladoras de Ligação a CCAAT/genética , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/genética , Mutação , Adulto , Fatores Etários , Alelos , Biomarcadores , Proteínas Estimuladoras de Ligação a CCAAT/química , Criança , Mutação em Linhagem Germinativa , Humanos , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...