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1.
Cereb Cortex ; 34(6)2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38879757

RESUMO

The reactions to novelty manifesting in mismatch negativity in the rat brain were studied. During dissociative anesthesia, mismatch negativity-like waves were recorded from the somatosensory cortex using an epidural 32-electrode array. Experimental animals: 7 wild-type Wistar rats and 3 transgenic rats. During high-dose anesthesia, deviant 1,500 Hz tones were presented randomly among many standard 1,000 Hz tones in the oddball paradigm. "Deviant minus standard_before_deviant" difference waves were calculated using both the classical method of Naatanen and method of cross-correlation of sub-averages. Both methods gave consistent results: an early phasic component of the N40 and later N100 to 200 (mismatch negativity itself) tonic component. The gamma and delta rhythms power and the frequency of down-states (suppressed activity periods) were assessed. In all rats, the amplitude of tonic component grew with increasing sedation depth. At the same time, a decrease in gamma power with a simultaneous increase in delta power and the frequency of down-states. The earlier phasic frontocentral component is associated with deviance detection, while the later tonic one over the auditory cortex reflects the orienting reaction. Under anesthesia, this slow mismatch negativity-like wave most likely reflects the tendency of the system to respond to any influences with delta waves, K-complexes and down-states, or produce them spontaneously.


Assuntos
Ratos Wistar , Animais , Masculino , Estimulação Acústica/métodos , Eletroencefalografia/métodos , Ratos , Ratos Transgênicos , Anestésicos Dissociativos/administração & dosagem , Anestésicos Dissociativos/farmacologia , Potenciais Evocados Auditivos/fisiologia , Córtex Somatossensorial/fisiologia , Ritmo Gama/fisiologia , Ritmo Delta/fisiologia , Ritmo Delta/efeitos dos fármacos
2.
Cancer Discov ; 14(3): 468-491, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38189443

RESUMO

Activating innate immunity in cancer cells through cytoplasmic nucleic acid sensing pathways, a phenomenon known as "viral mimicry," has emerged as an effective strategy to convert immunologically "cold" tumors into "hot." Through a curated CRISPR-based screen of RNA helicases, we identified DExD/H-box helicase 9 (DHX9) as a potent repressor of double-stranded RNA (dsRNA) in small cell lung cancers (SCLC). Depletion of DHX9 induced accumulation of cytoplasmic dsRNA and triggered tumor-intrinsic innate immunity. Intriguingly, ablating DHX9 also induced aberrant accumulation of R-loops, which resulted in an increase of DNA damage-derived cytoplasmic DNA and replication stress in SCLCs. In vivo, DHX9 deletion promoted a decrease in tumor growth while inducing a more immunogenic tumor microenvironment, invigorating responsiveness to immune-checkpoint blockade. These findings suggest that DHX9 is a crucial repressor of tumor-intrinsic innate immunity and replication stress, representing a promising target for SCLC and other "cold" tumors in which genomic instability contributes to pathology. SIGNIFICANCE: One promising strategy to trigger an immune response within tumors and enhance immunotherapy efficacy is by inducing endogenous "virus-mimetic" nucleic acid accumulation. Here, we identify DHX9 as a viral-mimicry-inducing factor involved in the suppression of double-stranded RNAs and R-loops and propose DHX9 as a novel target to enhance antitumor immunity. See related commentary by Chiappinelli, p. 389. This article is featured in Selected Articles from This Issue, p. 384.


Assuntos
Neoplasias Pulmonares , Ácidos Nucleicos , Carcinoma de Pequenas Células do Pulmão , Humanos , Carcinoma de Pequenas Células do Pulmão/genética , Interferons , Neoplasias Pulmonares/genética , Imunidade Inata , RNA de Cadeia Dupla , Microambiente Tumoral , Proteínas de Neoplasias , RNA Helicases DEAD-box/genética
3.
Neurosci Lett ; 788: 136839, 2022 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-35964824

RESUMO

Dopamine in the brain is involved in many important functions, including the regulation of wakefulness. There is also some evidence suggesting that the dopamine function is crucial in anesthetic function. The state of anesthesia is characterized by a change in the level of consciousness and a change in brain electrical activity. Due to impaired mechanisms of dopamine transportation back to the synaptic terminal, dopamine transporter (DAT) knockout and heterozygous rats have increased levels of the extracellular dopamine. In our work, we registered ECoG disturbances in knockout and heterozygous rats, as well as disturbances in tone and activity in acute experiments under the anesthesia Zoletil (tiletamine and zolazepam) from the somatosensory cortex using a NeuroNexus flat multielectrode array to study gamma activity. We also used four low-resistance electrodes to control the slow rhythm. Both low-resistance and high-resistance electrodes showed differences in the ECoG spectrum of heterozygotes and total knockouts from the wild type and from each other. Heterozygous rats for the DAT gene (HET) showed increased rapid beta and gamma activity and decreased slow delta activity, while complete knockouts (KO), on the contrary, showed increased delta activity and decreased beta and gamma activity. Thus, the ECoG spectrum of HET is shifted to the right, while that of KO is shifted to the left. Full knockouts also showed decreased spatial synchronization in the 30-100 Hz gamma range compared to the wild type (WT). It is assumed that sedation of HET and KO is shifted towards opposite directions compared to WT under the same anesthesia conditions.


Assuntos
Anestesia , Proteínas da Membrana Plasmática de Transporte de Dopamina , Animais , Dopamina , Proteínas da Membrana Plasmática de Transporte de Dopamina/genética , Eletrocorticografia , Heterozigoto , Camundongos , Camundongos Knockout , Ratos
4.
Mol Cancer Res ; 19(10): 1651-1665, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34158391

RESUMO

Nestin, a class IV intermediate filament protein, is generally considered as a putative marker of neural stem and progenitor cells in the central nervous system. Glioma is a common type of adult brain tumors, and glioblastoma (GBM) represents the most aggressive form of glioma. Here, we report that Nestin expression is significantly upregulated in human GBM, compared with other types of glioma. Nestin knockdown or deletion in U251 cells and tumor cells from GBM patients derived xenografts resulted in G2-M arrest, finally leading to apoptosis in tumor cells. Using proximity-dependent biotin identification method, we identified ßII-tubulin as an interacting protein of Nestin in U251 cells. Nestin stabilized ßII-tubulin in U251 cells through physical interaction. Knockdown of Nestin or ßII-tubulin disrupted spindle morphology in tumor cells. Our studies further revealed that Nestin deficiency in U251 cells and GBM PDX cells repressed tumor growth upon transplantation. Finally, we found that Nestin deficiency sensitized GBM cells to microtubule-destabilizing drugs such as vinblastine and vincristine. Our studies demonstrate the essential functions and underlying mechanisms of Nestin in the growth and drug response of GBM cells. IMPLICATIONS: Through interaction with ßII-tubulin, Nestin facilitates cell-cycle progression and spindle assembly of tumor cells in glioblastoma.


Assuntos
Neoplasias Encefálicas/metabolismo , Ciclo Celular/fisiologia , Glioblastoma/metabolismo , Nestina/metabolismo , Fuso Acromático/metabolismo , Animais , Apoptose/fisiologia , Linhagem Celular , Linhagem Celular Tumoral , Glioma/metabolismo , Células HEK293 , Humanos , Camundongos Nus , Camundongos SCID , Tubulina (Proteína)/metabolismo
5.
J Bacteriol ; 201(18)2019 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-31182496

RESUMO

Enterobacteriaceae produce amyloid proteins called curli that are the major proteinaceous component of biofilms. Amyloids are also produced by humans and are associated with diseases such as Alzheimer's. During the multistep process of amyloid formation, monomeric subunits form oligomers, protofibrils, and finally mature fibrils. Amyloid ß oligomers are more cytotoxic to cells than the mature amyloid fibrils. Oligomeric intermediates of curli had not been previously detected. We determined that turbulence inhibited biofilm formation and that, intriguingly, curli aggregates purified from cultures grown under high-turbulence conditions were structurally smaller and contained less DNA than curli preparations from cultures grown with less turbulence. Using flow cytometry analysis, we demonstrated that CsgA was expressed in cultures exposed to higher turbulence but that these cultures had lower levels of cell death than less-turbulent cultures. Our data suggest that the DNA released during cell death drives the formation of larger fibrillar structures. Consistent with this idea, addition of exogenous genomic DNA increased the size of the curli intermediates and led to binding to thioflavin T at levels observed with mature aggregates. Similar to the intermediate oligomers of amyloid ß, intermediate curli aggregates were more cytotoxic than the mature curli fibrils when incubated with bone marrow-derived macrophages. The discovery of cytotoxic curli intermediates will enable research into the roles of amyloid intermediates in the pathogenesis of Salmonella and other bacteria that cause enteric infections.IMPORTANCE Amyloid proteins are the major proteinaceous components of biofilms, which are associated with up to 65% of human bacterial infections. Amyloids produced by human cells are also associated with diseases such as Alzheimer's. The amyloid monomeric subunits self-associate to form oligomers, protofibrils, and finally mature fibrils. Amyloid ß oligomers are more cytotoxic to cells than the mature amyloid fibrils. Here we detected oligomeric intermediates of curli for the first time. Like the oligomers of amyloid ß, intermediate curli fibrils were more cytotoxic than the mature curli fibrillar aggregates when incubated with bone marrow-derived macrophages. The discovery of cytotoxic curli intermediates will enable research into the roles of amyloid intermediates in the pathogenesis of Salmonella and other bacteria that cause enteric infections.


Assuntos
Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica/fisiologia , Salmonella typhimurium/metabolismo , Proteínas de Bactérias/genética , Salmonella typhimurium/genética , Salmonella typhimurium/fisiologia
6.
Cell Cycle ; 17(23): 2622-2636, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30513041

RESUMO

We characterized a panel of cancer cells and found that they exhibited chromosome instability (CIN) that was associated with high frequencies of aberrant kinetochore:microtubule attachments. Failure to resolve these defective attachments before anaphase onset can lead to missegregation of chromosomes. Aurora B kinase is concentrated at the inner centromere where it contributes to multiple kinetochore functions, one of which is in error-correction. Analysis of several CIN cell lines showed that many aspects of Aurora B kinase functions were normal. Furthermore, the amount and activity of Aurora B kinase was not reduced at the kinetochores of CIN cells that were examined. However, phosphorylation of a centromeric biosensor for Aurora B in OVCAR10, MCF7 and U2OS cells was consistently reduced relative to non CIN cells. This suggested a localized problem with Aurora B's ability to phosphorylate substrates important for error correction. This possibility was supported by our ability to improve error correction and reduce the frequency of lagging chromosome in CIN cells by directing endogenous Aurora B to the region of centromere that was tested by the biosensor. Our studies suggest that the kinetochores of CIN cells have a defect that limits accessibility of Aurora B to substrates that are important for error-correction.


Assuntos
Aurora Quinase B/metabolismo , Instabilidade Cromossômica , Cinetocoros/metabolismo , Aneuploidia , Aurora Quinase B/antagonistas & inibidores , Aurora Quinase B/genética , Benzamidas/farmacologia , Linhagem Celular Tumoral , Segregação de Cromossomos , Humanos , Microtúbulos/metabolismo , Mitose , Fosforilação/efeitos dos fármacos , Quinazolinas/farmacologia , Interferência de RNA , RNA Interferente Pequeno/metabolismo
7.
EBioMedicine ; 22: 28-43, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28687497

RESUMO

Genome-Wide Association Studies (GWAS) and subsequent fine-mapping studies (>50) have implicated single nucleotide polymorphisms (SNPs) located at the CCDC170/C6ORF97-ESR1 locus (6q25.1) as being associated with the risk of breast cancer. Surprisingly, our analysis using genome-wide differential allele-specific expression (DASE), an indicator for breast cancer susceptibility, suggested that the genetic alterations of CCDC170, but not ESR1, account for GWAS-associated breast cancer risk at this locus. Breast cancer-associated CCDC170 nonsense mutations and rearrangements have also been detected, with the latter being specifically implicated in driving breast cancer. Here we report that the wild type CCDC170 protein localizes to the region of the Golgi apparatus and binds Golgi-associated microtubules (MTs), and that breast cancer-linked truncations of CCDC170 result in loss of Golgi localization. Overexpression of wild type CCDC170 triggers Golgi reorganization, and enhances Golgi-associated MT stabilization and acetyltransferase ATAT1-dependent α-tubulin acetylation. Golgi-derived MTs regulate cellular polarity and motility, and we provide evidence that dysregulation of CCDC170 affects polarized cell migration. Taken together, our findings demonstrate that CCDC170 plays an essential role in Golgi-associated MT organization and stabilization, and implicate a mechanism for how perturbations in the CCDC170 gene may contribute to the hallmark changes in cell polarity and motility seen in breast cancer.


Assuntos
Neoplasias da Mama/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Complexo de Golgi/metabolismo , Microtúbulos/metabolismo , Acetilação , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Polaridade Celular , Feminino , Predisposição Genética para Doença , Humanos , Células MCF-7 , Polimorfismo de Nucleotídeo Único , Ligação Proteica
8.
Proc Natl Acad Sci U S A ; 112(49): 15196-201, 2015 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-26598693

RESUMO

The hepatitis B virus (HBV) core protein is essential for HBV replication and an important target for antiviral drug discovery. We report the first, to our knowledge, high-resolution crystal structure of an antiviral compound bound to the HBV core protein. The compound NVR-010-001-E2 can induce assembly of the HBV core wild-type and Y132A mutant proteins and thermostabilize the proteins with a Tm increase of more than 10 °C. NVR-010-001-E2 binds at the dimer-dimer interface of the core proteins, forms a new interaction surface promoting protein-protein interaction, induces protein assembly, and increases stability. The impact of naturally occurring core protein mutations on antiviral activity correlates with NVR-010-001-E2 binding interactions determined by crystallography. The crystal structure provides understanding of a drug efficacy mechanism related to the induction and stabilization of protein-protein interactions and enables structure-guided design to improve antiviral potency and drug-like properties.


Assuntos
Antivirais/química , Vírus da Hepatite B/fisiologia , Proteínas do Core Viral/metabolismo , Replicação Viral/efeitos dos fármacos , Antivirais/metabolismo , Antivirais/farmacologia , Cristalografia por Raios X , Conformação Proteica
9.
Proc Natl Acad Sci U S A ; 111(35): 12859-64, 2014 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-25139996

RESUMO

Mutations inactivating the cilia-localized Pkd1 protein result in autosomal dominant polycystic kidney disease (ADPKD), a serious inherited syndrome affecting ∼ 1 in 500 people, in which accumulation of renal cysts eventually destroys kidney function. Severity of ADPKD varies throughout the population, for reasons thought to involve differences both in intragenic Pkd1 mutations and in modifier alleles. The scaffolding protein NEDD9, commonly dysregulated during cancer progression, interacts with Aurora-A (AURKA) kinase to control ciliary resorption, and with Src and other partners to influence proliferative signaling pathways often activated in ADPKD. We here demonstrate Nedd9 expression is deregulated in human ADPKD and a mouse ADPKD model. Although genetic ablation of Nedd9 does not independently influence cystogenesis, constitutive absence of Nedd9 strongly promotes cyst formation in the tamoxifen-inducible Pkd1fl/fl;Cre/Esr1(+) mouse model of ADPKD. This cystogenic effect is associated with striking morphological defects in the cilia of Pkd1(-/-);Nedd9(-/-) mice, associated with specific loss of ciliary localization of adenylase cyclase III in the doubly mutant genotype. Ciliary phenotypes imply a failure of Aurora-A activation: Compatible with this idea, Pkd1(-/-);Nedd9(-/-) mice had ciliary resorption defects, and treatment of Pkd1(-/-) mice with a clinical Aurora-A kinase inhibitor exacerbated cystogenesis. In addition, activation of the ADPKD-associated signaling effectors Src, Erk, and the mTOR effector S6 was enhanced, and Ca(2+) response to external stimuli was reduced, in Pkd1(-/-);Nedd9(-/-) versus Pkd1(-/-) mice. Together, these results indicated an important modifier action of Nedd9 on ADPKD pathogenesis involving failure to activate Aurora-A.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Sinalização do Cálcio/fisiologia , Rim/patologia , Rim Policístico Autossômico Dominante/genética , Rim Policístico Autossômico Dominante/patologia , Canais de Cátion TRPP/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Aurora Quinase A/antagonistas & inibidores , Aurora Quinase A/metabolismo , Cílios/fisiologia , Modelos Animais de Doenças , Células Epiteliais/citologia , Feminino , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Cultura Primária de Células , Triazóis/farmacologia
10.
PLoS One ; 6(5): e19880, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21611205

RESUMO

p120 loss destabilizes E-cadherin and could therefore result in tumor and/or metastasis-promoting activities similar to those caused by E-cadherin downregulation. Previously, we reported that p120 is essential in the intestine for barrier function, epithelial homeostasis and survival. Conditional p120 ablation in the mouse intestine induced severe inflammatory bowel disease, but long-term cancer-related studies were impossible because none of the animals survived longer than 21 days. Here, we used a tamoxifen-inducible mouse model (Vil-Cre-ER(T2);p120(fl/fl)) to limit the extent of p120 ablation and thereby enable long-term studies. Reducing p120 KO to ∼10% of the intestinal epithelium produced long-lived animals outwardly indistinguishable from controls. Effects of prolonged p120 absence were then evaluated at intervals spanning 2 to 18 months. At all time points, immunostaining revealed microdomains of p120-null epithelium interspersed with normal epithelium. Thus, stochastic p120 ablation is compatible with crypt progenitor cell function and permitted lifelong renewal of the p120-null cells. Consistent with previous observations, a barrier defect and frequent infiltration of neutrophils was observed, suggesting that focal p120 loss generates a microenvironment disposed to chronic inflammation. We report that 45% of these animals developed tumors within 18 months of tamoxifen induction. Interestingly, ß-catenin was upregulated in the majority, but none of the tumors were p120 null. Although further work is required to directly establish mechanism, we conclude that limited p120 ablation can promote tumorigenesis by an indirect non-cell autonomous mechanism. Given that byproducts of inflammation are known to be highly mutagenic, we suggest that tumorigenesis in this model is ultimately driven by the lifelong inability to heal chronic wounds and the substantially increased rates of stochastic gene mutation in tissue microenvironments subjected to chronic inflammation. Indeed, although technical issues precluded direct identification of mutations, ß-catenin upregulation in human colon cancer almost invariably reflects mutations in APC and/or ß-catenin.


Assuntos
Adenoma/metabolismo , Adenoma/patologia , Cateninas/deficiência , Cateninas/metabolismo , Técnicas de Inativação de Genes , Neoplasias Intestinais/metabolismo , Neoplasias Intestinais/patologia , Adenoma/imunologia , Animais , Proliferação de Células , Fatores Quimiotáticos/metabolismo , Cistos/metabolismo , Cistos/patologia , Citocinas/metabolismo , Células HEK293 , Humanos , Neoplasias Intestinais/imunologia , Intestino Grosso/imunologia , Intestino Grosso/metabolismo , Intestino Grosso/patologia , Intestino Delgado/imunologia , Intestino Delgado/metabolismo , Intestino Delgado/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infiltração de Neutrófilos , Lesões Pré-Cancerosas/metabolismo , Lesões Pré-Cancerosas/patologia , Regulação para Cima , delta Catenina
11.
J Clin Invest ; 120(6): 1824-35, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20484816

RESUMO

Epithelial-cadherin (E-cadherin) is a master organizer of the epithelial phenotype. Its function is regulated in part by p120-catenin (referred to herein as p120), a cytoplasmic binding partner that directly regulates cadherin stability. As it has been suggested that cadherins have a role in inflammatory bowel disease (IBD), we sought to investigate this further by assessing the effect of p120 deficiency in mouse small intestine and colon. p120 conditional KO mice were superficially normal at birth but declined rapidly and died within 21 days. Cell-cell adhesion defects and inflammation led to progressive mucosal erosion and terminal bleeding, similar to what is observed in a dominant-negative cadherin mouse model of IBD. Additionally, selective loss of adherens junctions and accumulation of atypical COX-2-expressing neutrophils in p120-null areas of the colon were observed. To elucidate the mechanism, direct effects of p120 deficiency were assessed in vitro in a polarizing colon cancer cell line. Notably, transepithelial electrical resistance was dramatically reduced, neutrophil binding was increased 30 fold, and levels of COX-2, an enzyme associated with IBD, were markedly increased in neutrophils. Our data suggest that p120 loss disrupts the neonatal intestinal barrier and amplifies neutrophil engagement and that these changes lead to catastrophic inflammation during colonization of the neonatal gut with bacteria and other luminal antigens. Thus, we conclude that p120 has an essential role in barrier function and epithelial homeostasis and survival in the intestine.


Assuntos
Junções Aderentes/metabolismo , Cateninas/fisiologia , Homeostase , Proteínas/metabolismo , Animais , Cateninas/genética , Cateninas/metabolismo , Adesão Celular/fisiologia , Citoplasma/metabolismo , Mucosa Intestinal/metabolismo , Camundongos , Camundongos Knockout , delta Catenina
12.
Nat Cell Biol ; 11(9): 1069-80, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19701196

RESUMO

Microtubules are indispensable for Golgi complex assembly and maintenance, which are integral parts of cytoplasm organization during interphase in mammalian cells. Here, we show that two discrete microtubule subsets drive two distinct, yet simultaneous, stages of Golgi assembly. In addition to the radial centrosomal microtubule array, which positions the Golgi in the centre of the cell, we have identified a role for microtubules that form at the Golgi membranes in a manner dependent on the microtubule regulators CLASPs. These Golgi-derived microtubules draw Golgi ministacks together in tangential fashion and are crucial for establishing continuity and proper morphology of the Golgi complex. We propose that specialized functions of these two microtubule arrays arise from their specific geometries. Further, we demonstrate that directional post-Golgi trafficking and cell migration depend on Golgi-associated CLASPs, suggesting that correct organization of the Golgi complex by microtubules is essential for cell polarization and motility.


Assuntos
Movimento Celular , Polaridade Celular , Complexo de Golgi/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Transporte Biológico , Linhagem Celular , Centrossomo/metabolismo , Dineínas/metabolismo , Humanos , Mitose
13.
Exp Cell Res ; 315(3): 542-55, 2009 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-19073175

RESUMO

Recent investigations have highlighted the importance of subcellular localization of mRNAs to cell function. While AKAP350A, a multifunctional scaffolding protein, localizes to the Golgi apparatus and centrosomes, we have now identified a cytosolic pool of AKAP350A. Analysis of AKAP350A scaffolded complexes revealed two novel interacting proteins, CCAR1 and caprin-1. CCAR1, caprin-1 and AKAP350A along with G3BP, a stress granule marker, relocate to RNA stress granules after arsenite treatment. Stress also caused loss of AKAP350 from the Golgi and fragmentation of the Golgi apparatus. Disruption of microtubules with nocodazole altered stress granule formation and changed their morphology by preventing fusion of stress granules. In the presence of nocodazole, arsenite induced smaller granules with the vast majority of AKAP350A and CCAR1 separated from G3BP-containing granules. Similar to nocodazole treatment, reduction of AKAP350A or CCAR1 expression also altered the size and number of G3BP-containing stress granules induced by arsenite treatment. A limited set of 69 mRNA transcripts was immunoisolated with AKAP350A even in the absence of stress, suggesting the association of AKAP350A with mRNA transcripts. These results provide the first evidence for the microtubule dependent association of AKAP350A and CCAR1 with RNA stress granules.


Assuntos
Proteínas de Ancoragem à Quinase A/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Ciclo Celular/metabolismo , Grânulos Citoplasmáticos/metabolismo , Proteínas do Citoesqueleto/metabolismo , Microtúbulos/metabolismo , RNA Mensageiro/metabolismo , Arsenitos/farmacologia , Proteínas de Transporte , Citosol/metabolismo , DNA Helicases , Complexo de Golgi/metabolismo , Células HeLa , Humanos , Nocodazol/farmacologia , Proteínas de Ligação a Poli-ADP-Ribose , Transporte Proteico , RNA Helicases , Proteínas com Motivo de Reconhecimento de RNA , Estabilidade de RNA
14.
J Cell Sci ; 121(Pt 2): 196-204, 2008 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-18187451

RESUMO

An organized microtubule array is essential for the polarized motility of fibroblasts. Dynamic microtubules closely interact with focal adhesion sites in migrating cells. Here, we examined the effect of focal adhesions on microtubule dynamics. We observed that the probability of microtubule catastrophes (transitions from growth to shrinkage) was seven times higher at focal adhesions than elsewhere. Analysis of the dependence between the microtubule growth rate and catastrophe probability throughout the cytoplasm revealed that a nonspecific (mechanical or spatial) factor provided a minor contribution to the catastrophe induction by decreasing microtubule growth rate at adhesions. Strikingly, at the same growth rate, the probability of catastrophes was significantly higher at adhesions than elsewhere, indicative of a site-specific biochemical trigger. The observed catastrophe induction occurred at adhesion domains containing the scaffolding protein paxillin that has been shown previously to interact with tubulin. Furthermore, replacement of full-length paxillin at adhesion sites by microinjected paxillin LIM2-LIM3 domains suppressed microtubule catastrophes exclusively at adhesions. We suggest that paxillin influences microtubule dynamics at focal adhesions by serving as a scaffold for a putative catastrophe factor and/or regulating its exposure to microtubules.


Assuntos
Regulação da Expressão Gênica , Microtúbulos/metabolismo , Paxilina/metabolismo , Animais , Adesão Celular , Movimento Celular , Citoplasma/metabolismo , Proteínas do Citoesqueleto/metabolismo , Fibroblastos/metabolismo , Glutationa Transferase/metabolismo , Carpa Dourada , Microscopia de Fluorescência , Microscopia de Vídeo , Modelos Biológicos , Paxilina/química , Estrutura Terciária de Proteína
15.
Dev Cell ; 12(6): 917-30, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17543864

RESUMO

Proper organization of microtubule arrays is essential for intracellular trafficking and cell motility. It is generally assumed that most if not all microtubules in vertebrate somatic cells are formed by the centrosome. Here we demonstrate that a large number of microtubules in untreated human cells originate from the Golgi apparatus in a centrosome-independent manner. Both centrosomal and Golgi-emanating microtubules need gamma-tubulin for nucleation. Additionally, formation of microtubules at the Golgi requires CLASPs, microtubule-binding proteins that selectively coat noncentrosomal microtubule seeds. We show that CLASPs are recruited to the trans-Golgi network (TGN) at the Golgi periphery by the TGN protein GCC185. In sharp contrast to radial centrosomal arrays, microtubules nucleated at the peripheral Golgi compartment are preferentially oriented toward the leading edge in motile cells. We propose that Golgi-emanating microtubules contribute to the asymmetric microtubule networks in polarized cells and support diverse processes including post-Golgi transport to the cell front.


Assuntos
Centrossomo/metabolismo , Complexo de Golgi/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Rede trans-Golgi/metabolismo , Células Cultivadas , Proteínas da Matriz do Complexo de Golgi , Células HeLa , Humanos , Proteínas de Membrana/metabolismo , Centro Organizador dos Microtúbulos , Epitélio Pigmentado Ocular/metabolismo , Fuso Acromático , Tubulina (Proteína)/metabolismo
16.
J Mol Biol ; 352(1): 117-24, 2005 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-16081102

RESUMO

The three-dimensional structure of the Pseudomonas aeruginosa bacteriophage phiKZ head has been determined by cryo-electron microscopy and image reconstruction to 18A resolution. The head has icosahedral symmetry measuring 1455 A in diameter along 5-fold axes and a unique portal vertex to which is attached an approximately 1800 A-long contractile tail. The 65 kDa major capsid protein, gp120, is organized into a surface lattice of hexamers, with T = 27 triangulation. The shape and size of the hexamers is similar to the hexameric building blocks of the bacteriophages T4, phi29, P22, and HK97. Pentameric vertices of the capsid are occupied by complexes composed of several special vertex proteins. The double-stranded genomic DNA is packaged into a highly condensed series of layers, separated by 24 A, that follow the contour of the inner wall of the capsid.


Assuntos
Fagos de Pseudomonas/ultraestrutura , Proteínas do Capsídeo/química , Proteínas do Capsídeo/ultraestrutura , Microscopia Crioeletrônica , DNA Viral/ultraestrutura , Modelos Moleculares , Peso Molecular , Fagos de Pseudomonas/genética , Pseudomonas aeruginosa/virologia
17.
Med. oral patol. oral cir. bucal (Internet) ; 9(3): 212-215, mayo-jul. 2004.
Artigo em Espanhol | IBECS | ID: ibc-143074

RESUMO

-Objetivo: estudiar la frecuencia y el espectro de las manifestaciones orales de consumidores de drogas infectados por VIH en la región de Perm. -Sujetos: 104 consumidores de droga seropositivos (69 hombres, 35 mujeres; edades desde 15 a 32; 13 co-infectados con virus de la hepatitis) y 13 consumidores de droga con SIDA (7 hombres, 6 mujeres; edades entre 16 y 37; 12 co-infectados con virus de la hepatitis). -Resultados: las formas más frecuentes de lesiones de la mucosa oral en el grupo de pacientes infectados por el VIH- candidiasis (32.7%), lesiones herpéticas (15.4%), queilitis glandular (3.9%), estomatitis aftosa recidivante (2%). La linfadenopatía regional fue observada en el 31% de los casos. Las lesiones ulceronecrotizantes de la mucosa oral fueron vistas en la región sublingual y la lengua en el 11.5% de los pacientes y se manifestaron con dolor, disartria, disfagia y disgeusia. Estas lesiones fueron halladas en consumidores de droga que se inyectaban los opioides sublingualmente. Los pacientes con SIDA tenían candidiasis oral (84.6%), lesiones herpéticas (53.8%), estomatitis aftosa recidivante (15.4%) y queilitis glandular (7%). Todos los pacientes con SIDA tenían xerostomía severa, y el 15.4% tenían hinchazón unilateral o bilateral de las glándulas parótidas. Se halló gingivoestomatitis ulceronecrotizante generalizada en el 50% de los pacientes pero no se identificaron las lesiones ulceronecrotizantes sublinguales. -Conclusiones: 1. El espectro de las lesiones de la cavidad oral de pacientes VIH/SIDA en la región de Perm es bastante amplio. 2. La diseminación de las lesiones de la cavidad oral está aumentando en proporción con la progresión de la enfermedad. 3. El cuidado dental de los pacientes VIH/SIDA debería incluir exámenes orales periódicos para monitorizar la progresión de su enfermedad y para aliviar los síntomas de las enfermedades oportunistas y neoplásicas, para mejorar la calidad de vida de los pacientes infectados por el VIH (AU)


-Objective: to study the frequency and spectrum of oral manifestations of HIV-infected drug-users in the Perm region.-Subjects: 104 seropositive HIV-infected drug-users (69 male, 35 female ; ages15 to 32 years; 13 co-infected with hepatitis viruses) and 13 AIDS-infected drug-users (7 male, 6 female ; ages16 to 37 years; 12 co-infected with hepatitis viruses).-Results: the most frequent forms of oral mucosal lesions in the HIV-infected group - candidiasis (32.7%), herpetic lesions (15.4%), cheilitis glandularis (3.9%), recurrent aphthous stomatitis (2%). Regional lymphadenopathy was observed in 31% cases. The ulceronecrotic oral mucosal lesions were seen in the sublingual region and tongue in 11.5% patients and manifested with pain, dysarthria, dysphagia, and dysgeusia. These lesions were found in drug-users who injected the opioids sublingually.AIDS patients had oral candidiasis (84.6%), herpetic lesions (53.8%), recurrent aphthous stomatitis (15.4%) and cheilitis glandularis (7%). All AIDS-patients had severe xerostomia, and 15.4% had unilateral or bilateral swelling of the parotid glands. Generalized ulceronecrotic gingivostomatitis was found in 50% of the patients but the sublingual ulceronecrotic lesions were not identified.-Conclusions: 1. The spectrum of oral cavity lesions of HIV/AIDS patients in Perm region is widespread enough. 2. Dissemination of oral cavity lesions is increasing in proportion of disease progression. 3. Dental care of HIV/AIDS patients should include periodic oral examinations to monitor their disease progression and to alleviate symptoms of oral opportunic and neoplastic diseases, to improve the life-style of the patients infected with HIV (AU)


Assuntos
Humanos , Transtornos Relacionados ao Uso de Substâncias/complicações , Infecções por HIV/complicações , Doenças da Boca/epidemiologia , Drogas Ilícitas/efeitos adversos , Mucosa Bucal , Candidíase Bucal/epidemiologia , Estomatite Herpética/epidemiologia , Xerostomia/epidemiologia , Úlceras Orais/epidemiologia
18.
Med Oral ; 9(3): 212-5, 2004.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-15122122

RESUMO

OBJECTIVE: To study the frequency and spectrum of oral manifestations of HIV-infected drug-users in the Perm region. SUBJECTS: 104 seropositive HIV-infected drug-users (69 male, 35 female; ages 15 to 32 years; 13 co-infected with hepatitis viruses) and 13 AIDS-infected drug-users (7 male, 6 female; ages 16 to 37 years; 12 co-infected with hepatitis viruses). RESULTS: The most frequent forms of oral mucosal lesions in the HIV-infected group -- candidiasis (32.7%), herpetic lesions (15.4%), cheilitis glandularis (3.9%), recurrent aphthous stomatitis (2%). Regional lymphadenopathy was observed in 31% cases. The ulceronecrotic oral mucosal lesions were seen in the sublingual region and tongue in 11.5% patients and manifested with pain, dysarthria, dysphagia, and dysgeusia. These lesions were found in drug-users who injected the opioids sublingually. AIDS patients had oral candidiasis (84.6%), herpetic lesions (53.8%), recurrent aphthous stomatitis (15.4%) and cheilitis glandularis (7%). All AIDS-patients had severe xerostomia, and 15.4% had unilateral or bilateral swelling of the parotid glands. Generalized ulceronecrotic gingivostomatitis was found in 50% of the patients but the sublingual ulceronecrotic lesions were not identified. CONCLUSIONS: 1. The spectrum of oral cavity lesions of HIV/AIDS patients in Perm region is widespread enough. 2. Dissemination of oral cavity lesions is increasing in proportion of disease progression. 3. Dental care of HIV/AIDS patients should include periodic oral examinations to monitor their disease progression and to alleviate symptoms of oral opportunic and neoplastic diseases, to improve the life-style of the patients infected with HIV.


Assuntos
Infecções por HIV/complicações , Úlceras Orais/etiologia , Abuso de Substâncias por Via Intravenosa/complicações , Língua/lesões , Adolescente , Adulto , Feminino , Humanos , Masculino , Doenças da Boca/epidemiologia , Doenças da Boca/etiologia , Necrose , Úlceras Orais/epidemiologia , Federação Russa , Língua/patologia
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