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1.
Immunol Med ; : 1-10, 2024 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-38907617

RESUMO

Although rapidly progressive glomerulonephritis (RPGN) is the main renal phenotype of microscopic polyangiitis (MPA), we aim to clarify the clinical features of slowly progressive MPA. This retrospective observational study included 12 patients diagnosed with MPA in our hospital between January 2012 and February 2022. We investigated the differences in surrogate markers, rate of decline of estimated glomerular filtration rate (eGFR) between the slowly progressive and rapidly progressive MPA groups. Of the 12 patients with MPA, 3 (25.0%) had slowly progressive MPA: MPA within 30% decrease in eGFR 3 months pretreatment, all of whom developed RPGN during the course. Patients with slowly progressive MPA had lower levels of C-reactive protein, myeloperoxidase anti-neutrophil cytoplasmic antibodies, and interleukin-6; higher levels of sialylated carbohydrate antigen KL-6. Slowly progressive MPA is not uncommon in our hospital. A linear relationship was found between slower rate of eGFR decline and lower surrogate markers of disease activity. Some MPA cases have slowly progressive glomerulonephritis leading to RPGN, which may be clinically characterized by low disease activity. It may be useful to measure myeloperoxidase anti-neutrophil cytoplasmic antibody in chronic kidney disease with concomitant urinary abnormalities to diagnose MPA with slowly progressive glomerulonephritis.


Rapidly progressive glomerulonephritis is the main renal phenotype of microscopic polyangiitis (MPA), and slowly progressive MPA is rarely observed.Slowly progressive MPA was not rare in our hospital and was characterized clinically by low disease activity and complicated by interstitial pneumonia.When encountering patients with undiagnosed chronic kidney disease complicated by interstitial pneumonia, measuring myeloperoxidase anti-nuetrophil cytoplasmic antibody regardless of the rate of renal function decline, potentially leads to the diagnosis of slowly progressive MPA.

2.
Cureus ; 16(4): e58740, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38779245

RESUMO

INTRODUCTION: The administration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines has played a pivotal role in managing the COVID-19 pandemic. Nonetheless, there have been instances of atypical immune reactions to the vaccine, notably among patients with autoimmune inflammatory rheumatic diseases such as rheumatoid arthritis (RA). AIM: This study was designed to analyze the cytokine profiles of RA patients who suffered from severe or fatal disease flares after receiving the SARS-CoV-2 mRNA vaccine, to unravel the immunological bases for such responses. METHODS: We conducted a retrospective observational study involving three RA patients. These individuals had their disease under control prior to experiencing severe disease flares post-mRNA vaccination. A detailed serum cytokine analysis was carried out and compared with that of a healthy control group. RESULTS: Post-vaccination, each patient displayed a marked cytokine storm, with notably increased levels of IL-1ß (342, 109, and 27.5 pg/mL, respectively), IL-6 (67.8, 82.7, and 201 pg/mL, respectively), IL-17A (172, 51.6, and 30.3 pg/mL, respectively), and TNF-α (279, 97.5, and 59.4 pg/mL, respectively). Two patients responded well to treatment with biological and synthetic DMARDs, including baricitinib and abatacept. Unfortunately, one patient passed away even after receiving tocilizumab. CONCLUSION: The findings from the comprehensive cytokine assays indicate severe cytokine abnormalities, pointing to cytokine storm syndrome. This suggests that SARS-CoV-2 mRNA vaccination may trigger a disruption in immune homeostasis, potentially leading to the acute worsening of pulmonary complications in RA patients, even those with previously low disease activity. It's necessary to weigh the risks of severe outcomes from COVID-19 against the potential for flares or other adverse reactions following vaccination. Such risk assessments should take into account the individual patient's health status, existing conditions, and other risk factors. Close follow-up after vaccination is crucial, especially for patients with RA.

3.
Leg Med (Tokyo) ; 68: 102419, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38342012

RESUMO

Our study was designed to examine the correlation between single nucleotide polymorphism (SNP) in the endoplasmic reticulum aminopeptidase 1 (ERAP1) gene, specifically focusing on rs27434, and plural tissue weight. We conducted this investigation using autopsy samples from the Japanese population. Blood samples were collected from 178 Japanese subjects who had undergone autopsies in Shimane Prefecture. Genomic DNA was subsequently extracted from these samples. SNP (rs27434, G>A substitution) was analyzed by polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP) analysis. In the present study, rs27434 exhibited a statistically significant association with brain weight (g) in both female and male individuals. Among males, rs27434 displayed significant relationships with liver weight (g), and body surface area (m2). In females, rs27434 was significantly related to the length of the appendix. Across both genders, individuals with GA and AA genotypes tended to exhibit higher levels in these respective measurements compared to those with the GG genotype. These results suggest that genetic variant of ERAP1 gene may influence the weight of the organs. To the best of our knowledge, this is the first study investigating the interaction between the association of rs27434 in the ERAP1 gene and data routinely measured at autopsy, such as tissue weight. However, conducting further investigations with larger population samples could provide more comprehensive insights to clarify this issue.


Assuntos
Aminopeptidases , Antígenos de Histocompatibilidade Menor , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Aminopeptidases/genética , Povo Asiático/genética , Autopsia , Encéfalo/metabolismo , Genótipo , Japão , Fígado , Antígenos de Histocompatibilidade Menor/genética , Tamanho do Órgão/genética , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição
4.
Intern Med ; 2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37779066

RESUMO

We herein report a 27-year-old woman who presented with recurrent knee pain. Laboratory findings revealed minimal inflammation. Arthrography revealed structures resembling adipose tissues. Magnetic resonance imaging showed a high signal intensity of these structures, leading to the diagnosis of lipoma arborescens (LA). Synovectomy was performed. Pathology revealed adipocyte proliferation and B-cell clusters but no T-cell infiltration. A serum cytokine analysis revealed low levels of interleukin-6 and tumor necrosis factor-α compared with patients with rheumatoid arthritis. The pathogenesis of LA remains unclear, but immunostaining and serum cytokine levels may provide valuable data for future investigations.

5.
Immunol Med ; 46(2): 97-107, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36950829

RESUMO

A 61-year-old man with no previous record of autoimmune disease developed fever, polyarthralgia, purpura, and urticaria-like rash 2 weeks after the first dose of the Moderna mRNA-1273 vaccine, and symptoms deteriorated following the second dose. He presented reduced erythrocyte and platelet counts, hyperferritinemia, high sIL-2R levels, and severe hypocomplementemia. We diagnosed hypocomplementemic urticarial vasculitis (HUVS), and his symptoms as well as laboratory findings improved following treatment with mPSL 1000 mg/day for 3 days and PSL 40 mg/day. Twelve weeks following treatment initiation, the patient relapsed with fever, sore throat, pancytopenia, and hyperferritinemia when the PSL dose was reduced to 12.5 mg/day. Bone marrow biopsy and MRI presented fatty marrow and hemophagocytosis. The patient's blood cells started recovering using ATG + CsA + EPAG therapy for hemophagocytic lymphohistiocytosis (HLH). This is the first case report of HUVS and HLH following SARS-CoV-2 mRNA vaccination. It is presumed that SARS-CoV-2 mRNA vaccine can induce the excessive production of certain types of cytokines, such as TNF-α, IL-1, IL-4, IL-5, IL-6, and IL-17 as a consequence of IL-6 Amplification (IL-6 Amp). SARS-CoV-2 mRNA-vaccines can cause disruption of immune homeostasis in healthy individuals. An extremely rare disease of HUVS complicated by HLH can be developed as a consequence.


Assuntos
COVID-19 , Hiperferritinemia , Linfo-Histiocitose Hemofagocítica , Urticária , Vasculite , Masculino , Humanos , Pessoa de Meia-Idade , Linfo-Histiocitose Hemofagocítica/etiologia , SARS-CoV-2 , Vacinas contra COVID-19/efeitos adversos , Interleucina-6 , Vacina de mRNA-1273 contra 2019-nCoV , Hiperferritinemia/complicações , COVID-19/complicações , Urticária/etiologia , Urticária/diagnóstico , Urticária/tratamento farmacológico , Febre/complicações , Vacinação , Vasculite/diagnóstico , Vasculite/patologia , RNA Mensageiro
6.
Front Immunol ; 13: 887783, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35603142

RESUMO

Objective: We evaluated changes of HTLV-1 proviral loads (PVLs) during treatment for rheumatoid arthritis (RA) and investigated whether these changes affect the clinical course in HTLV-1-positive RA patients. Methods: A total of 41 HTLV-1-positive RA patients were analyzed. Their clinical picture including disease activity [Disease Activity Score in 28 joints-erythrocyte sedimentation rate (DAS28-ESR), DAS28-CRP, simplified disease activity index (SDAI), and clinical disease activity index (CDAI)] and comorbidity were evaluated over a 2-year period. PVLs from peripheral blood mononuclear cells were investigated by real-time polymerase chain reaction (PCR). We investigated whether HTLV-1 PVLs is altered, or which clinical characteristics affect changes of HTLV1-PVLs during 2-year treatment. Results: Clinical disease activity was not changed during the 2-year observational period. The mean HTLV-1 PVL value change from baseline to 2 years was -1.2 copies/1000 PBMCs, which was not statistically significant. No baseline clinical characteristics influenced changes in HTLV-1 PVL. However, a numerical change of HTLV-1 PVLs was increased in 4 patients initiating the new biological/targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) at 2-10 months after starting the new b/ts DMARDs (numerical increase was 24.87 copies/1000 PBMCs). Infection occurred in 4 patients, and 3 of those patients showed an increased HTLV-1 PVL. Univariate analysis revealed an association between increase of HTLV-1 PVL and incidence of infection. Conclusions: Over 2 years, HTLV-1 PVL did not significantly change in our HTLV-1-positive RA patients. Individual changes in HTLV-1 PVL were correlated with incidence of infection but not disease activity which indicate that we may take precaution toward infection at the uptick of HTLV-1 PVL in HTLV-1-positive RA patients.


Assuntos
Antirreumáticos , Artrite Reumatoide , Infecções por HTLV-I , Vírus Linfotrópico T Tipo 1 Humano , Leucemia de Células T , Antirreumáticos/uso terapêutico , Artrite Reumatoide/tratamento farmacológico , Estudos de Coortes , Infecções por HTLV-I/complicações , Humanos , Leucócitos Mononucleares , Provírus , Carga Viral
7.
Sci Rep ; 11(1): 21175, 2021 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-34707207

RESUMO

Elevated intracardiac pressure at rest and/or exercise is a fundamental abnormality in heart failure with preserved ejection fraction (HFpEF). Fatty acid-binding protein 1 (FABP1) is proposed to be a sensitive biomarker for liver injury. We sought to determine whether FABP1 at rest would be elevated in HFpEF and would correlate with echocardiographic markers of intracardiac pressures at rest and during exercise. In this prospective study, subjects with HFpEF (n = 22) and control subjects without HF (n = 23) underwent resting FABP1 measurements and supine bicycle exercise echocardiography. Although levels of conventional hepatic enzymes were similar between groups, FABP1 levels were elevated in HFpEF compared to controls (45 [25-68] vs. 18 [14-24] ng/mL, p = 0.0008). FABP1 levels were correlated with radiographic and blood-based markers of congestion, hemodynamic derangements during peak exercise (E/e', r = 0.50; right atrial pressure, r = 0.35; pulmonary artery systolic pressure, r = 0.46), reduced exercise cardiac output (r = - 0.49), and poor exercise workload achieved (r = - 0.40, all p < 0.05). FABP1 distinguished HFpEF from controls with an area under the curve of 0.79 (p = 0.003) and had an incremental diagnostic value over the H2FPEF score (p = 0.007). In conclusion, FABP1 could be a novel hepatic biomarker that associates with hemodynamic derangements, reduced cardiac output, and poor exercise capacity in HFpEF.


Assuntos
Proteínas de Ligação a Ácido Graxo/sangue , Insuficiência Cardíaca/sangue , Idoso , Biomarcadores/sangue , Pressão Sanguínea , Débito Cardíaco , Ecocardiografia , Teste de Esforço , Feminino , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade
8.
Case Rep Hematol ; 2019: 8612031, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30937199

RESUMO

A 67-year-old male, with a known diagnosis of myelodysplastic syndromes with multilineage dysplasia (MDS-MLD) was admitted to our hospital with a primary complaint of subcutaneous bleeding in his left thigh. Laboratory data showed anaemia and prolongation of activated partial thromboplastin time (85.8 s, normal range 24-39 s) without thrombocytopenia. Coagulation factor VIII (FVIII) activity was less than 1% (normal range 60-150%), and a FVIII inhibitor was identified and quantified at 166 BU/mL to indicate a diagnosis of acquired haemophilia A (AHA). A recent, but sustained circulating monocytosis (>1 × 109/L) was observed, which combined with elevated numbers of neutrophil and monocytic cells in the marrow, suggested evolution of MDS-MLD to chronic myelomonocytic leukaemia (CMML), coinciding with AHA. Further analysis revealed a karyotype of 46, XY, i(14) (q10), which was the same abnormality previously identified in the patient. To treat bleeding caused by AHA, steroid and activated prothrombin complex concentrate were administered. Azacitidine (AZA) was used to treat CMML. During the clinical course, bleeding partially improved; however, subsequent acute myocardial infarction occurred on day 87. Worsening bone marrow failure was observed 4 months after the original admission, despite administration of AZA therapy, and the patient died due to bleeding from AHA. This case suggests that the evolution of MDS to CMML status can be associated with AHA conferring a bleeding tendency.

9.
IEEE Trans Biomed Circuits Syst ; 13(2): 352-363, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30676977

RESUMO

Various biosensing platforms for real-time monitoring and mapping of chemical signals in neural networks have been developed based on CMOS process technology. Despite their achievements, however, there remains a demand for an advanced method that can offer detailed insights into cellular functions with higher spatiotemporal resolution. Here, we present a pH image sensor that employs a high-density array of 256 × 256 pixels and readout circuitry designed for fast operation. The sensor's characteristics, such as the pH sensitivity of 55.1 mV/pH and higher frame speed of 1933 fps, are experimentally demonstrated and compared to those of state-of-the-art pH image sensors. Among them, our sensor presents the smallest pitch of 2 µm with a significantly high operation speed. This sensor can successfully detect a pH change, but also transform the measured data to a two-dimensional image series in real time. The practical spatial resolution of images is investigated by an evaluation method that we first propose in this paper. By this method, we confirm that our sensor can discriminate objects distanced over 4 µm apart, which is twice bigger than the pixel pitch. In order to analyze the degraded resolution and image blur, a capacitive coupling effect at an ion-sensitive membrane is suggested as the main factor and demonstrated by simulation.


Assuntos
Técnicas Biossensoriais , Imageamento Tridimensional , Calibragem , Simulação por Computador , Concentração de Íons de Hidrogênio , Modelos Teóricos , Transistores Eletrônicos
10.
Org Lett ; 19(3): 496-499, 2017 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-28102682

RESUMO

Ferns are known to produce onoceroids including onoceranes and serratanes having unusual structures among triterpenes. From the fern Lycopodium clavatum, a novel onoceroid synthase gene was cloned that showed high sequence identity with a previously identified α-onocerin synthase. Functional analysis by coexpression with pre-α-onocerin synthase in yeast led to the production of tohogenol and serratenediol. The result suggested that serratanes are directly biosynthesized from pre-α-onocerin and not from α-onocerin as previously assumed.


Assuntos
Lycopodium/química , Gleiquênias , Estrutura Molecular
11.
Chembiochem ; 17(4): 288-90, 2016 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-26663356

RESUMO

Onocerin is known for its unusual structure among triterpenoids, with a symmetrical structure that is formed by cyclizations at the both termini of dioxidosqualene. The nature of the enzyme catalyzing these unusual cyclizations has remained elusive for decades. Here, we report the cloning of genes responsible for these reactions; they exhibited unprecedented substrate specificities among oxidosqualene cyclase family members. Two genes, LCC and LCD, were identified from the fern Lycopodium clavatum. Expression in yeast revealed that both were required to produce α-onocerin. LCC, the first dioxidosqualene cyclase, catalyzed the production of a novel intermediate pre-α-onocerin from only dioxidosqualene as a substrate; LCD catalyzed the second half of the cyclization, exclusively from pre-α-onocerin. These results demonstrated that these two most unusual oxidosqualene cyclases were involved in onocerin biosynthesis.


Assuntos
Transferases Intramoleculares/metabolismo , Lycopodium/enzimologia , Triterpenos/metabolismo , Vias Biossintéticas , Ciclização , Genes de Plantas , Transferases Intramoleculares/genética , Lycopodium/química , Lycopodium/genética , Lycopodium/metabolismo , Especificidade por Substrato , Triterpenos/química
12.
Org Biomol Chem ; 13(26): 7331-6, 2015 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-26058429

RESUMO

Oxidosqualene cyclases (OSCs) catalyze the cyclization of an acyclic substrate into various polycyclic triterpenes through a series of cation-π cyclization and 1,2-rearrangement processes. The mechanisms by which OSCs control the fate of intermediate carbocation to generate each specific triterpene product have not yet been determined. The formation of ubiquitous sterol precursors in plants, cycloartenol and Cucurbitaceae-specific cucurbitadienol, only differs by the extent of the 1,2-rearrangement of methyl and hydride. In the present study, we identified critical residues in cycloartenol synthase and cucurbitadienol synthase that were primarily responsible for switching product specificities between the two compounds. The mutation of tyrosine 118 to leucine in cycloartenol synthase resulted in the production of cucurbitadienol as a major product, while the mutation of the corresponding residue leucine 125 to tyrosine in cucurbitadienol synthase resulted in the production of parkeol. Our discovery of this "switch" residue will open up future possibilities for the rational engineering of OSCs to produce the desired triterpenes.


Assuntos
Biocatálise , Transferases Intramoleculares/metabolismo , Triterpenos/química , Triterpenos/metabolismo , Ciclização , Transferases Intramoleculares/genética , Mutação
13.
J Diabetes Investig ; 3(6): 492-7, 2012 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-24843613

RESUMO

UNLABELLED: (J Diabetes Invest, doi: 10.1111/j.2040-1124.2012.00224.x, 2012) Aims/Introduction: The Japanese Red Cross Society introduced measurement of glycated albumin (GA) for all blood donors as a glycemic control marker. The GA levels were examined by sex and age. MATERIALS AND METHODS: GA was measured in 3.14 million blood donors who donated between April 2009 and March 2010. For the reference range for GA, values that were three times the reference range for glycated hemoglobin (Japan Diabetes Society value) were used. All donors were notified of their GA levels. For repeat donors, a comparison was made between the GA levels at the first and second donations to verify the GA change after notification. RESULTS: The mean GA was significantly lower in males than in females in donors aged <60 years. The mean GAs of both sexes increased with age and reached the same level of 14.8% in their 60s. The percentage of donors with prediabetes/diabetes (GA ≥16.5%) was 2.8% in males and 2.3% in females. In the normal high group (15.6% ≤ GA < 16.5%), the mean GA at the second donation was lower by 0.20% than at the first donation. In 42.4% of these donors, GA decreased to the normal range at the second donation. CONCLUSIONS: Overall, 2.7% of otherwise healthy Japanese blood donors had a high GA (GA ≥16.5%). Donor blood screening for GA represents an effective measure to identify people at risk of diabetes. The decrease in the GA level after GA notification might indicate the potential usefulness of this strategy to improve glycemic control among people with high GA.

14.
Appl Opt ; 46(22): 4963-7, 2007 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-17676102

RESUMO

A portable ellipsometer with a compact static polarimeter using an arrayed polarizer, an arrayed wave plate, and a CCD image sensor is developed. A high level of repeatability at a measurement speed of 0.3 s is demonstrated by measurement of SiO(2) films ranging from 2 to 300 nm in thickness deposited on an Si wafer. There is the potential to realize an ultracompact ellipsometer module by integrating the optical source and receiver, suitable for deployment in a variety of manufacturing equipment and measurement instruments.

15.
Anal Sci ; 22(10): 1283-9, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17038763

RESUMO

Temperature-dependent phase-vanishing processes between perfluorohexane (FC-72) and n-heptane (C7H16, volume ratio of 1:1 and phase-vanishing temperature>41 degrees C), were studied in a glass microchannel-microheater chip under solution-flow conditions. Without applying a voltage to the heater at 21 degrees C, the two liquids in the microchannel were separated into two streams at a solution flow rate (v) of 0.975 cm/s, while the phase boundary between FC-72 and C7H16 vanished in the downstream side of the heater at V=4.5 V. Then, we conducted Raman intensity imaging during the phase vanishing processes in the microchannel by monitoring the band at 756 (FC-72) or 1456 cm-1 (C7H16). At V=4.5 V and v=0.975 cm/s, although no phase boundary between the two liquids in the microchannel was observed, the relevant Raman intensity images indicated the inhomogeneous nature of the solution, and distribution of C7H16 to the FC-72 phase along with solution flow was observed.

16.
Phys Rev Lett ; 94(13): 136404, 2005 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-15904010

RESUMO

The molecular alignment of a merocyanine (MC) J-aggregate monolayer at the air-water interface was determined by a grazing incidence x-ray diffraction method. The obtained molecular arrangement apparently shows that the conventional formula, which accounts only for the transition dipole interaction, is not sufficient to figure out the exciton band wavelength, suggesting the importance of the electric dipole (ED) interaction. We derived a simple formula for the ED interaction energy under an extended dipole approximation and clarified the ED contribution in the MC J aggregate.

17.
Biochem Biophys Res Commun ; 315(1): 119-22, 2004 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-15013434

RESUMO

Rhythm is an important dynamic behavior in biological systems. We have been studying oscillatory reactions of enzymes induced by gradual entry of substances through semipermeable membrane. Not only enzymes but also a few species of substance of living system have been elucidated to cause oscillatory reaction. Here we present the oscillatory reaction by chondroitin sulfate in a system of gradual entry of calcium ion. Introducing calcium ion through dialysis membrane into chondroitin sulfate solution induces an oscillation of free calcium ion concentration in chondroitin sulfate solution. Simultaneously, it is elucidated that oscillation of conformation occurs with permeation of calcium ion. In both measurements, oscillations with 25h period are obtained. The phases of oscillation, however, differ slightly from each other. From these results, it is suggested that autocatalysis exerts in the contraction of chondroitin sulfate conformation. These phenomena are very intriguing for elucidating oscillation in living system.


Assuntos
Cálcio/metabolismo , Sulfatos de Condroitina/metabolismo , Membranas Artificiais , Cálcio/química , Sulfatos de Condroitina/química , Eletrodos , Potenciais da Membrana , Periodicidade , Permeabilidade
18.
J Biol Chem ; 278(8): 5864-70, 2003 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-12488317

RESUMO

V-1 is a 12-kDa protein consisting of three consecutive ANK repeats, which are believed to serve as the surface for protein-protein interactions. It is thought to have a role in neural development for its temporal profile of expression during murine cerebellar development, but its precise role remains unknown. Here we applied the proteomic approach to search for protein targets that interact with V-1. The V-1 cDNA attached with a tandem affinity purification tag was expressed in the cultured 293T cells, and the protein complex formed within the cells were captured and characterized by mass spectrometry. We detected two polypeptides specifically associated with V-1, which were identified as the alpha and beta subunits of the capping protein (CP, alternatively called CapZ or beta-actinin). CP regulates actin polymerization by capping the barbed end of the actin filament. The V-1.CP complex was detected not only in cultured cells transfected with the V-1 cDNA but also endogenously in cells as well as in murine cerebellar extracts. An analysis of the V-1/CP interaction by surface plasmon resonance spectroscopy showed that V-1 formed a stable complex with the CP heterodimer with a dissociation constant of 1.2 x 10(-7) m and a molecular stoichiometry of approximately 1:1. In addition, V-1 inhibited the CP-regulated actin polymerization in vitro in a dose-dependent manner. Thus, our results suggest that V-1 is a novel component that regulates the dynamics of actin polymerization by interacting with CP and thereby participates in a variety of cellular processes such as actin-driven cell movements and motility during neuronal development.


Assuntos
Actinas/metabolismo , Cerebelo/crescimento & desenvolvimento , Peptídeos e Proteínas de Sinalização Intercelular , Proteínas dos Microfilamentos/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Fatores de Despolimerização de Actina , Animais , Proteína de Capeamento de Actina CapZ , Proteínas de Transporte/química , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Linhagem Celular , Células Cultivadas , Destrina , Humanos , Rim , Cinética , Espectrometria de Massas , Camundongos , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/genética , Proteínas Recombinantes de Fusão/metabolismo , Transfecção
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