RESUMO
BACKGROUND: Recurrence rates of keloids have generally been reported at one time point. However, the longer the duration after treatment, the greater the likelihood that such lesions will recur. In this study, we analysed the time to recurrence during long-term follow-up. MATERIAL AND METHODS: We retrospectively reviewed recurrence-free interval in 52 patients with keloid (age 8-79 years) who had been treated between June 2006 and January 2011 using a standardised protocol developed by our group. RESULTS: Mean duration of follow-up was 37.5 (range, 7-120) months in patients with keloid. Kaplan-Meier survival curves revealed a statistically significant difference in recurrence-free interval between ear keloids and keloids excluding ear keloids. Recurrence rate for keloids was high in the first 2 years after treatment. CONCLUSIONS: Kaplan-Meier analysis was useful for understanding the tendency of recurrence of keloids after treatment using a standardised protocol.
Assuntos
Protocolos Clínicos/normas , Queloide/tratamento farmacológico , Adulto , Assistência ao Convalescente/métodos , Assistência ao Convalescente/estatística & dados numéricos , Idoso , Criança , Feminino , Glucocorticoides/farmacologia , Glucocorticoides/uso terapêutico , Humanos , Japão , Estimativa de Kaplan-Meier , Queloide/fisiopatologia , Assistência de Longa Duração/métodos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Triancinolona/farmacologia , Triancinolona/uso terapêuticoRESUMO
INTRODUCTION: Drowning is a comprehensive and exclusive diagnosis at autopsy. Autopsy findings such as pleural effusion and waterlogged lungs contribute to the diagnosis. Herein, we aim to reveal the practical usefulness and postmortem changes of the maxillary sinus fluid volume to diagnose drowning. METHODS: We evaluated 52 drowning and 59 nondrowning cases. The maxillary sinus fluid volume was measured using a computed tomography (CT) scan, and pleural effusion volume and lung weight were manually measured at autopsy. The utility of these three indices for diagnosing drowning and its postmortem changes was evaluated. RESULTS: The maxillary sinus fluid volume was significantly higher in drowning cases than in other external causes and cardiovascular death cases. Receiver operating characteristic curve analysis revealed that a total maxillary sinus fluid volume >1.04 mL more usefully indicated drowning (odds ratio, 8.19) than a total pleural effusion volume >175 mL (odds ratio, 7.23) and a total lung weight >829 g (odds ratio, 2.29). The combination of maxillary sinus fluid volume and pleural effusion volume more effectively predicted drowning than one index alone. Moreover, the maxillary sinus fluid volume was less influenced by the postmortem interval than the other two indices up to a week after death. CONCLUSION: Maxillary sinus fluid volume can be more useful than pleural effusion volume and lung weight with higher sensitivity and odds ratio for diagnosing drowning. IMPLICATIONS FOR PRACTICE: Fluid accumulation in both the maxillary sinuses strongly predicts drowning in the postmortem imaging.
Assuntos
Afogamento , Derrame Pleural , Humanos , Afogamento/diagnóstico por imagem , Seio Maxilar/diagnóstico por imagem , Autopsia/métodos , Derrame Pleural/diagnóstico por imagem , Mudanças Depois da MorteRESUMO
Purpose: This study evaluated the changes in psychological stress during in vitro fertilization and embryo transfer (IVF-ET) and the relationship of such stress to the patients' background and gender. Methods: Sixty couples undergoing IVF-ET were administered the State-Trait Anxiety Inventory-JYZ (STAI) test at six different points during IVF-ET procedures. Anxiety scores at each time point were recorded and analyzed according to gender, fertility status, and duration of treatment. Results: The median state anxiety score for women increased following induction until oocyte collection, after which it temporarily declined and then increased again until the pregnancy test. No such changes were noted in men. Scores for women who had undergone a shorter period of IVF treatments were higher while state and trait anxiety in men increased with a prolonged treatment period. Unsuccessful treatment increased the state and trait anxiety of women. Conclusions: Psychological stress changed periodically depending on the duration of the patients' treatment and fertility status also influenced anxiety levels. These findings will prove helpful in guiding psychological therapy and counseling for couples attempting to conceive by in vitro fertilization.
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OBJECTIVE: Olfactory dysfunction is a non-motor symptom in idiopathic Parkinson's disease (PD). We investigated whether this dysfunction differs among clinical subtypes of PD. METHODS: Participants comprised of 90 patients with idiopathic PD and without dementia. Olfactory function was evaluated using the odor stick identification test for Japanese, which evaluated the detection of 12 odorants familiar to Japanese participants. Patients were divided into tremor-dominant type (TDT), akinetic-rigid type (ART), and mixed type (MXT) PD subgroups using part III of the Unified Parkinson's Disease Rating Scale. RESULTS: Fifty-five patients were classified as ART, 21 as MXT, and 14 as TDT. There were no differences in age, sex, or duration of illness among the subtypes. Subjective symptoms of impaired sense of smell were significantly higher (P<0.05) in the ART than in the TDT. Mean odor identification score was 4.3 in the ART, 5.2 in MXT, and 6.6 in TDT. It was significantly lower in the ART than in the TDT (P<0.01). CONCLUSION: Olfactory dysfunction differed among the clinical subtypes of PD. This suggests that olfactory function might relate to prognosis of patients with PD.
Assuntos
Transtornos do Olfato/etiologia , Doença de Parkinson/complicações , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Odorantes , Doença de Parkinson/fisiopatologia , Prognóstico , Olfato/fisiologiaRESUMO
Stem cells from bone marrow, skeletal muscle and possibly other tissues can be identified by the 'side-population' (SP) phenotype. Although it has been assumed that expression of ABC transporters is responsible for this phenotype, the specific molecules involved have not been defined. Here we show that expression of the Bcrp1 (also known as Abcg2 murine/ABCG2 human) gene is a conserved feature of stem cells from a wide variety of sources. Bcrp1 mRNA was expressed at high levels in primitive murine hematopoietic stem cells, and was sharply downregulated with differentiation. Enforced expression of the ABCG2 cDNA directly conferred the SP phenotype to bone-marrow cells and caused a reduction in maturing progeny both in vitro and in transplantation-based assays. These results show that expression of the Bcrp1/ABCG2 gene is an important determinant of the SP phenotype, and that it might serve as a marker for stem cells from various sources.
Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas Inflamatórias de Macrófagos , Glicoproteínas de Membrana , Proteínas Associadas à Resistência a Múltiplos Medicamentos , Proteínas de Neoplasias , Células-Tronco/fisiologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/genética , Animais , Antígenos CD/metabolismo , Antígenos CD34/metabolismo , Biomarcadores , Células da Medula Óssea/fisiologia , Células Cultivadas , Quimiocinas CC , Citocinas/metabolismo , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos , Camundongos Mutantes , Proteínas Ribossômicas/metabolismo , Células-Tronco/citologia , Tetraspanina 29 , TransplantesRESUMO
We established the distribution of amino acid alterations in quinolone resistance-determining regions (QRDRs) of Streptococcus pneumoniae isolates in Japan and described the correlation of these alterations with serotypes determined by multilocus sequencing typing. Among 141 S. pneumoniae isolates, five levofloxacin-resistant isolates harbored mutations in both gyrA and parC and/or parE and were clonally unrelated. Among 136 levofloxacin-susceptible isolates, one isolate (MIC = 2 mg/l) had a first-step parC mutation at Asp78. Twenty isolates had Lys137Asp in parC and Ile460Val in parE and contained nine serotypes and eight clonal complexes (CCs), including all eight Colombia(23F)-26 (CC138) isolates. Eighty-one isolates had Ile460Val in parE alone and contained 14 serotypes and 16 CCs, including 36 of 37 Netherlands(3)-31 (CC180) isolates and all 22 Taiwan(19F)-14 (CC271) isolates. In contrast, seven of ten Taiwan(23F)-15 (CC242) isolates were wild-type. Although each QRDR genotype contained various serotypes and CCs, prevalent clones were mostly associated with a single QRDR genotype.
Assuntos
Antibacterianos/farmacologia , DNA Bacteriano/genética , Farmacorresistência Bacteriana , Genes Bacterianos , Infecções Pneumocócicas/microbiologia , Quinolonas/farmacologia , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , DNA Girase/genética , Análise Mutacional de DNA , DNA Topoisomerase IV/genética , Genótipo , Humanos , Japão , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Análise de Sequência de DNA , Streptococcus pneumoniae/isolamento & purificação , Adulto JovemRESUMO
An electron microscopic study revealed disruption of capillary endothelial tight junctions (TJs) in both biopsied muscle, taken at 5 years and 1 month of age, and the autopsied brain, taken at 13 years and 6 months of age, in a patient with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) and mitochondrial DNA (mtDNA) point mutation A3243G. This endothelial barrier disruption might result in vasogenic edema and systemic lactic acidosis, possibly the critical pathology of MELAS.
Assuntos
Encéfalo/patologia , Síndrome MELAS/patologia , Junções Íntimas/patologia , Adolescente , Encéfalo/ultraestrutura , DNA Mitocondrial/genética , Progressão da Doença , Feminino , Humanos , Síndrome MELAS/genética , Microscopia Eletrônica de Transmissão/métodos , Mutação Puntual/genética , Junções Íntimas/diagnóstico por imagem , UltrassonografiaRESUMO
Hematopoietic stem cells (HSCs) supply all blood cells throughout life by making use of their self-renewal and multilineage differentiation capabilities. A monoclonal antibody raised to the mouse homolog of CD34 (mCD34) was used to purify mouse HSCs to near homogeneity. Unlike in humans, primitive adult mouse bone marrow HSCs were detected in the mCD34 low to negative fraction. Injection of a single mCD34(lo/-), c-Kit+, Sca-1(+), lineage markers negative (Lin-) cell resulted in long-term reconstitution of the lymphohematopoietic system in 21 percent of recipients. Thus, the purified HSC population should enable analysis of the self-renewal and multilineage differentiation of individual HSCs.
Assuntos
Antígenos CD34/análise , Células da Medula Óssea , Hematopoese , Células-Tronco Hematopoéticas/citologia , Animais , Sequência de Bases , Diferenciação Celular , Linhagem da Célula , Separação Celular , Primers do DNA , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Fatores de TempoRESUMO
Ten Apollo 11 specimnens were divided into 24 samtples. Sodillim contents of 8 diverse specimens clluster tightly abolit 0.3 percent. Plagioclase separated from sample 10044 contains aboltt 1.09 percent Na; barium is not enriched in the plagioclase separate. Contents of the rare earths are strikingly high, and relative abtmndances resemble those of calcium-rich achondrites or abyssal basalts but are depleted in Eu by factors of 2 to 3 and in La by about 20 percent. The plagioclase separate is enriched in Eu and pyroxenes (and opaqtte minerals are Eu-depleted. Fine fractions of 10044 are abotit 20 to 40 percent richer in most rare earths (50 percent for Eu) than coarse fractions, probably becaitse of the presence of small grains in which rare earths are mnarkedly concentrated. "Microgabbro" 10045 is imnpoverished, relative to the soil, in rare eartlhs and Hf. Ratios by mass of Zr to Hf are comlparatively low. Abttndances of Mn, Co, Fe, Sc and Cr stiggest systematic differences between igneous rocks on one hanid and breccias and "soil" on the other. Fromn the Co abuindances, no more than about 3 percent of the present "soil" can consist of chondritic mleteorite conitamination.
RESUMO
The combination regimen of daclatasvir, asunaprevir, and beclabuvir (3DAA regimen) was developed as a fixed-dose combination for the treatment of hepatitis C virus (HCV) infection in Japan. The objectives of this analysis were to characterize the relationship between drug exposure and sustained virologic response at posttreatment week 12 (SVR12) in HCV-infected subjects and to evaluate the impact of demographic covariates and clinical factors on the exposure-response (E-R) relationship. The E-R efficacy analysis was performed with data from phase 2 and phase 3 studies in HCV-infected subjects treated with the 3DAA regimen. The relationship between the probability of achieving SVR12 and exposure to daclatasvir, asunaprevir, and beclabuvir was described using a logistic regression model and included assessments of the potential covariate effects. The impacts of the covariates on the rate of SVR12 and interactions of covariates with the individual drug effects were tested. The final model for SVR12 included effects of non-genotype-1a status, resistance-associated NS5A-Q30 substitution in genotype-1a subjects, and baseline RNA level on the intercept, and effect of prior peg-interferon failure on the beclabuvir slope. Sex, race, age, weight, fibrosis score, alanine transaminase, and cirrhosis status had no statistically significant impact on the rate of SVR12. The individual E-R relationships with each drug, were relatively flat, and the effects of exposure were not significant. With the exception of the NS5A-Q30 substitution in genotype-1a subjects, statistically significant covariate effects had little impact on SVR12 rates. Overall, the E-R model was developed that captured the high SVR12 rates and the effect of covariates for the 3DAA regimen in HCV-infected patients.
Assuntos
Benzazepinas/administração & dosagem , Hepacivirus/efeitos dos fármacos , Hepatite C/tratamento farmacológico , Imidazóis/administração & dosagem , Indóis/administração & dosagem , Isoquinolinas/administração & dosagem , Sulfonamidas/administração & dosagem , Adulto , Idoso , Substituição de Aminoácidos , Benzazepinas/farmacologia , Carbamatos , Combinação de Medicamentos , Feminino , Hepacivirus/genética , Hepatite C/virologia , Humanos , Imidazóis/farmacologia , Indóis/farmacologia , Isoquinolinas/farmacologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Pirrolidinas , Sulfonamidas/farmacologia , Resposta Viral Sustentada , Resultado do Tratamento , Valina/análogos & derivados , Proteínas não Estruturais Virais/genéticaRESUMO
Fukuyama type congenital muscular dystrophy accompanies central nervous system and ocular lesions. Morphological findings suggest that major central nervous system lesions, such as cortical dysplasia, are caused by the abnormal glia limitans due to an impairment of astrocytes. Increase of corpora amylacea and neurofibrillary tangles suggests acceleration of the aging process in the Fukuyama type congenital muscular dystrophy brain. Glycosylation of alpha-dystroglycan is decreased in the central nervous system of Fukuyama type congenital muscular dystrophy in a similar manner to the skeletal muscle, but dystroglycan mRNA levels appear to be increased. Glycosylated alpha-dystroglycan is reduced in the glia limitans formed by astrocytic endfeet. Slight accumulation of N(epsilon)-(carboxymethyl)lysine, an oxidative modification product, is observed in astrocytes of Fukuyama type congenital muscular dystrophy and in an astrocytoma cell line with suppressed fukutin expression. Cerebral cortical neurons of Fukuyama type congenital muscular dystrophy and controls react with an antibody for core alpha-dystroglycan but not with an antibody for glycosylated alpha-dystroglycan. Carboxymethyl lysine is accumulated in cortical neurons of a severe case of Fukuyama type congenital muscular dystrophy. Both astrocytes and neurons appear to be sensitive to oxidative stress when fukutin is suppressed. However, it is still unclear how the loss of fukutin causes astrocytic and neuronal dysfunction. Since the central nervous system is composed of several components that are closely related to each other, more investigations are needed for thorough understanding of the Fukuyama type congenital muscular dystrophy brain. Moreover, since astrocytes and epithelial cells may show different cellular responses to fukutin suppression, it seems important to evaluate the functions of fukutin in each type of cell or tissue, not only to prove the pathogenesis of Fukuyama type congenital muscular dystrophy, but also for applying appropriate therapies, especially those at molecular level.
Assuntos
Córtex Cerebral/patologia , Distrofias Musculares/patologia , Neuroglia/patologia , Neurônios/patologia , Astrócitos/patologia , Membrana Basal/patologia , Western Blotting , Sistema Nervoso Central/embriologia , Córtex Cerebral/metabolismo , Glicosilação , Humanos , Imuno-Histoquímica , Lisina/análogos & derivados , Lisina/metabolismo , Proteínas de Membrana/metabolismo , Músculo Esquelético/metabolismo , Distrofias Musculares/congênitoRESUMO
Thrombin mediates changes in endothelial barrier function and increases endothelial permeability. A feature of thrombin-enhanced endothelial hyperpermeability is contraction of endothelial cells (ECs), accompanied by formation of focal adhesions (FAs). Recently, a G protein-coupled receptor kinase-interacting protein, GIT1, was shown to regulate FA disassembly. We hypothesized that GIT1 modulates thrombin-induced changes in FAs. In human umbilical vein ECs (HUVECs), thrombin recruited GIT1 to FAs, where GIT1 colocalized with FAK and vinculin. Recruitment of GIT1 to FAs was dependent on activation of the small GTPase RhoA, and Rho kinase, as demonstrated by adenoviral transfection of dominant-negative RhoA and treatment with Y-27632. Thrombin stimulated GIT1 tyrosine phosphorylation with a time course similar to FAK phosphorylation in a Rho kinase- and Src-dependent manner. Depletion of GIT1 with antisense GIT1 oligonucleotides had no effect on basal cell morphology, but increased cell rounding and contraction of HUVECs, increased FA formation, and increased FAK tyrosine phosphorylation in response to thrombin, concomitant with increased endothelial hyperpermeability. These data identify GIT1 as a novel mediator in agonist-dependent signaling in ECs, demonstrate that GIT1 is involved in cell shape changes, and suggest a role for GIT1 as a negative feedback regulator that augments recovery of cell contraction.
Assuntos
Proteínas de Ciclo Celular/fisiologia , Células Endoteliais/metabolismo , Endotélio Vascular/citologia , Adesões Focais/fisiologia , Proteínas Ativadoras de GTPase/fisiologia , Fosfoproteínas/fisiologia , Transdução de Sinais/fisiologia , Trombina/fisiologia , Proteínas Adaptadoras de Transdução de Sinal , Amidas/farmacologia , Animais , Aorta , Bovinos , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/genética , Tamanho Celular/efeitos dos fármacos , Tamanho Celular/fisiologia , Células Cultivadas/citologia , Células Cultivadas/efeitos dos fármacos , Células Cultivadas/metabolismo , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Retroalimentação Fisiológica , Quinase 1 de Adesão Focal , Proteína-Tirosina Quinases de Adesão Focal , Proteínas Ativadoras de GTPase/antagonistas & inibidores , Proteínas Ativadoras de GTPase/genética , Humanos , Oligodesoxirribonucleotídeos Antissenso/farmacologia , Fosfoproteínas/antagonistas & inibidores , Fosfoproteínas/genética , Fosforilação/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Transporte Proteico , Proteínas Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas pp60(c-src)/fisiologia , Piridinas/farmacologia , RNA Interferente Pequeno/genética , Transdução de Sinais/efeitos dos fármacos , Trombina/genética , Transdução Genética , Transfecção , Veias Umbilicais , Vinculina/análise , Proteínas rac de Ligação ao GTP/fisiologia , Proteína rhoA de Ligação ao GTP/genética , Proteína rhoA de Ligação ao GTP/fisiologiaRESUMO
After several years of treatment for type 2 diabetes mellitus, a 69-year-old Japanese man developed an acute painful neuropathy, characterized by bilateral causalgia and dysaesthesia in his cheeks and around his eyes, typically 30 min to 3 h after meals. As his glycaemic control deteriorated, his haemoglobin (Hb) A1c level gradually increased from 7 - 8% to 10.3% and his symptoms became more severe. The pain radiated out along the distribution of the ophthalmic and maxillary divisions of the trigeminal nerve. The patient was treated with insulin therapy and his HbA1c level decreased from 10.3% to 6.8% within 7 months. Five months after initiating insulin therapy, his symptoms showed a dramatic improvement. This was a very unusual case of bilateral acute painful neuropathy that involved the ophthalmic and maxillary divisions of the trigeminal nerve, and in which aggravation of the symptoms clearly related to poor glycaemic control.
Assuntos
Causalgia/fisiopatologia , Diabetes Mellitus Tipo 2/complicações , Neuropatias Diabéticas/etiologia , Nervo Trigêmeo , Neuralgia do Trigêmeo/diagnóstico , Idoso , Diabetes Mellitus Tipo 2/terapia , Neuropatias Diabéticas/tratamento farmacológico , Neuropatias Diabéticas/fisiopatologia , Seguimentos , Humanos , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Masculino , Compostos de Sulfonilureia/uso terapêutico , Fatores de Tempo , Resultado do Tratamento , Neuralgia do Trigêmeo/tratamento farmacológico , Neuralgia do Trigêmeo/fisiopatologiaRESUMO
Niche has become the most important issue in stem cell biology, but it is still a hypothetical notion that cannot be defined in a better way than the microenvironment surrounding stem cells. Using a melanocyte stem cell system as a model, we have analyzed the cellular and molecular requirements for differentiation of quiescent stem cells. Our results demonstrate the multiple subsets within the stem cell compartment and thus suggests the complexity of niche.
Assuntos
Células-Tronco/citologia , Células-Tronco/metabolismo , Animais , Diferenciação Celular , Melanócitos/citologia , Melanócitos/metabolismo , Receptores Notch/genética , Receptores Notch/metabolismo , Transdução de Sinais , Proteínas Wnt/genética , Proteínas Wnt/metabolismoAssuntos
Eletroencefalografia , Epilepsia/diagnóstico , Gravação em Vídeo , Adolescente , Adulto , Criança , Pré-Escolar , Diagnóstico Diferencial , Humanos , Lactente , MasculinoRESUMO
1q21 is frequently involved in different types of translocation in many types of cancers. Jumping translocation (JT) is an unbalanced translocation that comprises amplified chromosomal segments jumping to various telomeres. In this study, we identified a novel gene human JTB (Jumping Translocation Breakpoint) at 1q21, which fused with the telomeric repeats of acceptor telomeres in a case of JT. hJTB (human JTB) encodes a trans-membrane protein that is highly conserved among divergent eukaryotic species. JT results in a hJTB truncation, which potentially produces an hJTB product devoid of the trans-membrane domain. hJTB is located in a gene-rich region at 1q21, called EDC (Epidermal Differentiation Complex). This is the first report identifying the gene involved in unbalanced translocations at 1q21.
Assuntos
Cromossomos Humanos Par 1/genética , Proteínas de Membrana/genética , Proteínas de Neoplasias , Neoplasias/genética , Translocação Genética , Sequência de Aminoácidos , Sequência de Bases , Diferenciação Celular/genética , Sequência Conservada , Células Epidérmicas , Células Eucarióticas , Feminino , Humanos , Leucemia/genética , Dados de Sequência Molecular , Síndromes Mielodisplásicas/genética , Neoplasias Ovarianas/genética , Homologia de Sequência de AminoácidosRESUMO
A monoclonal antibody, E12, to human Gc globulin was raised in murine somatic cell using purified Gc. The antibody was subtyped IgG2b kappa and had a kd of 3.0 x 10(-8) M for antigen Gc. Monospecificity for Gc was demonstrated by Western blotting of normal human serum using nondenaturing polyacrylamide gel electrophoresis. As judged by ELISA, actin inhibited binding of E12 to Gc in dose-dependent fashion. Affinity chromatography studies further showed that ternary complexes of actin-Gc-E12 were not formed, and actin displaced Gc from Gc-E12 complexes. Proteolytic digestion of Gc with trypsin showed that the monoclonal antibody E12 reacted with the major 30-kDa tryptic fragment containing the amino terminal fragment of Gc, but actin did not react with this fragment. These results indicate that interaction of actin with Gc causes conformational changes which inhibit binding of E12.
Assuntos
Actinas/metabolismo , Proteína de Ligação a Vitamina D/metabolismo , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/metabolismo , Ligação Competitiva , Linhagem Celular , Reações Cruzadas , Epitopos/metabolismo , Humanos , Hibridomas , Ligantes , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Ligação ProteicaRESUMO
The solution structure of calcium-bound calmodulin (CaM) complexed with an antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), has been determined by multidimensional NMR spectroscopy. The structure consists of one molecule of W-7 binding to each of the two domains of CaM. In each domain, the W-7 chloronaphthalene ring interacts with four methionine methyl groups and other aliphatic or aromatic side-chains in a deep hydrophobic pocket, the site responsible for CaM binding to CaM-dependent enzymes such as myosin light chain kinases (MLCKs) and CaM kinase II. This competitive binding at the same site between W-7 and CaM-dependent enzymes suggests the mechanism by which W-7 inhibits CaM to activate the enzymes. The orientation of the W-7 naphthalene ring in the N-terminal pocket is rotated approximately 40 degrees with respect to that in the C-terminal pocket. The W-7 ring orientation differs significantly from the Trp800 indole ring of smooth muscle MLCK bound to the C-terminal pocket and the phenothiazine ring of trifluoperazine bound to the N or C-terminal pocket. These comparative structural analyses demonstrate that the two hydrophobic pockets of CaM can accommodate a variety of bulky aromatic rings, which provides a plausible structural basis for the diversity in CaM-mediated molecular recognition.
Assuntos
Calmodulina/química , Conformação Proteica , Sulfonamidas/química , Animais , Sítios de Ligação , Calmodulina/metabolismo , Substâncias Macromoleculares , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Ligação Proteica , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Soluções , Sulfonamidas/metabolismo , Xenopus laevis/metabolismoRESUMO
Calmodulin (CaM) is a ubiquitous calcium (Ca(2+)) sensor which binds and regulates protein serine/threonine kinases along with many other proteins in a Ca(2+)-dependent manner. For this multi-functionality, conformational plasticity is essential; however, the nature and magnitude of CaM's plasticity still remains largely undetermined. Here, we present the 1.8 A resolution crystal structure of Ca(2+)/CaM, complexed with the 27-residue synthetic peptide corresponding to the CaM-binding domain of the nematode Caenorhabditis elegans Ca(2+)/CaM-dependent kinase kinase (CaMKK). The peptide bound in this crystal structure is a homologue of the previously NMR-derived complex with rat CaMKK, but benefits from improved structural resolution. Careful comparison of the present structure to previous crystal structures of CaM complexed with unrelated peptides derived from myosin light chain kinase and CaM kinase II, allow a quantitative analysis of the differences in the relative orientation of the N and C-terminal domains of CaM, defined as a screw axis rotation angle ranging from 156 degrees to 196 degrees. The principal differences in CaM interaction with various peptides are associated with the N-terminal domain of CaM. Unlike the C-terminal domain, which remains unchanged internally, the N-terminal domain of CaM displays significant differences in the EF-hand helix orientation between this and other CaM structures. Three hydrogen bonds between CaM and the peptide (E87-R336, E87-T339 and K75-T339) along with two salt bridges (E11-R349 and E114-K334) are the most probable determinants for the binding direction of the CaMKK peptide to CaM.