Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Hautarzt ; 72(3): 215-224, 2021 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-33580281

RESUMO

Dermatoses of the hands and feet cover a wide range of skin diseases that can occur in children and adolescents and are a frequent question in dermatological practice. Our synopsis of the most important differential diagnoses and their treatment is intended to provide better orientation for daily practice. A precise and detailed history is essential to establish a diagnosis, followed by clinical examination and specific examination methods. Cutaneous infection should always be excluded, as they occur very frequently. Impetigo, punctate keratolysis, blistering distal dactylitis, tinea manuum and pedum, hand-foot-mouth disease, herpes simplex digitalis and verrucae vulgaris as well as scabies are often found in the palmoplantar area and typically affect children and adolescents. In case of allergic contact dermatitis and dyshidrotic eczema, atopic diathesis in the medical history is of importance. However, we must not miss rare causes. Palmoplantar keratoses, for example, can be due to inflammatory dermatoses like pityriasis rubra pilaris (PRP) or may, as well as blistering diseases, result from hereditary disorders. Specialised centers can perform molecular genetic diagnosis and enhance patient care.


Assuntos
Dermatoses da Mão , Ceratodermia Palmar e Plantar , Pitiríase Rubra Pilar , Dermatopatias Infecciosas , Adolescente , Criança , Dermatoses da Mão/diagnóstico , Dermatoses da Mão/terapia , Humanos , Tinha
2.
Biochim Biophys Acta Biomembr ; 1862(9): 183342, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32416190

RESUMO

Peroxisomes are eukaryotic organelles that function in numerous metabolic pathways and defects in peroxisome function can cause serious developmental brain disorders such as adrenoleukodystrophy (ALD). Peroxisomal membrane proteins (PMPs) play a crucial role in regulating peroxisome function. Therefore, PMP homeostasis is vital for peroxisome function. Recently, we established that certain PMPs are degraded by the Ubiquitin Proteasome System yet little is known about how faulty/non-functional PMPs undergo quality control. Here we have investigated the degradation of Pxa1p, a fatty acid transporter in the yeast Saccharomyces cerevisiae. Pxa1p is a homologue of the human protein ALDP and mutations in ALDP result in the severe disorder ALD. By introducing two corresponding ALDP mutations into Pxa1p (Pxa1MUT), fused to mGFP, we show that Pxa1MUT-mGFP is rapidly degraded from peroxisomes in a proteasome-dependent manner, while wild type Pxa1-mGFP remains relatively stable. Furthermore, we identify a role for the ubiquitin ligase Ufd4p in Pxa1MUT-mGFP degradation. Finally, we establish that inhibiting Pxa1MUT-mGFP degradation results in a partial rescue of Pxa1p activity in cells. Together, our data demonstrate that faulty PMPs can undergo proteasome-dependent quality control. Furthermore, our observations may provide new insights into the role of ALDP degradation in ALD.


Assuntos
Membro 1 da Subfamília D de Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/genética , Adrenoleucodistrofia/genética , Proteínas de Saccharomyces cerevisiae/genética , Ubiquitina-Proteína Ligases/genética , Adrenoleucodistrofia/patologia , Humanos , Proteínas de Membrana/genética , Redes e Vias Metabólicas/genética , Mutação/genética , Peroxissomos/genética , Complexo de Endopeptidases do Proteassoma/genética , Proteólise , Saccharomyces cerevisiae/genética
3.
J Eur Acad Dermatol Venereol ; 33(12): 2253-2263, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31454113

RESUMO

Adherence describes how a patient follows a medical regime recommended by a healthcare provider. Poor treatment adherence represents a complex and challenging problem of international healthcare systems, as it has a substantial impact on clinical outcomes and patient safety and constitutes an important financial burden. Since it is one of the most common causes of treatment failure, it is extremely important for physicians to reliably distinguish between non-adherence and non-response. This systematic review aims to summarize the current literature on treatment adherence in dermatology, focusing on chronic inflammatory skin diseases such as psoriasis, atopic dermatitis and acne. A systematic literature search was performed using the PubMed Database, including articles from 2008 to 2018. Low treatment adherence is a multidimensional phenomenon defined by the interplay of numerous factors and should under no circumstances be considered as the patient's fault alone. Factors influencing treatment adherence in dermatology include patient characteristics and beliefs, treatment efficacy and duration, administration routes, disease chronicity and the disease itself. Moreover, the quality of the physician-patient relationship including physician-time available for the patient plays an important role. Understanding patients' adherence patterns and the main drivers of non-adherence creates opportunities to improve adherence in the future. Strategies to increase treatment adherence range from reminder programs to simplifying prescriptions or educational interventions. Absolute adherence to treatment may not be realistically achievable, but efforts need to be made to raise awareness in order to maximize adherence as far as possible.


Assuntos
Acne Vulgar/tratamento farmacológico , Dermatite Atópica/tratamento farmacológico , Psoríase/tratamento farmacológico , Cooperação e Adesão ao Tratamento , Doença Crônica , Humanos , Relações Médico-Paciente , Resultado do Tratamento
4.
Hautarzt ; 69(3): 210-216, 2018 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-29487960

RESUMO

Atopic eczema is a chronic recurrent inflammatory skin disease characterized by intensive pruritus and a high burden of disease. Based on a genetically determined skin barrier dysfunction, xerosis cutis and a tendency towards microbial skin infections are the leading clinical features. Mild and moderate disease manifestations are common, and usually treated with topical agents only. Treatment concepts are usually based on a combination of (i) topical basic therapy consisting of skin cleansing and barrier stabilizing emollients and (ii) topical anti-inflammatory therapy of visible skin lesions with topical corticosteroids and topical calcineurin inhibitors. Proactive therapy of the commonly affected and usually relapsing areas of skin is an important therapeutic option for long-term maintenance treatment of moderate to severe disease. Patients should be actively involved in planning of treatment, which should be adapted to individual patient factors such as age, involved body areas, type of skin lesions, as well as seasonal and climatic factors. New promising treatment options including topical phosphodiesterase inhibitors and topical Janus kinase inhibitors are currently being evaluated in clinical trials and may become a future treatment option for atopic eczema. This review article summarizes the current topical treatment options and new perspectives in the topical therapy of atopic eczema.


Assuntos
Dermatite Atópica/tratamento farmacológico , Fármacos Dermatológicos/uso terapêutico , Corticosteroides/uso terapêutico , Adulto , Inibidores de Calcineurina/uso terapêutico , Criança , Ensaios Clínicos como Assunto , Dermatite Atópica/diagnóstico , Dermatite Atópica/etiologia , Detergentes/uso terapêutico , Humanos , Lactente , Inibidores de Janus Quinases/uso terapêutico , Inibidores de Fosfodiesterase/uso terapêutico , Creme para a Pele/uso terapêutico
5.
Mucosal Immunol ; 9(4): 927-36, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26627459

RESUMO

The intestinal immune system is tailored to fight pathogens effectively while tolerating the indigenous microbiota. Impairments of this homeostatic interaction may contribute to the etiology of various diseases including inflammatory bowel diseases. However, the molecular architecture underlying this complex regulatory interaction is not well understood. Here, we show that the fruit fly Drosophila melanogaster has a multilayered intestinal immune system that ensures strictly localized antimicrobial responses. Enterocytes, a major cell population of the intestine, produced antimicrobial peptides (AMPs) in a FoxO- but not NF-κB-dependent manner. Consequently, animals impaired in FoxO-mediated signaling had a significantly lowered resistance to intestinal infections; they were unable to increase the expression of AMP genes and males showed an increased bacterial load in response to an infection. Conventional innate immune signaling converging onto NF-κB activation was operative in only a few regions of the intestine, comprising the proventriculus, copper cells, and intestinal stem cells. Taken together, our results imply that danger-mediated as well as conventional innate immune signaling constitute modules that contribute to the fruit fly's intestinal immune system. We propose that this special architecture ensures localized and efficient antimicrobial responses against invasive pathogens while preserving the microbiota.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/imunologia , Enterócitos/imunologia , Fatores de Transcrição Forkhead/metabolismo , Imunidade nas Mucosas , Intestinos/imunologia , Infecções por Serratia/imunologia , Serratia marcescens/imunologia , Administração Oral , Animais , Animais Geneticamente Modificados , Peptídeos Catiônicos Antimicrobianos/metabolismo , Carga Bacteriana , Proteínas de Drosophila/genética , Enterócitos/microbiologia , Fatores de Transcrição Forkhead/genética , Homeostase , Humanos , Doenças Inflamatórias Intestinais/imunologia , Intestinos/anatomia & histologia , Masculino , NF-kappa B/metabolismo , Transdução de Sinais
6.
Acta Neurol Scand ; 130(1): 46-52, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24571587

RESUMO

OBJECTIVES: There is convergent evidence for an important role of interleukin-16 (IL-16) in the pathogenesis of multiple sclerosis (MS). IL-16 serves as a chemoattractant for different immune cells that are involved in developing lesions. Here, we compared IL-16 levels of MS patients and controls and addressed the long-term effect of IFN-ß, the most common immunomodulatory MS therapy, on IL-16 serum levels in MS patients over 2 years. Beyond this, we analysed the expression of IL-16 in two CD4(+) T-cell subsets, Th1 and Th17 cells, which are important autoimmune mediators and affected by IFN-ß treatment, derived from myelin-specific T-cell transgenic mice. MATERIALS AND METHODS: IL-16 serum levels of 17 controls and of 16 MS patients before therapy and at months 1, 2, 3, 6, 9, 12 and 24 during IFN-ß1a therapy were determined by ELISA. MRI was performed before therapy, at months 12 and 24. IL-16 expression of in vitro differentiated murine myelin oligodendrocyte glycoprotein (MOG)-specific Th1 and Th17 cells was quantified by real-time PCR. RESULTS: Before therapy, MS patients showed significantly elevated IL-16 levels compared with controls irrespective of disease activity determined by MRI. Therapy with IFN-ß1a led to a significant linear decrease in IL-16 serum levels beginning after 2 months. MOG-specific Th17 cells expressed more IL-16 than Th1 cells. CONCLUSIONS: Reduction in increased IL-16 levels may be of relevance for the therapeutic effect of IFN-ß1a in MS. Easily accessible IL-16 serum levels hold a potential as biomarker of treatment efficacy in MS.


Assuntos
Fatores Imunológicos/uso terapêutico , Interferon beta/uso terapêutico , Interleucina-16/sangue , Esclerose Múltipla Recidivante-Remitente/tratamento farmacológico , Esclerose Múltipla Recidivante-Remitente/imunologia , Adulto , Animais , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Interferon beta-1a , Interleucina-16/biossíntese , Interleucina-16/imunologia , Imageamento por Ressonância Magnética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Pessoa de Meia-Idade , Esclerose Múltipla Recidivante-Remitente/sangue , Reação em Cadeia da Polimerase em Tempo Real , Células Th1/imunologia , Células Th1/metabolismo , Células Th17/imunologia , Células Th17/metabolismo , Adulto Jovem
7.
AJNR Am J Neuroradiol ; 33(7): 1356-62, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22383242

RESUMO

BACKGROUND AND PURPOSE: MRI markers of neuroaxonal damage in MS have emerged as critical long-term predictors of MS-related disability. Here we investigated the potential of whole-brain diffusivity and brain volume for the prediction of cross-sectional disability and short- to medium-term clinical evolution. MATERIALS AND METHODS: In this multimodal prospective longitudinal MRI study of 54 patients with MS (87% under immunomodulatory therapy, baseline and follow-up at a median of 12 months), ADC histogram analysis, WM lesion load, BPF, whole-brain atrophy rate, MSFC score, and EDSS score were obtained. A total of 44 patients with no relapse at both time points were included. RESULTS: At both time points, ADC histogram analysis provided robust predictors of the MSFC scores (maximal R(2) = 0.576, P < .001), incorporated cognition and fine-motor skill subscores, and EDSS scores. Significant changes beyond physiologic age-related changes at follow-up were noted for ADC histogram markers and BPF. Stronger diffusivity alterations and brain volume at baseline predicted MSFC decline, as demonstrated by multiple linear regression analysis (mean ADC, R(2) = 0.203; P = .003) and lower baseline BPF in patients with declined compared with stable MSFC scores (P = .001). Results were independent of intercurrent relapses. CONCLUSIONS: Diffusion histogram analysis provided stable surrogates of disability in MS and proved sensitive for monitoring disease progression during a median of 12 months. Advanced neuroaxonal pathology at baseline was indicative of an increased risk for sustained progression during a median of 12 months, independent of intercurrent relapses.


Assuntos
Encéfalo/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Esclerose Múltipla/patologia , Adulto , Feminino , Humanos , Masculino , Tamanho do Órgão , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
8.
Acta Neurol Scand ; 123(6): 400-6, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20849399

RESUMO

OBJECTIVES: Recently, associations of several single-nucleotide polymorphisms (SNPs) within the CLEC16A gene with multiple sclerosis (MS), type-I diabetes, and primary adrenal insufficiency were reported. METHODS: We performed linkage disequilibrium (LD) fine mapping with 31 SNPs from this gene, searching for the region of highest association with MS in a German sample consisting of 603 patients and 825 controls. RESULTS: Four SNPs located in intron 19 of the CLEC16A gene were found associated. We could replicate the finding for SNP rs725613 and were able to show for the first time the association of rs2041670, rs2080272 and rs998592 with MS. CONCLUSION: All described base polymorphisms are mapping to one LD block of approximately 50 kb within intron 19 of the CLEC16A gene, suggesting a pivotal role of this region for susceptibility of MS and possibly also for other autoimmune diseases.


Assuntos
Predisposição Genética para Doença/genética , Variação Genética , Lectinas Tipo C/genética , Proteínas de Transporte de Monossacarídeos/genética , Esclerose Múltipla/genética , Polimorfismo de Nucleotídeo Único/genética , Adolescente , Adulto , Idoso , Feminino , Testes Genéticos/métodos , Humanos , Desequilíbrio de Ligação , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/epidemiologia , Adulto Jovem
9.
Genes Immun ; 9(3): 259-63, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18354419

RESUMO

Multiple sclerosis (MS) is the most common chronic inflammatory neurologic disorder diagnosed in young adults and, due to its chronic course, is responsible for a substantial economic burden. MS is considered to be a multifactorial disease in which both genetic and environmental factors intervene. The well-established human leukocyte antigen (HLA) association does not completely explain the genetic impact on disease susceptibility. However, identification and validation of non-HLA-genes conferring susceptibility to MS has proven to be difficult probably because of the small individual contribution of each of these genes. Recently, associations with two single nucleotide polymorphisms (SNPs) in the IL2RA gene (rs12722489, rs2104286) and one SNP in the IL7RA gene (rs6897932) have been reported by several groups. These three SNPs were genotyped in a French and a German population of MS patients using the hME assay by the matrix-assisted laser desorption/ionization time of flight technology (Sequenom, San Diego, CA, USA). We show that these SNPs do contribute to the risk of MS in these two unrelated European MS patient populations with odds ratios varying from 1.1 to 1.5. The discovery and validation of new genetic risk factors in independent populations may help toward the understanding of MS pathogenesis by providing valuable information on biological pathways to be investigated.


Assuntos
Predisposição Genética para Doença/genética , Subunidade alfa de Receptor de Interleucina-2/genética , Esclerose Múltipla/genética , Receptores de Interleucina-7/genética , Adulto , Idoso , Feminino , França , Frequência do Gene , Genótipo , Alemanha , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
10.
Biotechniques ; 33(3): 592, 594, 596-8 passim, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12238769

RESUMO

GFP has established itself as a highly useful tool throughout many areas of modern biology. Recently, the novel fluorescent protein drFP583, also termed DsRed or RFP, was clonedfrom a coral of the Discosoma genus. The protein is only weakly homologous to GFP and has a red emission spectrum, which makes drFP583 an attractive candidate for in vivo double labeling together with GFP variants. However, wildtype drFP583 has several drawbacks, including inefficient folding of the protein, extremely slow maturation of the chromophore, and tetramerization even in dilute solutions. Here we report on important improvements to this reporter that lead to higher levels of fluorescent drFP583 species in the cell. We further characterized our best mutant for applications in yeast and mammalian cell biology.


Assuntos
Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Engenharia de Proteínas/métodos , Saccharomyces/genética , Saccharomyces/metabolismo , Sequência de Bases , Linhagem Celular , Evolução Molecular Direcionada/métodos , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação da Expressão Gênica , Células HeLa/metabolismo , Humanos , Proteínas Luminescentes/química , Proteínas Luminescentes/isolamento & purificação , Substâncias Macromoleculares , Dados de Sequência Molecular , Mutação , Ligação Proteica , Mapeamento de Interação de Proteínas/métodos , Controle de Qualidade , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteína Vermelha Fluorescente
11.
EMBO J ; 20(24): 6946-57, 2001 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-11742972

RESUMO

In yeast, the differentiation process at the end of meiosis generates four daughter cells inside the boundaries of the mother cell. A meiosis-specific plaque (MP) at the spindle pole bodies (SPBs) serves as the starting site for the formation of the prospore membranes (PSMs) that are destined to encapsulate the post-meiotic nuclei. Here we report the identification of Ady3p and Ssp1p, which are functional components of the leading edge protein (LEP) coat, that covers the ring-shaped opening of the PSMs. Ssp1p is required for the assembly of the LEP coat, which consists of at least three proteins (Ssp1p, Ady3p and Don1p). The assembly of the LEP coat starts with the formation of cytosolic precursors, which then bind in an Ady3p-dependent manner to the SPBs. Subsequent processes at the SPBs leading to functional LEP coats require Ssp1p and the MP components. During growth of the PSMs, the LEP coat functions in formation of the cup-shaped membrane structure that is indispensable for the regulated cellularization of the cytoplasm around the post-meiotic nuclei.


Assuntos
Proteínas Fúngicas/metabolismo , Fosfoproteínas/metabolismo , Saccharomyces cerevisiae/metabolismo , Esporos Fúngicos , Imunofluorescência , Espectrometria de Massas , Meiose , Microscopia Eletrônica , Ligação Proteica , Saccharomyces cerevisiae/fisiologia , Esporos Fúngicos/ultraestrutura
12.
Phytochemistry ; 58(5): 819-25, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11672748

RESUMO

Zea mays was incubated with the natural phytotoxin benzoxazolin-2(3H)-one (BOA) to investigate the detoxification process. A hitherto unknown detoxification product, 1-(2-hydroxyphenylamino)-1-deoxy-beta-gentiobioside 1,2-carbamate (3), was isolated and identified. A reinvestigation of known BOA detoxification products by NMR methods led to the finding that the structure of benzoxazolin-2(3H)-one-N-beta-glucoside (1) first reported from Avena sativa has to be revised. In fact, the correct structure is that of the isomeric 1-(2-hydroxyphenylamino)-1-deoxy-beta-glucoside 1,2-carbamate 2, which is structurally related to 3. It was now shown with a synthetic mixture of 1 and 2 that 1 underwent spontaneous isomerization to form 2 in solution. Thus, N-glucosylation of BOA in the plant led finally to the carbamate 2. In contrast to BOA-6-O-glucosylation, BOA-induced N-glucosylation appears first after 6-8 h of incubation. As soon as N-glucosylation is possible, BOA-6-O-glucoside is not further accumulated, whereas the amount of glucoside carbamate increases continuously during the next 40 h. Synthesis of gentiobioside carbamate seems to be a late event in BOA detoxification. All detoxification products are released into the environment via root exudation.


Assuntos
Benzoxazóis/farmacocinética , Carbamatos/análise , Carbamatos/isolamento & purificação , Glicosídeos/isolamento & purificação , Zea mays/metabolismo , Glicosídeos/análise , Glicosídeos/metabolismo , Inativação Metabólica/fisiologia , Raízes de Plantas/metabolismo
13.
Curr Biol ; 11(13): 1001-9, 2001 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-11470404

RESUMO

BACKGROUND: Meiosis is the process by which gametes are generated with half the ploidy of somatic cells. This reduction is achieved by three major differences in chromosome behavior during meiosis as compared to mitosis: the production of chiasmata by recombination, the protection of centromere-proximal sister chromatid cohesion, and the monoorientation of sister kinetochores during meiosis I. Mistakes in any of these processes lead to chromosome missegregation. RESULTS: To identify genes involved in meiotic chromosome behavior in Saccharomyces cerevisiae, we deleted 301 open reading frames (ORFs) which are preferentially expressed in meiotic cells according to microarray gene expression data. To facilitate the detection of chromosome missegregation mutants, chromosome V of the parental strain was marked by GFP. Thirty-three ORFs were required for the formation of wild-type asci, eight of which were needed for proper chromosome segregation. One of these (MAM1) is essential for the monoorientation of sister kinetochores during meiosis I. Two genes (MND1 and MND2) are implicated in the recombination process and another two (SMA1 and SMA2) in prospore membrane formation. CONCLUSIONS: Reverse genetics using gene expression data is an effective method for identifying new genes involved in specific cellular processes.


Assuntos
Genes Fúngicos , Meiose/genética , Saccharomyces cerevisiae/genética , Esporos Fúngicos/genética , Núcleo Celular/genética , Núcleo Celular/ultraestrutura , Segregação de Cromossomos/genética , Deleção de Genes , Perfilação da Expressão Gênica , Fases de Leitura Aberta , Fase S , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/fisiologia
14.
EMBO J ; 19(14): 3657-67, 2000 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-10899120

RESUMO

Spindle pole bodies (SPBs) are the centrosome equivalents in yeast, required for microtubule organization. In yeast, the SPB further serves as the attachment sites of the prospore membrane during meiosis. Here we report the identification of two new meiosis-specific components of the SPB, Mpc54p and Mpc70p, and the first protein specific for the prospore membrane, Don1p. Mpc54p and Mpc70p are not present in mitotic SPBs, and during meiosis II they are components of a meiosis-specific structural alteration of the outer plaque of the SPB. Both proteins are dispensable for the meiotic divisions but are essentially required for the formation of the prospore membrane. In the mpc54 and mpc70 mutants, the Don1p-containing precursors of the prospore membrane can still be found in the cytoplasm and associated with the SPB. Unexpectedly, however, the assembly of the precursors to a continuous membrane system is affected. Thus, the meiotic SPB is directly involved in the formation of a specialized membrane system, the membrane of the prospore.


Assuntos
Centrossomo/metabolismo , Membranas Intracelulares/metabolismo , Meiose , Saccharomyces cerevisiae/citologia , Sequência de Aminoácidos , Parede Celular/metabolismo , Parede Celular/ultraestrutura , Centrossomo/química , Centrossomo/ultraestrutura , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Membranas Intracelulares/ultraestrutura , Proteínas de Membrana/química , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Microscopia Eletrônica , Microscopia de Fluorescência , Modelos Biológicos , Dados de Sequência Molecular , Mutação , Fenótipo , Ligação Proteica , Precursores de Proteínas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/ultraestrutura , Alinhamento de Sequência , Esporos Fúngicos/citologia , Esporos Fúngicos/metabolismo , Esporos Fúngicos/ultraestrutura , Técnicas do Sistema de Duplo-Híbrido
15.
Biol Cell ; 91(4-5): 291-304, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10518996

RESUMO

In budding yeast microtubule organizing functions are provided by the spindle pole body (SPB), a multi-layered structure that is embedded in the nuclear envelope throughout the cell cycle. The SPB organizes the nuclear and cytoplasmic microtubules which are spatially and functionally distinct. Microtubule formation in yeast requires the Tub4p-complex, containing the gamma-tubulin Tub4p, and two additional proteins, the SPB components Spc97p and Spc98p. The Tub4p complex assembles in the cytoplasm and is then anchored to the sides of the SPB which organize microtubules. This is achieved by the binding of Spc97p and Spc98p to so-called gamma-tubulin complex binding proteins (GTBPs) at the SPB. Spc72p is the yeast GTBP at the cytoplasmic side of the SPB, while Spc110p is the nuclear GTBP. Both GTBPs control the number of Tub4p complexes associated with the SPB and thereby the number of microtubules formed. In addition, the GTBPs may regulate the activity of the Tub4p complex. Homologues of Spc97p and Spc98p have been identified from yeast to mammalian cells and these are also part of gamma-tubulin complexes, suggesting that these related proteins may also interact with GTBPs at the centrosome. Candidates for GTBPs have been identified in mammalian and insect cells.


Assuntos
Fuso Acromático/fisiologia , Leveduras/fisiologia , Tubulina (Proteína)/fisiologia
16.
EMBO J ; 18(15): 4180-95, 1999 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-10428957

RESUMO

The spindle pole body component Kar1p has a function in nuclear fusion during conjugation, a process known as karyogamy. The molecular role of Kar1p during this process is poorly understood. Here we show that the yeast gamma-tubulin complex-binding protein Spc72p interacts directly with the N-terminal domain of Kar1p, thereby targeting the gamma-tubulin complex to the half bridge, a substructure of the spindle pole body, where it organizes microtubules. This binding of Spc72p to Kar1p has only a minor role during vegetative growth, whereas it becomes essential for karyogamy in mating cells, explaining the important role of Kar1p in this process. We also show that the localization of Spc72p within the spindle pole body changes throughout the cell cycle and even more strongly in response to mating pheromone. Taken together, these observations suggest that the relocalization of Spc72p within the spindle pole body is the 'landmark' event in the pheromone-induced reorganization of the cytoplasmic microtubules.


Assuntos
Proteínas Fúngicas/metabolismo , Microtúbulos/fisiologia , Proteínas Nucleares/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Tubulina (Proteína)/metabolismo , Ligação Proteica , Proteínas Recombinantes de Fusão/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento
17.
Yeast ; 15(10B): 963-72, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10407276

RESUMO

Epitope tagging of proteins as a strategy for the analysis of function, interactions and the subcellular distribution of proteins has become widely used. In the yeast Saccharomyces cerevisiae, molecular biological techniques have been developed that use a simple PCR-based strategy to introduce epitope tags to chromosomal loci (Wach et al., 1994). To further employ the power of this strategy, a variety of novel tags was constructed. These tags were combined with different selectable marker genes, resulting in PCR amplificable modules. Only one set of primers is required for the amplification of any module. Furthermore, convenient laboratory techniques are described that facilitate the genetic manipulations of yeast strains, as well as the analysis of the epitope-tagged proteins.


Assuntos
Mapeamento de Epitopos , Genes Fúngicos , Reação em Cadeia da Polimerase/métodos , Saccharomyces cerevisiae/genética , Western Blotting , Proteínas Fúngicas/genética , Proteínas Fúngicas/imunologia , Saccharomyces cerevisiae/imunologia , Fuso Acromático/genética , Transformação Genética
18.
Proc Natl Acad Sci U S A ; 96(11): 6205-10, 1999 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-10339566

RESUMO

In yeast, microtubules are organized by the spindle pole body (SPB). The SPB is a disk-like multilayered structure that is embedded in the nuclear envelope via its central plaque, whereas the outer and inner plaques are exposed to the cytoplasm and nucleoplasm, respectively. How the SPB assembles is poorly understood. We show that the inner/central plaque is composed of a stable SPB subcomplex, containing the gamma-tubulin complex-binding protein Spc110p, calmodulin, Spc42p, and Spc29p. Spc29p acts as a linker between the central plaque component Spc42p and the inner plaque protein Spc110p. Evidence is provided that the calmodulin-binding site of Spc110p influences the binding of Spc29p to Spc110p. Spc42p also was identified as a component of a cytoplasmic SPB subcomplex containing Spc94p/Nud1p, Cnm67p, and Spc42p. Spc29p and Spc42p may be part of a critical interface of nucleoplasmic and cytoplasmic assembled SPB subcomplexes that form during SPB duplication. In agreement with this, overexpressed Spc29p was found to be a nuclear protein, whereas Spc42p is cytoplasmic. In addition, an essential function of SPC29 during SPB assembly is indicated by the SPB duplication defect of conditional lethal spc29(ts) cells and by the genetic interaction of SPC29 with CDC31 and KAR1, two genes that are involved in SPB duplication.


Assuntos
Proteínas Fúngicas/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/fisiologia , Fuso Acromático/fisiologia , Fuso Acromático/ultraestrutura , Sequência de Aminoácidos , Sítios de Ligação , Proteínas de Ligação a Calmodulina , Proteínas do Citoesqueleto , Proteínas Fúngicas/isolamento & purificação , Modelos Estruturais , Dados de Sequência Molecular , Membrana Nuclear/fisiologia , Membrana Nuclear/ultraestrutura , Proteínas Nucleares/isolamento & purificação , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Alinhamento de Sequência
19.
EMBO J ; 17(14): 3952-67, 1998 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-9670012

RESUMO

The yeast microtubule organizing centre (MTOC), known as the spindle pole body (SPB), organizes the nuclear and cytoplasmic microtubules which are functionally and spatially distinct. Microtubule organization requires the yeast gamma-tubulin complex (Tub4p complex) which binds to the nuclear side of the SPB at the N-terminal domain of Spc110p. Here, we describe the identification of the essential SPB component Spc72p whose N-terminal domain interacts with the Tub4p complex on the cytoplasmic side of the SPB. We further report that this Tub4p complex-binding domain of Spc72p is essential and that temperature-sensitive alleles of SPC72 or overexpression of a binding domain-deleted variant of SPC72 (DeltaN-SPC72) impair cytoplasmic microtubule formation. Consequently, polynucleated and anucleated cells accumulated in these cultures. In contrast, overexpression of the entire SPC72 results in more cytoplasmic microtubules compared with wild-type. Finally, exchange of the Tub4p complex-binding domains of Spc110p and Spc72p established that the Spc110p domain, when attached to DeltaN-Spc72p, was functional at the cytoplasmic site of the SPB, while the corresponding domain of Spc72p fused to DeltaN-Spc110p led to a dominant-negative effect. These results suggest that different components of MTOCs act as receptors for gamma-tubulin complexes and that they are essential for the function of MTOCs.


Assuntos
Proteínas Fúngicas/metabolismo , Proteínas dos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Proteínas de Saccharomyces cerevisiae , Tubulina (Proteína)/metabolismo , Proteínas de Ligação a Calmodulina , Núcleo Celular/metabolismo , Centrossomo/metabolismo , Clonagem Molecular , Citoplasma/metabolismo , Proteínas do Citoesqueleto , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas dos Microtúbulos/química , Proteínas dos Microtúbulos/genética , Peso Molecular , Proteínas Nucleares/metabolismo , Saccharomyces cerevisiae/citologia , Deleção de Sequência , Temperatura
20.
Mol Biol Cell ; 9(4): 775-93, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9529377

RESUMO

In the yeast Saccharomyces cerevisiae, microtubules are organized by the spindle pole body (SPB), which is embedded in the nuclear envelope. Microtubule organization requires the gamma-tubulin complex containing the gamma-tubulin Tub4p, Spc98p, and Spc97p. The Tub4p complex is associated with cytoplasmic and nuclear substructures of the SPB, which organize the cytoplasmic and nuclear microtubules. Here we present evidence that the Tub4p complex assembles in the cytoplasm and then either binds to the cytoplasmic side of the SPB or is imported into the nucleus followed by binding to the nuclear side of the SPB. Nuclear import of the Tub4p complex is mediated by the essential nuclear localization sequence of Spc98p. Our studies also indicate that Spc98p in the Tub4p complex is phosphorylated at the nuclear, but not at the cytoplasmic, side of the SPB. This phosphorylation is cell cycle dependent and occurs after SPB duplication and nucleation of microtubules by the new SPB and therefore may have a role in mitotic spindle function. In addition, activation of the mitotic checkpoint stimulates Spc98p phosphorylation. The kinase Mps1p, which functions in SPB duplication and mitotic checkpoint control, seems to be involved in Spc98p phosphorylation. Our results also suggest that the nuclear and cytoplasmic Tub4p complexes are regulated differently.


Assuntos
Núcleo Celular/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Fuso Acromático/fisiologia , Tubulina (Proteína)/metabolismo , Sequência de Aminoácidos , Transporte Biológico , Ciclo Celular/genética , Citoplasma , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Microtúbulos , Dados de Sequência Molecular , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Fosforilação , Saccharomyces cerevisiae/metabolismo , Tubulina (Proteína)/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...