Search results for " Helix"
showing 10 items of 106 documents
Tetracycline-controlled transgenic targeting from the SCL locus directs conditional expression to erythrocytes, megakaryocytes, granulocytes, and c-k…
2006
The stem cell leukemia gene SCL, also known as TAL-1, encodes a basic helix-loop-helix transcription factor expressed in erythroid, myeloid, megakaryocytic, and hematopoietic stem cells. To be able to make use of the unique tissue-restricted and spatio-temporal expression pattern of the SCL gene, we have generated a knock-in mouse line containing the tTA-2S tetracycline transactivator under the control of SCL regulatory elements. Analysis of this mouse using different tetracycline-dependent reporter strains demonstrated that switchable transgene expression was restricted to erythrocytes, megakaryocytes, granulocytes, and, importantly, to the c-kit-expressing and lineage-negative cell fracti…
NUPR1 works against the metabolic stress-induced autophagy-associated cell death in pancreatic cancer cells.
2013
The incidence of pancreatic adenocarcinoma is increasing with more than 43,000 predicted new cases in the US and 65,000 in Europe this year. Pancreatic cancer patients have a short life expectancy with less than 3–4% 5-y survival, which results in an equivalent incidence and mortality rate. One of the major challenges in pancreatic cancer is the identification of pharmacological approaches that overcome the resistance of this cancer to therapy. Intensive research in the past decades has led to the classification of pancreatic cancers and the identification of the driver key genetic events. Despite the advances in understanding the molecular mechanisms responsible for pancreatic cancer patho…
Common variants conferring risk of schizophrenia
2009
Schizophrenia is a complex disorder, caused by both genetic and environmental factors and their interactions. Research on pathogenesis has traditionally focused on neurotransmitter systems in the brain, particularly those involving dopamine. Schizophrenia has been considered a separate disease for over a century, but in the absence of clear biological markers, diagnosis has historically been based on signs and symptoms. A fundamental message emerging from genome-wide association studies of copy number variations (CNVs) associated with the disease is that its genetic basis does not necessarily conform to classical nosological disease boundaries. Certain CNVs confer not only high relative ris…
Notch signalling is off and is uncoupled from HES1 expression in Ewing's sarcoma
2010
Notch can act as an oncogene or as a tumour suppressor and thus can either promote or inhibit tumour cell growth. To establish Notch status in Ewing's sarcoma family of tumours (ESFT), we investigated the Notch pathway by gene expression profiling meta-analysis or immunohistochemistry in samples obtained from 96 and 24 ESFT patients, respectively. We found that although Notch receptors were highly expressed, Notch did not appear to be active, as evidenced by the absence of Notch receptors in cell nuclei. In contrast, we show that Notch receptors known to be active in colon adenocarcinoma, hepatocarcinoma, and pancreatic carcinoma stain cell nuclei in these tumours. High expression of the No…
Oligodendrocytes in mouse corpus callosum are coupled via gap junction channels formed by connexin47 and connexin32.
2010
According to previously published ultrastructural studies, oligodendrocytes in white matter exhibit gap junctions with astrocytes, but not among each other, while in vitro oligodendrocytes form functional gap junctions. We have studied functional coupling among oligodendrocytes in acute slices of postnatal mouse corpus callosum. By whole-cell patch clamp we dialyzed oligodendrocytes with biocytin, a gap junction-permeable tracer. On average 61 cells were positive for biocytin detected by labeling with streptavidin-Cy3. About 77% of the coupled cells stained positively for the oligodendrocyte marker protein CNPase, 9% for the astrocyte marker GFAP and 14% were negative for both CNPase and GF…
The membrane environment modulates self-association of the human GpA TM domain--implications for membrane protein folding and transmembrane signaling.
2010
Abstract The influence of lipid bilayer properties on a defined and sequence-specific transmembrane helix–helix interaction is not well characterized yet. To study the potential impact of changing bilayer properties on a sequence-specific transmembrane helix–helix interaction, we have traced the association of fluorescent-labeled glycophorin A transmembrane peptides by fluorescence spectroscopy in model membranes with varying lipid compositions. The observed changes of the glycophorin A dimerization propensities in different lipid bilayers suggest that the lipid bilayer thickness severely influences the monomer–dimer equilibrium of this transmembrane domain, and dimerization was most effici…
Influence of hydrophobic matching on association of model transmembrane fragments containing a minimised glycophorin A dimerisation motif
2005
AbstractThe principles that govern the folding and packing of membrane proteins are still not completely understood. In the present work, we have revisited the glycophorin A (GpA) dimerisation motif that mediates transmembrane (TM) helix association, one of the best-suited models of membrane protein oligomerisation. By using artificial polyleucine TM segments we have demonstrated in this study that a pattern of only five amino acids (GVxxGVxxT) promotes specific dimerisation. Further, we have used this minimised GpA motif to assess the influence of hydrophobic matching on the TM helix packing process in detergent micelles and found that this factor modulates helix–helix association and/or d…
Solution NMR structure of aD,L-alternating oligonorleucine as a model of ?-helix
2001
beta-Helix structures are of particular interest due to their capacity to form transmembrane channels with different transport properties. However, the relatively large number of beta-helices configurations does not allow a direct conformational analysis of beta-helical oligopeptides. A synthetic alternating D,L-oligopeptide with twelve norleucines (XIIMe) has been used as a model to get insight in the conformational features of beta-helix structures. The spatial configuration of XIIMe in solution has been determined by NMR. An extensive set of distances (nuclear Overhauser effect) and dihedral (J coupling constants) constraints have been included in molecular dynamics calculations. The NMR…
Predictive modeling of aryl hydrocarbon receptor (AhR) agonism
2020
Abstract The aryl hydrocarbon receptor (AhR) plays a key role in the regulation of gene expression in metabolic machinery and detoxification systems. In the recent years, this receptor has attracted interest as a therapeutic target for immunological, oncogenic and inflammatory conditions. In the present report, in silico and in vitro approaches were combined to study the activation of the AhR. To this end, a large database of chemical compounds with known AhR agonistic activity was employed to build 5 classifiers based on the Adaboost (AdB), Gradient Boosting (GB), Random Forest (RF), Multilayer Perceptron (MLP) and Support Vector Machine (SVM) algorithms, respectively. The built classifier…
Copper(II)-Binding Induces a Unique Polyproline Type II Helical Structure within the Ion-Binding Segment in the Intrinsically Disordered F-Domain of …
2019
Reproduction of the dominant vector of Zika and dengue diseases, Aedes aegypti mosquito, is controlled by an active heterodimer complex composed of the 20-hydroxyecdysone receptor (EcR) and ultraspiracle protein. Although A. aegypti EcR shares the structural and functional organization with other nuclear receptors, its C-terminus has an additional long F domain (AaFEcR). Recently, we showed that the full length AaFEcR is intrinsically disordered with the ability to specifically bind divalent metal ions. Here, we describe the details of the exhaustive structural and thermodynamic properties of Zn2+- and Cu2+-complexes with the AaFEcR domain, based on peptide models of its two putative metal …