1,109 research outputs found
Transcription Factor AP-2 Regulatory Signatures in Breast Cancer
No full textPhDAP-2 transcription factors are highly conserved basic helix-span-helix proteins whose
members ((x, ß, y, S and c) are crucial regulators of bryonic development. They also
play an important role in human neoplasia. uohis ochemical studies have detected
high levels of AP-2y expression in primary tumo of breast cancer patients. This high
expression has been correlated with reduced survival in all patients and reduced survival
in an ERa positive subset treated with hormone therapy. In breast cancer cell lines, AP-
2 factors have been implicated in the regulation of the ERBB2 proto-oncogene and ERa.
In an effort to further understand the role of AP-2y in breast carcinoma, this study has
sought to identify additional AP-2 activated cellular pathways and ultimately novel
transcriptional targets for AP-2 through the use of gene expression profiling.
RNAi using three independent AP-2y targeting sequences, has been used to deplete AP-
2y levels in the ERa positive MCF-7 breast carcinoma cell line, chosen as it exclusively
expresses the AP-2y family member. Microarrays were then utilised to create an AP-2y
dependent transcription profile. Statistical comparisons between non-silencing control
siRNA and AP-2y targeting siRNA groups identified a total of 162 gene expression
changes (p<0.01). These changes implicate AP-2y in the control of cell cycle
progression and developmental signalling. Indeed a role for AP-2y in the control of cell
cycle, in particular at the GUS transition, has been verified using flow cytometry.
Several of these gene expression changes, including IGFBP3, Transgelin and
KIAA1324, have been confirmed using qPCR and immunoblotting.
Finally, elevated levels of p21 mRNA and protein have been observed following AP-2y
silencing in MCF-7 cells. Additionally, the activity of a p21 promoter reporter is
repressed following transfection with an AP-2y expression construct in HepG2 cells.
These results coupled with ChIP experiments showing AP-2y occupancy at the proximal
promoter region of p21 in cycling MCF-7 cells, implicate AP-2y in the repression of
p21 transcription and suggest a role for AP2y in- the, control of cell cycle in breast
carcinoma in part through the transcriptional repression of p21
Managing Environmental Challenges with Anthropogenic Bedrock Modification: Archaeological Survey Evidence from the Upper Basin (USA) and the Island of Kos (Greece)
No full textHuman-environmental interaction studies typically focus on large-scale landscape modifications of vegetation or
soils and rarely address smaller-scale human alterations to site settings. This approach is based on a broad
concept of environment as “set” having spatially dispersed and regionally defined attributes, as opposed to
something that is mutable at the scale of individual groups of humans living at a specific location. This paper
examines how two prehistoric groups, the Final Neolithic to Early Bronze Age 2 occupants on the island of Kos,
Greece and the Late Formative Period occupants in the Upper Basin, northern Arizona, selected and modified
habitation locations involving exposed bedrock. Although chronologically separated by thousands of years and
occupying different continents, these two groups share similarities in population size, socio-political complexity,
and environmental challenges. In facing these challenges, both groups apply practical, but different, approaches
that utilized one of the most prevalent globally available resources – limestone bedrock
Análisis de la actividad científica y del consumo de información de los psicólogos españoles del ámbito universitario durante el período 1986-1995
No full textO parlamento das técnicas e dos homens: um estudo sobre as redefinições do trabalho numa indústria da Zona Franca de Manaus
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro tecnológico. Programa de Pós-Graduação em Engenharia de ProduçãoA tese intitulada "O Parlamento das Técnicas e dos Homens. Um estudo sobre as redefinições do trabalho numa indústria da Zona Franca de Manaus" investiga as redefinições do trabalho e os novos espaços de conhecimento emergentes no contexto do atual avanço científico e tecnológico através da conceituação, organização e desenvolvimento cognitivo do agente humano na planta produtiva enquanto mediada por novos atores tecnológicos como a tecnologia digital. Adota-se como horizonte de análise a identificação dos novos espaços teórico-práticos de formação do homem como perspectiva de alargamento da compreensão e prática dos processos cognitivos humanos no trabalho
Estrelas magnéticas quimicamente peculiares: Evolução, oscilações e Imageamento Doppler
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas - Programa de Pós-Graduação em Física.Apresentamos nesta tese os resultados de três estudos observacionais relacionados com as estrelas Ap, assim como a sub-classe das estrelas rapidamente oscilantes (roAp). No primeiro estudo, investigamos o estado evolutivo das estrelas Ap visando responder a seguinte pergunta: as estrelas nascem peculiares, ou desenvolvem suas peculiaridades ao longo de sua vida na seqüência principal? Para isso, observamos e classificamos 470 estrelas pertencentes a 18 aglomerados com idades entre 6.9 < log t < 8.1 e estudamos a freqüência de ocorrência de estrelas Ap em função da idade dos aglomerados
The interaction of double-stranded DNA and ExoIII family AP endonuclease
No full text<p><b>Copyright information:</b></p><p>Taken from "Role of the tryptophan residue in the vicinity of the catalytic center of exonuclease III family AP endonucleases: AP site recognition mechanism"</p><p>Nucleic Acids Research 2006;34(5):1552-1563.</p><p>Published online 15 Mar 2006</p><p>PMCID:PMC1408312.</p><p>© The Author 2006. Published by Oxford University Press. All rights reserved</p> A model for recognition of an AP site by the ExoIII family AP endonuclease. () Unbound forms of dsDNA containing an AP site (PDB ID: 1A9I) and human APE1 (PDB ID: 1BIX). The negative charge of the substrate DNA attracts the positively charged region of the enzyme. () An AP site recognition complex. When AP endonuclease encounters an AP site, the tryptophan residue in the vicinity of the catalytic site intercalates into an AP site pocket as an AP site ‘recognizer’. This recognition complex would immediately change into a reaction complex. () A cleavage reaction complex (PDB ID: 1DEW). To cleave on the 5′ side of the AP site, an abasic ribose ring is flipped out from the duplex interior and accommodated into a catalytic pocket with DNA kinking at the AP site
Sensorgrams for the binding of APE1 and its mutants to single- or double-stranded DNA containing AP sites
No full text<p><b>Copyright information:</b></p><p>Taken from "Role of the tryptophan residue in the vicinity of the catalytic center of exonuclease III family AP endonucleases: AP site recognition mechanism"</p><p>Nucleic Acids Research 2006;34(5):1552-1563.</p><p>Published online 15 Mar 2006</p><p>PMCID:PMC1408312.</p><p>© The Author 2006. Published by Oxford University Press. All rights reserved</p> The Overlay of sensorgrams represents interactions of the wild-type APE1 and mutant proteins with immobilized dsDNA (1620 RU) containing AP sites (), and immobilized ssDNA (989 RU) containing AP sites (). There were three AP sites in the immobilized single-stranded oligonucleotide (3AP-ssDNA). The immobilized double-stranded oligonucleotide containing three AP sites (3AP-dsDNA) was prepared by annealing 3AP-ssDNA and its complementary strand. The flow rate of the enzyme solution was 20 µl/min. Association and dissociation phases were both taken as 120 s each. For all the sensorgrams, the injection point was set as the zero time and the baseline prior to the injection was set to zero RU
Effect of tryptophan residues on interaction between peptides and double-stranded oligonucleotides containing AP sites or not
No full text<p><b>Copyright information:</b></p><p>Taken from "Role of the tryptophan residue in the vicinity of the catalytic center of exonuclease III family AP endonucleases: AP site recognition mechanism"</p><p>Nucleic Acids Research 2006;34(5):1552-1563.</p><p>Published online 15 Mar 2006</p><p>PMCID:PMC1408312.</p><p>© The Author 2006. Published by Oxford University Press. All rights reserved</p> () SPR analyses of the interaction between a peptide containing a tryptophan residue (11KWK, solid line) or not (11KAK, dashed line) and dsDNA not containing an AP site. The amount of immobilized oligonucleotides not containing AP sites (3Native-dsDNA) was 1515 RU. For all the sensorgrams, the injection point was set as the zero time and the baseline prior to the injection was set to zero RU. The 11KWK and 11KAK oligopeptides were KSRGKKGRSA and KSRGKKGRSK, respectively. () SPR analyses of the interaction between a peptide containing a tryptophan residue (11KWK, solid line) or not (11KAK, dashed line) and dsDNA containing three AP sites. The amount of immobilized oligonucleotide containing three AP sites (3AP-dsDNA) was 1500 RU. This analysis was carried out under the same experimental conditions as in (A), except for the immobilized oligonucleotide. () Fluorescence spectra of the peptide containing a tryptophan residue in the presence or absence of dsDNA containing an AP site. AP-dsDNA was the substrate used in the AP endonuclease assay (). The DNA sequences of AP-dsDNA and Native-dsDNA were the same excluding the presence of an AP site. Peptide and dsDNA were mixed at a molar ratio of 1:10. The excitation wavelength was 275 nm
Investigation of the regulation of exocytosis and endocytosis pathways in "Saccharomyces cerevisiae"
No full textPolarized growth and remodeling of the plasma membrane proteome in response to environmental changes in yeast depends on regulated exocytosis and endocytosis. The yeast chitin synthase III, Chs3, shuttles between internal compartments and the plasma membrane to allow its cell cycle-dependent expression at the bud neck and uniform discharge at the cell surface upon heat stress. The exomer complex, comprised of Chs5 and the ChAP family of cargo recognition subunits, mediates the direct, controlled export of Chs3 from the trans-Golgi network (TGN) to the plasma membrane. To further establish the role of exomer in regulated trafficking, we characterized a novel exomer-dependent cargo, the prion-domain containing protein, Pin2.
The Pin2 cytosolic domain encompasses an exomer-binding site, located within the C-terminal prion domain, and most likely another interaction site towards the N-terminal region. In parallel, we found that a vast portion of the ChAP Chs6, required for Chs3 export, confers Chs3 specificity, suggesting a proportionally large binding surface on the cargo.
Pin2, like Chs3, localizes to the plasma membrane in a polarized, cell cycle-dependent manner. Moreover Pin2 and Chs3 share several trafficking requirements. Apart from exomer-mediated export, Pin2 and Chs3 undergo active recycling through endocytosis and clathrin adaptor complex 1 (AP-1)-mediated retrograde transport from early endosomes to the TGN. Recognition of AP-1 and most likely of the AP-2 endocytic adaptor could occur through a tyrosine rich YGENYYY sequence in Pin2. The active shuttling of Pin2 between the TGN, early endosomes and the plasma membrane is required for the polarized localization of Pin2 and seems to allow its immediate, stress-responsive redistribution. Upon lithium treatment Pin2 is rapidly endocytosed and maintained in internal compartments. Stress relief results in fast re-export of Pin2 to the plasma membrane.
The Pin2 prion domain contains the exomer and potential AP-1/AP-2 binding motifs. Therefore aggregation of this region may modify the interaction of Pin2 with sorting machineries. Indeed, we found that polarized localization and maintenance of Pin2 in internal compartments is compromised in a Pin2(QNtoED), prion domain mutant. Mutation of QN residues to charged amino acids in Pin2(QNtoED) inhibits the formation of SDS-resistant prion aggregates upon overexpression.
Reversible posttranslational modifications contribute an additional level of Pin2 trafficking regulation. Ubiquitylation of Pin2 is required for its endocytosis under physiological conditions and seems to play a crucial role in Pin2 internalization upon lithium stress. Modification within a cluster of four cytosolic cysteines by palmitoylation seems to support Pin2 cell surface expression. Interestingly, the presence of two luminal cysteines, which engage in the formation of disulfide-linked pin structure, is crucial for Pin2 export. Together this data demonstrates that several cytosolic motifs and the Pin2 prion domain, as well as a defined luminal structure, determine the regulated trafficking of Pin2
Low velocity impact response of Automated Fiber Placement Advanced Placed Ply composites
No full textThis study explores the influence of the internal architecture in the low-velocity impact response of Automated Fiber Placement Advanced Placed Ply laminates. AP-PLY laminates with different lay-up are subjected to low velocity impact and compression after impact experiments. Different performance in terms of damage tolerance is obtained as a function of their internal architecture. Triaxial and quasi-isotropic AP-PLY configurations presented a reduced extension of the delamination in comparison to cross-ply panels. As a result, the cross-ply configuration exhibited a drastic loss in residual strength of 49.1% when subjected to 50 J of impact energy. Numerical simulations were employed to provide insight into the deformation and failure mechanisms (e.g., matrix cracking of directly impacted yarns, delamination or tow debonding), and assess the performance of AP-PLY against conventional angle-ply laminates, predicting larger delamination for the latter, showing the potential of the AP-PLY architecture to produce laminates with improved low-velocity impact performance.This research was supported by the Royal Society (grant number RGS/R2/180091). R. G. is financially supported through Project BIOINSP-CFRP (PID2020-119003GB-I00) financed by MCIN/AEI/ 10.13039/501100011033. J. P. would like to acknowledge the internal funding for young researchers and interdisciplinary projects of the University Carlos III of Madrid (grant number: UNION-CM-UC3M). For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) license to any Author Accepted Manuscript version arising from this submission
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