133 research outputs found

    Vectors for N- or C-terminal positioning of the yeast Gal4p DNA binding or activator domains

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    EMTREE drug terms: fungal protein; heat shock protein 90; hybrid protein; transcription factor EMTREE medical terms: amino terminal sequence; article; carboxy terminal sequence; DNA binding; DNA binding domain; expression vector; Gal4p domain; gene activation; gene activation domain; gene expression; nonhuman; plasmid; plasmid ADC; plasmid BDC; protein domain; protein protein interaction; technique; two hybrid system; yeast MeSH: Binding Sites; DNA-Binding Proteins; Genetic Vectors; Protein Structure, Tertiary; Recombinant Fusion Proteins; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Trans-Activation (Genetics); Transcription Factors; Two-Hybrid System Techniqu

    UCS protein function is partially restored in the Saccharomyces cerevisiae she4 mutant with expression of the human UNC45-GC, but not UNC45-SM

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    A dedicated UNC45, Cro1, She4 (UCS) domain-containing protein assists in the Hsp90-mediated folding of the myosin head. Only weak sequence conservation exists between the single UCS protein of simple eukaryotes (She4 in budding yeast) and the two UCS proteins of higher organisms (the general cell and striated muscle UNC45s; UNC45-GC and UNC45-SM, respectively). In vertebrates, UNC45-GC facilitates cytoskeletal functions, whereas the 55% identical UNC45-SM assists assembly of the contractile apparatus of cardiac and skeletal muscles. A Saccharomyces cerevisiae she4Ξ” mutant, totally lacking any UCS protein, was engineered to express as its sole Hsp90 either the Hsp90Ξ± or the Hsp90Ξ² isoforms of human cytosolic Hsp90. A transient induction of the human UNC45-GC, but not UNC45-SM, could rescue the defective endocytosis in these she4Ξ” cells at 39Β Β°C, irrespective of whether they possessed Hsp90Ξ± or Hsp90Ξ². UNC45-GC-mediated rescue of the localisation of a Myo5-green fluorescent protein (GFP) fusion to cortical patches at 39Β Β°C was more efficient in the yeast containing Hsp90Ξ±, though this may relate to more efficient functioning of Hsp90Ξ± as compared to Hsp90Ξ² in these strains. Furthermore, inducible expression of UNC45-GC, but not UNC45-SM, could partially rescue survival at a more extreme temperature (45Β Β°C) that normally causes she4Ξ” mutant yeast cells to lyse. The results indicate that UCS protein function has been most conserved-yeast to man-in the UNC45-GC, not UNC45-SM. This may reflect UNC45-GC being the vertebrate UCS protein that assists formation of the actomyosin complexes needed for cytokinesis, cell morphological change, and organelle trafficking-events also facilitated by the myosins in yeast

    Quality gap of educational services in viewpoints of students in Hormozgan University of medical sciences

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    <p>Abstract</p> <p>Background</p> <p>Higher education is growing fast and every day it becomes more and more exposed to globalization processes. The aim of this study was to determine the quality gap of educational services by using a modified SERVQUAL instrument among students in Hormozgan University of Medical Sciences.</p> <p>Methods</p> <p>A cross-sectional study was carried out at Hormozgan University of Medical Sciences in 2007. In this study, a total of 300 students were selected randomly and asked to complete a questionnaire that was designed according to SERVQUAL methods. This questionnaire measured students' perceptions and expectations in five dimensions of service that consists of assurance, responsiveness, empathy, reliability and tangibles. The quality gap of educational services was determined based on differences between students' perceptions and expectations.</p> <p>Results</p> <p>The results demonstrated that in each of the five SERVQUAL dimensions, there was a negative quality gap. The least and the most negative quality gap means were in the reliability (-0.71) and responsiveness (-1.14) dimensions respectively. Also, there were significant differences between perceptions and expectations of students in all of the five SERVQUAL dimensions (p < 0.001).</p> <p>Conclusion</p> <p>Negative quality gaps mean students' expectations exceed their perceptions. Thus, improvements are needed across all five dimensions.</p

    Adult liver transplantation: A UK clinical guideline - part 1: pre-operation

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    Liver transplantation is a highly successful treatment for all types of liver failure, some non-liver failure indications and liver cancer. Most referrals come from secondary care. This first part of a two-part guideline outlines who to refer, and how that referral should be made, including patient details and additional issues such as those relevant to alcohol and drug misuse. The process of liver transplant assessment involves the confirmation of the diagnosis and non-reversibility, an evaluation of comorbidities and exclusion of contraindications. Finally, those making it onto the waiting list require monitoring and optimising. Underpinning this process is a need for good communication between patient, their carers, secondary care and the liver transplant service, synchronised by the transplant coordinator. Managing expectation and balancing the uncertainty of organ availability against the inevitable progression of underlying liver disease requires sensitivity and honesty from all healthcare providers and the assessment of palliative care needs is an integral part of this process.</jats:p

    A Bronze Age Round Barrow Cemetery, Pit Alignments, Iron Age Burials, Iron Age Copper Working, and Later Activity at Four Crosses, Llandysilio, Powys.

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    Excavation undertaken at the Upper Severn valley round barrow cemetery at Four Crosses, Llandysilio between 2004 and 2006 has increased the known barrows and ring-ditches to some 26 monuments, and revealed additional burials. Based on limited dating evidence, and the data from earlier excavations, the majority of the barrows are thought to be constructed in the Bronze Age. The barrows are part of a larger linear cemetery and the landscape setting and wider significance of this linear barrow cemetery are explored within this report. Dating suggests two barrows were later, Iron Age additions. The excavation also investigated Iron Age and undated pit alignments, Middle Iron Age copper working and a small Romano-British inhumation cemetery and field systems. Much of this evidence reflects the continuing importance of the site for ritual and funerary activity

    Current quality of life and its determinants among opiate-dependent individuals five years after starting methadone treatment

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    This study explores the current QoL of opiate-dependent individuals who started outpatient methadone treatment at least 5 years ago and assesses the influence of demographic, psychosocial, drug and health-related variables on individuals' QoL. Participants (n = 159) were interviewed about their current QoL, psychological distress and severity of drug-related problems, using the Lancashire Quality of Life Profile, the Brief Symptom Inventory and the Addiction Severity Index. Potential determinants of QoL were assessed in a multiple linear regression analysis. Five years after the start of methadone treatment, opiate-dependent individuals report low QoL scores on various domains. No association was found between drug-related variables and QoL, but a significant negative impact of psychological distress was identified. Severity of psychological distress, taking medication for psychological problems and the inability to change one's living situation were associated with lower QoL. Having at least one good friend and a structured daily activity had a significant, positive impact on QoL. Opiate-dependent individuals' QoL is mainly determined by their psychological well-being and a number of psychosocial variables. These findings highlight the importance of a holistic approach to treatment and support in methadone maintenance treatment, which goes beyond fixing the negative physical consequences of opiate dependence

    Rapid deacetylation of yeast Hsp70 mediates the cellular response to heat stress

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    Hsp70 is a highly conserved molecular chaperone critical for the folding of new and denatured proteins. While traditional models state that cells respond to stress by upregulating inducible HSPs, this response is relatively slow and is limited by transcriptional and translational machinery. Recent studies have identified a number of post-translational modifications (PTMs) on Hsp70 that act to fine-tune its function. We utilized mass spectrometry to determine whether yeast Hsp70 (Ssa1) is differentially modified upon heat shock. We uncovered four lysine residues on Ssa1, K86, K185, K354 and K562 that are deacetylated in response to heat shock. Mutation of these sites cause a substantial remodeling of the Hsp70 interaction network of co-chaperone partners and client proteins while preserving essential chaperone function. Acetylation/deacetylation at these residues alter expression of other heat-shock induced chaperones as well as directly influencing Hsf1 activity. Taken together our data suggest that cells may have the ability to respond to heat stress quickly though Hsp70 deacetylation, followed by a slower, more traditional transcriptional response

    Distribution of misfolded prion protein seeding activity alone does not predict regions of neurodegeneration

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    Protein misfolding is common across many neurodegenerative diseases, with misfolded proteins acting as seeds for "prion-like" conversion of normally folded protein to abnormal conformations. A central hypothesis is that misfolded protein accumulation, spread and distribution is restricted to specific neuronal populations of the central nervous system and thus predict regions of neurodegeneration. We examined this hypothesis using a highly sensitive assay system for detection of misfolded protein seeds in a murine model of prion disease. Misfolded prion protein seeds were observed widespread throughout the brain accumulating in all brain regions examined irrespective of neurodegeneration. Importantly neither time of exposure nor amount of misfolded protein seeds present determined regions of neurodegeneration. We further demonstrate two distinct microglia responses in prion infected brains, a 11 novel homeostatic response in all regions and an innate immune response restricted to sites of 12 neurodegeneration. Therefore accumulation of misfolded prion protein alone does not define targeting 13 of neurodegeneration which instead results only when misfolded prion protein accompanies a specific 14 innate immune response

    Probing Molecular Mechanisms of the Hsp90 Chaperone: Biophysical Modeling Identifies Key Regulators of Functional Dynamics

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    Deciphering functional mechanisms of the Hsp90 chaperone machinery is an important objective in cancer biology aiming to facilitate discovery of targeted anti-cancer therapies. Despite significant advances in understanding structure and function of molecular chaperones, organizing molecular principles that control the relationship between conformational diversity and functional mechanisms of the Hsp90 activity lack a sufficient quantitative characterization. We combined molecular dynamics simulations, principal component analysis, the energy landscape model and structure-functional analysis of Hsp90 regulatory interactions to systematically investigate functional dynamics of the molecular chaperone. This approach has identified a network of conserved regions common to the Hsp90 chaperones that could play a universal role in coordinating functional dynamics, principal collective motions and allosteric signaling of Hsp90. We have found that these functional motifs may be utilized by the molecular chaperone machinery to act collectively as central regulators of Hsp90 dynamics and activity, including the inter-domain communications, control of ATP hydrolysis, and protein client binding. These findings have provided support to a long-standing assertion that allosteric regulation and catalysis may have emerged via common evolutionary routes. The interaction networks regulating functional motions of Hsp90 may be determined by the inherent structural architecture of the molecular chaperone. At the same time, the thermodynamics-based β€œconformational selection” of functional states is likely to be activated based on the nature of the binding partner. This mechanistic model of Hsp90 dynamics and function is consistent with the notion that allosteric networks orchestrating cooperative protein motions can be formed by evolutionary conserved and sparsely connected residue clusters. Hence, allosteric signaling through a small network of distantly connected residue clusters may be a rather general functional requirement encoded across molecular chaperones. The obtained insights may be useful in guiding discovery of allosteric Hsp90 inhibitors targeting protein interfaces with co-chaperones and protein binding clients
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