1,409 research outputs found

    The human papillomavirus 16 E2 protein is stabilised in S phase

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    The human papillomavirus 16 E2 protein regulates transcription from, and replication of, the viral genome and is also required for segregation of the viral genome via interaction with mitotic bodies. To regulate DNA replication E2 interacts with sequences around the origin of replication and recruits the viral helicase E1 via a protein-protein interaction, which then initiates viral genome replication. The replication role of E2 must originally function in a host cell S phase. In this report, we demonstrate that E2 is stabilised in the S phase of the cell cycle and that this stabilisation is accompanied by an increase in phosphorylation of the protein. This increased phosphorylation and stability are likely required for optimum viral DNA replication and therefore identification of the enzymes involved in regulating these properties of E2 will provide targets for therapeutic intervention in the viral life cycle. Preliminary studies have identified E2 as a Cdk2 substrate demonstrating this enzyme as a candidate kinase for mediating the in vivo phosphorylation of HPV16 E2

    Dezinformatsiya: The past, present and future of ‘fake news’

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    Regulation of peptide import through phosphorylation of Ubr1, the ubiquitin ligase of the N-end rule pathway

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    Substrates of the N-end rule pathway include proteins with destabilizing N-terminal residues. These residues are recognized by E3 ubiquitin ligases called N-recognins. Ubr1 is the N-recognin of the yeast Saccharomyces cerevisiae. Extracellular amino acids or short peptides up-regulate the peptide transporter gene PTR2, thereby increasing the capacity of a cell to import peptides. Cup9 is a transcriptional repressor that down-regulates PTR2. The induction of PTR2 by peptides or amino acids involves accelerated degradation of Cup9 by the N-end rule pathway. We report here that the Ubr1 N-recognin, which conditionally targets Cup9 for degradation, is phosphorylated in vivo at multiple sites, including Ser300 and Tyr277. We also show that the type-I casein kinases Yck1 and Yck2 phosphorylate Ubr1 on Ser300, and thereby make possible (“prime”) the subsequent (presumably sequential) phosphorylations of Ubr1 on Ser296, Ser292, Thr288, and Tyr277 by Mck1, a kinase of the glycogen synthase kinase 3 (Gsk3) family. Phosphorylation of Ubr1 on Tyr277 by Mck1 is a previously undescribed example of a cascade-based tyrosine phosphorylation by a Gsk3-type kinase outside of autophosphorylation. We show that the Yck1/Yck2-mediated phosphorylation of Ubr1 on Ser300 plays a major role in the control of peptide import by the N-end rule pathway. In contrast to phosphorylation on Ser300, the subsequent (primed) phosphorylations, including the one on Tyr277, have at most minor effects on the known properties of Ubr1, including regulation of peptide import. Thus, a biological role of the rest of Ubr1 phosphorylation cascade remains to be identified

    What supervisors say in their feedback:construction of CanMEDS roles in workplace settings

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    The CanMEDS framework has been widely adopted in residency education and feedback processes are guided by it. It is, however, only one of many influences on what is actually discussed in feedback. The sociohistorical culture of medicine and individual supervisors' contexts, experiences and beliefs are also influential. Our aim was to find how CanMEDS roles are constructed in feedback in a postgraduate curriculum-in-action. We applied a set of discourse analytic tools to written feedback from 591 feedback forms from 7 hospitals, including 3150 feedback comments in which 126 supervisors provided feedback to 120 residents after observing their performance in authentic settings. The role of Collaborator was constructed in two different ways: a cooperative discourse of equality with other workers and patients; and a discourse, which gave residents positions of power-delegating, asserting and 'taking a firm stance'. Efficiency-being fast and to the point emerged as an important attribute of physicians. Patients were seldom part of the discourses and, when they were, they were constructed as objects of communication and collaboration rather than partners. Although some of the discourses are in line with what might be expected, others were in striking contrast to the spirit of CanMEDS. This study's findings suggest that it takes more than a competency framework, evaluation instruments, and supervisor training to change the culture of workplaces. The impact on residents of training in such demanding, efficiency-focused clinical environments is an important topic for future research

    What is to blame for postnatal pelvic floor dysfunction in primiparous women — Pre-pregnancy or intrapartum risk factors?

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    Background: The aetiology of pelvic floor dysfunction (PFD) is still poorly understood. However childbearing is recognized as a major risk factor. Objectives: To elucidate the natural history of PFD by investigating the impact of the mode of delivery on postnatal pelvic floor dysfunction in primiparas, when PFD existing before the first pregnancy is taken into consideration. Study design: 4P-study (Prevalence and Predictors of Pelvic floor dysfunction in Primips) is a prospective cohort study, nested within the Screening for Pregnancy Endpoints (SCOPE) study set in a tertiary referral teaching hospital with 9000 deliveries annually. Established and proposed risk factors for urinary, fecal, prolapse and sexual dysfunction and the severity of symptoms for each of these outcomes were assessed using the Australian Pelvic Floor Questionnaire in 1482 nulliparous women, who each completed the questionnaire in early pregnancy. Of these, 1060 (72%) repeated the questionnaire 12 months postpartum. Outcomes were analyzed using multivariate ordinal logistic regression. Results: Significant (p < 0.05) risk factors for postpartum PFD were pre-pregnancy presence of similar symptoms Odds Ratio (OR) (5.0–30.0), smoking (OR 2.2–4.6), recurrent UTI (OR 2.2–17.3), high hip circumference (OR1.4–1.6), vigorous exercising (OR 3.1–17.9), induction of labor (OR 1.5–2.3), forceps delivery (OR 1.8–8.8), and 3rd degree perineal tear (OR 2.4–2.7). Cesarean section was associated with a lower risk of stress urinary incontinence (OR 0.3–0.5). Other common pre-pregnancy significant (p < 0.05) risk factors for various PFD types prior to the first pregnancy were: diagnosed depression – (OR 1.6–2.1), high BMI (OR 3.1), strenuous exercising (OR 1.3–2.2), recurrent UTI (OR 1.5–2.5) and lower educational achievement (OR 1.5–1.6). Conclusions: Pre-pregnancy PFD was mainly associated with modifiable risk factors such as smoking and exercising. The main risk factor for postpartum PFD was the presence of similar symptoms prior to pregnancy, followed by anthropometric and intrapartum factors. Hip circumference seems to be a better predictor of PFD compared to BMI. When pre-pregnancy PFD was included in the analysis, Cesarean section was protective only for stress urinary incontinence, while delivery by forceps increased the risk of prolapse
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