1,722 research outputs found

    Hsp90-binding immunophilins link p53 to dynein during p53 transport to the nucleus

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    The tumor suppressor protein p53 is known to be transported to the nucleus along microtubular tracks by cytoplasmic dynein. However, the connection between p53 and the dynein motor protein complex has not been established. Here, we show that hsp90.binding immunophilins link p53.hsp90 complexes to dynein and that prevention of that linkage in vivo inhibits the nuclear movement of p53. First, we show that p53.hsp90 heterocomplexes from DLD-1 human colon cancer cells contain an immunophilin (FKBP52, CyP-40, or PP5) as well as dynein. p53.hsp90.immunophilin.dynein complexes can be formed by incubating immunopurified p53 with rabbit reticulocyte lysate, and we show by peptide competition that the immunophilins link via their tetratricopeptide repeat domains to p53-bound hsp90 and by means of their PPIase domains to the dynein complex. The linkage of immunophilins to the dynein motor is indirect by means of the dynamitin component of the dynein-associated dynactin complex, and we show that purified FKBP52 binds directly by means of its PPIase domain to purified dynamitin. By using a temperature-sensitive mutant of p53 where cytoplasmic-nuclear movement occurs by shift to permissive temperature, we show that p53 movement is impeded when p53 binding to hsp90 is inhibited by the hsp90 inhibitor radicicol. Also, nuclear movement of p53 is inhibited when immunophilin binding to dynein is competed for by expression of a PPIase domain fragment in the same manner as when dynein linkage to cargo is dissociated by expression of dynamitin. This is the first demonstration of the linkage between an hsp90-chaperoned transcription factor and the system for its retrograde movement to the nucleus both in vitro and in vivo.Fil: Galigniana, Mario Daniel. University of Michigan; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Harrell, Jennifer M.. University of Michigan; Estados UnidosFil: O´Hagen, Heather M.. University of Michigan; Estados UnidosFil: Ljungman, Mats. University of Michigan; Estados UnidosFil: Pratt, William B.. University of Michigan; Estados Unido

    Who is pirating medical literature? A bibliometric review of 28 million Sci-Hub downloads.

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    We aimed to define the proportion of downloads on Sci-Hub that are medical in nature and to consider these data at the national level, evaluating the relation between density of medical literature downloads and scientific output, national income classifications, and indicators of internet penetrance

    Mutant p53R270H drives altered metabolism and increased invasion in pancreatic ductal adenocarcinoma

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    Pancreatic cancer is characterized by nearly universal activating mutations in KRAS. Among other somatic mutations, TP53 is mutated in more than 75% of human pancreatic tumors. Genetically engineered mice have proven instrumental in studies of the contribution of individual genes to carcinogenesis. Oncogenic Kras mutations occur early during pancreatic carcinogenesis and are considered an initiating event. In contrast, mutations in p53 occur later during tumor progression. In our model, we recapitulated the order of mutations of the human disease, with p53 mutation following expression of oncogenic Kras. Further, using an inducible and reversible expression allele for mutant p53, we inactivated its expression at different stages of carcinogenesis. Notably, the function of mutant p53 changes at different stages of carcinogenesis. Our work establishes a requirement for mutant p53 for the formation and maintenance of pancreatic cancer precursor lesions. In tumors, mutant p53 becomes dispensable for growth. However, it maintains the altered metabolism that characterizes pancreatic cancer and mediates its malignant potential. Further, mutant p53 promotes epithelial-mesenchymal transition (EMT) and cancer cell invasion. This work generates new mouse models that mimic human pancreatic cancer and expands our understanding of the role of p53 mutation, common in the majority of human malignancies

    Guided internet-administered self-help to reduce symptoms of anxiety and depression among adolescents and young adults diagnosed with cancer during adolescence (U-CARE: YoungCan): a study protocol for a feasibility trial.

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    Published onlineJournal ArticleThis is the final version of the article. Available from BMJ Publishing Group via the DOI in this record.INTRODUCTION: A subgroup of adolescents and young adults diagnosed with cancer during adolescence reports elevated levels of anxiety and depressive symptoms and unmet needs for psychological support. Evidence-based psychological treatments tailored for this population are lacking. This protocol describes a feasibility study of a guided-internet-administered self-help programme (YoungCan) primarily targeting symptoms of anxiety and depression among young persons diagnosed with cancer during adolescence and of the planned study procedures for a future controlled trial. METHODS/ANALYSIS: The study is an uncontrolled feasibility trial with a pre-post and 3-month follow-up design. Potential participants aged 15-25 years, diagnosed with cancer during adolescence, will be identified via the Swedish Childhood Cancer Registry. 30 participants will be included. Participants will receive YoungCan, a 12-week therapist-guided, internet-administered self-help programme consisting primarily of cognitive-behavioural therapy organised into individually assigned modules targeting depressive symptoms, worry and anxiety, body dissatisfaction and post-traumatic stress. Interactive peer support and psychoeducative functions are also available. Feasibility outcomes include: recruitment and eligibility criteria; data collection; attrition; resources needed to complete the study and programme; safety procedures; participants' and therapists' adherence to the programme; and participants' acceptability of the programme and study methodology. Additionally, mechanisms of impact will be explored and data regarding symptoms of anxiety, depression, post-traumatic stress, body dissatisfaction, reactions to social interactions, quality of life, axis I diagnoses according to the Mini International Neuropsychiatric Interview and healthcare service use will be collected. Exploratory analyses of changes in targeted outcomes will be conducted. ETHICS/DISSEMINATION: This feasibility protocol was approved by the Regional Ethical Review Board in Uppsala, Sweden (ref: 2016/210). Findings will be disseminated to relevant research, clinical, health service and patient communities through publications in peer-reviewed and popular science journals and presentations at scientific and clinical conferences. TRIAL REGISTRATION NUMBER: ISRCTN97835363.This work was supported by the Swedish Childhood Cancer Foundation, grant number PR2013-0039. This funding source had no role in the design of this study and will not have any role during its execution, analyses, interpretation of the data or decision to submit results

    UVSSA and USP7, a new couple in transcription-coupled DNA repair

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    Transcription-coupled nucleotide excision repair (TC-NER) specifically removes transcription-blocking lesions from our genome. Defects in this pathway are associated with two human disorders: Cockayne syndrome (CS) and UV-sensitive syndrome (UVSS). Despite a similar cellular defect in the UV DNA damage response, patients with these syndromes exhibit strikingly distinct symptoms; CS patients display severe developmental, neurological, and premature aging features, whereas the phenotype of UVSS patients is mostly restricted to UV hypersensitivity. The exact molecular mechanism behind these clinical differences is still unknown; however, they might be explained by additional functions of CS proteins beyond TC-NER. A short overview of the current hypotheses addressing possible molecular mechanisms and the proteins involved are presented in this review. In addition, we will focus on two new players involved in TC-NER which were recently identified: UV-stimulated scaffold protein A (UVSSA) and ubiquitin-specific protease 7 (USP7). UVSSA has been found to be the causative gene for UVSS and, together with USP7, is implicated in regulating TC-NER activity. We will discuss the function of UVSSA and USP7 and how the discovery of these proteins contributes to a better understanding of the molecular mechanisms underlying the clinical differences between UVSS and the more severe CS
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