Different animal cell types have distinctive and characteristic sizes. How a particular cell size is specified by differentiation programs and physiology remains one of the fundamental unknowns in cell biology. In this Review, we explore the evidence that individual cells autonomously sense and specify their own size.
View Article and Find Full Text PDFIn order to assess the feasibility of amplicon-based parallel next generation sequencing (NGS) for the diagnosis of myeloproliferative neoplasms (MPN), we investigated multiplex-PCR of 212 amplicons covering genomic mutational hotspots in 48 cancer-related genes. Samples from 64 patients with MPN and five controls as well as seven (myeloid) cell lines were analyzed. Healthy donor and reactive erythrocytosis samples showed several frequent single-nucleotide polymorphisms (SNPs) but no known pathogenic mutation.
View Article and Find Full Text PDFTo address how the configuration of conjugated ubiquitins determines the recognition of substrates by the proteasome, we analyzed the degradation kinetics of substrates with chemically defined ubiquitin configurations. Contrary to the view that a tetraubiquitin chain is the minimal signal for efficient degradation, we find that distributing the ubiquitins as diubiquitin chains provides a more efficient signal. To understand how the proteasome actually discriminates among ubiquitin configurations, we developed single-molecule assays that distinguished intermediate steps of degradation kinetically.
View Article and Find Full Text PDFBiological processes require specific enzymatic reactions, paradoxically involving short recognition sequences. As an example, cell-cycle timing depends on a sequence of ubiquitylation events mediated by the anaphase-promoting complex (APC) based on short redundant motifs. To understand the origin of specificity, we designed single-molecule fluorescence assays that capture transient ubiquitylation reactions.
View Article and Find Full Text PDFUnlabelled: Malignant pleural mesothelioma (MPM) is often fatal, and studies have revealed that aberrant miRNAs contribute to MPM development and aggressiveness. Here, a screen of miRNAs identified reduced levels of miR-223 in MPM patient specimens. Interestingly, miR-223 targets Stathmin (STMN1), a microtubule regulator that has been associated with MPM.
View Article and Find Full Text PDFAims: Since 2007, Health Promotion Switzerland has implemented a national priority program for a healthy body weight. This article provides insight into the methodological challenges and results of the program evaluation.
Methods: Evaluation of the long-term program required targeted monitoring and evaluation projects addressing different outcome levels.
Proc Natl Acad Sci U S A
February 2015
Background: Prognosis of malignant pleural mesothelioma (MPM) is poor, and predicting the outcomes of treatment is difficult. Here we investigate the potential of microRNA expression to estimate prognosis of MPM patients.
Methods: Candidate microRNAs from microarray profiling of tumor samples from 8 long (median: 53.
Wnt signaling plays a critical role in embryonic development, and genetic aberrations in this network have been broadly implicated in colorectal cancer. We find that the Wnt receptor Frizzled2 (Fzd2) and its ligands Wnt5a/b are elevated in metastatic liver, lung, colon, and breast cancer cell lines and in high-grade tumors and that their expression correlates with markers of epithelial-mesenchymal transition (EMT). Pharmacologic and genetic perturbations reveal that Fzd2 drives EMT and cell migration through a previously unrecognized, noncanonical pathway that includes Fyn and Stat3.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2014
Rapid progression through the cell cycle and a very short G1 phase are defining characteristics of embryonic stem cells. This distinct cell cycle is driven by a positive feedback loop involving Rb inactivation and reduced oscillations of cyclins and cyclin-dependent kinase (Cdk) activity. In this setting, we inquired how ES cells avoid the potentially deleterious consequences of premature mitotic entry.
View Article and Find Full Text PDFAs a group closely related to chordates, hemichordate acorn worms are in a key phylogenic position for addressing hypotheses of chordate origins. The stomochord of acorn worms is an anterior outgrowth of the pharynx endoderm into the proboscis. In 1886 Bateson proposed homology of this organ to the chordate notochord, crowning this animal group "hemichordates.
View Article and Find Full Text PDFTargeted degradation of proteins through the ubiquitin-proteasome system (UPS) via the activities of E3 ubiquitin ligases regulates diverse cellular processes, and misregulation of these enzymes contributes to the pathogenesis of human diseases. One of the challenges facing the UPS field is to delineate the complete cohort of substrates for a particular E3 ligase. Advances in mass spectrometry and the development of antibodies recognizing the Lys-ϵ-Gly-Gly (diGly) remnant from ubiquitinated proteins following trypsinolysis have provided a tool to address this question.
View Article and Find Full Text PDFThe primary cilium has an important role in signaling; defects in structure are associated with a variety of human diseases. Much of the most basic biology of this organelle is poorly understood, even basic mechanisms, such as control of growth and resorption. We show that the activity of the anaphase-promoting complex (APC), an E3 that regulates the onset of anaphase, destabilizes axonemal microtubules in the primary cilium.
View Article and Find Full Text PDFProtein microarrays are extremely useful for detecting substrates of phosphorylation, substrates of ubiquitylation, or other post-translational modifications. The ability to screen binding interactions as well as post-translational modifications of thousands of proteins at once has improved our ability to identify their targets. Utilizing such systems in combination with functional mammalian cell extracts that preserve enzymatic activity offers advantages in identifying semi-quantitative changes of these interactions in the context of specific cellular conditions.
View Article and Find Full Text PDFNegative symptoms in schizophrenia have been grouped into the 2 factors of apathy and diminished expression, which might be caused by separable pathophysiological mechanisms. Recently, it has been proposed that apathy could be due to dysfunctional integration of reward and effort during decision making. We asked whether apathy in particular is associated with stronger devaluation ("discounting") of monetary rewards that require physical effort.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
July 2014
Attainment of the differentiated state during the final stages of somatic cell differentiation is closely tied to cell cycle progression. Much less is known about the role of the cell cycle at very early stages of embryonic development. Here, we show that molecular pathways involving the cell cycle can be engineered to strongly affect embryonic stem cell differentiation at early stages in vitro.
View Article and Find Full Text PDFBackground: Mass spectrometry-based proteomics enables the global identification and quantification of proteins and their posttranslational modifications in complex biological samples. However, proteomic analysis requires a complete and accurate reference set of proteins and is therefore largely restricted to model organisms with sequenced genomes.
Results: Here, we demonstrate the feasibility of deep genome-free proteomics by using a reference proteome derived from heterogeneous mRNA data.
Anaphase-promoting complex Cdc20 (APC(Cdc20)) plays pivotal roles in governing mitotic progression. By suppressing APC(Cdc20), antimitotic agents activate the spindle-assembly checkpoint and induce apoptosis after prolonged treatment, whereas depleting endogenous Cdc20 suppresses tumorigenesis in part by triggering mitotic arrest and subsequent apoptosis. However, the molecular mechanism(s) underlying apoptosis induced by Cdc20 abrogation remains poorly understood.
View Article and Find Full Text PDFThe long-held but erroneous assumption of never-ending rapid growth in biomedical science has created an unsustainable hypercompetitive system that is discouraging even the most outstanding prospective students from entering our profession--and making it difficult for seasoned investigators to produce their best work. This is a recipe for long-term decline, and the problems cannot be solved with simplistic approaches. Instead, it is time to confront the dangers at hand and rethink some fundamental features of the US biomedical research ecosystem.
View Article and Find Full Text PDFPolypharmacology (action of drugs against multiple targets) represents a tempting avenue for new drug development; unfortunately, methods capable of exploiting the known polypharmacology of drugs for target deconvolution are lacking. Here, we present an ensemble approach using elastic net regularization combined with mRNA expression profiling and previously characterized data on a large set of kinase inhibitors to identify kinases that are important for epithelial and mesenchymal cell migration. By profiling a selected optimal set of 32 kinase inhibitors in a panel against six cell lines, we identified cell type-specific kinases that regulate cell migration.
View Article and Find Full Text PDFAkt, also known as protein kinase B, plays key roles in cell proliferation, survival and metabolism. Akt hyperactivation contributes to many pathophysiological conditions, including human cancers, and is closely associated with poor prognosis and chemo- or radiotherapeutic resistance. Phosphorylation of Akt at S473 (ref.
View Article and Find Full Text PDFO-GlcNAc transferase (OGT) is a serine/threonine glycosyltransferase that is essential for development and continues to be critically important throughout life. Understanding OGT's complex biology requires identifying its substrates. Here we demonstrate the utility of a microarray approach for discovering novel OGT substrates.
View Article and Find Full Text PDFIntroduction: Lymphoma is among the five most frequent malignancies during pregnancy while anaplastic large-cell lymphoma (ALCL) is rare, accounting only for 2-3 % of all adult-onset non-Hodgkin lymphomas.
Case Report: A 23-year-old gravida 1, para 1 presented with puerperal mastitis and septicemia following secondary cesarean section. Mastitis had been present for a week prior to delivery.
Introduction: Epigenetic inactivation of tumor suppressor genes is involved in the development of malignant pleural mesothelioma (MPM). ZIC1, a potential tumor suppressor gene involved in regulating cell growth and apoptosis, was investigated in MPM cell lines and tumors.
Methods: ZIC1 expression and promoter methylation were evaluated in MPM cell lines and tumor samples by quantitative polymerase chain reaction (PCR), Combined Bisulfite Restriction Analysis, and methylation-specific PCR.
Prostate MRI image segmentation has been an area of intense research due to the increased use of MRI as a modality for the clinical workup of prostate cancer. Segmentation is useful for various tasks, e.g.
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