Roles of Gβγ in membrane recruitment and activation of p110γ/p101 phosphoinositide 3-kinase γ

Receptor-regulated class I phosphoinositide 3-kinases (PI3K) phosphorylate the membrane lipid phosphatidylinositol (PtdIns)-4,5-P2 to PtdIns-3,4,5-P3. This, in turn, recruits and activates cytosolic effectors with PtdIns-3,4,5-P3–binding pleckstrin homology (PH) domains, thereby controlling important cellular functions such as proliferation, survival, or chemotaxis. The class IB p110γ/p101 PI3Kγ is activated by Gβγ on stimulation of G protein–coupled receptors. It is currently unknown whether in living cells Gβγ acts as a membrane anchor or an allosteric activator of PI3Kγ, and which role its noncatalytic p101 subunit plays in its activation by Gβγ. Using GFP-tagged PI3Kγ subunits expressed in HEK cells, we show that Gβγ recruits the enzyme from the cytosol to the membrane by interaction with its p101 subunit. Accordingly, p101 was found to be required for G protein–mediated activation of PI3Kγ in living cells, as assessed by use of GFP-tagged PtdIns-3,4,5-P3–binding PH domains. Furthermore, membrane-targeted p110γ displayed basal enzymatic activity, but was further stimulated by Gβγ, even in the absence of p101. Therefore, we conclude that in vivo, Gβγ activates PI3Kγ by a mechanism assigning specific roles for both PI3Kγ subunits, i.e., membrane recruitment is mediated via the noncatalytic p101 subunit, and direct stimulation of Gβγ with p110γ contributes to activation of PI3Kγ

AKT1 and MYC Induce Distinctive Metabolic Fingerprints in Human Prostate Cancer

Cancer cells may overcome growth factor dependence by deregulating oncogenic and/or tumor-suppressor pathways that affect their metabolism, or by activating metabolic pathways de novo with targeted mutations in critical metabolic enzymes. It is unknown whether human prostate tumors develop a similar metabolic response to different oncogenic drivers or a particular oncogenic event results in its own metabolic reprogramming. Akt and Myc are arguably the most prevalent driving oncogenes in prostate cancer. Mass spectrometry–based metabolite profiling was performed on immortalized human prostate epithelial cells transformed by AKT1 or MYC, transgenic mice driven by the same oncogenes under the control of a prostate-specific promoter, and human prostate specimens characterized for the expression and activation of these oncoproteins. Integrative analysis of these metabolomic datasets revealed that AKT1 activation was associated with accumulation of aerobic glycolysis metabolites, whereas MYC overexpression was associated with dysregulated lipid metabolism. Selected metabolites that differentially accumulated in the MYC-high versus AKT1-high tumors, or in normal versus tumor prostate tissue by untargeted metabolomics, were validated using absolute quantitation assays. Importantly, the AKT1/MYC status was independent of Gleason grade and pathologic staging. Our findings show how prostate tumors undergo a metabolic reprogramming that reflects their molecular phenotypes, with implications for the development of metabolic diagnostics and targeted therapeutics.Fil: Priolo, Carmen. Department of Medical Oncology. Dana Farber Cancer Institute. Brigham and Women's Hospital; Estados UnidosFil: Pyne, Saumyadipta. Department of Medical Oncology. Dana Farber Cancer Institute. Brigham and Women's Hospital; Estados UnidosFil: Rose, Joshua. Department of Medical Oncology. Dana Farber Cancer Institute. Brigham and Women's Hospital; Estados UnidosFil: Regan, Erzsébet Ravasz. Harvard Medical School; Estados UnidosFil: Zadra, Giorgia. Department of Medical Oncology. Dana Farber Cancer Institute. Brigham and Women's Hospital; Estados UnidosFil: Photopoulos, Cornelia. Department of Medical Oncology. Dana Farber Cancer Institute. Brigham and Women's Hospital; Estados UnidosFil: Cacciatore, Stefano. Department of Medical Oncology. Dana Farber Cancer Institute. Brigham and Women's Hospital; Estados UnidosFil: Schultz, Denise. Johns Hopkins University; Estados UnidosFil: Scaglia, Natalia. Department of Medical Oncology. Dana Farber Cancer Institute. Brigham and Women's Hospital; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: McDunn, Jonathan. Metabolon Inc.; Estados UnidosFil: de Marzo, Angelo M.. Johns Hopkins University; Estados UnidosFil: Loda, Massimo. Department of Pathology. Brigham and Women's Hospital; Estados Unidos. Department of Medical Oncology. Dana Farber Cancer Institute. Brigham and Women's Hospital; Estados Unidos. University of Cambridge; Estados Unidos. King's College London. Division of Cancer Studies; Estados Unido

Silicon Photomultiplier Research and Development Studies for the Large Size Telescope of the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) is the the next generation facility of imaging atmospheric Cherenkov telescopes; two sites will cover both hemispheres. CTA will reach unprecedented sensitivity, energy and angular resolution in very-high-energy gamma-ray astronomy. Each CTA array will include four Large Size Telescopes (LSTs), designed to cover the low-energy range of the CTA sensitivity ($\sim$20 GeV to 200 GeV). In the baseline LST design, the focal-plane camera will be instrumented with 265 photodetector clusters; each will include seven photomultiplier tubes (PMTs), with an entrance window of 1.5 inches in diameter. The PMT design is based on mature and reliable technology. Recently, silicon photomultipliers (SiPMs) are emerging as a competitor. Currently, SiPMs have advantages (e.g. lower operating voltage and tolerance to high illumination levels) and disadvantages (e.g. higher capacitance and cross talk rates), but this technology is still young and rapidly evolving. SiPM technology has a strong potential to become superior to the PMT one in terms of photon detection efficiency and price per square mm of detector area. While the advantage of SiPMs has been proven for high-density, small size cameras, it is yet to be demonstrated for large area cameras such as the one of the LST. We are working to develop a SiPM-based module for the LST camera, in view of a possible camera upgrade. We will describe the solutions we are exploring in order to balance a competitive performance with a minimal impact on the overall LST camera design.Comment: 8 pages, 5 figures. In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

On Geometric Alignment in Low Doubling Dimension

In real-world, many problems can be formulated as the alignment between two geometric patterns. Previously, a great amount of research focus on the alignment of 2D or 3D patterns, especially in the field of computer vision. Recently, the alignment of geometric patterns in high dimension finds several novel applications, and has attracted more and more attentions. However, the research is still rather limited in terms of algorithms. To the best of our knowledge, most existing approaches for high dimensional alignment are just simple extensions of their counterparts for 2D and 3D cases, and often suffer from the issues such as high complexities. In this paper, we propose an effective framework to compress the high dimensional geometric patterns and approximately preserve the alignment quality. As a consequence, existing alignment approach can be applied to the compressed geometric patterns and thus the time complexity is significantly reduced. Our idea is inspired by the observation that high dimensional data often has a low intrinsic dimension. We adopt the widely used notion "doubling dimension" to measure the extents of our compression and the resulting approximation. Finally, we test our method on both random and real datasets, the experimental results reveal that running the alignment algorithm on compressed patterns can achieve similar qualities, comparing with the results on the original patterns, but the running times (including the times cost for compression) are substantially lower

Transplacental Transmission of Bluetongue Virus 8 in Cattle, UK

To determine whether transplacental transmission could explain overwintering of bluetongue virus in the United Kingdom, we studied calves born to dams naturally infected during pregnancy in 2007–08. Approximately 33% were infected transplacentally; some had compromised health. In all infected calves, viral load decreased after birth; no evidence of persistent infection was found

Effectiveness of neonatal pulse oximetry screening for detection of critical congenital heart disease in daily clinical routine—results from a prospective multicenter study

Pulse oximetry screening (POS) has been proposed as an effective, noninvasive, inexpensive tool allowing earlier diagnosis of critical congenital heart disease (cCHD). Our aim was to test the hypothesis that POS can reduce the diagnostic gap in cCHD in daily clinical routine in the setting of tertiary, secondary and primary care centres. We conducted a prospective multicenter trial in Saxony, Germany. POS was performed in healthy term and post-term newborns at the age of 24–72 h. If an oxygen saturation (SpO2) of ≤95% was measured on lower extremities and confirmed after 1 h, complete clinical examination and echocardiography were performed. POS was defined as false-negative when a diagnosis of cCHD was made after POS in the participating hospitals/at our centre. From July 2006–June 2008, 42,240 newborns from 34 institutions have been included. Seventy-two children were excluded due to prenatal diagnosis (n = 54) or clinical signs of cCHD (n = 18) before POS. Seven hundred ninety-five newborns did not receive POS, mainly due to early discharge after birth (n = 727; 91%). In 41,445 newborns, POS was performed. POS was true positive in 14, false positive in 40, true negative in 41,384 and false negative in four children (three had been excluded for violation of study protocol). Sensitivity, specificity, positive and negative predictive value were 77.78%, 99.90%, 25.93% and 99.99%, respectively. With POS as an adjunct to prenatal diagnosis, physical examination and clinical observation, the percentage of newborns with late diagnosis of cCHD was 4.4%. POS can substantially reduce the postnatal diagnostic gap in cCHD, and false-positive results leading to unnecessary examinations of healthy newborns are rare. POS should be implemented in routine postnatal care

Nitration of the Egg-Allergen Ovalbumin Enhances Protein Allergenicity but Reduces the Risk for Oral Sensitization in a Murine Model of Food Allergy

Nitration of proteins on tyrosine residues, which can occur due to polluted air under "summer smog" conditions, has been shown to increase the allergic potential of allergens. Since nitration of tyrosine residues is also observed during inflammatory responses, this modification could directly influence protein immunogenicity and might therefore contribute to food allergy induction. In the current study we have analyzed the impact of protein nitration on sensitization via the oral route.BALB/c mice were immunized intragastrically by feeding untreated ovalbumin (OVA), sham-nitrated ovalbumin (snOVA) or nitrated ovalbumin (nOVA) with or without concomitant acid-suppression. To analyze the impact of the sensitization route, the allergens were also injected intraperitoneally. Animals being fed OVA or snOVA under acid-suppressive medication developed significantly elevated levels of IgE, and increased titers of specific IgG1 and IgG2a antibodies. Interestingly, oral immunizations of nOVA under anti-acid treatment did not result in IgG and IgE formation. In contrast, intraperitoneal immunization induced high levels of OVA specific IgE, which were significantly increased in the group that received nOVA by injection. Furthermore, nOVA triggered significantly enhanced mediator release from RBL cells passively sensitized with sera from allergic mice. Gastric digestion experiments demonstrated protein nitration to interfere with protein stability as nOVA was easily degraded, whereas OVA and snOVA remained stable up to 120 min. Additionally, HPLC-chip-MS/MS analysis showed that one tyrosine residue (Y(107)) being very efficiently nitrated is part of an ovalbumin epitope recognized exclusively after oral sensitization.These data indicated that despite the enhanced triggering capacity in existing allergy, nitration of OVA may be associated with a reduced de novo sensitizing capability via the oral route due to enhanced protein digestibility and/or changes in antibody epitopes