WASP-80b has a dayside within the T-dwarf range

AHMJT is a Swiss National Science Foundation (SNSF) fellow under grant number P300P2-147773. MG and EJ are Research Associates at the F.R.S-FNRS; LD received the support the support of the F.R.I.A. fund of the FNRS. DE, KH, and SU acknowledge the financial support of the SNSF in the frame of the National Centre for Competence in Research ‘PlanetS’. EH and IR acknowledge support from the Spanish Ministry of Economy and Competitiveness (MINECO) and the ‘Fondo Europeo de Desarrollo Regional’ (FEDER) through grants AYA2012-39612-C03-01 and ESP2013-48391-C4-1-R.WASP-80b is a missing link in the study of exo-atmospheres. It falls between the warm Neptunes and the hot Jupiters and is amenable for characterisation, thanks to its host star's properties. We observed the planet through transit and during occultation with Warm Spitzer. Combining our mid-infrared transits with optical time series, we find that the planet presents a transmission spectrum indistinguishable from a horizontal line. In emission, WASP-80b is the intrinsically faintest planet whose dayside flux has been detected in both the 3.6 and 4.5 $\mu$m Spitzer channels. The depths of the occultations reveal that WASP-80b is as bright and as red as a T4 dwarf, but that its temperature is cooler. If planets go through the equivalent of an L-T transition, our results would imply this happens at cooler temperatures than for brown dwarfs. Placing WASP-80b's dayside into a colour-magnitude diagram, it falls exactly at the junction between a blackbody model and the T-dwarf sequence; we cannot discern which of those two interpretations is the more likely. Flux measurements on other planets with similar equilibrium temperatures are required to establish whether irradiated gas giants, like brown dwarfs, transition between two spectral classes. An eventual detection of methane absorption in transmission would also help lift that degeneracy. We obtained a second series of high-resolution spectra during transit, using HARPS. We reanalyse the Rossiter-McLaughlin effect. The data now favour an aligned orbital solution and a stellar rotation nearly three times slower than stellar line broadening implies. A contribution to stellar line broadening, maybe macroturbulence, is likely to have been underestimated for cool stars, whose rotations have therefore been systematically overestimated. [abridged]Publisher PDFPeer reviewe

An unbiased proteomic screen reveals caspase cleavage is positively and negatively regulated by substrate phosphorylation

Post-translational modifications of proteins regulate diverse cellular functions, with mounting evidence suggesting that hierarchical cross-talk between distinct modifications may fine-tune cellular responses. For example, in apoptosis, caspases promote cell death via cleavage of key structural and enzymatic proteins that in some instances is inhibited by phosphorylation near the scissile bond. In this study, we systematically investigated how protein phosphorylation affects susceptibility to caspase cleavage using an N-terminomic strategy, namely, a modified terminal amino isotopic labeling of substrates (TAILS) workflow, to identify proteins for which caspase-catalyzed cleavage is modulated by phosphatase treatment. We validated the effects of phosphorylation on three of the identified proteins and found that Yap1 and Golgin-160 exhibit decreased cleavage when phosphorylated, whereas cleavage of MST3 was promoted by phosphorylation. Furthermore, using synthetic peptides we systematically examined the influence of phosphoserine throughout the entirety of caspase-3, -7, and -8 recognition motifs and observed a general inhibitory effect of phosphorylation even at residues considered outside the classical consensus motif. Overall, our work demonstrates a role for phosphorylation in controlling caspase-mediated cleavage and shows that N-terminomic strategies can be tailored to study cross-talk between phosphorylation and proteolysis. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc

The Exoplanet Eccentricity Distribution from Kepler Planet Candidates

The eccentricity distribution of exoplanets is known from radial velocity surveys to be divergent from circular orbits beyond 0.1 AU. This is particularly the case for large planets where the radial velocity technique is most sensitive. The eccentricity of planetary orbits can have a large effect on the transit probability and subsequently the planet yield of transit surveys. The Kepler mission is the first transit survey that probes deep enough into period-space to allow this effect to be seen via the variation in transit durations. We use the Kepler planet candidates to show that the eccentricity distribution is consistent with that found from radial velocity surveys to a high degree of confidence. We further show that the mean eccentricity of the Kepler candidates decreases with decreasing planet size indicating that smaller planets are preferentially found in low-eccentricity orbits.Comment: 6 pages, 4 figures, accepted for publication in MNRA

The thermal emission of the exoplanets WASP-1b and WASP-2b

We present a comparative study of the thermal emission of the transiting exoplanets WASP-1b and WASP-2b using the Spitzer Space Telescope. The two planets have very similar masses but suffer different levels of irradiation and are predicted to fall either side of a sharp transition between planets with and without hot stratospheres. WASP-1b is one of the most highly irradiated planets studied to date. We measure planet/star contrast ratios in all four of the IRAC bands for both planets (3.6-8.0um), and our results indicate the presence of a strong temperature inversion in the atmosphere of WASP-1b, particularly apparent at 8um, and no inversion in WASP-2b. In both cases the measured eclipse depths favor models in which incident energy is not redistributed efficiently from the day side to the night side of the planet. We fit the Spitzer light curves simultaneously with the best available radial velocity curves and transit photometry in order to provide updated measurements of system parameters. We do not find significant eccentricity in the orbit of either planet, suggesting that the inflated radius of WASP-1b is unlikely to be the result of tidal heating. Finally, by plotting ratios of secondary eclipse depths at 8um and 4.5um against irradiation for all available planets, we find evidence for a sharp transition in the emission spectra of hot Jupiters at an irradiation level of 2 x 10^9 erg/s/cm^2. We suggest this transition may be due to the presence of TiO in the upper atmospheres of the most strongly irradiated hot Jupiters.Comment: 10 pages, submitted to Ap

Frontiers in Pigment Cell and Melanoma Research

We identify emerging frontiers in clinical and basic research of melanocyte biology and its associated biomedical disciplines. We describe challenges and opportunities in clinical and basic research of normal and diseased melanocytes that impact current approaches to research in melanoma and the dermatological sciences. We focus on four themes: (1) clinical melanoma research, (2) basic melanoma research, (3) clinical dermatology, and (4) basic pigment cell research, with the goal of outlining current highlights, challenges, and frontiers associated with pigmentation and melanocyte biology. Significantly, this document encapsulates important advances in melanocyte and melanoma research including emerging frontiers in melanoma immunotherapy, medical and surgical oncology, dermatology, vitiligo, albinism, genomics and systems biology, epidemiology, pigment biophysics and chemistry, and evolution

Protons as Second Messenger Regulators of G Protein Signaling

In response to environmental stress cells often generate pH signals that serve to protect vital cellular components and reprogram gene expression for survival. A major barrier to our understanding of this process has been the identification of signaling proteins that detect changes in intracellular pH. To identify candidate pH sensors we developed a computer algorithm that searches proteins for networks of proton-binding sidechains. This analysis indicates that Gα subunits, the principal transducers of G protein-coupled receptor signals, are pH sensors. Our structure-based calculations and biophysical investigations reveal that Gα subunits contain networks of pH-sensing sidechains buried between their Ras and helical domains. We show further that proton binding induces changes in conformation that promote Gα phosphorylation and suppress receptor-initiated signaling. Together, our computational, biophysical and cellular analyses reveal a new and unexpected function for G proteins as mediators of stress-response signaling

WASP-80b has a dayside within the T-dwarf range

WASP-80b is a missing link in the study of exoatmospheres. It falls between the warm Neptunes and the hot Jupiters and is amenable for characterization, thanks to its host star's properties. We observed the planet through transit and during occultation with Warm Spitzer. Combining our mid-infrared transits with optical time series, we find that the planet presents a transmission spectrum indistinguishable from a horizontal line. In emission, WASP-80b is the intrinsically faintest planet whose dayside flux has been detected in both the 3.6 and 4.5 μm Spitzer channels. The depths of the occultations reveal that WASP-80b is as bright and as red as a T4 dwarf, but that its temperature is cooler. If planets go through the equivalent of an L-T transition, our results would imply that this happens at cooler temperatures than for brown dwarfs. Placing WASP-80b's dayside into a colour-magnitude diagram, it falls exactly at the junction between a blackbody model and the T-dwarf sequence; we cannot discern which of those two interpretations is the more likely. WASP-80b's flux density is as low as GJ436b at 3.6 μm; the planet's dayside is also fainter, but bluer than HD189733Ab's nightside (in the [3.6] and [4.5]Spitzer bands). Flux measurements on other planets with similar equilibrium temperatures are required to establish whether irradiated gas giants, such as brown dwarfs, transition between two spectral classes. An eventual detection of methane absorption in transmission would also help lift that degeneracy. We obtained a second series of high-resolution spectra during transit, using HARPS. We reanalyse the Rossiter-McLaughlin effect. The data now favour an aligned orbital solution and a stellar rotation nearly three times slower than stellar line broadening implies. A contribution to stellar line broadening, maybe macroturbulence, is likely to have been underestimated for cool stars, whose rotations have therefore been systematically overestimate

Expression of Drug Targets in Patients Treated with Sorafenib, Carboplatin and Paclitaxel

Introduction: Sorafenib, a multitarget kinase inhibitor, targets members of the mitogen-activated protein kinase (MAPK) pathway and VEGFR kinases. Here we assessed the association between expression of sorafenib targets and biomarkers of taxane sensitivity and response to therapy in pre-treatment tumors from patients enrolled in ECOG 2603, a phase III comparing sorafenib, carboplatin and paclitaxel (SCP) to carboplatin, paclitaxel and placebo (CP). Methods: Using a method of automated quantitative analysis (AQUA) of in situ protein expression, we quantified expression of VEGF-R2, VEGF-R1, VEGF-R3, FGF-R1, PDGF-Rβ, c-Kit, B-Raf, C-Raf, MEK1, ERK1/2, STMN1, MAP2, EB1 and Bcl-2 in pretreatment specimens from 263 patients. Results: An association was found between high FGF-R1 and VEGF-R1 and increased progression-free survival (PFS) and overall survival (OS) in our combined cohort (SCP and CP arms). Expression of FGF-R1 and VEGF-R1 was higher in patients who responded to therapy ((CR+PR) vs. (SD+PD+ un-evaluable)). Conclusions: In light of the absence of treatment effect associated with sorafenib, the association found between FGF-R1 and VEGF-R1 expression and OS, PFS and response might reflect a predictive biomarker signature for carboplatin/paclitaxel-based therapy. Seeing that carboplatin and pacitaxel are now widely used for this disease, corroboration in another cohort might enable us to improve the therapeutic ratio of this regimen. © 2013 Jilaveanu et al