Differential Roles for STIM1 and STIM2 in Store-Operated Calcium Entry in Rat Neurons

The interaction between Ca2+ sensors STIM1 and STIM2 and Ca2+ channel-forming protein ORAI1 is a crucial element of store-operated calcium entry (SOCE) in non-excitable cells. However, the molecular mechanism of SOCE in neurons remains unclear. We addressed this issue by establishing the presence and function of STIM proteins. Real-time polymerase chain reaction from cortical neurons showed that these cells contain significant amounts of Stim1 and Stim2 mRNA. Thapsigargin (TG) treatment increased the amount of both endogenous STIM proteins in neuronal membrane fractions. The number of YFP-STIM1/ORAI1 and YFP-STIM2/ORAI1 complexes was also enhanced by such treatment. The differences observed in the number of STIM1 and STIM2 complexes under SOCE conditions and the differential sensitivity to SOCE inhibitors suggest their distinct roles. Endoplasmic reticulum (ER) store depletion by TG enhanced intracellular Ca2+ levels in loaded with Fura-2 neurons transfected with YFP-STIM1 and ORAI1, but not with YFP-STIM2 and ORAI1, which correlated well with the number of complexes formed. Moreover, the SOCE inhibitors ML-9 and 2-APB reduced Ca2+ influx in neurons expressing YFP-STIM1/ORAI1 but produced no effect in cells transfected with YFP-STIM2/ORAI1. Moreover, in neurons transfected with YFP-STIM2/ORAI1, the increase in constitutive calcium entry was greater than with YFP-STIM1/ORAI1. Our data indicate that both STIM proteins are involved in calcium homeostasis in neurons. STIM1 mainly activates SOCE, whereas STIM2 regulates resting Ca2+ levels in the ER and Ca2+ leakage with the additional involvement of STIM1

Homogenizing GPS integrated water vapour time series: methodology and benchmarking the algorithms on synthetic datasets

We would like to thank the COST Action ES1206 GNSS4SWEC for financial support

Performance of various homogenization tools on a synthetic benchmark dataset of GPS and ERA-interim IWV differences

Presentación realizada en: IAG-IASPEI 39th Joint Scientific Assembly celebrada en Kobe, Japón, del 30 de julio al 4 de agosto de 2017

Study on homogenization of synthetic GNSS-Retrieved IWV time series and its impact on trend estimates with autoregressive noise

Póster presentado en: EGU General Assembly celebrada del 23 al 28 de abril de 2017 en Viena, Austria.A synthetic benchmark dataset of Integrated Water Vapour (IWV) was created within the activity of “Data homogenisation” of sub-working group WG3 of COST ES1206 Action. The benchmark dataset was created basing on the analysis of IWV differences retrieved by Global Positioning System (GPS) International GNSS Service (IGS) stations using European Centre for Medium-Range Weather Forecats (ECMWF) reanalysis data (ERA-Interim). Having analysed a set of 120 series of IWV differences (ERAI-GPS) derived for IGS stations, we delivered parameters of a number of gaps and breaks for every certain station. Moreover, we estimated values of trends, significant seasonalities and character of residuals when deterministic model was removed. We tested five different noise models and found that a combination of white and autoregressive processes of first order describes the stochastic part with a good accuracy. Basing on this analysis, we performed Monte Carlo simulations of 25 years long data with two different types of noise: white as well as combination of white and autoregressive processes. We also added few strictly defined offsets, creating three variants of synthetic dataset: easy, less complicated and fully complicated. The synthetic dataset we present was used as a benchmark to test various statistical tools in terms of homogenisation task. In this research, we assess the impact of the noise model, trend and gaps on the performance of statistical methods to detect simulated change points

Homogenization of tropospheric data: evaluating the algorithms under the presence of autoregressive process

Presentación realizada en: IX Hotine-Marussi Symposium celebrado en Roma del 18 al 22 de junio de 2018.This research was supported by the Polish National Science Centre, grant No. UMO-2016/21/B/ST10/02353

Trans-Species Polymorphism and Selection in the MHC Class II DRA Genes of Domestic Sheep

Highly polymorphic genes with central roles in lymphocyte mediated immune surveillance are grouped together in the major histocompatibility complex (MHC) in higher vertebrates. Generally, across vertebrate species the class II MHC DRA gene is highly conserved with only limited allelic variation. Here however, we provide evidence of trans-species polymorphism at the DRA locus in domestic sheep (Ovis aries). We describe variation at the Ovar-DRA locus that is far in excess of anything described in other vertebrate species. The divergent DRA allele (Ovar-DRA*0201) differs from the sheep reference sequences by 20 nucleotides, 12 of which appear non-synonymous. Furthermore, DRA*0201 is paired with an equally divergent DRB1 allele (Ovar-DRB1*0901), which is consistent with an independent evolutionary history for the DR sub-region within this MHC haplotype. No recombination was observed between the divergent DRA and B genes in a range of breeds and typical levels of MHC class II DR protein expression were detected at the surface of leukocyte populations obtained from animals homozygous for the DRA*0201, DRB1*0901 haplotype. Bayesian phylogenetic analysis groups Ovar-DRA*0201 with DRA sequences derived from species within the Oryx and Alcelaphus genera rather than clustering with other ovine and caprine DRA alleles. Tests for Darwinian selection identified 10 positively selected sites on the branch leading to Ovar-DRA*0201, three of which are predicted to be associated with the binding of peptide antigen. As the Ovis, Oryx and Alcelaphus genera have not shared a common ancestor for over 30 million years, the DRA*0201 and DRB1*0901 allelic pair is likely to be of ancient origin and present in the founding population from which all contemporary domestic sheep breeds are derived. The conservation of the integrity of this unusual DR allelic pair suggests some selective advantage which is likely to be associated with the presentation of pathogen antigen to T-cells and the induction of protective immunity

The Pathogenic Potential of Campylobacter concisus Strains Associated with Chronic Intestinal Diseases

Campylobacter concisus has garnered increasing attention due to its association with intestinal disease, thus, the pathogenic potential of strains isolated from different intestinal diseases was investigated. A method to isolate C. concisus was developed and the ability of eight strains from chronic and acute intestinal diseases to adhere to and invade intestinal epithelial cells was determined. Features associated with bacterial invasion were investigated using comparative genomic analyses and the effect of C. concisus on host protein expression was examined using proteomics. Our isolation method from intestinal biopsies resulted in the isolation of three C. concisus strains from children with Crohn's disease or chronic gastroenteritis. Four C. concisus strains from patients with chronic intestinal diseases can attach to and invade host cells using mechanisms such as chemoattraction to mucin, aggregation, flagellum-mediated attachment, “membrane ruffling”, cell penetration and damage. C. concisus strains isolated from patients with chronic intestinal diseases have significantly higher invasive potential than those from acute intestinal diseases. Investigation of the cause of this increased pathogenic potential revealed a plasmid to be responsible. 78 and 47 proteins were upregulated and downregulated in cells infected with C. concisus, respectively. Functional analysis of these proteins showed that C. concisus infection regulated processes related to interleukin-12 production, proteasome activation and NF-κB activation. Infection with all eight C. concisus strains resulted in host cells producing high levels of interleukin-12, however, only strains capable of invading host cells resulted in interferon-γ production as confirmed by ELISA. These findings considerably support the emergence of C. concisus as an intestinal pathogen, but more significantly, provide novel insights into the host immune response and an explanation for the heterogeneity observed in the outcome of C. concisus infection. Moreover, response to infection with invasive strains has substantial similarities to that observed in the inflamed mucosa of Crohn's disease patients

STIM2 regulates PKA-dependent phosphorylation and trafficking of AMPARs

STIMs (STIM1 and STIM2 in mammals) are transmembrane proteins that reside in the endoplasmic reticulum (ER) and regulate store-operated Ca2+ entry (SOCE). The function of STIMs in the brain is only beginning to be explored, and the relevance of SOCE in nerve cells is being debated. Here we identify STIM2 as a central organizer of excitatory synapses. STIM2, but not its paralogue STIM1, influences the formation of dendritic spines and shapes basal synaptic transmission in excitatory neurons. We further demonstrate that STIM2 is essential for cAMP/PKA-dependent phosphorylation of the AMPA receptor (AMPAR) subunit GluA1. cAMP triggers rapid migration of STIM2 to ER–plasma membrane (PM) contact sites, enhances recruitment of GluA1 to these ER-PM junctions, and promotes localization of STIM2 in dendritic spines. Both biochemical and imaging data suggest that STIM2 regulates GluA1 phosphorylation by coupling PKA to the AMPAR in a SOCE-independent manner. Consistent with a central role of STIM2 in regulating AMPAR phosphorylation, STIM2 promotes cAMP-dependent surface delivery of GluA1 through combined effects on exocytosis and endocytosis. Collectively our results point to a unique mechanism of synaptic plasticity driven by dynamic assembly of a STIM2 signaling complex at ER-PM contact sites

The Great American Crime Decline : Possible Explanations

This chapter examines the most important features of the crime decline in the United States during the 1990s-2010s but also takes a broader look at the violence declines of the last three centuries. The author argues that violent and property crime trends might have diverged in the 1990s, with property crimes increasingly happening in the online sphere and thus traditional property crime statistics not being reflective of the full picture. An important distinction is made between ‘contact crimes’ and crimes that do not require a victim and offender to be present in the same physical space. Contrary to the uncertainties engendered by property crime, the declines in violent (‘contact’) crime are rather general, and have been happening not only across all demographic and geographic categories within the United States but also throughout the developed world. An analysis of research literature on crime trends has identified twenty-four different explanations for the crime drop. Each one of them is briefly outlined and examined in terms of conceptual clarity and empirical support. Nine crime decline explanations are highlighted as the most promising ones. The majority of these promising explanations, being relative newcomers in the crime trends literature, have not been subjected to sufficient empirical scrutiny yet, and thus require further research. One potentially fruitful avenue for future studies is to examine the association of the most promising crime decline explanations with improvements in self-control