Concerted Transport and Phosphorylation of Diacylglycerol at ER-PM Contacts Sites Regulates Phospholipid Dynamics During Stress

A universal response of plants to environmental stresses is the activation of plasma membrane (PM) phospholipase C (PLC) that hydrolyzes phosphatidylinositol phosphate (PIP) to produce soluble inositol phosphate (IP) and diacylglycerol (DAG). DAG produced in this way can be either phosphorylated by PM diacylglycerol kinases (DGKs) to produce the second messenger phosphatidic acid (PA) or transferred to the endoplasmic reticulum (ER) by the Synaptotagmin 1 (SYT1) protein at ER-PM Contact Sites (CS). In Arabidopsis, the clearance of DAG at the PM (avoiding deleterious accumulation) by the transfer activity of SYT is essential to maintain PM stability after stress. In this study we identify that DGK1 and DGK2 form a module with SYT1 at ER-PM CS through interaction of their C1 and C2 domains respectively. Global transcriptomic and metabolomic analyses confirms that SYT1 and DGK1/DGK2 are functionally related and lipidomic analysis supports the hypothesis that DGK1 and DGK2 function at the ER by phosphorylating DAG transferred by SYT1 from the PM. DGK1 and DGK2 show structural similarity to human DGKε, the DGK isoform that function at ER-PM CS in the phosphoinositide (PI) cycle. Our data indicate that components of the PI cycle are conserved between animals and plants and provide a novel mechanism leading to an increase in the efficiency of the PI cycle by channeling the transport and hydrolysis of DAG at the ER-PM CS

Plasmodium falciparum heterochromatin protein 1 binds to tri-methylated histone 3 lysine 9 and is linked to mutually exclusive expression of var genes

Increasing experimental evidence shows a prominent role of histone modifications in the coordinated control of gene expression in the human malaria parasite Plasmodium falciparum. The search for the histone-mark-reading machinery that translates histone modifications into biological processes, such as formation of heterochromatin and antigenic variation is of foremost importance. In this work, we identified the first member of a histone modification specific recognition protein, an orthologue of heterochromatin protein 1 (PfHP1). Analysis of the PfHP1 amino-acid sequence revealed the presence of the two characteristic HP1 domains: a chromodomain (CD) and a chromo shadow domain (CSD). Recombinant CD binds to di- and tri-methylated lysine 9 from histone H3, but not to unmodified or methylated histone H3 in lysine 4. PfHP1 is able to interact with itself to form dimers, underlying its potential role in aggregating nucleosomes to form heterochromatin. Antibodies raised against PfHP1 detect this molecule in foci at the perinuclear region. ChIP analysis using anti-PfHP1 shows that this protein is linked to heterochromatin of subtelomeric non-coding repeat regions and monoallelic expression of the major virulence var gene family. This is the first report implicating an HP1 protein in the control of antigenic variation of a protozoan parasite

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

Observation of the Baryonic Flavor-Changing Neutral Current Decay Lambda_b -> Lambda mu+ mu-

We report the first observation of the baryonic flavor-changing neutral current decay Lambda_b -> Lambda mu+ mu- with 24 signal events and a statistical significance of 5.8 Gaussian standard deviations. This measurement uses ppbar collisions data sample corresponding to 6.8fb-1 at sqrt{s}=1.96TeV collected by the CDF II detector at the Tevatron collider. The total and differential branching ratios for Lambda_b -> Lambda mu+ mu- are measured. We find B(Lambda_b -> Lambda mu+ mu-) = [1.73+-0.42(stat)+-0.55(syst)] x 10^{-6}. We also report the first measurement of the differential branching ratio of B_s -> phi mu+ mu- using 49 signal events. In addition, we report branching ratios for B+ -> K+ mu+ mu-, B0 -> K0 mu+ mu-, and B -> K*(892) mu+ mu- decays.Comment: 8 pages, 2 figures, 4 tables. Submitted to Phys. Rev. Let