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排序方式: 共有81条查询结果,搜索用时 843 毫秒
21.
Meriem El Ghachi Nicole Howe Rodolphe Auger Alexandre Lambion Annick Guiseppi François Delbrassine Guillaume Manat Sophie Roure Sabine Peslier Eric Sauvage Lutz Vogeley Juan-Carlos Rengifo-Gonzalez Paulette Charlier Dominique Mengin-Lecreulx Maryline Foglino Thierry Touzé Martin Caffrey Frédéric Kerff 《Cellular and molecular life sciences : CMLS》2017,74(12):2319-2332
Type 2 phosphatidic acid phosphatases (PAP2s) can be either soluble or integral membrane enzymes. In bacteria, integral membrane PAP2s play major roles in the metabolisms of glycerophospholipids, undecaprenyl-phosphate (C55-P) lipid carrier and lipopolysaccharides. By in vivo functional experiments and biochemical characterization we show that the membrane PAP2 coded by the Bacillus subtilis yodM gene is the principal phosphatidylglycerol phosphate (PGP) phosphatase of B. subtilis. We also confirm that this enzyme, renamed bsPgpB, has a weaker activity on C55-PP. Moreover, we solved the crystal structure of bsPgpB at 2.25 Å resolution, with tungstate (a phosphate analog) in the active site. The structure reveals two lipid chains in the active site vicinity, allowing for PGP substrate modeling and molecular dynamic simulation. Site-directed mutagenesis confirmed the residues important for substrate specificity, providing a basis for predicting the lipids preferentially dephosphorylated by membrane PAP2s. 相似文献
22.
Lincoln MR Montpetit A Cader MZ Saarela J Dyment DA Tiislar M Ferretti V Tienari PJ Sadovnick AD Peltonen L Ebers GC Hudson TJ 《Nature genetics》2005,37(10):1108-1112
Genetic susceptibility to multiple sclerosis is associated with genes of the major histocompatibility complex (MHC), particularly HLA-DRB1 and HLA-DQB1 (ref. 1). Both locus and allelic heterogeneity have been reported in this genomic region. To clarify whether HLA-DRB1 itself, nearby genes in the region encoding the MHC or combinations of these loci underlie susceptibility to multiple sclerosis, we genotyped 1,185 Canadian and Finnish families with multiple sclerosis (n = 4,203 individuals) with a high-density SNP panel spanning the genes encoding the MHC and flanking genomic regions. Strong associations in Canadian and Finnish samples were observed with blocks in the HLA class II genomic region (P < 4.9 x 10(-13) and P < 2.0 x 10(-16), respectively), but the strongest association was with HLA-DRB1 (P < 4.4 x 10(-17)). Conditioning on either HLA-DRB1 or the most significant HLA class II haplotype block found no additional block or SNP association independent of the HLA class II genomic region. This study therefore indicates that MHC-associated susceptibility to multiple sclerosis is determined by HLA class II alleles, their interactions and closely neighboring variants. 相似文献
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25.
Jacquemont S Reymond A Zufferey F Harewood L Walters RG Kutalik Z Martinet D Shen Y Valsesia A Beckmann ND Thorleifsson G Belfiore M Bouquillon S Campion D de Leeuw N de Vries BB Esko T Fernandez BA Fernández-Aranda F Fernández-Real JM Gratacòs M Guilmatre A Hoyer J Jarvelin MR Kooy RF Kurg A Le Caignec C Männik K Platt OS Sanlaville D Van Haelst MM Villatoro Gomez S Walha F Wu BL Yu Y Aboura A Addor MC Alembik Y Antonarakis SE Arveiler B Barth M Bednarek N Béna F Bergmann S Beri M Bernardini L 《Nature》2011,478(7367):97-102
26.
Roppolo D De Rybel B Tendon VD Pfister A Alassimone J Vermeer JE Yamazaki M Stierhof YD Beeckman T Geldner N 《Nature》2011,473(7347):380-383
Polarized epithelia are fundamental to multicellular life. In animal epithelia, conserved junctional complexes establish membrane diffusion barriers, cellular adherence and sealing of the extracellular space. Plant cellular barriers are of independent evolutionary origin. The root endodermis strongly resembles a polarized epithelium and functions in nutrient uptake and stress resistance. Its defining features are the Casparian strips, belts of specialized cell wall material that generate an extracellular diffusion barrier. The mechanisms localizing Casparian strips are unknown. Here we identify and characterize a family of transmembrane proteins of previously unknown function. These 'CASPs' (Casparian strip membrane domain proteins) specifically mark a membrane domain that predicts the formation of Casparian strips. CASP1 displays numerous features required for a constituent of a plant junctional complex: it forms complexes with other CASPs; it becomes immobile upon localization; and it sediments like a large polymer. CASP double mutants display disorganized Casparian strips, demonstrating a role for CASPs in structuring and localizing this cell wall modification. To our knowledge, CASPs are the first molecular factors that are shown to establish a plasma membrane and extracellular diffusion barrier in plants, and represent a novel way of epithelial barrier formation in eukaryotes. 相似文献
27.
Alexandre Lipschutz 《Cellular and molecular life sciences : CMLS》1946,2(11):460-461
Summary Experimental proofs are given that the antifibromatogenic action of certain steroids is not simply concomitant with their physiological activities (progestational, androgenic, cortical). It is an antiplastic actionper se, taking place directly on the territory sensitive to the neoplastic action of the strogen. Antiplastic steroids are probably an integrant part of a physiological anti-tumoural autodefensive system. 相似文献
28.
J Brachet H Alexandre 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1978,286(11):895-898
The K+ ionophore valinomycin very quickly arrests cleavage in sea urchin and mouse eggs at concentrations ranging between 10 and 3 micron. Development of Axolotl and Xenopus eggs is not arrested before the blastula or gastrula stage. The motility of sea urchin sperm, blastulae and gastrulae is suppressed, within a few minutes, by 1-9 micron valinomycin. 相似文献
29.
Summary The action of angiotensin II on cardiac uptake of norepinephrine was investigated in the rat in vivo and in vitro. In contrast to desipramine, neither infusion of subpressive (10 ng/kg/min) or pressive (50–150 ng/kg/min) amounts of angiotensin on intact and/or binephrectomized rats, nor incubation of cardiac slices with angiotensin II (10–5; 10–9
M) impair the accumulation of tritiated norepinephrine and the level of metabolites. It is thus concluded that there is no inhibiting action of angiotensin II on the cardiac uptake of norepinephrine. 相似文献
30.
Stipanovich A Valjent E Matamales M Nishi A Ahn JH Maroteaux M Bertran-Gonzalez J Brami-Cherrier K Enslen H Corbillé AG Filhol O Nairn AC Greengard P Hervé D Girault JA 《Nature》2008,453(7197):879-884
Dopamine orchestrates motor behaviour and reward-driven learning. Perturbations of dopamine signalling have been implicated in several neurological and psychiatric disorders, and in drug addiction. The actions of dopamine are mediated in part by the regulation of gene expression in the striatum, through mechanisms that are not fully understood. Here we show that drugs of abuse, as well as food reinforcement learning, promote the nuclear accumulation of 32-kDa dopamine-regulated and cyclic-AMP-regulated phosphoprotein (DARPP-32). This accumulation is mediated through a signalling cascade involving dopamine D1 receptors, cAMP-dependent activation of protein phosphatase-2A, dephosphorylation of DARPP-32 at Ser 97 and inhibition of its nuclear export. The nuclear accumulation of DARPP-32, a potent inhibitor of protein phosphatase-1, increases the phosphorylation of histone H3, an important component of nucleosomal response. Mutation of Ser 97 profoundly alters behavioural effects of drugs of abuse and decreases motivation for food, underlining the functional importance of this signalling cascade. 相似文献