13,699 research outputs found
TACC3-ch-TOG track the growing tips of microtubules independently of clathrin and Aurora-A phosphorylation
Full text linkThe interaction between TACC3 (transforming acidic coiled coil protein 3) and the microtubule polymerase ch-TOG (colonic, hepatic tumor overexpressed gene) is evolutionarily conserved. Loading of TACC3–ch-TOG onto spindle microtubules requires the phosphorylation of TACC3 by Aurora-A kinase and the subsequent interaction of TACC3 with clathrin to form a microtubule binding surface. Whether there is a pool of TACC3–ch-TOG that is independent of clathrin in human cells, and what is the function of this pool, are open questions. Here, we report that TACC3 is recruited to the plus-ends of microtubules by its association with ch-TOG and that this pool is independent of phosphorylation and binding to clathrin. The plus-end binding of TACC3–ch-TOG persists in interphase and we propose that one cellular function of TACC3–ch-TOG is to modulate cell migration. We also describe the distinct subcellular pools of TACC3, ch-TOG and clathrin. TACC3 is often described as a centrosomal protein, but we show that there is no significant population of TACC3 at centrosomes. The delineation of distinct protein pools reveals a simplified view of how these proteins are organized and controlled by post-translational modification
Ice chemistry of acetaldehyde reveals competitive reactions in the first step of the Strecker synthesis of alanine: formation of HO-CH(CH3)-NH2 vs. HO-CH(CH3)-CN
No full textInternational audienceThe understanding of compound formation in laboratory simulated astrophysical environments is an important challenge in obtaining information on the chemistry occurring in these environments. We here investigate by means of both laboratory experiments and quantum chemical calculations the ice-based reactivity of acetaldehyde (CH 3 CHO) with ammonia (NH 3) and hydrogen cyanide (HCN) in excess of water (H 2 O) promoted by temperature. A priori, this study should give information on alanine (2 HN–CH(CH 3)–COOH) formation (the simplest chiral amino acid detected in meteorites), since these reactions concern the first steps of its formation through the Strecker synthesis. However, infrared spectroscopy, mass spectrometry with HC 14 N or HC 15 N isotopologues and B3LYP-D3 results converge to indicate that an H 2 O-dominated ice containing CH 3 CHO, NH 3 and HCN not only leads to the formation of α-aminoethanol (2 HN–CH(CH 3)–OH, the product compound of the first step of the Strecker mechanism) and its related polymers (2 HN–(CH(CH 3)–O) n –H) due to reaction between CH 3 CHO and NH 3 , but also to the 2-hydroxypropionitrile (HO–CH(CH 3)–CN) and its related polymers (H–(O–CH(CH 3)) n –CN) from direct reaction between CH 3 CHO and HCN. The ratio between these two species depends on the initial NH 3 /HCN ratio in the ice. Formation of α-aminoethanol is favoured when the NH 3 concentration is larger than HCN. We also show that the presence of water is essential for the formation of HO–CH(CH 3)–CN, contrarily to 2 HN–CH(CH 3)–OH whose formation also takes place in absence of H 2 O ice. As in astrophysical ices NH 3 is more abundant than HCN, formation of α-aminoethanol should consequently be favoured compared to 2-hydroxypropionitrile, thus pointing out α-aminoethanol as a plausible intermediate species for alanine synthesis through the Strecker mechanism in astrophysical ices
FcgammaRII mediates platelet aggregation caused by disintegrins and GPIIb/IIIa monoclonal antibody, AP2.
No full textHMOX1 gene promoter alleles and high HO-1 levels are associated with severe malaria in Gambian children.
Full text linkHeme oxygenase 1 (HO-1) is an essential enzyme induced by heme and multiple stimuli associated with critical illness. In humans, polymorphisms in the HMOX1 gene promoter may influence the magnitude of HO-1 expression. In many diseases including murine malaria, HO-1 induction produces protective anti-inflammatory effects, but observations from patients suggest these may be limited to a narrow range of HO-1 induction, prompting us to investigate the role of HO-1 in malaria infection. In 307 Gambian children with either severe or uncomplicated P. falciparum malaria, we characterized the associations of HMOX1 promoter polymorphisms, HMOX1 mRNA inducibility, HO-1 protein levels in leucocytes (flow cytometry), and plasma (ELISA) with disease severity. The (GT)(n) repeat polymorphism in the HMOX1 promoter was associated with HMOX1 mRNA expression in white blood cells in vitro, and with severe disease and death, while high HO-1 levels were associated with severe disease. Neutrophils were the main HO-1-expressing cells in peripheral blood, and HMOX1 mRNA expression was upregulated by heme-moieties of lysed erythrocytes. We provide mechanistic evidence that induction of HMOX1 expression in neutrophils potentiates the respiratory burst, and propose this may be part of the causal pathway explaining the association between short (GT)(n) repeats and increased disease severity in malaria and other critical illnesses. Our findings suggest a genetic predisposition to higher levels of HO-1 is associated with severe illness, and enhances the neutrophil burst leading to oxidative damage of endothelial cells. These add important information to the discussion about possible therapeutic manipulation of HO-1 in critically ill patients
A dynamic buffer management scheme based on rate estimation in packet-switched networks
No full textGlobal Telecommunications Conference, 2001. GLOBECOM '01. IEE
Lysophosphatidic acid up-regulates expression of interleukin-8 and -6 in granulosa-lutein cells through its receptors and nuclear factor-kappaB dependent pathways: implications for angiogenesis of corpus luteum and ovarian hyperstimulation
No full textSynthesis and study of azo-dye compounds: Various molecular stackings from different polarities of the molecules
No full text[[abstract]]One non-F-containing and two F-containing azo-dye compounds were prepared to investigate their molecular stackings by X-ray crystallography. Introduction of the F-atom into the aromatic moiety of azo-dye compounds leads to a variation of the charge distribution and consequently to different molecular stackings. Accordingly, the mesogenic behaviors in the solid state are different.[[note]]SC
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