Regulation of Angiopoietin Signalling by Soluble Tie2 Ectodomain and Engineered Ligand Trap.

Angiopoietin-1 (Angpt1) is a glycoprotein ligand important for maintaining the vascular system. It signals via a receptor tyrosine kinase expressed on the surface on endothelial cells, Tie2. This receptor can undergo regulated ectodomain cleavage that releases the ligand-binding domain (sTie2) into the circulation.

The RNA binding protein hnRNP-K mediates post-transcriptional regulation of uncoupling protein-2 by angiopoietin-1.

Angiopoietin-1 (Ang1) is a ligand for the receptor tyrosine kinase Tie2 and has key roles in the development of the vascular system and vascular protection. In a screen to define signalling pathways regulated by Ang1 in endothelial cells we found the RNA-binding protein hnRNP-K to be phosphorylated in response to Ang1. The ligand stimulated both tyrosine phosphorylation of hnRNP-K and recruitment of the tyrosine kinase Src to the RNA-binding protein.

Molecular control of angiopoietin signalling.

The angiopoietins act through the endothelial receptor tyrosine kinase Tie2 to regulate vessel maturation in angiogenesis and control quiescence and stability of established vessels. The activating ligand, Ang1 (angiopoietin-1), is constitutively expressed by perivascular cells, and the ability of endothelial cells to respond to the ligand is controlled at the level of the Ang1 receptor. This receptor interacts with the related protein Tie1 on the cell surface, and Tie1 inhibits Ang1 signalling through Tie2.

Gastric schwannoma in a female patient with pulmonary tuberculosis - a clinicopathological assessment and diagnosis.

Schwannomas, or neurinomas, are generally benign, slow-growing, asymptomatic neoplasms originating from the Schwann cells of a nerve sheath. As a part of spindle cell mesenchymal tumours, schwannomas arising from the gastrointestinal tract (GIT) are unusual; however, when they occur, the most common site involved is the stomach, which represents 0.2% of all gastric tumours.

Effects of angiopoietins-1 and -2 on the receptor tyrosine kinase Tie2 are differentially regulated at the endothelial cell surface.

Angiopoietin-1 (Ang1) and Ang2 are ligands for the receptor tyrosine kinase Tie2. Structural data suggest that the two ligands bind Tie2 similarly. However, in endothelial cells Ang1 activates Tie2 whereas Ang2 can act as an apparent antagonist.

Functional importance of Asp37 from a family 11 xylanase in the binding to two proteinaceous xylanase inhibitors from wheat.

Aspergillus niger xylanase is a target enzyme of the two wheat proteinaceous inhibitors, XIP-I and TAXI-I. We previously suggested that the xylanase "thumb" region was XIP-I binding site. Here, we expressed the Asp37Ala mutant in Pichia pastoris and showed that the mutation abolished the enzyme capacity to interact with both inhibitors, suggesting a direct contact at the active site.

The inhibition specificity of recombinant Penicillium funiculosum xylanase B towards wheat proteinaceous inhibitors.

The filamentous fungus Penicillium funiculosum produces a mixture of modular and non-modular xylanases belonging to different glycoside hydrolase (GH) families. In the present study, we heterologously expressed the cDNA encoding GH11 xylanase B (XYNB) and studied the enzymatic properties of the recombinant enzyme. Expression in Escherichia coli led to the partial purification of a glutathione fusion protein from the soluble fraction whereas the recombinant protein produced in Pichia pastoris was successfully purified using a one-step chromatography.

The dual nature of the wheat xylanase protein inhibitor XIP-I: structural basis for the inhibition of family 10 and family 11 xylanases.

The xylanase inhibitor protein I (XIP-I) from wheat Triticum aestivum is the prototype of a novel class of cereal protein inhibitors that inhibit fungal xylanases belonging to glycoside hydrolase families 10 (GH10) and 11 (GH11). The crystal structures of XIP-I in complex with Aspergillus nidulans (GH10) and Penicillium funiculosum (GH11) xylanases have been solved at 1.7 and 2.

Potential role of glycosidase inhibitors in industrial biotechnological applications.

The nutrient content of food and animal feed may be improved through new knowledge about enzymatic changes in complex carbohydrates. Enzymatic hydrolysis of complex carbohydrates containing alpha or beta glycosidic bonds is very important in nutrition and in several technological processes. These enzymes are called glycosidases (Enzyme Class 3.

Specific characterization of substrate and inhibitor binding sites of a glycosyl hydrolase family 11 xylanase from Aspergillus niger.

The importance of aromatic and charged residues at the surface of the active site of a family 11 xylanase from Aspergillus niger was evaluated using site-directed mutagenesis. Ten mutant proteins were heterologously produced in Pichia pastoris, and their biochemical properties and kinetic parameters were determined. The specific activity of the Y6A, Y10A, Y89A, Y164A, and W172A mutant enzymes was drastically reduced.