29 research outputs found

    An N-Terminal Extension to UBA5 Adenylation Domain Boosts UFM1 Activation: Isoform-Specific Differences in Ubiquitin-like Protein Activation

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Modification of proteins by the ubiquitin-like protein, UFM1, requires activation of UFM1 by the E1-activating enzyme, UBA5. In humans, UBA5 possesses two isoforms, each comprising an adenylation domain, but only one containing an N-terminal extension. Currently, the role of the N-terminal extension in UFM1 activation is not clear. Here we provide structural and biochemical data on UBA5 N-terminal extension to understand its contribution to UFM1 activation. The crystal structures of the UBA5 long isoform bound to ATP with and without UFM1 show that the N-terminus not only is directly involved in ATP binding but also affects how the adenylation domain interacts with ATP. Surprisingly, in the presence of the N-terminus, UBA5 no longer retains the 1:2 ratio of ATP to UBA5, but rather this becomes a 1:1 ratio. Accordingly, the N-terminus significantly increases the affinity of ATP to UBA5. Finally, the N-terminus, although not directly involved in the E2 binding, stimulates transfer of UFM1 from UBA5 to the E2, UFC1.Marie Curie Career Integration GrantIsrael Science FoundationIsraeli Cancer Associatio

    Wheeze in Preschool Age Is Associated with Pulmonary Bacterial Infection and Resolves after Antibiotic Therapy

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    BACKGROUND: Neonates with airways colonized by Haemophilus influenzae, Streptococcus pneumoniae or Moraxella catarrhalis are at increased risk for recurrent wheeze which may resemble asthma early in life. It is not clear whether chronic colonization by these pathogens is causative for severe persistent wheeze in some preschool children and whether these children might benefit from antibiotic treatment. We assessed the relevance of bacterial colonization and chronic airway infection in preschool children with severe persistent wheezing and evaluated the outcome of long-time antibiotic treatment on the clinical course in such children. METHODOLOGY/PRINCIPAL FINDINGS: Preschool children (n = 42) with severe persistent wheeze but no symptoms of acute pulmonary infection were investigated by bronchoscopy and bronchoalveolar lavage (BAL). Differential cell counts and microbiological and virological analyses were performed on BAL samples. Patients diagnosed with bacterial infection were treated with antibiotics for 2-16 weeks (n = 29). A modified ISAAC questionnaire was used for follow-up assessment of children at least 6 months after bronchoscopy. Of the 42 children with severe wheezing, 34 (81%) showed a neutrophilic inflammation and 20 (59%) of this subgroup had elevated bacterial counts (≥ 10⁴ colony forming units per milliliter) suggesting infection. Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis were the most frequently isolated species. After treatment with appropriate antibiotics 92% of patients showed a marked improvement of symptoms upon follow-up examination. CONCLUSIONS/SIGNIFICANCE: Chronic bacterial infections are relevant in a subgroup of preschool children with persistent wheezing and such children benefit significantly from antibiotic therapy

    Study of angulations of visceral abdominals arteries in their abdominal aorta emergency

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    Recently, fenestrated, branched and stent grafts have been developed in order to treat endovascular aneurysmal pathology at the level of the aorta in the emergence of the visceral arteries. For the implantation of stents, it is necessary to have a precise planimetry of the origin and orientation of the visceral branches in order firstly to perform the correct manufacture of the endoprosthesis and secondly the placement with precision of the same. The knowledge of the emergency of the vessels of the aortic wall and its orientation knowing the angle of emergency. The data obtained for the planning of the endovascular treatment of 37 patients in order to obtain data from the descriptive point of view of this sector

    Valoración de los ángulos del cuello del aneurisma de aorta abdominal. Estudio en 507 pacientes

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    Angulation in different planes of the neck of abdominal aortic aneurysms may be considered a limiting factor in the implantation of different prostheses in the treatment of this pathology. It is necessary to make an assessment of the angles in different planes in routine studies prior to the planning of the procedures and especially by AngioTAC. The study evaluated the measurement of 507 patients with abdominal aortic aneurysms and treated endovascular procedures and of whom the complete information was available at the level of neck angulations. In a prospective and descriptive study the situation of this aortic sector was evaluated, contributing information about the tendency in the morphological presentation of the aorta in patients with this aetiolog

    The crystal structure and conformations of an unbranched mixed tri-ubiquitin chain containing K48 and K63 linkages.

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.The ability of ubiquitin to function in a wide range of cellular processes is ascribed to its capacity to cause a diverse spectrum of modifications. While a target protein can be modified with monoubiquitin, it can also be modified with ubiquitin chains. The latter include seven types of homotypic chains as well as mixed ubiquitin chains. In a mixed chain, not all the isopeptide bonds are restricted to a specific lysine of ubiquitin, resulting in a chain possessing more than one type of linkage. While structural characterization of homotypic chains has been well elucidated, less is known about mixed chains. Here we present the crystal structure of a mixed tri-ubiquitin chain at 3.1-Å resolution. In the structure, the proximal ubiquitin is connected to the middle ubiquitin via K48 and these two ubiquitins adopt a compact structure as observed in K48 di-ubiquitin. The middle ubiquitin links to the distal ubiquitin via its K63 and these ubiquitins adopt two conformations, suggesting a flexible structure. Using small-angle X-ray scattering, we unexpectedly found differences between the conformational ensembles of the above tri-ubiquitin chains and chains possessing the same linkages but in the reverse order. In addition, cleavage of the K48 linkage by DUB is faster if this linkage is at the distal end. Taken together, our results suggest that in mixed chains, not only the type of the linkages but also their sequence determine the structural and functional properties of the chain.The work was supported by a Marie Curie Career Integration grant (PCIG13-GA-2013-630755) to R.W

    CFD modelling of abdominal aortic aneurysm on hemodynamic loads using a realistic geometry with CT

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    The objective of this study is to find a correlation between the abdominal aortic aneurysm (AAA) geometric parameters, wall stress shear (WSS), abdominal flow patterns, intraluminal thrombus (ILT), and AAA arterial wall rupture using computational fluid dynamics (CFD). Real AAA 3D models were created by three-dimensional (3D) reconstruction of in vivo acquired computed tomography (CT) images from 5 patients. Based on 3D AAA models, high quality volume meshes were created using an optimal tetrahedral aspect ratio for the whole domain. In order to quantify the WSS and the recirculation inside the AAA, a 3D CFD using finite elements analysis was used. The CFD computation was performed assuming that the arterial wall is rigid and the blood is considered a homogeneous Newtonian fluid with a density of 1050¿kg/m3 and a kinematic viscosity of Pa·s. Parallelization procedures were used in order to increase the performance of the CFD calculations. A relation between AAA geometric parameters (asymmetry index (ß), saccular index (¿), deformation diameter ratio (¿), and tortuosity index (e)) and hemodynamic loads was observed, and it could be used as a potential predictor of AAA arterial wall rupture and potential ILT formation.Peer Reviewe
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