Mutations in VKORC1 cause warfarin resistance and multiple coagulation factor deficiency type 2

Coumarin derivatives such as warfarin represent the therapy of choice for the long-term treatment and prevention of thromboembolic events. Coumarins target blood coagulation by inhibiting the vitamin K epoxide reductase multiprotein complex (VKOR). This complex recycles vitamin K 2,3-epoxide to vitamin K hydroquinone, a cofactor that is essential for the post-translational gamma-carboxylation of several blood coagulation factors. Despite extensive efforts, the components of the VKOR complex have not been identified. The complex has been proposed to be involved in two heritable human diseases: combined deficiency of vitamin-K-dependent clotting factors type 2 (VKCFD2; Online Mendelian Inheritance in Man (OMIM) 607473), and resistance to coumarin-type anticoagulant drugs (warfarin resistance, WR; OMIM 122700). Here we identify, by using linkage information from three species, the gene vitamin K epoxide reductase complex subunit 1 (VKORC1), which encodes a small transmembrane protein of the endoplasmic reticulum. VKORC1 contains missense mutations in both human disorders and in a warfarin-resistant rat strain. Overexpression of wild-type VKORC1, but not VKORC1 carrying the VKCFD2 mutation, leads to a marked increase in VKOR activity, which is sensitive to warfarin inhibition.     

The peroxisomal protein import machinery – a case report of transient ubiquitination with a new flavor

The peroxisomal protein import machinery displays remarkable properties. Be it its capacity to accept already folded proteins as substrates, its complex architecture or its energetics, almost every aspect of this machinery seems unique. The list of unusual properties is still growing as shown by the recent finding that one of its central components, Pex5p, is transiently monoubiquitinated at a cysteine residue. However, the data gathered in recent years also suggest that the peroxisomal import machinery is not that exclusive and similarities with p97/Cdc48-mediated processes and with multisubunit RING-E3 ligases are starting to emerge. Here, we discuss these data trying to distill the principles by which this complex machinery operates. Received 16 July 2008; received after revision 25 August 2008; accepted 29 August 2008     

Inactivation of the proximal NPXY motif impairs early steps in LRP1 biosynthesis

The proximal NPXY and distal NPXYXXL motifs in the intracellular domain of LRP1 play an important role in regulation of the function of the receptor. The impact of single and double inactivating knock-in mutations of these motifs on receptor maturation, cell surface expression, and ligand internalization was analyzed in mutant and control wild-type mice and MEFs. Single inactivation of the proximal NPXY or in combination with inactivation of the distal NPXYXXL motif are both shown to be associated with an impaired maturation and premature proteasomal degradation of full-length LRP1. Therefore, only a small mature LRP1 pool is able to reach the cell surface resulting indirectly in severe impairment of ligand internalization. Single inactivation of the NPXYXXL motif revealed normal maturation, but direct impairment of ligand internalization. In conclusion, the proximal NPXY motif proves to be essential for early steps in the LRP1 biosynthesis, whereas NPXYXXL appears rather relevant for internalization.     

Human motor neuron generation from embryonic stem cells and induced pluripotent stem cells

Motor neuron diseases (MNDs) are a group of neurological disorders that selectively affect motor neurons. There are currently no cures or efficacious treatments for these diseases. In recent years, significant developments in stem cell research have been applied to MNDs, particularly regarding neuroprotection and cell replacement. However, a consistent source of motor neurons for cell replacement is required. Human embryonic stem cells (hESCs) could provide an inexhaustible supply of differentiated cell types, including motor neurons that could be used for MND therapies. Recently, it has been demonstrated that induced pluripotent stem (iPS) cells may serve as an alternative source of motor neurons, since they share ES characteristics, self-renewal, and the potential to differentiate into any somatic cell type. In this review, we discuss several reproducible methods by which hESCs or iPS cells are efficiently isolated and differentiated into functional motor neurons, and possible clinical applications.     

MicroRNA miR-196a is a central regulator of HOX-B7 and BMP4 expression in malignant melanoma

Since bone morphogenetic proteins (BMPs) play an important role in melanoma progression, we aimed to determine the molecular mechanisms leading to overexpression of BMP4 in melanoma cells compared to normal melanocytes. With our experimental approach we revealed that loss of expression of a microRNA represents the starting point for a signaling cascade finally resulting in overexpression of BMP4 in melanoma cells. In detail, strongly reduced expression of the microRNA miR-196a in melanoma cells compared to healthy melanocytes leads to enhanced HOX-B7 mRNA and protein levels, which subsequently raise Ets-1 activity by inducing basic fibroblast growth factor (bFGF). Ets-1 finally accounts for induction of BMP4 expression. We were furthermore able to demonstrate that bFGF-mediated induction of migration is achieved via activation of BMP4, thus determining BMP4 as major modulator of migration in melanoma. In summary, our study provides insights into the early steps of melanoma progression and might thereby harbor therapeutic relevance.     

53BP1 facilitates long-range DNA end-joining during V(D)J recombination

Variable, diversity and joining (V(D)J) recombination and class-switch recombination use overlapping but distinct non-homologous end joining pathways to repair DNA double-strand-break intermediates. 53BP1 is a DNA-damage-response protein that is rapidly recruited to sites of chromosomal double-strand breaks, where it seems to function in a subset of ataxia telangiectasia mutated (ATM) kinase-, H2A histone family member X (H2AX, also known as H2AFX)- and mediator of DNA damage checkpoint 1 (MDC1)-dependent events. A 53BP1-dependent end-joining pathway has been described that is dispensable for V(D)J recombination but essential for class-switch recombination. Here we report a previously unrecognized defect in the joining phase of V(D)J recombination in 53BP1-deficient lymphocytes that is distinct from that found in classical non-homologous-end-joining-, H2ax-, Mdc1- and Atm-deficient mice. Absence of 53BP1 leads to impairment of distal V-DJ joining with extensive degradation of unrepaired coding ends and episomal signal joint reintegration at V(D)J junctions. This results in apoptosis, loss of T-cell receptor alpha locus integrity and lymphopenia. Further impairment of the apoptotic checkpoint causes propagation of lymphocytes that have antigen receptor breaks. These data suggest a more general role for 53BP1 in maintaining genomic stability during long-range joining of DNA breaks.     

An Action Design Research Approach within Enterprise Engineering

Enterprise engineering (EE) is emerging as a new discipline that is multi-disciplinary in nature. As highlighted by researchers within the EE discipline, the current status of EE endeavours as taken by several universities is unclear, which led to several initiatives and publications to develop a research agenda within the enterprise engineering research community. This article builds upon existing work aimed at establishing EE as a discipline, also accepting the epistemological stance of idealism, pragmatism and existential phenomenology as argued by Hoogervorst as an appropriate stance for EE research, prior to suggesting action design research (ADR) as an appropriate research method for EE research. More so, the article presents an Action Design Research within Enterprise Engineering (ADR-in-EE) approach as the main contribution to guide prospective EE researchers towards research within the EE discipline. The ADR-in-EE approach is based on ADR, but provides additional guidance by incorporating the use of an Enterprise Evolution Contextualisation Model, as well as creativity facilitation in the form of Univation’s brainstorming method. As a second contribution, we experiment with the ADR-in-EE approach and use a survey to extract feedback on the usefulness of the approach. The research findings are mostly positive, with qualitative feedback on further improving ADR-in-EE approach.     

Inhibition or augmentation of PHA-induced lymphocyte transformation by factors of cultured lymphoblastoid cell lines

Summary Stimulation of human peripheral blood lymphocytes by phytohemagglutinin (PHA) was found to be suppressed or augmented by the addition of supernatants or cell dialysates of cultured lymphoblastoid cell lines.This research was supported by a grant from the United States-Israel Binational Science Foundation (BSF), Jerusalem, Israel.We wish to thank Mrs L. Ashani and Mrs D. Bernhout-Maiberger for their valuable technical assistance.     

澳门建筑遗产之移植特征

澳门历史城区被新增为世界历史文化遗产,澳门历史建筑的价值也正逐步被发掘,它是我国最古老的西式建筑遗产,也是东西方建筑艺术的综合体现,是中国历史城市中极具特色的组合.其中,"移植性"是澳门建筑遗产一个重要的文化特征,并体现在其城市格局、建筑风格、建筑构造与细部装饰中,反映出澳门建筑对来自世界各地不同文化的移植与包容.