Development of a Novel Green Fluorescent Protein-Based Binding Assay to Study the Association of Plakins with Intermediate Filament Proteins.

Protein-protein interactions are fundamental for most biological processes, such as the formation of cellular structures and enzymatic complexes or in signaling pathways. The identification and characterization of protein-protein interactions are therefore essential for understanding the mechanisms and regulation of biological systems. The organization and dynamics of the cytoskeleton, as well as its anchorage to specific sites in the plasma membrane and organelles, are regulated by the plakins. These structurally related proteins anchor different cytoskeletal networks to each other and/or to other cellular structures. The association of several plakins with intermediate filaments (IFs) is critical for maintenance of the cytoarchitecture. Pathogenic mutations in the genes encoding different plakins can lead to dramatic manifestations, occurring principally in the skin, striated muscle, and/or nervous system, due to cytoskeletal disorganization resulting in abnormal cell fragility. Nevertheless, it is still unclear how plakins bind to IFs, although some general rules are slowly emerging. We here describe in detail a recently developed protein-protein fluorescence binding assay, based on the production of recombinant proteins tagged with green fluorescent protein (GFP) and their use as fluid-phase fluorescent ligands on immobilized IF proteins. Using this method, we have been able to assess the ability of C-terminal regions of GFP-tagged plakin proteins to bind to distinct IF proteins and IF domains. This simple and sensitive technique, which is expected to facilitate further studies in this area, can also be potentially employed for any kind of protein-protein interaction studies.

Intracellular membrane association of the N-terminal domain of classical swine fever virus NS4B determines viral genome replication and virulence.

Classical swine fever virus (CSFV) causes a highly contagious disease in pigs that can range from a severe haemorrhagic fever to a nearly unapparent disease, depending on the virulence of the virus strain. Little is known about the viral molecular determinants of CSFV virulence. The nonstructural protein NS4B is essential for viral replication. However, the roles of CSFV NS4B in viral genome replication and pathogenesis have not yet been elucidated. NS4B of the GPE-  vaccine strain and of the highly virulent Eystrup strain differ by a total of seven amino acid residues, two of which are located in the predicted trans-membrane domains of NS4B and were described previously to relate to virulence, and five residues clustering in the N-terminal part. In the present study, we examined the potential role of these five amino acids in modulating genome replication and determining pathogenicity in pigs. A chimeric low virulent GPE- -derived virus carrying the complete Eystrup NS4B showed enhanced pathogenicity in pigs. The in vitro replication efficiency of the NS4B chimeric GPE-  replicon was significantly higher than that of the replicon carrying only the two Eystrup-specific amino acids in NS4B. In silico and in vitro data suggest that the N-terminal part of NS4B forms an amphipathic α-helix structure. The N-terminal NS4B with these five amino acid residues is associated with the intracellular membranes. Taken together, this is the first gain-of-function study showing that the N-terminal domain of NS4B can determine CSFV genome replication in cell culture and viral pathogenicity in pigs.

Promoting palliative care in the community: production of the primary palliative care toolkit by the European Association of Palliative Care Taskforce in primary palliative care

BACKGROUND A multidisciplinary European Association of Palliative Care Taskforce was established to scope the extent of and learn what facilitates and hinders the development of palliative care in the community across Europe. AIM To document the barriers and facilitators for palliative care in the community and to produce a resource toolkit that palliative care specialists, primary care health professionals or policymakers, service developers, educationalists and national groups more generally could use to facilitate the development of palliative care in their own country. DESIGN (1) A survey instrument was sent to general practitioners with knowledge of palliative care services in the community in a diverse sample of European countries. We also conducted an international systematic review of tools used to identify people for palliative care in the community. (2) A draft toolkit was then constructed suggesting how individual countries might best address these issues, and an online survey was then set up for general practitioners and specialists to make comments. Iterations of the toolkit were then presented at international palliative care and primary care conferences. RESULTS Being unable to identify appropriate patients for palliative care in the community was a major barrier internationally. The systematic review identified tools that might be used to help address this. Various facilitators such as national strategies were identified. A primary palliative care toolkit has been produced and refined, together with associated guidance. CONCLUSION Many barriers and facilitators were identified. The primary palliative care toolkit can help community-based palliative care services to be established nationally.