The relevance of globalization to nursing: a concept analysis.

BACKGROUND: This paper emerged alongside the development of learning materials for a new unit of study on global health and nursing. The proposed unit was for inclusion in a graduate entry master of nursing course leading to registration. It became evident that there has been growing attention within the nursing literature to the demands of an increasingly globalized world and the subsequent challenges confronting nursing as a profession. At the same time, the literature is inconsistent and contains mixed messages with regard to how nurses and nursing might respond to these challenges. AIM: This paper aims to (i) present the findings of a narrative analysis of the current nursing discourse on globalization, and (ii) to identify directional cohesiveness for the nursing profession in the seemingly disparate literature. METHOD: Concept analysis following extensive literature review. FINDINGS: Several nursing authors argue that nurses globally are increasingly sharing concerns expressed by nurses at a local level. Concerns such as the future sustainability of the profession and more specifically practice concerns such as the continuing failure of nurses to adequately deal with social justice issues requires careful consideration by every nurse. While strategies recommended for dealing with these concerns lack a cohesive thread, some interesting themes and innovative recommendations have emerged. For example, the need for nurses to consider replacing environmental considerations with ecological considerations and that nurses consider preventative nursing practice beyond the immediate needs of clients and from a more global perspective.

Hasten slowly: a needs analysis for nurse and village health worker education in East Timor.

This article reports on a needs analysis undertaken to determine the educational needs of nurses and health workers in East Timor. The needs analysis, which used a theoretical framework described by Wass (1994), was conducted in both Australia and East Timor. It addressed the current health status of the East Timorese people and the educational requirements of East Timorese nurses and village health workers. Utilizing interviews, field observations and data from the World Health Organization and the United Nations, the following four categories of needs were assessed: felt; expressed; comparative; and normative. The findings document the almost complete destruction of the health infrastructure in East Timor and demonstrate the urgent need for assistance in the re-establishment and enhancement of nursing and primary health care education programmes. A series of recommendations outlining nurse and village health care worker education programmes are proposed.

Characterization of syntenin, a syndecan-binding PDZ protein, as a component of cell adhesion sites and microfilaments.

Syntenin is a PDZ protein that binds the cytoplasmic C-terminal FYA motif of the syndecans. Syntenin is widely expressed. In cell fractionation experiments, syntenin partitions between the cytosol and microsomes. Immunofluorescence microscopy localizes endogenous and epitope-tagged syntenin to cell adhesion sites, microfilaments, and the nucleus. Syntenin is composed of at least three domains. Both PDZ domains of syntenin are necessary to target reporter tags to the plasma membrane. The addition of a segment of 10 amino acids from the N-terminal domain of syntenin to these PDZ domains increases the localization of the tags to stress fibers and induces the formation of long, branching plasma membrane extensions. The addition of the complete N-terminal region, in contrast, reduces the localization of the tags to plasma membrane/adhesion sites and stress fibers, and reduces the morphotypical effects. Recombinant domains of syntenin with the highest plasma membrane localization display the lowest nuclear localization. Syndecan-1, E-cadherin, beta-catenin, and alpha-catenin colocalize with syntenin at cell-cell contacts in epithelial cells, and coimmunoprecipitate with syntenin from extracts of these cells. These results suggest a role for syntenin in the composition of adherens junctions and the regulation of plasma membrane dynamics, and imply a potential role for syntenin in nuclear processes.

Syntenin-syndecan binding requires syndecan-synteny and the co-operation of both PDZ domains of syntenin.

Syntenin is an adaptor-like molecule that binds to the cytoplasmic domains of all four vertebrate syndecans. Syntenin-syndecan binding involves the C-terminal part of syntenin that contains a tandem of PDZ domains. Here we provide evidence that each PDZ domain of syntenin can interact with a syndecan. Isolated or combined mutations of the carboxylate binding lysines in the inter-betaAbetaB loops and of the alphaB1 residues in either one or both the PDZ domains of syntenin all reduce syntenin-syndecan binding in yeast two-hybrid, blot-overlay, and surface plasmon resonance assays. PDZ2 mutations have more pronounced effects on binding than PDZ1 mutations, but complete abrogation of syntenin-syndecan binding requires the combination of both the lysine and the alphaB1 mutations in both the PDZ domains of syntenin. Isothermal calorimetric titration of syntenin with syndecan peptide reveals the presence of two binding sites in syntenin. Yet, unlike a tandem of two PDZ2 domains and a reconstituted PDZ1+PDZ2 tandem, a tandem of two PDZ1 domains and isolated PDZ1 or PDZ2 domains do not interact with syndecan bait. We conclude to a co-operative binding mode whereby neither of these two PDZ domains is sufficient by itself but where PDZ2 functions as a "major" or "high affinity" syndecan binding domain, and PDZ1 functions as an "accessory" or "low affinity" syndecan binding domain. The paired, but not the isolated PDZ domains of syntenin bind also strongly to the immobilized cytoplasmic domains of neurexin and B-class ephrins. By inference, these data suggest a model whereby recruitment of syntenin to membrane surfaces requires two compatible types of bait that are in "synteny" (occurring together in location) and engages both PDZ domains of syntenin. The synteny of compatible bait may result from the assemblies and co-assemblies of syndecans and other similarly suited partners in larger supramolecular complexes. In general, an intramolecular combination of PDZ domains that are weak, taken individually, would appear to be designed to detect rather than drive the formation of specific molecular assemblies.

Syntenin, a PDZ protein that binds syndecan cytoplasmic domains.

The syndecans are transmembrane proteoglycans that place structurally heterogeneous heparan sulfate chains at the cell surface and a highly conserved polypeptide in the cytoplasm. Their versatile heparan sulfate moieties support various processes of molecular recognition, signaling, and trafficking. Here we report the identification of a protein that binds to the cytoplasmic domains of the syndecans in yeast two-hybrid screens, surface plasmon resonance experiments, and ligand-overlay assays. This protein, syntenin, contains a tandem repeat of PDZ domains that reacts with the FYA C-terminal amino acid sequence of the syndecans. Recombinant enhanced green fluorescent protein (eGFP)-syntenin fusion proteins decorate the plasmamembrane and intracellular vesicles, where they colocalize and cosegregate with syndecans. Cells that overexpress eGFP-syntenin show numerous cell surface extensions, suggesting effects of syntenin on cytoskeleton-membrane organization. We propose that syntenin may function as an adaptor that couples syndecans to cytoskeletal proteins or cytosolic downstream signal-effectors.

Heparan sulfate proteoglycans. Essential co-factors in receptor-mediated processes with relevance to the biology of the vascular wall.

Heparan sulfate (HS), a mixed bag of complex, heterogeneous and highly charged polysaccharides, is an essential co-factor in a large number of receptor-ligand interactions and cellular pathways. These co-factor functions depend on the binding-interactions of the HS chains with the ligand or receptor, or both. These binding interactions and the ensuing functional effects often depend on defined carbohydrate sequences within the HS chains, whereby the required sequences are not always represented within all natural forms of the polysaccharide. The proteins that are substituted with HS resort from a limited number of protein families, with different cellular, subcellular and supramolecular associations, and show differential activities in functional assays. It is likely that the natural co-factor functions of the HS proteoglycans depend on glycan-protein and protein-protein interactions that are subject to modulation, both at the glycan and protein levels.

Substrate requirements for transglutaminases. Influence of the amino acid residue preceding the amine donor lysine in a native protein.

Thirteen recombinant alpha A-crystallin mutants were constructed that differed in the type of amino acid residue directly preceding the sole amine donor lysine for transglutaminases in this protein. The capacity of these mutants to be cross-linked to amine acceptor substrates by tissue transglutaminase and factor XIII was assessed. Two different biotinylated glutamine-containing oligopeptides were used as amine acceptor probes. It appears that the type of residue preceding the amine donor lysine has a considerable influence on the substrate potential of alpha A-crystallin for transglutaminases. This influence shows qualitatively similar trends for tissue transglutaminase and factor XIII and is irrespective of the amine acceptor probe. In general, glycine or aspartic acid before the amine donor lysine has the strongest adverse effects on substrate reactivity, and proline, histidine, and tryptophan are less favorable. Valine, arginine, and phenylalanine, and to a more variable or somewhat lesser extent also serine, alanine, leucine, tyrosine, and asparagine, have an enhancing effect. This pattern of preference is largely in agreement with that observed for the limited number of characterized amine donor lysines in protein substrates for transglutaminases. It can be concluded that tissue transglutaminase and factor XIII have a rather broad yet clearly differentiated tolerance with respect to the residue preceding the amine donor lysine substrate in native proteins.

The amine-donor substrate specificity of tissue-type transglutaminase. Influence of amino acid residues flanking the amine-donor lysine residue.

The amine-donor substrate specificity of tissue-type transglutaminase has been studied in a series of recombinant alpha A-crystallin mutants. These mutant proteins have been provided with a potential substrate lysine residue, flanked by different amino acid residues, in the C-terminal extended arm of alpha A-crystallin. A biotinylated amine-acceptor hexapeptide was used as a probe for labelling the amine-donor sites. Wild-type bovine alpha A-crystallin does not function as an amine-donor substrate for tissue-type transglutaminase. Yet, upon introduction of a lysine residue at the C-terminal or penultimate position, all mutant alpha A-crystallins act as amine-donor substrates, although to different extents. This shows that accessibility is the primary requirement for a lysine residue to function as an amine-donor substrate for transglutaminase and that the enzyme has a broad tolerance towards the neighbouring residues. However, the nature of the flanking amino acid residues does clearly affect the reactivity of the substrate lysine residue. Notably, we found that a proline or glycine residue in front of the substrate lysine has a strong adverse effect on the substrate reactivity as compared to a preceding leucine, serine, alanine or arginine residue.

Lys-17 is the amine-donor substrate site for transglutaminase in beta A3-crystallin.

The bovine lens protein beta A3-crystallin has recently been shown to be an amine-donor (Lys) substrate for tissue-type transglutaminase, using a newly developed amine-acceptor hexapeptide as a probe (Groenen, P.J.T.A., Seccia, M., Smulders, R.H.P.H., Gravela, E., Cheeseman, K.H., Bloemendal, H., and de Jong, W.W. (1993) Biochem. J. 295, 399-404). In the present study, the reactive amine-donor site has been identified by site-directed mutagenesis of the putative substrate lysine. The mutation Lys-17-->Arg abolishes the substrate capacity. This residue, located in the N-terminal extension of the polypeptide, thus acts as the sole amine-donor substrate in beta A3-crystallin. Our finding reinforces the notion that, in the crystallins, all amine-donor as well as amine-acceptor substrate sites reside in the N- or C-terminal arms. Transglutaminase-mediated cross-linking of beta A3-crystallin also gives rise to a beta A3 dimer, presumably due to the fact that Lys-17 can be cross-linked to the previously established Gln-7 or Gln-8 amine-acceptor site.

Functional analysis of the promoter of the gene encoding the acidic ribosomal protein L45 in yeast.

The gene encoding the acidic ribosomal protein L45 in yeast is expressed coordinately with other rp-genes. The promoter region of this gene harbours binding sites for CP1 and ABF1. We demonstrate that the CP1-site is not involved in the transcription activation of the L45-gene. Rather, the ABF1-site, through deviating from the consensus sequence (RTARY3N3ACG), appears to be essential for efficient transcription. Replacement of this site by a consensus RAP1-binding site (an RPG box) did not alter the transcriptional yield of the L45-gene. An additional transcription activating region is present downstream of the ABF1-site. The relevant nucleotide sequence, which is repeated in the L45-gene promoter, gives rise to complex formation with a yeast protein extract in a bandshift assay. The results indicate that the L45-gene promoter has a complex architecture.

Affinity cleavage and targeted catalysis of proteins using the avidin-biotin system.

The avidin-biotin system was used in order to target enzymes to their substrates in complex mixtures of proteins in solution. The approach described here thus mimics natural systems in which enzymes usually act in selective fashion, due, perhaps, to proximity effects. For affinity cleavage studies, biotinyl transferrin was used as a model target substrate. Avidin or streptavidin was then employed to bridge between the biotinylated target protein and a biotinyl protease. Bovine serum albumin was included in the reaction mixtures to assess the level of nonspecific cleavage. In the case of an unbiotinylated target protein, avidin could be used to inhibit the hydrolytic action of the biotinyl protease. In some systems, a biotinyl antibody could be used to direct the avidin-bridged biotinyl protease to an unbiotinylated target antigen. The data support the contention that preferential cleavage reflects two separate phenomena: (i) avidin confers a conformational alteration of the biotinylated target protein, and (ii) the biotinyl protease is targeted (via the avidin bridge) to the proximity of the biotinylated target protein, thereby promoting cleavage of the conformationally altered molecule. This is the first report in which a proteolytic enzyme could be selectively targeted to specifically hydrolyze a defined protein substrate in solutions containing a complex mixture of other proteins. The approach appears to be a general phenomenon for "targeted catalysis", appropriate for other applications, particularly for affinity cleavage and targeted catalysis of cell-based macromolecules.