33 resultados para Eberwein,Jen


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This paper presents findings from an empirical study of banking customer experiences with the adoption of Internet banking. Using a qualitative, interpretive grounded theory approach and single and group interviews, the study explores customer perceptions and experiences and provides an understanding of how and why specific factors affect their decision whether or not to bank on the Internet in the current era. The findings are used to develop a theoretical framework which conceptualizes and links consumer issues influencing the adoption of this application, and we also provide a set of recommendations for banks. Specifically, the findings suggest that convenience – in particular, time savings – is the major motivator to bank on the Internet, while there are a range of other influential factors which could be modulated by banks. The results also highlight increasing online risk acceptance by customers and the growing importance of deep levels of customer support for online services. Key gender differences in attitudes to Internet banking are highlighted. This study suggests that organizations will improve their management of customer attitudes to new Internet service applications by understanding the need to proactively address customer fears and misconceptions about the technologies involved.

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The segment C-terminal to the hydrophobic motif at the V5 domain of protein kinase C (PKC) is the least conserved both in length and in amino acid identity among all PKC isozymes. By generating serial truncation mutants followed by biochemical and functional analyses, we show here that the very C terminus of PKCα is critical in conferring the full catalytic competence to the kinase and for transducing signals in cells. Deletion of one C-terminal amino acid residue caused the loss of ~60% of the catalytic activity of the mutant PKCα, whereas deletion of 10 C-terminal amino acid residues abrogated the catalytic activity of PKCα in immune complex kinase assays. The PKCα C-terminal truncation mutants were found to lose their ability to activate mitogen-activated protein kinase, to rescue apoptosis induced by the inhibition of endogenous PKC in COS cells, and to augment melatonin-stimulated neurite outgrowth. Furthermore, molecular dynamics simulations revealed that the deletion of 1 or 10 C-terminal residues results in the deformation of the V5 domain and the ATP-binding pocket, respectively. Finally, PKCα immunoprecipitated using an antibody against its C terminus had only marginal catalytic activity compared with that of the PKCα immunoprecipitated by an antibody against its N terminus. Therefore, the very C-terminal tail of PKCα is a novel determinant of the catalytic activity of PKC and a promising target for selective modulation of PKCα function. Molecules that bind preferentially to the very C terminus of distinct PKC isozymes and suppress their catalytic activity may constitute a new class of selective inhibitors of PKC.

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Protein kinase C (PKC) is a family of serine/threonine protein kinases that are pivotal in cellular regulation. Since its discovery in 1977, PKCs have been known as cytosolic and peripheral membrane proteins. However, there are reports that PKC can insert into phospholipids vesicles in vitro. Given the intimate relationship between the plasma membrane and the activation of PKC, it is important to determine whether such “membrane-inserted” form of PKC exists in mammalian cells or tissues. Here, we report the identification of an integral plasma membrane pool for all the 10 PKC isozymes in vivo by their ability to partition into the detergent-rich phase in Triton X-114 phase partitioning, and by their resistance to extractions with 0.2 M sodium carbonate (pH 11.5), 2 M urea and 2 M sodium chloride. The endogenous integral membrane pool of PKC in mouse fibroblasts is found to be acutely regulated by phorbol ester or diacylglycerol, suggesting that this pool of PKC may participate in cellular processes known to be regulated by PKC. At least for PKCα, the C2–V3 region at the regulatory domain of the kinase is responsible for membrane integration. Further exploration of the function of this novel integral plasma membrane pool of PKC will not only shed new light on molecular mechanisms underlying its cellular functions but also provide new strategies for pharmaceutical modulation of this important group of kinases.

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Protein kinase C (PKC) is a key regulator of cell proliferation, differentiation, and apoptosis and is one of the drug targets of anticancer therapy. Recently, a single point mutation (D294G) in PKCα has been found in pituitary and thyroid tumors with more invasive phenotype. Although the PKCα-D294G mutant is implicated in the progression of endocrine tumors, no apparent biochemical/cell biological abnormalities underlying tumorigenesis with this mutant have been found. We report here that the PKCα-D294G mutant is unable to bind to cellular membranes tightly despite the fact that it translocates to the membrane as efficiently as the wild-type PKCα upon treatment of phorbol ester. The impaired membrane binding is associated with this mutant's inability to transduce several antitumorigenic signals as it fails to mediate phorbol ester–stimulated translocation of myristoylated alanine–rich protein kinase C substrate (MARCKS), to activate mitogen-activated protein kinase and to augment melatonin-stimulated neurite outgrowth. Thus, the PKCα-D294G is a loss-of-function mutation. We propose that the wild-type PKCα may play important antitumorigenic roles in the progression of endocrine tumors. Therefore, developing selective activators instead of inhibitors of PKCα might provide effective pharmacological interventions for the treatment of certain endocrine tumors.

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In this article, we explore the role of the C-terminus (V5 domain) of PKCvar epsilon plays in the catalytic competence of the kinase using serial truncations followed by immune-complex kinase assays. Surprisingly, removal of the last seven amino acid residues at the C-terminus of PKCvar epsilon resulted in a PKCvar epsilon-Δ731 mutant with greatly reduced intrinsic catalytic activity while truncation of eight amino acid residues at the C-terminus resulted in a catalytically inactive PKCvar epsilon mutant. Computer modeling and molecular dynamics simulations showed that the last seven and/or eight amino acid residues of PKCvar epsilon were involved in interactions with residues in the catalytic core. Further truncation analyses revealed that the hydrophobic phosphorylation motif was dispensable for the physical interaction between PKCvar epsilon and 3-phosphoinositide-dependent kinase-1 (PDK-1) as the PKCvar epsilon mutant lacking both the turn and the hydrophobic motifs could still be co-immunoprecipitated with PDK-1. These results provide fresh insights into the biochemical and structural basis underlying the isozyme-specific regulation of PKC and suggest that the very C-termini of PKCs constitute a promising new target for the development of novel isozyme-specific inhibitors of PKC.

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This paper explores Australian domestic customers' choices with regard to Internet banking, examining why it is taken up by some Australians and not others. The constructivist conceptual framework and the grounded nature of the method enabled in-depth exploration of key issues not undertaken before by the mainly positivist studies. The purposeful sample of 32 participants was selected to represent the major categories of people relevant to the research. Everett Rogers' famous analysis of 'diffusion of innovations' was one theoretical framework used to illuminate the findings; the other was digital divide factors in relation to banking choices. The findings include 1) that the major motivation for people to adopt Internet banking is convenience, closely linked to time savings and ease of accessibility, as well as confidence and skill in Internet use; and 2) that, at the time of the study, digital divide factors were playing an important part in banking choices.

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The purpose of this study was to explore the effect of physical disabilities (PD) on the quality of life (QoL) of adolescents aged from 10 to 18 years. Sixty-three adolescents with PD (aged 14.9 ± 2.4 years) from primary (5th grade or above) to high schools in Kaohsiung City volunteered to participate in this research; 282 children without disability (aged 13.8 ± 2.3 years) attending schools in the same geographical region were recruited as controls. The Student Version of the Comprehensive Quality of Life Scale was used in this study. This is a multidimensional self-report, global measure of subjective and objective QoL. Multivariate analysis of variance revealed that the two groups were significantly different in objective QoL (F = 11.53, p < 0.001). Material wellbeing was substantially lower in the PD group when compared to the control group. In contrast, domains such as productivity, safety, and emotion were higher in the PD group. Among the subjective scales, the PD group showed higher productivity and better emotion when compared to the control group. No significant correlation was observed between objective and subjective overall QoL scores (r = 0.20, p = 0.12) in the PD group. These findings showed that subjects with PD in regular schools demonstrated different patterns in objective and subjective QoL when compared to those without PD. Both subjective and objective domains are important when measuring QoL of adolescents with PD.

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PRK1/PKN is a member of the protein kinase C (PKC) superfamily of serine/threonine protein kinases. Despite its important role as a RhoA effector, limited information is available regarding how this kinase is regulated. We show here that the last seven amino acid residues at the C-terminus is dispensable for the catalytic activity of PRK1 but is critical for the in vivo stability of this kinase. Surprisingly, the intact hydrophobic motif in PRK1 is dispensable for 3-phosphoinositide-dependent kinase-1 (PDK-1) binding and phosphorylation of the activation loop, as the PRK1-Δ940 mutant lacking the last two residues of the hydrophobic motif and the last 5 residues at the C-terminus interacts with PDK-1 in vivo and has a similar specific activity as the wild-type protein. We also found that the last four amino acid residues at the C-terminus of PRK1 is critical for the full lipid responsiveness as the PRK1-Δ942 deletion mutant is no longer activated by arachidonic acid. Our data suggest that the very C-terminus in PRK1 is critically involved in the control of the catalytic activity and activation by lipids. Since this very C-terminal segment is the least conserved among members of the PKC superfamily, it would be a promising target for isozyme-specific pharmaceutical interventions.

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PRK1 is a lipid- and Rho GTPase-activated serine/threonine protein kinase implicated in the regulation of receptor trafficking, cytoskeletal dynamics and tumorigenesis. Although Rho binding has been mapped to the HR1 region in the regulatory domain of PRK1, the mechanism involved in the control of PRK1 activation following Rho binding is poorly understood. We now provide the first evidence that the very C-terminus beyond the hydrophobic motif in PRK1 is essential for the activation of this kinase by RhoA. Deletion of the HR1 region did not completely abolish the binding of PRK1-ΔHR1 to GTPγS-RhoA nor the activation of this mutant by GTPγS-RhoA in vitro. In contrast, removing of the last six amino acid residues from the C-terminus of PRK1 or truncating of a single C-terminal residue from PRK1-ΔHR1 completely abrogated the activation of these mutants by RhoA both in vitro and in vivo. The critical dependence of the very C-terminus of PRK1 on the signaling downstream of RhoA was further demonstrated by the failure of the PRK1 mutant lacking its six C-terminal residues to augment lisophosphatidic acid-elicited neurite retraction in neuronal cells. Thus, we show that the HR1 region is necessary but not sufficient in eliciting a full activation of PRK1 upon binding of RhoA. Instead, such activation is controlled by the very C-terminus of PRK1. Our results also suggest that the very C-terminus of PRK1, which is the least conserved among members of the protein kinase C superfamily, is a potential drug target for pharmacological intervention of RhoA-mediated signaling pathways

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Postoperative cholangitis is a frequent and unpredictable complication of unknown etiology following bile duct reconstruction (BDR), particularly for biliary atresia. This study was undertaken to correlate the growth of bacteria in the hepaticojejunostomy with that in the liver after BDR. Quantitative bacterial culture was done on the specimens taken from the liver and from the hepaticojejunostomy at 1 week (group 1, n = 7), 1 month (group 2, n = 7), and 2 months (group 3, n = 7) following BDR with Roux-en-Y hepaticojejunostomy in piglets after 2 weeks of common bile duct ligation. The histological examination of the liver and the hepaticojejunostomy, as well as serial monitoring of hemogram and liver function tests, were performed to correlate the findings with the bacterial concentration of the liver and the hepaticojejunostomy following BDR. The bacterial concentration of the hepaticojejunostomy, expressed as log10 colony-forming units per gram (log10 CFU/g) of the hepaticojejunostomy, showed a progressive decrease from 8.38 ± 1.36 in group 1, 7.07 ± 2.54 in group 2, to 3.56 ± 1.31 in group 3 (p = 0.001). The log10 CFU/g of the liver also showed a progressive decrease from 5.02 ± 1.59 in group 1, 3.16 ± 1.56 in group 2, to 2.19 ± 1.09 in group 3 (p = 0.006). There was a significant positive correlation of the log10 CFU/g of the liver (n = 21) with that of the hepaticojejunostomy (n = 21) following BDR (r = 0.600, p = 0.004). Most of the infectious pathogens isolated from the liver were also isolated from the hepaticojejunostomy. The changes in hemoglobin, bilirubin, albumin, and ammonia significantly correlated with the changes of the bacterial concentration of the liver. The results of the study suggests that hepatic bacterial proliferation after BDR is significantly affected by microbial overgrowth in the bilioenteric anastomosis and is associated with deteriorated liver function and hemogram.

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PRK2/PKNγ is a Rho effector and a member of the protein kinase C superfamily of serine/threonine kinases. Here, we explore the structure–function relationship between various motifs in the C-terminal half of PRK2 and its kinase activity and regulation. We report that two threonine residues at conserved phosphoacceptor position in the activation loop and the turn motif are essential for the catalytic activity of PRK2, but the phosphomimetic Asp-978 at hydrophobic motif is dispensable for kinase catalytic  competence. Moreover, the PRK2-Δ958 mutant with the turn motif truncated still interacts with 3-phosphoinositide-dependent kinase-1 (PDK-1). Thus, both the intact hydrophobic motif and the turn motif in PRK2 are dispensable for the binding of PDK-1. We also found that while the last seven amino acid residues at the C-terminus of PRK2 are not required for the activation of the kinase by RhoA in vitro, however, the extreme C-terminal segment is critical for the full activation of PRK2 by RhoA in cells in a GTP-dependent manner. Our data suggest that the extreme C-terminus of PRK2 may represent a potential drug target for effector-specific pharmacological intervention of Rho-medicated biological processes.

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This paper argues that Janet Frame’s 1988 novel, The Carpathians, can be read as a series of manoeuvres operating at the frontiers of exegesis and fiction. The overall effect of these manoeuvres is to interrogate the conditions of an exegetical (or literary critical) engagement with Frame’s writings. In particular, The Carpathians drills down into the metaphorics of one of the key notions of literary criticism: critical distance. Critical distance is a catch phrase of exegesis, as well as of literary criticism, because it serves to appropriately position the exegete (like the literary critic) as both near to and distant from the object of study: the literary text. However, Frame’s fictional/Scientific concept of the Gravity Star deconstructs the metaphorics of distance and, by extension, critical distance itself, by suggesting a para-doxical relationship of propinquity and remoteness. The Gravity Star is ‘both relatively close and seven billion light years away.’ Thus, Frame introduces chaos into language and logic, with the dual effect of undermining exegetical activity (which depends on the  metaphorics linked to critical distance) and of creatively multiplying the meanings of The Carpathians. In this way, Frame’s novel replaces conventional exegesis with creative exegesis. My paper also looks at the games Frame plays, in this novel and in Towards Another Summer (2007), with Roland Barthes’s notion of the ‘death of the Author.’ Like critical distance, the Author is a prop for exegesis that certain manoeuvres of writing can undermine, thus allowing the literary text to reproduce itself on an interior plane.

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Spam is commonly known as unsolicited or unwanted email messages in the Internet causing potential threat to Internet Security. Users spend a valuable amount of time deleting spam emails. More importantly, ever increasing spam emails occupy server storage space and consume network bandwidth. Keyword-based spam email filtering strategies will eventually be less successful to model spammer behavior as the spammer constantly changes their tricks to circumvent these filters. The evasive tactics that the spammer uses are patterns and these patterns can be modeled to combat spam. This paper investigates the possibilities of modeling spammer behavioral patterns by well-known classification algorithms such as Naïve Bayesian classifier (Naive Bayes), Decision Tree Induction (DTI) and Support Vector Machines (SVMs). Preliminary experimental results demonstrate a promising detection rate of around 92%, which is considerably an enhancement of performance compared to similar spammer behavior modeling research.