Interaction of the Akt substrate, AS160, with the glucose transporter 4 vesicle marker protein, insulin-regulated aminopeptidase

Insulin-regulated aminopeptidase (IRAP), a marker of glucose transporter 4 (GLUT4) storage vesicles (GSVs), is the only protein known to traffic with GLUT4. In the basal state, GSVs are sequestered from the constitutively recycling endosomal system to an insulin-responsive, intracellular pool. Insulin induces a rapid translocation of GSVs to the cell surface from this pool, resulting in the incorporation of IRAP and GLUT4 into the plasma membrane. We sought to identify proteins that interact with IRAP to further understand this GSV trafficking process. This study describes our identification of a novel interaction between the amino terminus of IRAP and the Akt substrate, AS160 (Akt substrate of 160 kDa). The validity of this interaction was confirmed by coimmunoprecipitation of both overexpressed and endogenous proteins. Moreover, confocal microscopy demonstrated colocalization of these proteins. In addition, we demonstrate that the IRAP-binding domain of AS160 falls within its second phosphotyrosine-binding domain and the interaction is not regulated by AS160 phosphorylation. We hypothesize that AS160 is localized to GLUT4-containing vesicles via its interaction with IRAP where it inhibits the activity of Rab substrates in its vicinity, effectively tethering the vesicles intracellularly.

Identification of modulating residues defining the catalytic cleft of insulin-regulated aminopeptidase

Inhibition of insulin-regulated aminopeptidase (IRAP) has been demonstrated to facilitate memory in rodents, making IRAP a potential target for the development of cognitive enhancing therapies. In this study, we generated a 3-D model of the catalytic domain of IRAP based on the crystal structure of leukotriene A4 hydrolase (LTA4H). This model identified two key residues at the ‘entrance’ of the catalytic cleft of IRAP, Ala427 and Leu483, which present a more open arrangement of the S1 subsite compared with LTA4H. These residues may define the size and 3-D structure of the catalytic pocket, thereby conferring substrate and inhibitor specificity. Alteration of the S1 subsite by the mutation A427Y in IRAP markedly increased the rate of substrate cleavage V of the enzyme for a synthetic substrate, although a corresponding increase in the rate of cleavage of peptide substrates Leu-enkephalin and vasopressin was was not apparent. In contrast, [L483F]IRAP demonstrated a 30-fold decrease in activity due to changes in both substrate affinity and rate of substrate cleavage. [L483F]IRAP, although capable of efficiently cleaving the N-terminal cysteine from vasopressin, was unable to cleave the tyrosine residue from either Leu-enkephalin or Cyt6-desCys1-vasopressin (2–9), both substrates of IRAP. An 11-fold reduction in the affinity of the peptide inhibitor norleucine1-angiotensin IV was observed, whereas the affinity of angiotensin IV remained unaltered. In additionm we predict that the peptide inhibitors bind to the catalytic site, with the NH2-terminal P1 residue occupying the catalytic cleft (S1 subsite) in a manner similar to that proposed for peptide substrates.

Sequence requirements for the export of the Plasmodium falciparum Maurer's clefts protein REX2

A short motif termed Plasmodium export element (PEXEL) or vacuolar targeting signal (VTS) characterizes Plasmodium proteins exported into the host cell. These proteins mediate host cell modifications essential for parasite survival and virulence. However, several PEXEL-negative exported proteins indicate that the currently predicted malaria exportome is not complete and it is unknown whether and how these proteins relate to PEXEL-positive export. Here we show that the N-terminal 10 amino acids of the PEXEL-negative exported protein REX2 (ring-exported protein 2) are necessary for its targeting and that a single-point mutation in this region abolishes export. Furthermore we show that the REX2 transmembrane domain is also essential for export and that together with the N-terminal region it is sufficient to promote export of another protein. An N-terminal region and the transmembrane domain of the unrelated PEXEL-negative exported protein SBP1 (skeleton-binding protein 1) can functionally replace the corresponding regions in REX2, suggesting that these sequence features are also present in other PEXEL-negative exported proteins. Similar to PEXEL proteins we find that REX2 is processed, but in contrast, detect no evidence for N-terminal acetylation.

A comparative study of supervised learning techniques for data-driven haptic simulation

This paper focuses on the choice of a supervised learning algorithm and possible data preprocessing in the domain of data-driven haptic simulation. This is done through a comparison of the performance of different supervised learning techniques with and without data preprocessing. The simulation of haptic interactions with deformable objects using data-driven methods has emerged as an alternative to parametric methods. The accuracy of the simulation depends on the empirical data and the learning method. Several methods were suggested in the literature and here we provide a comparison between their performance and applicability to this domain. We selected four examples to be compared: singular learning mechanism which is artificial neural networks (ANN), attribute selection followed by ANN learning process, ensemble of multiple learning techniques, and attribute selection followed by the learning ensemble. These methods performance was compared in the domain of simulating multiple interactions with a deformable object with nonlinear material behavior.

Gender differences in the performance of individuating acts

Although several studies in social psychology suggest that male participants are more likely than female ones to engage in individuating behaviors, other studies have found no gender differences in willingness to perform individuating acts. This study posits that differences in findings across past investigations may be attributed to the chosen domain of individuating behavior. The content of the Individuation Scale (Maslach, Stapp, & Santee, 1985) is examined in terms of Bakan's (1966) agency‐communion theory to identify two types of individuating behaviors that are consistent with men's gender role orientations (i.e., eliciting conflict, leadership), one type of individuating behavior that is consistent with women's gender role orientations (i.e., personal disclosures), and a gender‐neutral type of individuation (i.e., performance). Responses to the scale are obtained from a sample of business school students (N = 273) and a more heterogeneous mail survey sample (N = 621). A sequence of measurement invariance tests of a 4‐factor correlated model of the individuation measure indicates a high degree of equivalence in the meaning of the measure across gender groups. Subsequent latent‐means structure analysis examines gender differences in willingness to perform the 4 types of individuation behaviors captured in the scale. In the student sample, there were no mean differences in willingness to perform any of the 4 types of individuating acts. However, in the mail survey sample, findings of mean differences supported hypotheses derived from agency‐communion theory: For men as compared with women, the latent means for leadership and eliciting conflict were higher and the latent mean for personal disclosure was lower.

Aggregation of preferences in recommender systems

This chapter gives an overview of aggregation functions toward their use in recommender systems. Simple aggregation functions such as the arithmetic mean are often employed to aggregate user features, item ratings, measures of similarity, etc., however many other aggregation functions exist which could deliver increased accuracy and flexibility to many systems. We provide definitions of some important families and properties, sophisticated methods of construction, and various examples of aggregation functions in the domain of recommender systems.

A discourse study of Persian ra

The object marker râ in Persian has been studied extensively in the domain of sentence level syntax. It has been claimed that it functions as a definiteness marker, a specificity marker, and a topicalization marker. This paper focuses on the way it signals identifiability of discourse referents. It is argued that the identifiabilty phenomenon, an aspect of the theory of information flow, can adequately explain the role of this particle as used in actual discourse.

Increasing the sensitivity of the AQoL inventory for the evaluation of interventions affecting mental health

This paper presents the rationale and psychometric analysis for extending the inventory of the Assessment of Quality of Life (AQoL)-6D instrument. The resulting AQoL-8D has an 8 dimensional, 35 item inventory with greater sensitivity in the domain of mental health.The paper briefly reviews the existing QoL instruments used for economic evaluation of health programs. It outlines the steps adopted in developing the AQoL descriptive inventories and, specifically, the methods adopted for data collection and analysis for the AQoL-8D inventory.Three instruments are presented. The first, PsyQoL, is a 22 item instrument which represents the best statistical fit for the measurement of mental health related quality of life. The second, PsyQoL-Brief is a reduced form instrument which is combined with AQoL-6D as the basis for the third instrument, the AQoL-8D. Psychometric properties of the first instrument are excellent and the second are good. The full AQoL-8D has satisfactory properties. Results from a comparison with the original AQoL-6D are reported. The mental health content of AQoL-8D is unique amongst MAU instruments and, along with other AQoL instruments, unique in its derivation from psychometric analysis. Its application to mental health patients and the public demonstrates its ability to discriminate between the groups with greater sensitivity than the previous AQoL-6D instrument.

MEDIATOR25 acts as an integrative hub for the regulation of jasmonate-responsive gene expression in arabidopsis

The PHYTOCHROME AND FLOWERING TIME1 gene encoding the MEDIATOR25 (MED25) subunit of the eukaryotic Mediator complex is a positive regulator of jasmonate (JA)-responsive gene expression in Arabidopsis (Arabidopsis thaliana). Based on the function of the Mediator complex as a bridge between DNA-bound transcriptional activators and the RNA polymerase II complex, MED25 has been hypothesized to function in association with transcriptional regulators of the JA pathway. However, it is currently not known mechanistically how MED25 functions to regulate JA-responsive gene expression. In this study, we show that MED25 physically interacts with several key transcriptional regulators of the JA signaling pathway, including the APETALA2 (AP2)/ETHYLENE RESPONSE FACTOR (ERF) transcription factors OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF59 and ERF1 as well as the master regulator MYC2. Physical interaction detected between MED25 and four group IX AP2/ERF transcription factors was shown to require the activator interaction domain of MED25 as well as the recently discovered Conserved Motif IX-1/EDLL transcription activation motif of MED25-interacting AP2/ERFs. Using transcriptional activation experiments, we also show that OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF59- and ERF1-dependent activation of PLANT DEFENSIN1.2 as well as MYC2-dependent activation of VEGETATIVE STORAGE PROTEIN1 requires a functional MED25. In addition, MED25 is required for MYC2-dependent repression of pathogen defense genes. These results suggest an important role for MED25 as an integrative hub within the Mediator complex during the regulation of JA-associated gene expression.

Twitter tsunami early warning network : a social network analysis of Twitter information flows

In the aftermath of earthquakes, tsunamis, such as the 2011 Great East Japan Tsunami, caused enormous damage around the world. With the extreme disaster events of the past, nations improved disaster preparedness and response through sensors and tsunami early warning systems. Even with system usage, however, governments still need to warn the targeted citizens – who may be anywhere within the vulnerable areas – of predicted tsunami and ordered mass evacuations within a very limited lead time. While social media research is on the rise outside the domain of social networking, very little is written about Twitter use for tsunami early warning. In this research, therefore, we examined the utility of Twitter as a tsunami early warning network, which engages citizens and disaster management agencies in diffusing disaster information. We conducted a social network analysis of Twitter information flows among the central disaster warning agency’s Twitter followers during the 2012 Indonesia Earthquake.

A truncated fragment of Src protein kinase generated by calpain-mediated cleavage is a mediator of neuronal death in excitotoxicity

Excitotoxicity resulting from overstimulation of glutamate receptors is a major cause of neuronal death in cerebral ischemic stroke. The overstimulated ionotropic glutamate receptors exert their neurotoxic effects in part by overactivation of calpains, which induce neuronal death by catalyzing limited proteolysis of specific cellular proteins. Here, we report that in cultured cortical neurons and in vivo in a rat model of focal ischemic stroke, the tyrosine kinase Src is cleaved by calpains at a site in the N-terminal unique domain. This generates a truncated Src fragment of ?52 kDa, which we localized predominantly to the cytosol. A cell membrane-permeable fusion peptide derived from the unique domain of Src prevents calpain from cleaving Src in neurons and protects against excitotoxic neuronal death. To explore the role of the truncated Src fragment in neuronal death, we expressed a recombinant truncated Src fragment in cultured neurons and examined how it affects neuronal survival. Expression of this fragment, which lacks the myristoylation motif and unique domain, was sufficient to induce neuronal death. Furthermore, inactivation of the prosurvival kinase Akt is a key step in its neurotoxic signaling pathway. Because Src maintains neuronal survival, our results implicate calpain cleavage as a molecular switch converting Src from a promoter of cell survival to a mediator of neuronal death in excitotoxicity. Besides unveiling a new pathological action of Src, our discovery of the neurotoxic action of the truncated Src fragment suggests new therapeutic strategies with the potential to minimize brain damage in ischemic stroke.

Isolation breeds naivety : island living robs Australian varanid lizards of toad-toxin immunity via four-base-pair mutation

Since their introduction to the toad-free Australian continent cane toads (Bufo marinus) have caused a dramatic increase in naïve varanid mortality when these large lizards attempt to feed on this toxic amphibian. In contrast Asian–African varanids, which have coevolved with toads, are resistant to toad toxin. Toad toxins, such as Bufalin target the H1-H2 domain of the α1 subunit of the sodium-potassium-ATPase enzyme. Sequencing of this domain revealed identical nucleotide sequences in four Asian as well as in three African varanids, and identical sequences in all 11 Australian varanids. However, compared to the Asian–African varanids, the Australian varanids showed four-base-pair substitutions, resulting in the alteration in three of the 12 amino acids representing the H1-H2 domain. The phenotypic effect of the substitutions was investigated in human embryonic kidney (HEK) 293 cells stably transfected with the Australian and the Asian–African H1-H2 domains. The transfections resulted in an approximate 3000-fold reduction in resistance to Bufalin in the Australian HEK293 cells compared to the Asian–African HEK293 cells, demonstrating the critical role of this minor mutation in providing Bufalin resistance. Our study hence presents a clear link between genotype and phenotype, a critical step in understanding the evolution of phenotypic diversity.

Managing the implementation of business intelligence systems : a critical success factors framework

The implementation of a BI system is a complex undertaking requiring considerable resources. Yet there is a limited authoritative set of CSFs for management reference. This article represents a first step of filling in the research gap. The authors utilized the Delphi method to conduct three rounds of studies with 15 BI system experts in the domain of engineering asset management organizations. The study develops a CSFs framework that consists of seven factors and associated contextual elements crucial for BI systems implementation. The CSFs are committed management support and sponsorship, business user-oriented change management, clear business vision and well-established case, business-driven methodology and project management, business-centric championship and balanced project team composition, strategic and extensible technical framework, and sustainable data quality and governance framework. This CSFs framework allows BI stakeholders to holistically understand the critical factors that influence implementation success of BI systems.

More than a game : the impact of sport-based youth mentoring schemes on developing resilience toward violent extremism

This paper draws upon the findings of an evaluation of “More than a Game”, a sport-focused youth mentoring program in Melbourne, Australia that aimed to develop a community-based resilience model using team-based sports to address issues of identity, belonging, and cultural isolation amongst young Muslim men in order to counter forms of violent ex-tremism. In this essay we focus specifically on whether the intense embodied encounters and emotions experienced in team sports can help break down barriers of cultural and religious difference between young people and facilitate ex-periences of resilience, mutual respect, trust, social inclusion and belonging. Whilst the project findings are directly rel-evant to the domain of countering violent extremism, they also contribute to a growing body of literature which con-siders the relationship between team-based sport, cross-cultural engagement and the development of social resilience, inclusion and belonging in other domains of youth engagement and community-building.

Adulthood fracture and quality of life : A population-based study of Australian men

Background: Our objective was to investigate associations between adulthood fracture and quality of life (QOL) in men. Methods: For 448 men aged 50-85 years and enrolled in the Geelong Osteoporosis Study, we measured QOL using the validated (Australian) World Health Organization Quality of Life-Brief Version (WHOQOL-Bref) in the domains of physical health, psychological health, social relationships, and the environment. Self-reported adulthood fractures were categorized as recent or non-recent ( ≤ 10 years or > 10 years pre-QOL assessment, respectively). Lifestyle and health information were self-reported. Results: One hundred seventy four men (38.8%) sustained at least one fracture, 26% of which had occurred within the last 10 years. Compared with men who had never had an adulthood fracture, a non-recent fracture was more likely associated with poorer QOL in the physical health domain (age-adjusted odds ratio [OR] 0.47, 95% confidence interval [95%CI] 0.27-0.83), but not in any other domain. Men who had sustained a recent fracture reported a lower QOL in the domain of psychological health (age-adjusted OR 0.48, 95%CI 0.24-0.97), with a trend observed for lower QOL in the domains of physical health and environment. No further associations were observed. All results were sustained in further models that were adjusted for smoking, alcohol, physical inactivity, and body mass index. Conclusions: We present novel data examining associations between fracture status and QOL in a populationbased sample of Australian men using the WHOQOL-Bref. Recent fractures were associated with poorer QOL in the domain of psychological health while non-recent fractures were more likely associated poorer QOL for physical health. These findings have important implications for healthcare post-fracture.