The Experts below are selected from a list of 152907 Experts worldwide ranked by ideXlab platform
Sangram S Sisodia - One of the best experts on this subject based on the ideXlab platform.
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evidence that the nf motif in transmembrane domain 4 of presenilin 1 is critical for binding with pen 2
Journal of Biological Chemistry, 2005Co-Authors: Seonghun Kim, Sangram S SisodiaAbstract:Macromolecular complexes containing presenilins (PS1 and PS2), nicastrin, anterior pharynx defective phenotype 1 (APH-1), and PS enhancer 2 (PEN-2) mediate the intramembranous, gamma-secretase cleavage of beta-amyloid precursor protein (APP), Notch, and a variety of type 1 membrane proteins. We previously demonstrated that PEN-2 is critical for promoting endoproteolysis of PS1 and that the proximal two-thirds of transmembrane domain (TMD) 1 of PEN-2 is required for binding with PS1. In this study, we sought to identify the structural domains of PS1 that are necessary for binding with PEN-2. To address this issue, we generated a series of constructs encoding PS1 mutants harboring deletions or replacements of specific TMDs of PS1-NTF, and examined the effects of encoded molecules on interactions with PEN-2, stabilization and endoproteolysis of PS1, and gamma-secretase activity. We now show that PS1 TMDs 1 and 2 and the intervening hydrophilic loop are dispensable for binding to PEN-2. Furthermore, analysis of chimeric PS1 molecules that harbor replacements of each TMD with corresponding transmembrane segments from the sterol regulatory element-binding protein cleavage activating protein (SCAP) revealed that the PS1-SCAP TMD4 mutant failed to coimmunoprecipitate endogenous PEN-2, strongly suggesting that the fourth TMD of PS1 is required for interaction with PEN-2. Further mutational analyses revealed that the "NF" sequence within the TMD4 of PS1 is the minimal motif that is required for binding with PEN-2, promoting PS1 endoproteolysis and gamma-secretase activity.
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a sequence within the first transmembrane domain of pen 2 is critical for pen 2 mediated endoproteolysis of presenilin 1
Journal of Biological Chemistry, 2005Co-Authors: Seonghun Kim, Sangram S SisodiaAbstract:Macromolecular complexes containing presenilins (PS), nicastrin (NCT), APH-1, and PEN-2 mediate the γ-secretase cleavage of the β-amyloid precursor protein and Notch. APH-1 and NCT stabilize the PS1 holoprotein, whereas PEN-2 is critical for endoproteolysis of PS1. To define the structural domains of PEN-2 that are necessary for mediating PS1 endoproteolysis and γ-secretase activity, we coexpressed APH-1, NCT, and PS1 together with a series of PEN-2 mutants, which harbored deletions in hydrophilic segments, or chimeric PEN-2 molecules that contained heterologous transmembrane domains (TMDs). We now report that with the exception of the PEN-2 variants with deletions proximal to the TMDs, the vast majority of the deletion variants were functional. Mutants that were nonfunctional were also unstable but were rescued by transposition of a heterologous sequence containing conservative amino acid substitutions into the deleted region. Notably, the carboxyl-terminal hydrophilic domain of PEN-2 was dispensable for promoting PS1 endoproteolysis but was critical for stabilizing the resulting PS1 derivatives. More importantly, we demonstrated that a chimeric PEN-2 with a replacement of the TMD2 with the TMD1 from sterol regulatory element binding protein 1 (SREBP-1) is fully functional but that a chimeric PEN-2 with a replacement of the TMD1 with the TMD2 from SREBP-1 is not. The function of this latter chimera was rescued by the replacement of the proximal two-thirds of the SREBP-1 TMD2 with the proximal two-thirds of the authentic TMD1 from PEN-2. These results suggest that the proximal two-thirds of the PEN-2 TMD1 is functionally important for endoproteolysis of PS1 holoproteins and the generation of PS1 fragments, essential components of the γ-secretase complex.
Harald Steiner - One of the best experts on this subject based on the ideXlab platform.
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length and overall sequence of the pen 2 c terminal domain determines its function in the stabilization of presenilin fragments
Journal of Neurochemistry, 2005Co-Authors: Stefan Prokop, Christian Haass, Harald SteinerAbstract:γ-Secretase is an aspartyl protease complex that catalyzes the intramembrane cleavage of a subset of type I transmembrane proteins including the β-amyloid precursor protein (APP) implicated in Alzheimer's disease. Presenilin (PS), nicastrin (NCT), anterior pharynx defective (APH-1) and presenilin enhancer-2 (PEN-2) constitute the active γ-secretase complex. PEN-2, the smallest subunit, is required for triggering PS endoproteolysis. Stabilization of the resultant N- and C-terminal fragments, which carry the catalytically active site aspartates, but not endoproteolysis itself, requires the C-terminal domain of PEN-2. To functionally dissect the C-terminal domain we created C-terminal deletion mutants and mutagenized several evolutionary highly conserved residues. The PEN-2 mutants were then probed for functional complementation of a PEN-2 knockdown, which displays deficient PS1 endoproteolysis and impaired NCT maturation. Progressive truncation of the C-terminus caused increasing loss of function. This was also observed for an internal deletion mutant as well as for C-terminally tagged PEN-2 with a twofold elongated C-terminal domain. Interestingly, only simultaneous, but not individual substitution of the highly conserved D90, F94, P97 and G99 residues with alanine interfered with PEN-2 function. All loss of function mutants identified allowed PS1 endoproteolysis, but failed to stably associate with the resultant PS1 fragments, which like the PEN-2 loss of function mutants underwent proteasomal degradation. However, complex formation of the PEN-2 mutants with PS1 fragments could be recovered when proteasomal degradation was blocked. Taken together, our data suggest that the PS-subunit stabilizing function of PEN-2 depends on length and overall sequence of its C-terminal domain.
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requirement of pen 2 for stabilization of the presenilin n c terminal fragment heterodimer within the γ secretase complex
Journal of Biological Chemistry, 2004Co-Authors: Stefan Prokop, Keiro Shirotani, Dieter Edbauer, Christian Haass, Harald SteinerAbstract:Gamma-secretase is a protease complex composed of presenilin (PS), nicastrin (NCT), APH-1, and PEN-2, which catalyzes intramembrane cleavage of several type I transmembrane proteins including the Alzheimer's disease-associated beta-amyloid precursor protein. We generated stable RNA interference-mediated PEN-2 knockdown cells to probe mutant PEN-2 variants for functional activity. Knockdown of PEN-2 was associated with impaired NCT maturation and deficient PS1 endoproteolysis, which was efficiently rescued by wild type or N-terminally tagged PEN-2 but not by C-terminally tagged PEN-2 or by the C-terminally truncated PEN-2-DeltaC mutant. Although the latter mutants rescued the PS1 holoprotein accumulation associated with the PEN-2 knockdown, they failed to restore normal levels of the PS1 N- and C-terminal fragments and to maturate NCT. PEN-2-DeltaC was highly unstable and rapidly turned over by proteasomal degradation consistent with its failure to become stably incorporated into the gamma-secretase complex. In addition, expression of PEN-2-DeltaC caused a selective instability of the PS1 N-/C-terminal fragment heterodimer that underwent proteasomal degradation, whereas NCT and APH-1 were stable. Interestingly, when we knocked down PEN-2 in the background of the endoproteolysis-deficient PS1 Deltaexon9 mutant, immature NCT still accumulated, demonstrating that PEN-2 is also required for gamma-secretase complex maturation when PS endoproteolysis cannot occur. Taken together, our data suggest that PEN-2 is required for the stabilization of the PS fragment heterodimer within the gamma-secretase complex following PS endoproteolysis. This function critically depends on the PEN-2 C terminus. Moreover, our data show that PEN-2 is generally required for gamma-secretase complex maturation independent of its activity in PS1 endoproteolysis.
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pen 2 is an integral component of the γ secretase complex required for coordinated expression of presenilin and nicastrin
Journal of Biological Chemistry, 2002Co-Authors: Harald Steiner, Stefan Prokop, Dieter Edbauer, Edith Winkler, Gabriele Basset, Aya Yamasaki, Marcus Kostka, Christian HaassAbstract:Abstract The Alzheimer disease-associated presenilin (PS) proteins apparently provide the active site of γ-secretase, an unusual intramembrane-cleaving aspartyl protease. PSs principally occur as high molecular weight protein complexes that contain nicastrin (Nct) and additional so far unidentified components. Recently, PEN-2 has been implicated in γ-secretase function. Here we identify PEN-2 as a critical component of PS1/γ-secretase and PS2/γ-secretase complexes. Strikingly, in the absence of PS1 and PS1/PS2, PEN-2 levels are strongly reduced. Similarly, PEN-2 levels are reduced upon RNA interference-mediated down-regulation of Nct. On the other side, down-regulation of PEN-2 by RNA interference is associated with reduced PS levels, impaired Nct maturation, and deficient γ-secretase complex formation. We conclude that PEN-2 is an integral γ-secretase complex component and that γ-secretase complex components are expressed in a coordinated manner.
Christian Haass - One of the best experts on this subject based on the ideXlab platform.
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length and overall sequence of the pen 2 c terminal domain determines its function in the stabilization of presenilin fragments
Journal of Neurochemistry, 2005Co-Authors: Stefan Prokop, Christian Haass, Harald SteinerAbstract:γ-Secretase is an aspartyl protease complex that catalyzes the intramembrane cleavage of a subset of type I transmembrane proteins including the β-amyloid precursor protein (APP) implicated in Alzheimer's disease. Presenilin (PS), nicastrin (NCT), anterior pharynx defective (APH-1) and presenilin enhancer-2 (PEN-2) constitute the active γ-secretase complex. PEN-2, the smallest subunit, is required for triggering PS endoproteolysis. Stabilization of the resultant N- and C-terminal fragments, which carry the catalytically active site aspartates, but not endoproteolysis itself, requires the C-terminal domain of PEN-2. To functionally dissect the C-terminal domain we created C-terminal deletion mutants and mutagenized several evolutionary highly conserved residues. The PEN-2 mutants were then probed for functional complementation of a PEN-2 knockdown, which displays deficient PS1 endoproteolysis and impaired NCT maturation. Progressive truncation of the C-terminus caused increasing loss of function. This was also observed for an internal deletion mutant as well as for C-terminally tagged PEN-2 with a twofold elongated C-terminal domain. Interestingly, only simultaneous, but not individual substitution of the highly conserved D90, F94, P97 and G99 residues with alanine interfered with PEN-2 function. All loss of function mutants identified allowed PS1 endoproteolysis, but failed to stably associate with the resultant PS1 fragments, which like the PEN-2 loss of function mutants underwent proteasomal degradation. However, complex formation of the PEN-2 mutants with PS1 fragments could be recovered when proteasomal degradation was blocked. Taken together, our data suggest that the PS-subunit stabilizing function of PEN-2 depends on length and overall sequence of its C-terminal domain.
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requirement of pen 2 for stabilization of the presenilin n c terminal fragment heterodimer within the γ secretase complex
Journal of Biological Chemistry, 2004Co-Authors: Stefan Prokop, Keiro Shirotani, Dieter Edbauer, Christian Haass, Harald SteinerAbstract:Gamma-secretase is a protease complex composed of presenilin (PS), nicastrin (NCT), APH-1, and PEN-2, which catalyzes intramembrane cleavage of several type I transmembrane proteins including the Alzheimer's disease-associated beta-amyloid precursor protein. We generated stable RNA interference-mediated PEN-2 knockdown cells to probe mutant PEN-2 variants for functional activity. Knockdown of PEN-2 was associated with impaired NCT maturation and deficient PS1 endoproteolysis, which was efficiently rescued by wild type or N-terminally tagged PEN-2 but not by C-terminally tagged PEN-2 or by the C-terminally truncated PEN-2-DeltaC mutant. Although the latter mutants rescued the PS1 holoprotein accumulation associated with the PEN-2 knockdown, they failed to restore normal levels of the PS1 N- and C-terminal fragments and to maturate NCT. PEN-2-DeltaC was highly unstable and rapidly turned over by proteasomal degradation consistent with its failure to become stably incorporated into the gamma-secretase complex. In addition, expression of PEN-2-DeltaC caused a selective instability of the PS1 N-/C-terminal fragment heterodimer that underwent proteasomal degradation, whereas NCT and APH-1 were stable. Interestingly, when we knocked down PEN-2 in the background of the endoproteolysis-deficient PS1 Deltaexon9 mutant, immature NCT still accumulated, demonstrating that PEN-2 is also required for gamma-secretase complex maturation when PS endoproteolysis cannot occur. Taken together, our data suggest that PEN-2 is required for the stabilization of the PS fragment heterodimer within the gamma-secretase complex following PS endoproteolysis. This function critically depends on the PEN-2 C terminus. Moreover, our data show that PEN-2 is generally required for gamma-secretase complex maturation independent of its activity in PS1 endoproteolysis.
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pen 2 is an integral component of the γ secretase complex required for coordinated expression of presenilin and nicastrin
Journal of Biological Chemistry, 2002Co-Authors: Harald Steiner, Stefan Prokop, Dieter Edbauer, Edith Winkler, Gabriele Basset, Aya Yamasaki, Marcus Kostka, Christian HaassAbstract:Abstract The Alzheimer disease-associated presenilin (PS) proteins apparently provide the active site of γ-secretase, an unusual intramembrane-cleaving aspartyl protease. PSs principally occur as high molecular weight protein complexes that contain nicastrin (Nct) and additional so far unidentified components. Recently, PEN-2 has been implicated in γ-secretase function. Here we identify PEN-2 as a critical component of PS1/γ-secretase and PS2/γ-secretase complexes. Strikingly, in the absence of PS1 and PS1/PS2, PEN-2 levels are strongly reduced. Similarly, PEN-2 levels are reduced upon RNA interference-mediated down-regulation of Nct. On the other side, down-regulation of PEN-2 by RNA interference is associated with reduced PS levels, impaired Nct maturation, and deficient γ-secretase complex formation. We conclude that PEN-2 is an integral γ-secretase complex component and that γ-secretase complex components are expressed in a coordinated manner.
A Pleil - One of the best experts on this subject based on the ideXlab platform.
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results from an international multicenter trial evaluating the ease of use of and preference for a newly developed disposable injection pen for the treatment of growth hormone deficiency in treatment naive children and adults
Medical Devices : Evidence and Research, 2014Co-Authors: A Pleil, Feyza Darendeliler, Helmuth G Dorr, Katherine Hutchinson, Hartmut A WollmannAbstract:Previous research has reported that ease of use of and preference for a delivery device are associated with greater patient compliance – an important factor in achieving optimal therapeutic results. The objective of this study was to assess the ease-of-use of a new disposable pen (GoQuick®, Pfizer, Inc.) versus the current reusable pen (GENOTROPIN Pen®, Pfizer, Inc.) to inject a daily dose of recombinant DNA origin human growth hormone, Genotropin® (somatropin) in standard practice. In this randomized, crossover, multicenter, multinational, open-label study, ease-of-use of and preference for the two pens were assessed in three treatment-naive populations: 1) parents of very young children; 2) parent–child dyads; and 3) adults via use of a validated self-report Injection Pen Assessment Questionnaire (IPAQ) after 2 months of at-home-use experience. The primary endpoint was the proportion of participants who reported the new disposable pen to be no different from or easier to use than the current reusable pen. Safety was also assessed and reported according to local legal requirements. Of the 120 screened patients, 119 were included in the ease-of-use analysis and all were included in the safety analyses. In all, 67.2% found the new somatropin disposable pen to be no different from or easier to use than the reusable pen (95% confidence interval: 58.8–75.7). Most adverse events were mild or moderate. No deaths or device- or treatment-related serious adverse events were reported. These results suggest that improvements made to the reusable somatropin pen are tangible and recognizable to treatment-naive patients and their caregivers, child–caregiver dyads, and adults, and may positively impact continued compliance with therapy. Registry information ClinicalTrials.gov identifier: {"type":"clinical-trial","attrs":{"text":"NCT01112865","term_id":"NCT01112865"}}NCT01112865.
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psychometric assessment of the injection pen assessment questionnaire ipaq measuring ease of use and preference with injection pens for human growth hormone
Health and Quality of Life Outcomes, 2012Co-Authors: A Pleil, Miriam Kimel, Natasa Rajicic, J Mccormack, Judith HeyhadaviAbstract:To examine the psychometric properties of the Injection Pen Assessment Questionnaire (IPAQ) including the following: 1) item and scale characteristics (e.g., frequencies, item distributions, and factor structure), 2) reliability, and 3) validity. Focus groups and one-on-one dyad interviews guided the development of the IPAQ. The IPAQ was subsequently tested in 136 parent–child dyads in a Phase 3, 2-month, open-label, multicenter trial for a new Genotropin® disposable pen. Factor analysis was performed to inform the development of a scoring algorithm, and reliability and validity of the IPAQ were evaluated using the data from this two months study. Psychometric analyses were conducted separately for each injection pen. Confirmatory factor analysis provides evidence supporting a second order factor solution for four subscales and a total IPAQ score. These factor analysis results support the conceptual framework developed from previous qualitative research in patient dyads using the reusable pen. However, the IPAQ subscales did not consistently meet acceptable internal consistency reliability for some group level comparisons. Cronbach’s alphas for the total IPAQ score for both pens were 0.85, exceeding acceptable levels of reliability for group comparisons. The total IPAQ score is a useful measure for evaluating ease of use and preference for injection pens in clinical trials among patient dyads receiving hGH. The psychometric properties of the individual subscales, mainly the lower internal consistency reliability of some of the subscales and the predictive validity findings, do not support the use of subscale scores alone as a primary endpoint.
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ease of use and preference for a new disposable self injection pen compared with a reusable pen for administering recombinant human growth hormone a multicenter 2 month single arm open label clinical trial in patient caregiver dyads
Clinical Therapeutics, 2010Co-Authors: Judith Heyhadavi, A Pleil, Natasa Rajicic, Larry Deeb, John S Fuqua, Lawrence A Silverman, Barry J Reiner, Ron S Newfield, Michael P Wajnrajch, Jose CaraAbstract:Abstract Background: Improved ease of use of drug-delivery devices may enhance compliance. Development of an easier-to-use device for administration of recombinant human growth hormone (rhGH) may thus be beneficial for patients and their caregivers. Objective: This study compared ease of use and preference for a new disposable rhGH injection pen relative to previous experience with the currently available reusable pen in standard practice. Both pens deliver the same formulation of rhGH. Methods: This multicenter, single-arm, open-label study assessed ease of use and preference for the 2 injection pens in patient-caregiver dyads. Eligible children were aged 8 through 18 years, were currently being treated with rhGH, and had been compliant with use of the current reusable pen for ≥3 months before study entry. A validated self-reported Injection Pen Assessment Questionnaire was administered twice during the study—at baseline (to assess perceptions of the reusable pen) and after 2 months of use of the new disposable pen—to assess ease of use of the individual pens (rated on a 5-point Likert-type scale), the comparative ease of use of the 2 pens, and pen preference. The primary end point was the proportion of dyads who rated the new pen as no different or easier to use than the current pen. Regardless of treatment or suspected causal relationship to the investigational product, all observed or volun- teered adverse events (AEs) were recorded and rated as mild, moderate, or severe. Results: Of 137 screened dyads, 136 (91 boys, 45 girls) were included in the safety population and 133 were included in the efficacy population. The children had a mean age of 12.3 years, a mean weight of 42.2 kg, a mean height of 145.9 cm, and a mean body mass index of 19.3 kg/m 2 ; 84.6% of the children were white. The majority (82.4%) of adult dyad members were subjects' mothers. The adult dyad members were more likely than the child members to be responsible for preparing the injection (82.0%) and administering the injection (72.9%). Overall, 73.7% of dyads rated the new disposable pen no different or easier to use than the reusable pen (95% CI, 66.2%–81.2%), and 65.2% rated the disposable pen no different or preferable to the reusable pen (95% CI, 57.0%–73.3%). Overall, 60 all-causality AEs occurred in 28 subjects (20.6%), most of them (93.3%) either mild or moderate in intensity. Eight device-related AEs occurred in 7 subjects (5.1%) (injection-site hematoma in 3 and injection-site pain in 5). The most common AEs were headache (7 events), injection-site pain (5), upper respiratory tract infection (4), and pyrexia (4). No deaths or serious AEs were reported. Conclusions: Nearly three quarters of patients and caregivers reported that the new disposable pen was no Accepted for publication October 1, 2010. different or easier to use than the reusable pen, and nearly two thirds preferred the disposable pen. No safety concerns were identified. The findings suggest that the improvements in the new pen were recognized by patients and caregivers.
Martin Curley - One of the best experts on this subject based on the ideXlab platform.
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twelve principles for open innovation 2 0
Nature, 2016Co-Authors: Martin CurleyAbstract:Evolve governance structures, practices and metrics to accelerate innovation in an era of digital connectivity, writes Martin Curley.
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capitalizing on open innovation 2 0
2013Co-Authors: Martin Curley, Piero FormicaAbstract:New venture creation takes place within human–human and human–technology interactions. Experiencing interactions as they occur in the real life is in the nature of business creation. Open Innovation 2.0 (OI 2.0) is an emergent and powerful new paradigm for balancing hands-on experimentation with theoretical knowledge. In doing so, OI 2.0 provides the opportunities for elevating high ambition entrepreneurship through systemic changes, instead of piecemeal siloed reforms, in the experimentation process.