instruction:
In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.
question:
Ebola virus (EboV) belongs to the Filoviridae family of viruses that causes severe and fatal hemhorragic fever. Infection by EboV involves fusion between the virus and host cell membranes mediated by the envelope glycoprotein GP2 of the virus. Similar to the envelope glycoproteins of other viruses, the central feature of the GP2 ectodomain postfusion structure is a six-helix bundle formed by the protein's N-and C-heptad repeat regions (NHR and CHR, respectively). Folding of this six-helix bundle provides the energetic driving force for membrane fusion; in other viruses, designed agents that disrupt formation of the six-helix bundle act as potent fusion inhibitors. To interrogate determinants of EboV GP2-mediated membrane fusion, we designed model proteins that consist of the NHR and CHR segments linked by short protein linkers. Circular dichroism and gel filtration studies indicate that these proteins adopt stable ahelical folds consistent with design. Thermal denaturation indicated that the GP2 six-helix bundle is highly stable at pH 5.3 (melting temperature, T m , of 86.8 6 2.0°C and van't Hoff enthalpy, DH vH , of 228.2 6 1.0 kcal/mol) and comparable in stability to other viral membrane fusion six-helix bundles. We found that the stability of our designed a-helical bundle proteins was dependent on buffering conditions with increasing stability at lower pH. Small pH differences (5.3-6.1) had dramatic effects (DT m 5 37°C) suggesting a mechanism for conformational control that is dependent on environmental pH. These results suggest a role for low pH in stabilizing six-helix bundle formation during the process of GP2-mediated viral membrane fusion.
answer:
Designed protein mimics of the Ebola virus glycoprotein GP2 a-helical bundle: Stability and pH effects


question:
This review examines the question of whether exercise can be used as an experimental model to further our understanding of innate antimicrobial peptides and proteins (AMPs) and their role in susceptibility to infection at mucosal surfaces. There is strong evidence to suggest that AMPs, in combination with cellular and physical factors, play an important role in preventing infection. Although AMPs act directly on microorganisms, there is increasing recognition that they also exert their protective effect via immunomodulatory mechanisms, especially in noninflammatory conditions. Further studies that manipulate physiologically relevant concentrations of AMPs are required to shed light on the role they play in reducing susceptibility to infection. Evidence shows that in various form prolonged and/or exhaustive exercise is a potent modulator of the immune system, which can either sharpen or blunt the immune response to pathogens. The intensity and duration of exercise can be readily controlled in experimental settings to manipulate the degree of physical stress. This would allow for an investigation into a potential dose-response effect between exercise and AMPs. In addition, the use of controlled exercise could provide an experimental model by which to examine whether changes in the concentration of AMPs alters susceptibility to illness.
answer:
Antimicrobial peptides and proteins, exercise and innate mucosal immunity


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Angiotensin-converting enzyme 2 (ACE2) gene therapy aimed at counteracting pancreatic ACE2 depletion improves glucose regulation in two diabetic mouse models: db/db mice and angiotensin II-infused mice. A disintegrin and metalloproteinase 17 (ADAM17) can cause shedding of ACE2 from the cell membrane. The aim of our studies was to determine whether ADAM17 depletes ACE2 levels in pancreatic islets and ␤-cells. Dynamics of ADAM17-mediated ACE2 shedding were investigated in 832/13 insulinoma cells. Within a wide range of ACE2 expression levels, including the level observed in mouse pancreatic islets, overexpression of ADAM17 increases shed ACE2 and decreases cellular ACE2 levels. We provide a mathematical description of shed and cellular ACE2 activities as a function of the ADAM17 activity. The effect of ADAM17 on the cellular ACE2 content was relatively modest with an absolute control strength value less than 0.25 and approaching 0 at low ADAM17 activities. Although we found that ADAM17 and ACE2 are both expressed in pancreatic islets, the ␤-cell is not the major cell type expressing ACE2 in islets. During diabetes progression in 8-, 12-, and 15-week-old db/db mice, ACE2 mRNA and ACE2 activity levels in pancreatic islets were not decreased over time nor significantly decreased compared with nondiabetic db/m mice. Levels of ADAM17 mRNA and ADAM17 activity were also not significantly changed. Inhibiting basal ADAM17 activity in mouse islets failed to affect ACE2 levels. We conclude that whereas ADAM17 has the ability to shed ACE2, ADAM17 does not deplete ACE2 from pancreatic islets in diabetic db/db mice. (Endocrinology 156: 4411-4425, 2015 ) Endocrinology, December 2015, 156(12):4411-4425 press.endocrine.org/journal/endo 4411 Pedersen et al ACE2 and ADAM17 in Pancreatic Islets Endocrinology, December 2015, 156(12):4411-4425 Pedersen et al ACE2 and ADAM17 in Pancreatic Islets Endocrinology, December 2015, 156(12):4411-4425 Pedersen et al ACE2 and ADAM17 in Pancreatic Islets Endocrinology, December 2015, 156(12):4411-4425 Pedersen et al ACE2 and ADAM17 in Pancreatic Islets Endocrinology, December 2015, 156(12):4411-4425
answer:

Dynamics of ADAM17-Mediated Shedding of ACE2 Applied to Pancreatic Islets of Male db/db Mice