Identification of membrane-bound variant of metalloendopeptidase neurolysin (EC 3.4.24.16) as the non-AT1, non-AT2 angiotensin binding site

Recently, we discovered a novel non-AT1, non-AT2 angiotensin binding site in rodent and human brain membranes, which is distinctly different from angiotensin receptors and key proteases processing angiotensins. It is hypothesized to be a new member of the renin-angiotensin system. This study was designed to isolate and identify this novel angiotensin binding site. An angiotensin analog, photoaffinity probe 125I-SBpa-Ang II was used to specifically label the non-AT1, non-AT2 angiotensin binding site in mouse forebrain membranes, followed by a two-step purification procedure based on the molecular size and isoelectric point of the photoradiolabeled binding protein. Purified samples were subjected to 2-D gel electrophoresis followed by mass spectrometry identification of proteins in the 2-D gel sections containing radioactivity. LC-MS/MS analysis revealed eight protein candidates, of which the four most abundant were immunoprecipitated (IP) after photoradiolabeling. IP studies indicated that the angiotensin binding site might be the membrane-bound variant of metalloendopeptidase neurolysin (EC 3.4.24.16). To verify these observations, radioligand binding and photoradiolabeling experiments were conducted in membrane preparations of HEK293 cells overexpressing mouse neurolysin or thimet oligopeptidase (EC 3.4.24.15), a closely related metalloendopeptidase of the same family. These experiments also identified neurolysin as the non-AT1, non-AT2 angiotensin binding site. Finally, brain membranes of mice lacking neurolysin were nearly devoid of the non-AT1, non-AT2 angiotensin binding site, further establishing membrane-bound neurolysin as the binding site. Future studies will focus on the functional significance of this highly specific, high affinity interaction between neurolysin and angiotensins

Peering into microscale details of mountain winds

A grand challenge from the wind energy industry is to provide reliable forecasts on mountain winds several hours in advance at microscale (similar to 100 m) resolution. This requires better microscale wind-energy physics included in forecasting tools, for which field observations are imperative. While mesoscale (similar to 1 km) measurements abound, microscale processes are not monitored in practice nor do plentiful measurements exist at this scale. After a decade of preparation, a group of European and U.S. collaborators conducted a field campaign during 1 May-15 June 2017 in Vale Cobrao in central Portugal to delve into microscale processes in complex terrain. This valley is nestled within a parallel double ridge near the town of Perdigao with dominant wind climatology normal to the ridges, offering a nominally simple yet natural setting for fundamental studies. The dense instrument ensemble deployed covered a similar to 4 km x 4 km swath horizontally and similar to 10 km vertically, with measurement resolutions of tens of meters and seconds. Meteorological data were collected continuously, capturing multiscale flow interactions from synoptic to microscales, diurnal variability, thermal circulation, turbine wake and acoustics, waves, and turbulence. Particularly noteworthy are the extensiveness of the instrument array, space-time scales covered, use of leading-edge multiple-lidar technology alongside conventional tower and remote sensors, fruitful cross-Atlantic partnership, and adaptive management of the campaign. Preliminary data analysis uncovered interesting new phenomena. All data are being archived for public use