Deubiquitinase USP47/UBP64E Regulates β-Catenin Ubiquitination and Degradation and Plays a Positive Role in Wnt Signaling

Wnt signaling plays important roles in development and tumorigenesis. A central question about the Wnt pathway is the regulation of β-catenin. Phosphorylation of β-catenin by CK1α and GSK3 promotes β-catenin binding to β-TrCP, leading to β-catenin degradation through the proteasome. The phosphorylation and ubiquitination of β-catenin have been well characterized; however, it is unknown whether and how a deubiquitinase is involved. In this study, by screening RNA interference (RNAi) libraries, we identified USP47 as a deubiquitinase that prevents β-catenin ubiquitination. Inactivation of USP47 by RNAi increased β-catenin ubiquitination, attenuated Wnt signaling, and repressed cancer cell growth. Furthermore, USP47 deubiquitinates itself, whereas β-TrCP promotes USP47 ubiquitination through interaction with an atypical motif in USP47. Finally, in vivo studies in the Drosophila wing suggest that UBP64E, the USP47 counterpart in Drosophila, is required for Armadillo stabilization and plays a positive role in regulating Wnt target gene expression

Ground Ammonia Concentrations over China Derived from Satellite and Atmospheric Transport Modeling

As a primary basic gas in the atmosphere, atmospheric ammonia (NH3) plays an important role in determining air quality, environmental degradation, and climate change. However, the limited ground observation currently presents a barrier to estimating ground NH3 concentrations on a regional scale, thus preventing a full understanding of the atmospheric processes in which this trace gas is involved. This study estimated the ground NH3 concentrations over China, combining the Infrared Atmospheric Sounding Interferometer (IASI) satellite NH3 columns and NH3 profiles from an atmospheric chemistry transport model (CTM). The estimated ground NH3 concentrations showed agreement with the variability in annual ground NH3 measurements from the Chinese Nationwide Nitrogen Deposition Monitoring Network (NNDMN). Great spatial heterogeneity of ground NH3 concentrations was found across China, and high ground NH3 concentrations were found in Northern China, Southeastern China, and some areas in Xinjiang Province. The maximum ground NH3 concentrations over China occurred in summer, followed by spring, autumn, and winter seasons, which were in agreement with the seasonal patterns of NH3 emissions in China. This study suggested that a combination of NH3 profiles from CTMs and NH3 columns from satellite obtained reliable ground NH3 concentrations over China

Dry Particulate Nitrate Deposition in China

A limited number of ground measurements of dry particulate nitrate deposition (NO₃^–) makes it difficult and challenging to fully know the status of the spatial and temporal variations of dry NO₃^– depositions over China. This study tries to expand the ground measurements of NO₃^– concentrations at monitoring sites to a national scale, based on the Ozone Monitoring Instrument (OMI) NO₂ columns, NO₂ profiles from an atmospheric chemistry transport model (Model for Ozone and Related chemical Tracers, version 4, MOZART-4) and monitor-based sources, and then estimates the NO₃^– depositions on a regional scale based on an inferred model. The ground NO₂ concentrations were first derived from NO₂ columns and the NO₂ profiles, and then the ground NO₃^– concentrations were derived from the ground NO₂ concentrations and the relationship between NO₂ and NO₃^– based on Chinese Nationwide Nitrogen Deposition Monitoring Network (NNDMN). This estimated dry NO₃^– depositions over China will be helpful in determining the magnitude and pollution status in regions without ground measurements, supporting the construction plan of environmental monitoring in future