The epithelial sodium channel (ENaC) plays an important role in regulating sodium balance, extracellular volume, and blood pressure. Evidence suggests the α and γ subunits of ENaC are cleaved during assembly before they are inserted into the apical membranes of epithelial cells, and maximal activity of ENaC depends on cleavage of the extracellular loops of α and γ subunits. Here, we report that Xenopus 2F3 cells apically express the cysteine protease cathepsin B, as indicated by two-dimensional gel electrophoresis and mass spectrometry analysis. Recombinant GST ENaC α, β, and γ subunit fusion proteins were expressed in Escherichia coli and then purified and recovered from bacterial inclusion bodies. In vitro cleavage studies revealed the full-length ENaC α subunit fusion protein was cleaved by active cathepsin B but not the full-length β or γ subunit fusion proteins. Both single channel patch clamp studies and short circuit current experiments show ENaC activity decreases with the application of a cathepsin B inhibitor directly onto the apical side of 2F3 cells. We suggest a role for the proteolytic cleavage of ENaC by cathepsin B, and we suggest two possible mechanisms by which cathepsin B could regulate ENaC. Cathepsin B may cleave ENaC extracellularly after being secreted or intracellularly, while ENaC is present in the Golgi or in recycling endosomes.
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http://dx.doi.org/10.1074/jbc.M111.338574 | DOI Listing |
Am J Physiol Renal Physiol
January 2025
George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, Utah; University of Utah Spencer Fox Eccles School of Medicine.
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January 2025
Institute of Chemistry, University of Campinas - UNICAMP, PO Box 6154, 13083-970 Campinas, SP, Brazil. Electronic address:
Front Cell Infect Microbiol
September 2024
China Institute of Veterinary Drug Control, Beijing, China.
P32 protein serves as a crucial structural component of Goat pox virus (GTPV), which causes a highly virulent infectious disease in sheep and goats. Despite the fact that P32 has been widely expressed in the previous studies, it is difficult to obtain recombinant P32 efficiently. This study aimed to achieve soluble expression of P32 recombinant protein and to develop its specific monoclonal antibody.
View Article and Find Full Text PDFNMR Biomed
December 2024
Department of Electric and Electronic Engineering, University of Bristol, Bristol, UK.
Understanding the effects of white matter (WM) axon fibre microstructure on T1 relaxation is important for neuroimaging. Here, we have studied the interrelationship between T1 and axon fibre configurations at 3T and 7T. T1 and S0 (=signal intensity at zero TI) were computed from MP2RAGE images acquired with six inversion recovery times.
View Article and Find Full Text PDFACS Appl Mater Interfaces
September 2024
Xiamen Key Laboratory of Optoelectronic Materials and Advanced Manufacturing, Institute of Luminescent Materials and Information Displays, College of Materials Science and Engineering, Huaqiao University, Xiamen 361021, China.
NaV(PO)F (NVPF), a typical sodium superionic conductor (NASICON) type structure, has attracted much interest as a potential positive electrode in sodium-ion battery. However, the inherently poor electronic conductivity of phosphates compromises the electrochemical properties of this material. Here, we develop a general strategy to improve the electrochemical performance by preparing a new composite material "polyaniline (PANI)@NVPF" using a Pickering emulsion method.
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