Plasma Membrane Abundance of Human Aquaporin 5 Is Dynamically Regulated by Multiple Pathways.Kitchen, P., Oberg, F., Sjohamn, J., Hedfalk, K., Bill, R.M., Conner, A.C., Conner, M.T., Tornroth-Horsefield, S.
(2015) Plos One 10: e0143027-e0143027
- PubMed: 26569106
- DOI: 10.1371/journal.pone.0143027
- Primary Citation of Related Structures:
- PubMed Abstract:
Aquaporin membrane protein channels mediate cellular water flow. Human aquaporin 5 (AQP5) is highly expressed in the respiratory system and secretory glands where it facilitates the osmotically-driven generation of pulmonary secretions, saliva, sweat ...
Aquaporin membrane protein channels mediate cellular water flow. Human aquaporin 5 (AQP5) is highly expressed in the respiratory system and secretory glands where it facilitates the osmotically-driven generation of pulmonary secretions, saliva, sweat and tears. Dysfunctional trafficking of AQP5 has been implicated in several human disease states, including Sjögren's syndrome, bronchitis and cystic fibrosis. In order to investigate how the plasma membrane expression levels of AQP5 are regulated, we studied real-time translocation of GFP-tagged AQP5 in HEK293 cells. We show that AQP5 plasma membrane abundance in transfected HEK293 cells is rapidly and reversibly regulated by at least three independent mechanisms involving phosphorylation at Ser156, protein kinase A activity and extracellular tonicity. The crystal structure of a Ser156 phosphomimetic mutant indicates that its involvement in regulating AQP5 membrane abundance is not mediated by a conformational change of the carboxy-terminus. We suggest that together these pathways regulate cellular water flow.
Biomedical Research Centre, Sheffield Hallam University, Sheffield, United Kingdom.,Department of Biochemistry and Structural Biology, Centre for Molecular Protein Science, Lund University, Lund, Sweden.,Molecular Organization and Assembly in Cells Doctoral Training Centre, University of Warwick, Coventry, United Kingdom.,Clinical and Experimental Medicine, The Medical School, University of Birmingham, Birmingham, United Kingdom.,Department of Chemistry, University of Gothenburg, Gothenburg, Sweden.,School of Life and Health Sciences, Aston University, Birmingham, United Kingdom.