Institute of
bioorganic chemistry

Researchers from the Institute of Bioorganic Chemistry, Russian Academy of Sciences, from the Laboratory of Receptor Cell Biology, Laboratory of Molecular Theranostics and the Group of Molecular Physiology, together with colleagues from the I Prokhorov General Physics Institute and Moscow State University, a genetically encoded fluorescent sensor for measuring the pH of the extracellular medium in the slightly alkaline range has been created. To accomplish this task, a number of chimeric proteins were obtained, which are the previously described pH sensor SypHer3s with different transmembrane domains: from CIRL2, ErBb2, TrkA, IR, and neurexin-1. Among these fusion proteins, only the variant with the transmembrane domain of neurexin-1 was localized on the cell membrane. This protein was named SypHerExtra. Using the method of fluorescence lifetime imaging microscopy (FLIM) on living tumor cells, it was demonstrated that SypHerExtra can be successfully used to determine extracellular pH, while SypHer3s can be used to measure intracellular pH. The results are published in the journal Biosensors. Learn more