title: Engineering a subcellular targetable, red-emitting, and ratiometric fluorescent probe for Ca2+ and its bioimaging applications.
abstract: A new, visible-light-excited and red-emitting fluorescent Ca(2+) probe, STDBT, was synthesized, which consists of 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid as a Ca(2+)-chelating moiety and two benzothiazolium hemicyanine dyes as fluorophores. The spectral profiles of its free and Ca(2+)-bound forms were studied. Upon addition of Ca(2+), the fluorescence spectra of STDBT displayed a significant enhancement (about 48-fold) in fluorescence intensity and a 20-nm blueshift (from 600 to 580 nm) in the emission spectrum. Both the absorption and the excitation spectra of STDBT showed a very large (more than 100 nm) hypsochromic shift in the long-wavelength maxima upon binding with Ca(2+). Interestingly, in contrast with the commonly used Ca(2+) indicator Fluo-3, when the acetoxymethyl ester of STDBT enters into cells, it distributes both in the cytosol and the nucleus, but displays a very clear boundary between the two compartments. This allows STDBT to be used as a double targetable Ca(2+) probe that can be used to report cytoplasmic Ca(2+) and nuclear Ca(2+) simultaneously.
authors.affiliation: Department of Chemistry, School of Science, Beijing Institute of Technology, Beijing 100081, China.
authors.forename: Baocun
authors.initials: B
authors.lastname: Zhu
authors.forename: Hongying
authors.initials: H
authors.lastname: Jia
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.forename: Haipeng
authors.initials: H
authors.lastname: Liu
authors.forename: Weihong
authors.initials: W
authors.lastname: Tan
mesh_terms: D052160:Benzothiazoles / Q000737:chemistry; D002118:Calcium / Q000032:analysis* / Q000378:metabolism; D002413:Cations, Divalent / Q000032:analysis / Q000378:metabolism; D002460:Cell Line; D002466:Cell Nucleolus / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism*; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D018613:Microscopy, Confocal / Q000379:methods*
chemical_list: D052160:Benzothiazoles; D002413:Cations, Divalent; D005456:Fluorescent Dyes; D004533:Egtazic Acid; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium