title: Structure-guided design of a reversible fluorogenic reporter of protein-protein interactions.
abstract: A reversible green fluorogenic protein-fragment complementation assay was developed based on the crystal structure of UnaG, a recently discovered fluorescent protein. In living mammalian cells, the nonfluorescent fragments complemented and rapidly became fluorescent upon rapamycin-induced FKBP and Frb protein interaction, and lost fluorescence when the protein interaction was inhibited. This reversible fluorogenic reporter, named uPPI [UnaG-based protein-protein interaction (PPI) reporter], uses bilirubin (BR) as the chromophore and requires no exogenous cofactor. BR is an endogenous molecule in mammalian cells and is not fluorescent by itself. uPPI may have many potential applications in visualizing spatiotemporal dynamics of PPIs.
authors.affiliation: Department of Pharmaceutical Chemistry, University of California-San Francisco, San Francisco, California.|Cardiovascular Research Institute, University of California-San Francisco, San Francisco, California.
authors.forename: Tsz-Leung
authors.initials: TL
authors.lastname: To
authors.affiliation: Department of Pharmaceutical Chemistry, University of California-San Francisco, San Francisco, California.|Cardiovascular Research Institute, University of California-San Francisco, San Francisco, California.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Pharmaceutical Chemistry, University of California-San Francisco, San Francisco, California.|Cardiovascular Research Institute, University of California-San Francisco, San Francisco, California.
authors.forename: Xiaokun
authors.initials: X
authors.lastname: Shu
mesh_terms: D001663:Bilirubin / Q000378:metabolism; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D018613:Microscopy, Confocal / Q000379:methods; D008958:Models, Molecular; D061848:Optical Imaging / Q000379:methods; D025941:Protein Interaction Mapping / Q000379:methods*; D060066:Protein Interaction Maps; D020123:Sirolimus / Q000378:metabolism; D022021:Tacrolimus Binding Proteins / Q000378:metabolism
chemical_list: D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins; D022021:Tacrolimus Binding Proteins; D001663:Bilirubin; D020123:Sirolimus
keywords: fluorescent reporter; green fluorescent protein; protein-fragment complementation assay; protein-protein interaction