title: Site-specific, orthogonal labeling of proteins in intact cells with two small biarsenical fluorophores.
abstract: The fusion of fluorescent proteins to proteins of interest has greatly advanced fluorescence microscopy, but is often limited by their large size. Here, we report site-specific, orthogonal labeling of two cellular proteins in intact cells with two small fluorescent dyes: fluorescein arsenical hairpin binder, FlAsH, and its red analogue, ReAsH, which bind to tetracysteine motifs. Development of a sequential labeling method to two different motifs, CCPGCC and FLNCCPGCCMEP, allowed site-specific labeling with FlAsH and ReAsH, respectively. Using the cell surface receptor for parathyroid hormone and its cytosolic binding protein, beta-arrestin2, we show their selective visualization in intact cells and analyze their interaction by colocalization and fluorescence resonance energy transfer (FRET). We propose that this method may be widely applied to label intracellular proteins and to study their interactions in intact cells with minimal disturbance of their function.
authors.affiliation: Institute of Pharmacology and Toxicology, Rudolf Virchow Center University of Wurzburg, Versbacher Strasse 9, 97078 Wurzburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Zürn
authors.forename: Christoph
authors.initials: C
authors.lastname: Klenk
authors.forename: Ulrike
authors.initials: U
authors.lastname: Zabel
authors.forename: Susanne
authors.initials: S
authors.lastname: Reiner
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Lohse
authors.forename: Carsten
authors.initials: C
authors.lastname: Hoffmann
mesh_terms: D000595:Amino Acid Sequence; D019390:Arrestins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D002460:Cell Line; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D011485:Protein Binding; D011506:Proteins / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D044168:Receptor, Parathyroid Hormone, Type 1 / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D000071557:beta-Arrestins
chemical_list: D019390:Arrestins; D005456:Fluorescent Dyes; D011506:Proteins; D044168:Receptor, Parathyroid Hormone, Type 1; D000071557:beta-Arrestins