title: Imaging farnesyl protein transferase using a topologically activated probe.
abstract: We report on the development and application of a "smart" activatable peptide-based probe for detection of Ras-related farnesyl protein transferase (FPT). Upon farnesylation by FPT, the probe was brought close to a hydrophobic milieu and as a consequence emitted fluorescent light that could be detected by several media, such as fluorescence microscopy, a plate reader, and an optical imaging system. A FPT activity assay confirmed the specificity of the probe (IC50 = 1.2 muM) for FPT compared to that of the native peptide (IC50 = 0.17 muM). In addition, the probe has remarkable binding constant, Kd = 26 nM. The specificity of enzyme activation was proved in pure enzyme assays as well as in cell-based assays. Furthermore, the fluorescent enhancement of the probe was 30-fold stronger than the control peptide in a live cell assay.
authors.affiliation: Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Wellington
authors.initials: W
authors.lastname: Pham
authors.forename: Pamela
authors.initials: P
authors.lastname: Pantazopoulos
authors.forename: Anna
authors.initials: A
authors.lastname: Moore
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000737:chemistry* / Q000378:metabolism; D001943:Breast Neoplasms / Q000201:enzymology; D045744:Cell Line, Tumor; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D010446:Peptide Fragments / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D018631:ras Proteins / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D010446:Peptide Fragments; D019883:Alkyl and Aryl Transferases; C064911:p21(ras) farnesyl-protein transferase; D018631:ras Proteins