A bone cancer cell transfected with a fusion gene for GFP-PTHrP. PTHrP is a parathyroid hormone related protein . Localization of PTHrP (here the fusion protien) in cytoplasm or nucleus is dependent on cell cycle phases. This sequence of images show GFP-PTHrP is actively transported from cytoplasm to nucleus after photo-bleaching (FRAP). The assay is useful in investigating a new drug's mechanisms.
This image was taken on the AOMF Two-Photon microscope.

-- Submitted by John Xu, Miikana Therapeutics.