Cells are genetically modified to express a
luminophore, e.g., a modified (F64L, S65T, Y66H)
Green Fluorescent Protein (GFP, EGFP) coupled to a component of an
intracellular signalling pathway such as a
transcription factor, a cGMP- or cAMP-dependent
protein kinase, a
cyclin-,
calmodulin- or
phospholipid-dependent or mitogen-activated
serine / threonin
protein kinase, a
tyrosine protein kinase, or a protein
phosphatase (e.g. PKA, PKC, Erk,
Smad, VASP,
actin, p38, Jnk1, PKG, IkappaB, CDK2, Grk5, Zap70, p85, protein-
tyrosine phosphatase 1C, Stat5,
NFAT, NFkappaB, RhoA, PKB). An influence modulates the
intracellular signalling pathway in such a way that the
luminophore is being redistributed or translocated with the component in living cells in a manner experimentally determined to be correlated to the degree of the influence. Measurement of redistribution is performed by recording of
light intensity,
fluorescence lifetime, polarization,
wavelength shift,
resonance energy transfer, or other properties by an apparatus consisting of e.g. a
fluorescence microscope and a
CCD camera. Data stored as digital images are processed to numbers representing the degree of redistribution. The method can be used as a screening program for identifying a compound that modulates a component and is capable of treating a
disease related to the function of the component.