Photoproteins: important new tools in drug discovery.
The G protein-coupled receptor (GPCR) family is a major target for drug discovery, and most, if not all, GPCRs can couple to Ca2+ signaling. Consequently, there are a number of cellbased, primary, high-throughput screening (HTS) assays used for drug discovery that assess changes in intracellular Ca2+ as a functional readout of GPCR activation. Historically, changes in intracellular Ca2+ levels have been readily detected using fluorescent dyes that emit light in proportion to changes in intracellular Ca2+ concentration. An alternative approach to indirectly measure changes in Ca2+ concentrations involves the use of recombinantly expressed biosensor photoproteins, of which aequorin is a prototypic example. These biosensors have the advantage that they provide an intense luminescent signal in response to elevations in intracellular Ca2+. This exquisite sensitivity, the high signal-to-noise ratios, and the ability to target expression to discrete subcellular sites (in order to detect Ca2+ microdomains) have made photoproteins a principal choice in a wide range of GPCR drug discovery programs. Photoproteins are also finding increasing use in detecting activation of other molecular target classes such as ligand-gated ion channels and transporters. This review focuses upon the use of calcium photoproteins principally for use in GPCR drug discovery and HTS.
Eglen
Richard M
RM
Bio-discovery, PerkinElmer Life and Analytical Sciences, Waltham, MA 02451, USA. richard.eglen@perkinelmer.com
Reisine
Terry
T
D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000235:genetics / Q000502:physiology; D015195:Drug Design; D005456:Fluorescent Dyes; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics* / Q000502:physiology*; D010600:Pharmacology / Q000639:trends*; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000502:physiology; D012106:Research
D005456:Fluorescent Dyes; D008164:Luminescent Proteins; D043562:Receptors, G-Protein-Coupled; D002118:Calcium