A bright new light
5 Aug 2010 by Evoluted New Media
Fluorescent probes that allow scientists to monitor the activity of individual cells in real time and target a crucial class of proteins may form the basis of new drug targets.
Fluorescent probes that allow scientists to monitor the activity of individual cells in real time and target a crucial class of proteins may form the basis of new drug targets.
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On the left, a group of FAP-labelled cells glow orange in the presence of a fluorogen dye. After GPCRs are activated, the receptors move to the inside the cell, leaving many fewer on the surface, as shown in the image on the right Credit Carnegie Mellon University |
Scientists from Carnegie Mellon University invented fluromodules, probes consisting of two components; a fluorogen-activating protein (FAP) and a non-fluorescent protein called a fluorogen. FAP is attached to the protein of interest – in this case G protein-coupled receptors (GPCRs) – and the fluorogen is engineered to find to the FAP. Upon meeting they cast a glow which allows researchers to study their location and activity.
GPCRs are popular drug targets because they play a pivotal role in cells’ chemical communication circuits by interacting with neurotransmitters and hormones. They initiate a response and retreat from the cell membrane into the interior. Jonathan Jarvik and colleagues engineered a fluoromodule that would determine when this happens.
They genetically expressed FAP fused to beta2 adrengenic receptor (b2AR), a protein present in the brain, heart, lung and other tissues. When they introduced the fluorogen, it bound to the FAP-tagged GPCR on the cell surface and emitted a bright glow. When activated, the receptor retreated into the cell and fluorescence dimmed.
Jarvik said the biosensor is notable because it looks directly at the receptor and provides a homogeneous assay that can be scaled to screen large numbers of molecules to identify new drug leads.
“Drugs that target GPCRs make up approximately 30% of all pharmaceuticals currently on the market, including some of the most prescribed drugs,” he said, “This prevalence makes assays for the receptors a billion dollar industry.”
The researchers hope the technology can be used across other receptors and cell surface proteins and are currently researching its broader applications.
