Critical to all forms of life is the ability to temporally regulate cellular processes based on environment/circumstance. Whereas the downstream regulatory processes can involve biochemical modification (phosphorylation, allosteric inhibition, etc.) and/or changes to transcription/translation profiles, the initial “sensing” event occurs predominantly through membrane receptor signaling (Figure 1).
Figure 1. Membrane receptor signaling. Extracellular stimuli are initially “sensed” predominantly through membrane receptors. Transmission of the signal inside the cell can result in regulation via biochemical modifications and or changes to transcription/translation.
As described in the Technology Overview, xCELLigence real time cell analysis (RTCA) interrogates the ability of electrodes in the bottom of E-Plate wells to conduct electric current. Adhesion of cells to these electrodes impedes electric current, providing exquisite sensitivity to (1) the number of cells present, (2) the size/morphology of the cells, and (3) how tightly the cells are interacting with the plate surface. Membrane receptor signaling very often results in biochemical changes that directly, or indirectly, affect one or more of the above three parameters. Real-time impedance monitoring by xCELLigence makes it possible to capture everything from size/shape changes occurring in the first two minutes after GPCR ligand addition to changes in proliferation rate over the 48 hours following growth factor addition. For specific examples of using xCELLigence to study receptor signaling, see: