Detection of phospholipase C-β2 activation by G-protein subunits

Suzanne Scarlata, Loren Runnels, Marlo Rebecchi

Research output: Contribution to journalConference article


Many neurotransmitters and hormones convey their signals into cells via transmembrane receptors that activate heterotrimeric G proteins which in turn activate phospholipase C-β (PLC-β). Activation of PLC-β by the αq and βy subunits of G proteins results in activation of protein kinase C and release of Ca2+ from intracellular stores, which in turn results in a multitude cellular changes. We have recently found that activation of PLC-β by G proteins occurs by lateral association on the membrane surface. Here, we have measured the affinity of the membrane-bound species by fluorescence energy transfer and have conducted time-resolved studies to assess the lifetime of the PLC-G protein complexes in order to understand PLC signaling inside the cell. To better interpret these results, we outline methods to convert the two-dimensional dissociation constant measured for the membrane-bound proteins to a three dimensional one. We also detail calculations to determine the concentrations at which non-specific protein-protein interactions occurs due to membrane crowding. To differentiate between the physical association of PLC-G complexes and activation, we have developed a real-time fluorescence-based PLC-β activity to determine the length of time that PLC-β remains active after G protein dissociation. A model for activation will be presented.

Original languageEnglish (US)
Pages (from-to)76-85
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - Dec 1 1998
Externally publishedYes
EventAdvances in Optical Biophysics - San Jose, CA, United States
Duration: Jan 25 1998Jan 26 1998


All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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