A Novel Method to Study Localized Chemistries in Cells Using Optical Tweezers

Mor "Myrrh" Sagy
University of Texas, Austin

The study of intracellular processes, such as signal transduction cascades, has long been plagued by the limitations of currently available techniques. Most methods provide limited spatio-temporal resolution of the events of interest, or are so specific as be of little use as general techniques. We are developing a method to perturb a single cell at a specific time and location in varying ways. An optical trap is used to move a submicrometer-diameter particle, covalently coated with protein molecules, into a cell. This particle is held in a chosen location while the response of the cell to the addition of this localized protein is studied.
The enzyme protein kinase A (PKA) is known to play a role in cell differentiation, as its activation leads to axon growth. Therefore, we have designed an experiment to explore the role of PKA in the signaling cascades that lead to axon growth, using the NG108-15 neuroblastoma-glioma fusion cell line as model neural cells. PKA is covalently linked to microparticles, which are individually moved into a cell by the optical tweezers and held at a specific location. Physiological responses to the placement of these particles at different cellular coordinates are under investigation.