The Pelet Lab uses microscopy techniques to study the behavior of single cells. Isogenic cells subjected to the same stimulus can display striking differences in the activation of signaling proteins or in the expression of down-stream genes. We use these differences to understand the underlying mechanisms regulating these signal transduction pathways.

In this video, yeast cells were stressed with 0.2M NaCl. These cells have been tagged with fluorescent proteins. The histones were tagged with a CFP (blue) to localize the nuclei of the cell. The MAPK Hog1 is tagged with mCherry (red) to observe the activation of the signaling cascade. The cells also bear a fluorescent expression reporter (green) which is not expressed in vegetative cells but is strongly induced upon osmotic stress. The quantification of this type of time lapse movies allows to correlate the activity of various elements of a signal transduction cascade in individual cells.