Our objective is to quantitatively measure the activity of proteins in cellular signaling networks to understand the relationships of these intracellular pathways in regulating cell health and disease. These networks are composed of interacting proteins and small molecules that work together in a concerted manner to regulate the cell in response to its environment. Despite the importance of these key signaling molecules in controlling the behavior of cells, most of these proteins and metabolites can not be quantified in single cells. There is a need throughout biology for new technologies to identify and understand the molecular circuits within single cells. A research goal is to develop new methods that will broaden the range of measurements possible at the single-cell level and then to utilize these methods to address fundamental biologic questions. We are pursuing this task by bringing to bear diverse techniques from chemistry, physics, biology and engineering to develop new analytical tools to track signal transduction within individual cells. Our research is a multidisciplinary program for the development and application of new analytical methods with two main focus areas: 1) techniques to monitor cellular signaling, and 2) microfabricated cellular analysis systems.

A major focus is the quantitative measurement of the enzymatic activity of signal transduction proteins in cells. A micro-analytical technology and biochemical assay that enables the activity of one or more enzymes to be measured simultaneously in a single cell has been pioneered by the laboratory. Current work is extending this novel single-cell assay system beyond protein kinase signaling to phosphorylation of lipid second messengers and palmitoylation of proteins. A number of collaborations are in place studying cancer-relevant signal transduction mechanisms including the identification of resistance to kinase inhibitors in patients with chronic myelogenous leukemia (CML). Another focus of the group is microfabricated devices to analyze signaling in cells. The laboratory is developing polymer-based devices for the manipulation and analysis of live cells. These efforts include the development of disposable yet integrated micro-systems for chemical analysis of cells from patients with leukemia, and high-throughput sampling and performance of chemical separations of single cells.

An additional facet of the lab involves the use of state-of-the-art microfabrication techniques and chemical surface modifications to produce a platform technology for the analysis, selection, and collection of individual cells and colonies. This work addresses a fundamental need in almost all areas of biomedical research- the ability to separate single or colonies of cells from within a heterogeneous population. The technology enables arrays of cells growing adherently to be screened for a particular characteristic followed by collection of the desired cells while the cells remain adherent to their growth surface. Ongoing work in this area includes efforts to rapidly establish stable genetically engineered cell lines as well as sorting cells based on their temporal behavior. A future goal is to extend this method the collection of cancer stem cells from small sample sizes for example biopsies from mice or humans.