The cytoplasmic kinases that transmit the signal from the plasma membrane to various MAP kinase proteins include the MAP/Extracellular signal-regulated kinase (ERK) Kinase Kinase (MEKK) proteins. To date, at least four MEKK proteins have been identified based on a homology to similar protein kinases found in the budding yeast, Saccharomyces cerevisiae. However, the extracellular molecules that regulate the MEKK proteins remain largely undefined in mammalian cells. A major focus in the Vaillancourt laboratory is the characterization of MEKK4 in cellular signal transduction pathways.
Current research focuses on the regulation of MEKK4 by the growth factor, heregulin, which activates the HER2/HER3 receptor signaling pathway. Notably, activation of the HER2/HER3 pathway is critical in some forms of breast cancer thus implicating MEKK4 in breast cancer cell signaling. Activation of breast cancer cells with heregulin results in synthesis of lactate and extracellular secretion of lactate which creates a pH changed in the extracellular environment. Current students are investigating the role of extracellular lactate in breast cancer cell biology.
BA, Biology, St. Anselm College (New Hampshire), 1984
PhD, Pharmacology, University of Wisconsin, Madison, 1992