During my tenure in Dr. Lombroso’s lab, my research focused on understanding the molecular mechanisms involved in the regulation of the neuron-specific tyrosine phosphatase, STEP. The findings established that reversible phosphorylation plays a role in regulating the activity of STEP. The two neurotransmitters dopamine and glutamate regulate the phosphorylation status and activity of STEP (J. Neurosci., 2000; Nat. Neurosci., 2003). The studies further demonstrated that ERK MAP kinase is a substrate of STEP. Based on these findings I proposed that STEP might play a role in the regulation of fear memory formation through its regulation of ERK and received the NARSAD Young Investigator Award in 2004 (Biol. Psych., 2007). In collaboration with Pfizer I also generated the STEP knockout mice, which we later used to demonstrate that knockdown of STEP leads to increased basal activation of ERK (Synapse, 2009). In addition, I also participated in several collaborative research projects, which established the role of STEP in the regulation of NMDA receptor function (Neuron, 2002; PNAS, 2005; Nat. Neurosci., 2005). Current research in my laboratory at the University of New Mexico focuses on the role of STEP in modulating signaling pathways involved in neurodegenerative disorders related to excitotoxicity, with emphasis on cerebral ischemia and Huntington’s chorea.