Stroke is the sudden loss of brain functions due to disturbance in blood supply to the brain and it is the second most common cause of death worldwide. Ischaemic stroke, which results from occlusion of an artery, accounts for ~85% of stroke cases. Following ischaemic injury, glutamate-induced excitotoxicity along with other pathophysiological mechanisms including peri-infarct depolarization, inflammation and apoptosis-like pathways interplay to induce brain cell death. The non-receptor protein tyrosine kinase, c-Src, which is involved in many cellular signaling pathways is also indispensible to neuronal survival. Paradoxically, previous studies from our group revealed that c-Src is also a key enforcer of excitotoxic neuronal death underpinning ischaemic stroke-induced brain damage. We demonstrated in primary cortical neurons undergoing excitotoxic cell death and in a rat model of stroke that, c-Src is cleaved in the unique domain near its N-terminus by the Ca2+-activated protease calpain to form a ~52 kDa truncated fragment. Lentiviral expression of the recombinant truncated c-Src fragment (Src∆N) was sufficient to induce cell death, suggesting its neurotoxic function. Pre-treatment of cultured primary cortical neurons with a membrane-permeable peptide (TAT-Src peptide) derived from the unique domain of c-Src effectively prevents calpain cleavage and protects against neuronal death following glutamate over-stimulation. Thus we hypothesise that this calpain mediated cleavage of c-Src is a key event underpinning excitotoxic neuronal death and this Src∆N is a pro-death signalling protein that functions to induce neuronal death. The aim of my project is to delineate the molecular mechanism by which this Src∆N induces neuronal death. Specifically, I propose to identify the cellular proteins that bind to and are phosphorylated by Src∆N in neurons. I also like to validate the neuroprotective role of this peptide in an animal model of stroke. Results of my proposed studies will shed new light on the molecular basis of neuronal death in excitotoxicity and may facilitate the development of new therapeutic strategies to subdue brain injury in acute ischaemic stroke.