Proteolytic processing of Src to generate the neurotoxic truncated fragment ΔNSrc is also a pathological event directing neuronal death (18), and we demonstrated the substrate-specific calpain inhibitor Tat-Src could protect against neuronal cell loss in vivo (Fig. 6), small-molecule compounds mimicking TAT-Src peptide in specifically blocking calpain cleavage of Src in neurons (Fig. 6) are potential neuroprotective drug candidates to reduce excitotoxic neuronal loss in neurological disorders. Here, SRC is linked to nervous system disorder.