Abstract
Recent progress in the imaging techniques has made it available to real-timely monitor the dynamics of signaling transduction and cellular function. We have studied the spatial and temporal imaging and control of cellular functions by combining real-time imaging with protein transduction and gene expression. We have developed a new method called Protein Therapy to deliver proteins, peptides and biologically active compounds into eukaryotic cells by poly-arginines protein transduction domain (PTD). Functional peptides fused with 11-arginine (11R) could efficiently penetrate across the plasma membrane and target to specific subcellualr compartments. By real-time imaging we could detect the spatiotemporal transduction of 11R-FITC in live neurons and Hela cells. With such spatial and temporal control of the delivery of functional peptides we could specifically regulate the intracellular signaling and control the physiological and pathological functions. Introduction of calcineurin autoinhibitory peptide with 11R-PTD potently inhibited CaN phosphotase activites and efficiently prevented glutamate-induced neuronal death. Similarly transduction of calpastatin peptide fused with 11R inhibited the activity of calpain. Further we monitored the dynamic movement and morphological changes of mitochondria by expressing mitochondria-targeted fluorescent protein in cultured hippocampal neurons. We found that distinctive mitochondrial changes were regulated by channel specific Ca2+ signaling and these changes control neuronal survival and death. [Jpn J Physiol 54 Suppl:S15 (2004)]
