Satoshi P. Tsunoda

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The introduction of two microbial opsin-based tools, channelrhodopsin-2 (ChR2) and halorhodopsin (NpHR), to neuroscience has generated interest in fast, multimodal, cell type-specific neural circuit control. Here we describe a cation-conducting channelrhodopsin (VChR1) from Volvox carteri that can drive spiking at 589 nm, with excitation maximum red-shifted(More)
Accumulation of pathological tau protein is a major hallmark of Alzheimer's disease. Tau protein spreads from the entorhinal cortex to the hippocampal region early in the disease. Microglia, the primary phagocytes in the brain, are positively correlated with tau pathology, but their involvement in tau propagation is unknown. We developed an adeno-associated(More)
Channelrhodopsins (CHR1 and CHR2) are light-gated ion channels acting as sensory photoreceptors in Chlamydomonas reinhardtii. In neuroscience, they are used to trigger action potentials by light in neuronal cells, tissues, or living animals. Here, we demonstrate that Chlamydomonas cells with low CHR2 content exhibit photophobic and phototactic responses(More)
Prx (peroxiredoxin) is a multifunctional redox protein with thioredoxin-dependent peroxidase activity. Prx4 is present as a secretory protein in most tissues, whereas in sexually mature testes it is anchored in the ER (endoplasmic reticulum) membrane of spermatogenic cells via an uncleaved N-terminal hydrophobic peptide. We generated a Prx4 knockout mouse(More)
Aquaporin-1 (AQP1) is a membrane channel that allows rapid water movement driven by a transmembrane osmotic gradient. It was claimed to have a secondary function as a cyclic nucleotide-gated ion channel. However, upon reconstitution into planar bilayers, the ion channel exhibited a 10-fold lower single channel conductance than in Xenopus oocytes and a(More)
ErbB3 receptor tyrosine kinase has been shown to induce tumor progression in several types of cancer through heterodimerization with ErbB2. However, the role of ErbB3 and its ligand heregulin (HRG) in tumor metastasis remains poorly understood. In the present study, we tried to clarify their contributions to the metastasis of ErbB3-overexpressing B16-BL6(More)
Protein folding homeostasis in the endoplasmic reticulum (ER) requires efficient protein thiol oxidation, but also relies on a parallel reductive process to edit disulfides during the maturation or degradation of secreted proteins. To critically examine the widely held assumption that reduced ER glutathione fuels disulfide reduction, we expressed a modified(More)
The F(1)F(0) ATP synthase is the smallest motor enzyme known. Previous studies had established that the central stalk, made of the gamma and epsilon subunits in the F(1) part and c subunit ring in the F(0) part, rotates relative to a stator composed of alpha(3)beta(3)deltaab(2) during ATP hydrolysis and synthesis. How this rotation is regulated has been(More)
Channelrhodopsins (ChRs) are light-gated ion channels that control photomovement of microalgae. In optogenetics, ChRs are widely applied for light-triggering action potentials in cells, tissues, and living animals, yet the spectral properties and photocycle of ChR remain obscure. In this study, we cloned a ChR from the colonial alga Volvox carteri, VChR.(More)
Channelrhodopsin-2 is a light-gated ion channel and a major tool of optogenetics. It is used to control neuronal activity via blue light. Here we describe the construction of color-tuned high efficiency channelrhodopsins (ChRs), based on chimeras of Chlamydomonas channelrhodopsin-1 and Volvox channelrhodopsin-1. These variants show superb expression and(More)