Mitsubishi

About: Mitsubishi is a company organization based out in Tokyo, Japan. It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 53115 authors who have published 54821 publications receiving 870150 citations. The organization is also known as: Mitsubishi Group of Companies & Mitsubishi Companies.

Regulation of mitochondrial pyruvate dehydrogenase activity by tau protein kinase I/glycogen synthase kinase 3beta in brain

Abstract: According to the amyloid hypothesis for the pathogenesis of Alzheimer disease, beta-amyloid peptide (betaA) directly affects neurons, leading to neurodegeneration and tau phosphorylation In rat hippocampal culture, betaA exposure activates tau protein kinase I/glycogen synthase kinase 3beta (TPKI/GSK-3beta), which phosphorylates tau protein into Alzheimer disease-like forms, resulting in neuronal death To elucidate the mechanism of betaA-induced neuronal death, we searched for substrates of TPKI/GSK-3beta in a two-hybrid system and identified pyruvate dehydrogenase (PDH), which converts pyruvate to acetyl-CoA in mitochondria PDH was phosphorylated and inactivated by TPKI/GSK-3beta in vitro and also in betaA-treated hippocampal cultures, resulting in mitochondrial dysfunction, which would contribute to neuronal death In cholinergic neurons, betaA impaired acetylcholine synthesis without affecting choline acetyltransferase activity, which suggests that PDH is inactivated by betaA-induced TPKI/GSK-3beta Thus, TPKI/GSK-3beta regulates PDH and participates in energy metabolism and acetylcholine synthesis These results suggest that TPKI/GSK-3beta plays a key role in the pathogenesis of Alzheimer disease

Semiconductor memory device

Abstract: The invention provides a semiconductor memory device which can easily constitute a large-capacity memory system for a compact information terminal at low cost. The semiconductor memory device (RAM) which receives a command from a CPU to read and write data is connected to a storage flash memory for reading and writing data in predetermined access units. The RAM includes a flash interface circuit for generating a control signal required for data access to the flash memory in synchronism with the command from the CPU, and a pseudo-SRAM serving as a memory element which can be randomly accessed. The RAM reads/writes data from/to either the flash memory or the pseudo-SRAM in accordance with the commands from the CPU.