Kumamoto University

About: Kumamoto University is a education organization based out in Kumamoto, Kumamoto, Japan. It is known for research contribution in the topics: Cancer & Population. The organization has 19602 authors who have published 35513 publications receiving 901260 citations. The organization is also known as: Kumamoto Daigaku.

Ca2+– and Calmodulin‐Dependent Phosphorylation of Microtubule‐Associated Protein 2 and t Factor, and Inhibition of Microtubule Assembly

Abstract: Microtubule-associated proteins (MAPs) were phosphorylated by a Ca2+– and calmodulin-dependent protein kinase from rat brain cytosol. The maximal amount of phosphate incorporated into MAPs was 25 nmol of phosphate/mg protein. A Ka value of the enzyme for calmodulin was 57.0 nM, with MAPs as substrates. Among MAPs, MAP2 and t factor were phosphorylated in a Ca2 +-and calmodulin-dependent manner. The phosphorylation of MAPs led to an inhibition of microtubule assembly in accordance with its degree. This reaction was dependent on addition of the enzyme, Ca2+, and calmodulin, and had a greater effect on the initial rate of microtubule assembly rather than on the final extent. The critical tubulin concentration for microtubule assembly was unchanged by the MAPs phosphorylation. Therefore assembly and disassembly of brain microtubule are regulated by the Ca2+- and calmodulin-dependent protein kinase that requires only a nanomolar concentration of calmodulin for activation.

Functional Organogel Based on a Salicylideneaniline Derivative with Enhanced Fluorescence Emission and Photochromism

Abstract: A new organogelator based on a salicylideneaniline derivative with cholesterol moieties was synthesized, and it was proposed that it could gelate various organic solvents, such as 1-butanol, 1-octanol, butyl acetate, tetrachloromethane, benzene, toluene through combination with a gelation test. From the results of analysis by UV/Vis absorption, circular dichroism (CD), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies and semiempirical (AM1) calculations, we believed that the gelator molecules could self-assemble into left-handed helical nanofibers through unimolecular layer packing, which further twisted into the thicker fibers and constructed 3D networks in the gel phase. Interestingly, the organogel exhibited strong fluorescence enhancement relative to a solution of the same concentration because of the formation of J aggregations. Meanwhile, photochromism of the organogel could take place under UV-light irradiation. Both strong fluorescence emission and photochromism properties were concurrent in one system based on a salicylideneaniline derivative. It was suggested that the self-assembly of the functional organogelator could lead to unique photophysical properties.

Immunohistochemical localization of Ca2+/calmodulin-dependent protein kinase II in rat brain and various tissues.

Abstract: Polyclonal antibodies against Ca2+/calmodulin-de-pendent protein kinase II (CaM kinase II) of rat brain were prepared by immunizing rabbits and then purified by antigen-affinity column The antibodies which recognized both sub-units of the enzyme with MrS 49K and 60K were used for the study on the distribution of CaM kinase II in formalin-fixed, paraffin-embedded tissues In the brain, a light-microscopic study demonstrated strong immunoreactivity in neu-ronal somata and dendrites and weak immunoreactivity in nuclei The densely stained regions included cerebral cortex, hippocampal formation, striatum, substantia nigra, and cer-ebellar cortex In substantia nigra, neurites were stained, but not neuronal somata Electron microscopy revealed that the immunoreactive product was highly concentrated at the postsynaptic densities In addition to neurons, weak immunoreactivity was also demonstrated in glial cells, such as as-trocytes and ependymal cells of ventricles and epithelial cells of choroid plexus In other tissues, strong immunoreactivity was observed in the islet of pancreas and moderate immunoreactivity in skeletal muscle and kidney tubules Immunoreactivity was demonstrated in all of the tissues tested The results suggest that CaM kinase II is widely distributed in the tissues

Stabilized β-Catenin Functions through TCF/LEF Proteins and the Notch/RBP-Jκ Complex To Promote Proliferation and Suppress Differentiation of Neural Precursor Cells

Abstract: The proliferation and differentiation of neural precursor cells are mutually exclusive during brain development. Despite its importance for precursor cell self renewal, the molecular linkage between these two events has remained unclear. Fibroblast growth factor 2 (FGF2) promotes neural precursor cell proliferation and concurrently inhibits their differentiation, suggesting a cross talk between proliferation and differentiation signaling pathways downstream of the FGF receptor. We demonstrate that FGF2 signaling through phosphatidylinositol 3 kinase activation inactivates glycogen synthase kinase 3beta (GSK3beta) and leads to the accumulation of beta-catenin in a manner different from that in the Wnt canonical pathway. The nuclear accumulated beta-catenin leads to cell proliferation by activating LEF/TCF transcription factors and concurrently inhibits neuronal differentiation by potentiating the Notch1-RBP-Jkappa signaling pathway. beta-Catenin and the Notch1 intracellular domain form a molecular complex with the promoter region of the antineurogenic hes1 gene, allowing its expression. This signaling interplay is especially essential for neural stem cell maintenance, since the misexpression of dominant-active GSK3beta completely inhibits the self renewal of neurosphere-forming stem cells and prompts their neuronal differentiation. Thus, the GSK3beta/beta-catenin signaling axis regulated by FGF and Wnt signals plays a pivotal role in the maintenance of neural stem/precursor cells by linking the cell proliferation to the inhibition of differentiation.