Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
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Special Issue
Volume 89, Issue 6
Displaying 1-4 of 4 articles from this issue
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Reviews
  • Structure and function studies on enzymes with a catalytic carboxyl group(s): from ribonuclease T1 to carboxyl peptidases
    Kenji TAKAHASHI
    2013 Volume 89 Issue 6 Pages 201-225
    Published: June 11, 2013
    Released on J-STAGE: June 11, 2013
    DOIhttps://doi.org/10.2183/pjab.89.201
    JOURNAL FREE ACCESS
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    A group of enzymes, mostly hydrolases or certain transferases, utilize one or a few side-chain carboxyl groups of Asp and/or Glu as part of the catalytic machinery at their active sites. This review follows mainly the trail of studies performed by the author and his colleagues on the structure and function of such enzymes, starting from ribonuclease T1, then extending to three major types of carboxyl peptidases including aspartic peptidases, glutamic peptidases and serine-carboxyl peptidases.

    (Communicated by Shigekazu NAGATA, M.J.A.)
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  • Molecular properties of muscarinic acetylcholine receptors
    Tatsuya HAGA
    2013 Volume 89 Issue 6 Pages 226-256
    Published: June 11, 2013
    Released on J-STAGE: June 11, 2013
    DOIhttps://doi.org/10.2183/pjab.89.226
    JOURNAL FREE ACCESS
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    Muscarinic acetylcholine receptors, which comprise five subtypes (M1-M5 receptors), are expressed in both the CNS and PNS (particularly the target organs of parasympathetic neurons). M1-M5 receptors are integral membrane proteins with seven transmembrane segments, bind with acetylcholine (ACh) in the extracellular phase, and thereafter interact with and activate GTP-binding regulatory proteins (G proteins) in the intracellular phase: M1, M3, and M5 receptors interact with Gq-type G proteins, and M2 and M4 receptors with Gi/Go-type G proteins. Activated G proteins initiate a number of intracellular signal transduction systems. Agonist-bound muscarinic receptors are phosphorylated by G protein-coupled receptor kinases, which initiate their desensitization through uncoupling from G proteins, receptor internalization, and receptor breakdown (down regulation). Recently the crystal structures of M2 and M3 receptors were determined and are expected to contribute to the development of drugs targeted to muscarinic receptors. This paper summarizes the molecular properties of muscarinic receptors with reference to the historical background and bias to studies performed in our laboratories.

    (Communicated by Masanori OTSUKA, M.J.A.)
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  • My career as an immunoglycobiologist
    Donald M. MARCUS
    2013 Volume 89 Issue 6 Pages 257-269
    Published: June 11, 2013
    Released on J-STAGE: June 11, 2013
    DOIhttps://doi.org/10.2183/pjab.89.257
    JOURNAL FREE ACCESS
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    The research program of my laboratory included three major topics: the structures and immunology of human carbohydrate blood group and glycosphingolipid antigens; the tissue distribution, subcellular localization and biosynthesis of glycosphingolipids; and the structural basis of the binding of carbohydrates by antibodies and lectins.

    (Communicated by Kunihiko SUZUKI, M.J.A.)
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  • Neuronal mechanism of epileptogenesis in EL mouse
    Jiro SUZUKI
    2013 Volume 89 Issue 6 Pages 270-280
    Published: June 11, 2013
    Released on J-STAGE: June 11, 2013
    DOIhttps://doi.org/10.2183/pjab.89.270
    JOURNAL FREE ACCESS
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    The convulsions of the EL mouse (EL) were described by Imaizumi et al. in 1954 and were established as epilepsy by Suzuki in 1976. The EL mouse has been kept as an inbred strain and is considered one of the best animal models originated in Japan. The mode of inheritance is autosomal dominant, and environmental risk factors for seizure occurrence are hypothesised to contribute to the polygenic background. Paroxysmal activities in the EL brain arise from the parietal cortex (PCX) and are augmented in the hippocampus, demonstrated by electrophysiology and autoradiography using 2-deoxy glucose when clinical symptoms of seizures appeared. The neurons in the EL PCX, where GABA activity is lower than that of DDY PCX demonstrate increased excitability to proprioceptive sensory input. After repetitive seizure-provoking stimuli, seizures are more easily induced, eventually occurring spontaneously. This phenomenon of “abnormal plasticity” is also observed in the EEG, decreasing GABA activity, expression of the immediately early gene, and various biochemical and molecular processes. This phenomenon is similar to the learning or progressive process of certain neurological diseases.

    (Communicated by Takashi SUGIMURA, M.J.A.)
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