Molecular and Cellular Neurosciences

Laboratory of Neural Membrane Biology

Shigeo Takamori, Ph.D., D.V.M

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Synaptic vesicles (SVs) are the storage organelle for neurotransmitters and undergo exocytosis for vesicular release, therefore play an important role in synaptic transmission. SVs are equipped with various types of membrane-associated proteins, such as pumps, transporters, and many distinct families of proteins for membrane trafficking and fusion, therefore it is fundamental to understand how these membrane proteins operate in concert with other proteins at the presynaptic terminals and contribute to the execution and regulation of synaptic transmission.

We have been primarily interested in the mechanism of how neurotransmitters are sequestered and stored in SVs, and how the amount of neurotransmitters is determined and regulated. By taking advantage of the identification of vesicular neurotransmitter transporters, we have been developing a biochemical reconstitution system for the recombinant transporter proteins by which we can monitor transporter activity in separation from other cellular components. We apply this technique for the structure-function analysis of the transporter proteins to understand transport mechanism. Furthermore, we are interested in molecular machinery required for SV formation during brain development, and how SV proteins, including vesicular transporters, are properly conveyed to the presynaptic terminals and thereafter sorted into SVs.

To address to these fundamental questions, we combine biochemical approach, cell biological and biophysical techniques, molecular genetics, and an optical imaging technique.

Research topics

1. Bioenergetics of neurotransmitter uptake into synaptic vesicles
2. Molecular mechanism for synaptic vesicle acidification
3. Molecular anatomy of neuronal large dense core vesicles
4. Molecular basis for neurite, synapse, and SV formation

Selected publications

1. Egashira Y., Takase M., Watanabe S., Ishida J., Fukamizu A., Kaneko R., Yanagawa Y. & Takamori S. (2016) Unique pH dynamics in GABAergic synaptic vesicles illuminates the mechanism and kinetics of GABA loading.Proc. Natl. Acad. Sci. USA. 113(38):10702-7.
2. Tsujimura K., et al. (2015) miR-199a Links MeCP2 with mTOR Signaling and Its Dysregulation Leads to Rett Syndrome Phenotypes. Cell Rep. 12:1-15.
3. Egashira Y., Takase M. & Takamori S. (2015) Monitoring of Vacuolar-type H+ ATPase-mediated Proton Influx into Synaptic Vesicles. J. Neurosci. 35(8):3701-10.
4. Kumamaru E., Egashira Y., Takenaka R. & Takamori S. (2014) Valproic acid selectively suppresses the formation of inhibitory synapses in cultured cortical neurons. Neurosci Lett. 569, 142-7.
5. Schenck S., Wojcik S.M., Brose N., & Takamori S. (2009) A chloride conductance in VGLUT1 underlies maximal glutamate loading into synaptic vesicles. Nat. Neurosci. 12, 156-162.
6. Takamori S. (2006) VGLUT:‘exciting’times for glutamatergic research? Neurosci. Res. 55, 343-51 (Review article).
7. Takamori S., et. al. (2006) Molecular anatomy of a trafficking organelle. Cell 127, 831-46.
8. Wojcik S.M., Rhee J.S., Herzog E., Sigler A., Jahn R., * Takamori S., * Brose N. & * Rosenmund C. (2004) An essential role for vesicular glutamate transporter 1 (VGLUT1) in postnatal development and control of quantal size. Proc. Natl. Acad. Sci. USA. 101, 7158-63. * corresponding authors.
9. Stobrawa S.M., et al. (2001) Disruption of ClC-3, a chloride channel expressed on synaptic vesicles, leads to a loss of the hippocampus. Neuron 29, 185-196.
10. Takamori S., Rhee J.S., Rosenmund C. & Jahn R. (2000) Identification of a vesicular glutamate transporter that defines a glutamatergic phenotype in neurons. Nature 407, 189-194.

Members

Shigeo Takamori, Ph.D., D.V.M. (Principal investigator, Professor)
Kyoko Hanawa, Ph.D. (Research associate professor)
Hiroyuki Kawano, Ph.D. (Research assistant professor）

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