Interdisciplinary Program for Biomedical Sciences (IPBS) | Osaka University, Institute for Academic Initiatives, Program for Leading Graduate Schools

A research paper by Kouhei Takeshita, PhD, our own program staff, has been accepted by the journal, Nature Structure & Molecular Biology, in the 2014 March issue.
 

Congratulations to Assistant Professor Kouhei Takeshita!

Research Abstract

Electrical signals play critical roles in heart beating, sensation, memory and metabolism.  Voltage-gated ion channels are key proteins that function in cellular membranes for electrical signals.  Hv1 (VSOP) is the unique ion channel protein that was discovered in Japan.  It has a voltage-sensor domain (VSD) with dual roles of voltage sensing and proton permeation. Its gating of proton conduction pathway is sensitive to pH gradient and extracellular Zn²⁺. We succeeded to solve a crystal structure of mouse Hv1 in the resting state at 3.45 Å resolution. The structure showed a ‘closed Wagasa (Japanese umbrella)’ shape with a long helix running through the cell membrane to the cytoplasm and featured a wide inner-accessible vestibule. Voltage sensing amino acids on the protein were located below the phenylalanine-containing “gascket” region in the center of membrane, indicating that structure was in resting state. The extracellular region of each protomer coordinated a Zn²⁺, which is rich in seminal fluid to suppress sperm motility before ejaculation. These findings provide a platform for understanding the general principles of electrical signals in neuron and muscle, and pH homeostasis in blood cells.

For more, please visit related links below.

http://www.med.osaka-u.ac.jp/pub/phys2/okamura/research/presenteng.html

http://www.protein.osaka-u.ac.jp/rcsfp/supracryst/en/info/bl44xu.html

Institute for Academic Initiatives
Interdisciplinary Program for Biomedical Scienses (IPBS)
Kohei Takeshita, Ph.D.
Specially-Appointed Assistant Professor