2013 Fiscal Year Final Research Report
Functions of vacuolar H+-ATPases and voltage-gated proton channels coexisted in the plasma membrane of osteoclasts
| Project/Area Number |
23390043
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General physiology
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| Research Institution | Osaka City University |
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Principal Investigator |
KUNO Miyuki 大阪市立大学, 医学(系)研究科(研究院), 准教授 (00145773)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAI Hiromu 大阪市立大学, 大学院・医学研究科, 研究員 (90382192)
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| Research Collaborator |
海住 太郎 , 学部学生
李 光帥 , 大学院学生
川脇 順子 , 共同研究室職員
日野 佳子 , 研究補佐員
森浦 芳枝 , 研究補佐員
清水 有希子 , 研究補佐員
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| Project Period (FY) |
2011-04-01 – 2014-03-31
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| Keywords | 生理学 / 生体分子 / 細胞・組織 / 生理活性 / シグナル伝達 / プロトン |
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| Research Abstract |
Osteoclasts express two types of electrogenic H+-selective transport mechanisms at the plasma membrane, that is, vacuolar H+-ATPases (V-ATPases) and voltage-gated proton channels. Identifying these H+ currents in single cells under the whole-cell clamp configuration, we showed that V-ATPases were predominant at physiological intracellular pH (>7.0) and membrane potentials (<-20 mV), but that H+ efflux via the H+ channels exceeded those of V-ATPases at voltages higher than the activation threshold, suggesting that the two mechanisms switch their roles quickly. The increase in intracellular pH via V-ATPases inhibited activation of nearby H+ channels, but not vice versa. Elevation of intracellular pH, either by weak bases or V-ATPases, facilitated dynamin-dependent endocytic internalization of H+ channels. The data presented an idea of the reserving pool for H+ channels and suggested novel mechanisms for interaction between V-ATPases and H+ channels in osteoclasts.
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