Radiation-induced expression of N-terminal-deleted RhoGDIbeta: its biological relevance and applicability of individual radiation-risk assessment

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K00556
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Risk sciences of radiation and chemicals
• Research Institution: Prefectural University of Hiroshima
• Principal Investigator: TATSUKA MASAAKI 県立広島大学, 生命環境学部, 教授 (50216991)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 放射線被曝 / バイオドジメトリ

Outline of Final Research Achievements

RhoGDIbeta is an intracellular signaling protein that regulates Rho family GTPases. RhoGDIbeta is highly expressed in epithelial and hematopoietic cells. When exposed to radiation, RhoGDIbeta is truncated at the N-terminus and translocated from the cell membrane to the cytoplasm. Here, we have demonstrated that the truncated protein is accumulated and affects mitotic spindle orientation via Cdc42 inhibition in radiation-exposed and regrowing HeLa cells. Additionally, we have found that the truncated protein can be detected in the thymus of mice after X-irradiation, suggesting its potential as biomarker for radiation risk assessment.

Free Research Field

放射線生物学

Academic Significance and Societal Importance of the Research Achievements

RhoGDIbetaは細胞内シグナル伝達分子のひとつとして、RhoファミリーGタンパク質を制御する。alpha、beta、gammaの3種類が存在するRhoGDIの中で、RhoGDIbetaのみに3型カスパーゼ切断サイトが存在するが、その切断後の生理機能には不明の点の多かった。本研究において、ゲノムストレス後の再増殖過程にある細胞に分裂軸制御との関係において生理的機能のあることを見つけた学術的意義は大きい。また、また、その発現が、電離放射線照射後の白血球に検出可能性であることを見つけており、放射線被曝後の健康管理に役立つ可能性を見出した点での社会的意義も大きい。