Elucidation of contact-dependent secretory regulation of Vibrio parahaemolyticus T3SS2

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K08829
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Bacteriology (including mycology)
• Research Institution: Nagasaki University (2019); Osaka University (2017-2018)
• Principal Investigator: KODAMA Toshio 長崎大学, 熱帯医学研究所, 教授 (20346133)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 腸炎ビブリオ / 3型分泌装置 / effector / gatekeeper

Outline of Final Research Achievements

The pathogenesis of many Gram-negative pathogens arises from a type III secretion system (T3SS), whereby bacterial proteins, effectors, are directly injected into host cells. The injected effectors then modify the host cell functions. Bacteria need both to recognize host cell attachment and to switch the type of secreted proteins for effective delivery of effector proteins. In this study, we identified gatekeeper proteins that play important roles in a T3SS2 secretion switch of Vibrio parahaemolyticus, a causative agent of food-borne gastroenteritis. We also found that potassium ion (K+), which is present in high concentrations inside the host cell but in low concentrations outside, is a key factor for the secretion switch. Thus, V. parahaemolyticus senses the high intracellular K+ concentration, triggering the effective injection of effectors.

Free Research Field

病原細菌学

Academic Significance and Societal Importance of the Research Achievements

感染症の蔓延は社会にとって大きな脅威である。病原菌の感染機構を明らかにすることは、感染症の予防法、治療法、さらには感染拡大の制御法を考える上で有用なヒントになる。本研究では、食中毒原因菌の一つである腸炎ビブリオの下痢誘導機構の一端が明らかとなった。本研究で着目した3型分泌装置は多くのグラム病原細菌の共通の病原因子として知られている。したがって、本研究で得られた知見は他の病原細菌の制御法を考える上でも有用な情報となり得る。