Studies on the physiological functions of TolC, an outer membrane channel protein, in Ensifer meliloti

• Project/Area Number: 25450117
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Applied microbiology
• Research Institution: Ritsumeikan University
• Principal Investigator: Eda Shima 立命館大学, 生命科学部, 助教 (50420005)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Project Status: Completed (Fiscal Year 2015)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2015: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2014: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2013: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
• Keywords: 根粒菌 / 外膜タンパク質 / トランスポーター / TolCタンパク質 / 細胞表層構造 / TolC

Outline of Final Research Achievements

An Ensifer meliloti strain carrying a null tolC mutation shows pleiotropic phenotypes such as high sensitivity to osmotic/salt stress, decreased motility, and reduced exopolysaccharide production. Transcriptomic profiling analysis revealed that the tolC mutation affects expression of a large number of genes, including those encoding enzymes required for lipopolysaccharide synthesis and those involved in signal transduction of stress responses. By the analysis of pseudo-revertants of the tolC mutant, it was suggested that the disrupted lipid homeostasis in the tolC mutant cell envelope results in subsequent activation of several stress-response signal transduction pathways.