Tension-induced pore formation in phase-separated lipid membrane and the effect of tension on EGCg-induced pore formation

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K05525
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Biological physics/Chemical physics/Soft matter physics
• Research Institution: Suzuka National College of Technology
• Principal Investigator: Tamba Yukihiro 鈴鹿工業高等専門学校, その他部局等, 准教授 (50436911)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: GUV / ポア形成 / 張力

Outline of Final Research Achievements

We investigated the stability of giant unilamellar vesicles (GUVs) with coexisting liquid-disordered (ld) and liquid-ordered (lo) phases of lipid membranes. Using micropipet aspiration method, the rate constants of tension-induced pore formation in the phase-separated membranes were obtained. The line tension of the pore of lo and ld coexisting phase membrane was almost the same as that of ld phase membrane. Next, we examined the effect of the tension on the EGCg-induced burst of GUVs as a result of pore formation in ld phase membrane using micropipete aspiration method. The fraction of burst of GUVs decreased with increasing the applied tension in the range of low tension which did not induced rupture of aspirated GUVs. We also examined the EGCg-induced fractional change in area of the membranes. Based on these results, we discuss the mechanism of the EGCg-induced pore formation in the ld phase membrane.

Free Research Field

生物物理

Academic Significance and Societal Importance of the Research Achievements

ある種の抗菌性ペプチドなど外来物質は細菌の細胞膜に結合し、その膜に孔（ポア）を空ける。これは最近注目されている自然免疫の一つであるが、この様な外来物質がどの様なメカニズムで生体膜のバリア機能を破壊し膜中にポアを形成するのか、またどの様な構造のポアを誘起するのかについては不明な点が多い。本研究では実際の生体膜を模した物性の異なる相が混在する脂質膜におけるポア形成に着目し、その形成位置や安定性を検討した。また、フラボノイドの一種、茶カテキン・エピガロカテキンガレート(EGCg)が、この様な脂質膜に形成するポアについてその形成メカニズムを検討した。