北京大学定量生物学中心

学术报告 

题    目: Assembly of tight junction belts by surface condensation

报告人: 赵雪萍博士

宁波诺丁汉大学理工学院数学系助理教授

时  间: 11月10日（周一）13:00-14:00

地    点: 吕志和楼B101

主持人: 齐志 教授

摘要:

At the cell-cell contact site of the living cell membrane, Tight junctions form to seal tissues. Assembly of Tight junctions involves oligomerization of membrane receptors, surface binding, and phase separation of cytosolic scaffold proteins. Interestingly, this surface phase separation process occurs in the undersaturated cytosolic scaffold protein concentration. The underneath mechanism is not explored yet. Here we investigate why the surface phase separation happens at a concentration far below the saturation level and explore how the receptor controls the shape and spatial localization of tight junctions. We derive a thermodynamic theory for a three-dimensional cytosolic domain in the presence of a two-dimensional flat membrane. Protein molecules in the cytosolic domain can not only diffuse freely but also bind to the membrane, forming a membrane-bound layer. Combining the experiments and theory, we find that strong binding affinity facilitates the surface phase separation in the two-dimensional membrane at very low cytosolic concentration. Moreover, total receptor amount and oligomerization control the pattern of surface condensates in the membrane. Our work suggests that surface binding combined receptor oligomerization represents a versatile mechanism to control the formation of the protein-rich domain at intra-cellular surfaces.

KEY WORDS:

Liquid-liquid phase separation; Tight junction; Membrane phase separation; Surface binding; Thermodynamic theory.

REFERENCES

1. Zhao X., et al. New Journal of Physics. 2024 26, 103025.

2. Sun D., et al. Developmental Cell. 2024.

3. Zhao X., et al. New Journal of Physics. 2021 23(12), 123003.

4. Beutel O., et al. Cell. 2019 179(4):923-936.e11.

报告人简介：

赵雪萍博士于2018年毕业于美国南卡罗来纳大学数学系，师从王奇教授，主要从事基于能量变分原理的相场模型建模与偏微分方程保结构数值算法研究。2019年至2021年，赵博士在德国德累斯顿马克斯·普朗克研究所担任研究员，与Frank Jülicher 教授和 Christoph A. Weber 教授合作，开展生物膜相关液-液相分离系统的数学物理建模及生物物理理论研究。2022年，赵博士在厦门大学担任助理研究员，与沈捷教授（宁波东方理工大学数学科学学院）合作，继续从事保结构数值算法相关研究。自2023年2月起，赵博士加入宁波诺丁汉大学理工学院数学系，任助理教授、博士生导师，并先后入选浙江省高层次人才、宁波市领军人才。截至目前，赵雪萍博士已在 PNAS、Developmental Cell、Journal of Computational Physics、Journal of Scientific Computing、New Journal of Physics、Nucleic Acids Research 等高影响力期刊发表SCI论文10余篇；主持国家自然科学基金项目1项、宁波市甬江基金项目1项。