机械力调控的LIMD1相分离对黏着斑成熟和细胞迁移的作用研究

黏着斑是细胞与细胞外基质互作的场所，也是机械力信号传入细胞的重要途径。黏着斑需要经历一个与机械力耦合的成熟过程才能具备细胞-微环境双向交流的功能。这一过程中近千种蛋白被迅速募集，但目前对其时空动态调控的机制还知之甚少。相分离近年来被用以解释无膜细胞器的动态组装过程和分子机制，并已在细胞-细胞紧密连接的形成中被证实发挥重要作用。相分离是否介导黏着斑成熟及力学响应成为本领域极具创新性和挑战性的问题。我们发现了LIMD1蛋白具有力敏感的黏着斑定位并可发生相分离。我们计划以黏着斑成熟过程的调控为核心科学问题，利用前期工作中建立的高通量黏着斑动态分析方法和定向迁移研究体系，全面阐明LIMD1及其(共)相分离对黏着斑成熟过程的影响、对细胞力学感应和定向迁移的作用。本研究将有望建立新的黏着斑成熟理论、拓展相分离的生物学意义，对伤口愈合、免疫应答和肿瘤转移等重要的生理、病理过程具有重要意义。

Cells sense and respond to extra-cellular environment through cell-matrix adhesions. Interestingly, the maturation of focal adhesions (FAs) is reciprocally force-dependent. How this mechano-chemical coordination is achieved at cellular and molecular levels remains enigmatic. Meanwhile, how biomechanical cues in the extracellular environment dictate the status of cell motility is yet to be determined. LIMD1, a member of the LIM domain proteins, localizes to the FAs and has been reported to negatively regulate cell signaling in response to tension. We identified the force sensitive recruitment of LIMD1 to the FAs and discovered the phase separation property of LIMD1 both in vitro and in vivo. Here we propose to study the role of LIMD1 (co)phase separation in focal adhesion maturation and directional cell migration. We propose a model in which localization of LIMD1 to the FAs, triggered by mechanical force, serves as a phase separation hub for assembling and organizing late FA proteins, allowing for effective FA maturation and efficient cellular mechano-transduction. Our study will shed new lights on fields of cellular adhesions and phase separation and will contribute to the understanding of processes involving cell adhesion and migration, including wound healing, immune responses and cancer metastasis.