背景回顾：Invasive or penetrative growth is critical for developmental and reproductive processes (e.g., pollen tube penetration of pistils) and disease progression (e.g., cancer metastasis and fungal hyphae invasion). The invading or penetrating cells experience drastic changes in mechanical pressure from the surroundings and must balance growth with cell integrity. 

主要研究：Here, we show that Arabidopsis pollen tubes sense and/or respond to mechanical changes via a cell-surface receptor kinase Buddha's Paper Seal 1 (BUPS1) while emerging from compressing female tissues. 

结果1-突变体：BUPS1-defective pollen tubes fail to maintain cell integrity after emergence from these tissues. 

结果2-模拟：The mechano-transduction function of BUPS1 is established by using a microfluidic channel device mimicking the mechanical features of the in vivo growth path. 

结果3-BUPS1下游：BUPS1-based mechano-transduction activates Rho-like GTPase from Plant 1 (ROP1) GTPase to promote exocytosis that facilitates secretion of BUPS1’s ligands for mechanical signal amplification and cell wall rigidification in pollen tubes. 

结论：These findings uncover a membrane receptor-based mechano-transduction system for cells to cope with the physical challenges during invasive or penetrative growth.

 摘 要 

侵入性或穿透性生长对于发育和生殖过程（如花粉管穿透雌蕊）以及病程（如癌症转移和真菌菌丝侵入）都至关重要。侵入或穿透的细胞经历了来自周围环境的机械压力的剧烈变化，必须平衡生长和细胞完整性之间的平衡。本文中，作者发现拟南芥的花粉管在充满机械压力的雌性组织中进行穿透性生长时，通过细胞表面受体激酶BUPS1来感知并响应机械变化。BUPS1功能缺陷的花粉管，在雌蕊中穿透生长时，不能维持细胞的完整性。作者利用微流控通道装置，模拟体内生长路径的机械力特性，建立了BUPS1的机械转导功能。基于BUPS1的机械转导激活了ROP1 GTP酶，从而促进胞吐，加速BUPS1配基的分泌，从而放大花粉管中的机械信号和细胞壁僵固。本文的研究揭示了一个基于膜受体的机械转导系统，帮助细胞在侵入或穿刺生长过程中应对物理压力。