Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA; Nanobiology Institute, Yale University, West Haven, CT 06516, USA.
Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA.
Cell Rep. 2024 Sep 24;43(9):114725. doi: 10.1016/j.celrep.2024.114725. Epub 2024 Sep 13.
Mechanical forces are transmitted from the actin cytoskeleton to the membrane during clathrin-mediated endocytosis (CME) in the fission yeast Schizosaccharomyces pombe. End4p directly transmits force in CME by binding to both the membrane (through the AP180 N-terminal homology [ANTH] domain) and F-actin (through the talin-HIP1/R/Sla2p actin-tethering C-terminal homology [THATCH] domain). We show that 7 pN force is required for stable binding between THATCH and F-actin. We also characterized a domain in End4p, Rend (rod domain in End4p), that resembles R12 of talin. Membrane localization of Rend primes the binding of THATCH to F-actin, and force-induced unfolding of Rend at 15 pN terminates the transmission of force. We show that the mechanical properties (mechanical stability, unfolding extension, hysteresis) of Rend and THATCH are tuned to form a circuit for the initiation, transmission, and termination of force between the actin cytoskeleton and membrane. The mechanical circuit by Rend and THATCH may be conserved and coopted evolutionarily in cell adhesion complexes.
在裂殖酵母 Schizosaccharomyces pombe 的网格蛋白介导的胞吞作用 (CME) 过程中，机械力从肌动蛋白细胞骨架传递到膜上。End4p 通过与膜（通过 AP180 N 端同源 [ANTH] 结构域）和 F- 肌动蛋白（通过衔接蛋白 talin-HIP1/R/Sla2p 肌动蛋白连接 C 端同源 [THATCH] 结构域）结合，直接在 CME 中传递力。我们表明，THATCH 与 F- 肌动蛋白之间稳定结合需要 7 pN 的力。我们还对 End4p 中的一个结构域 Rend（End4p 中的杆状结构域）进行了表征，该结构域类似于 talin 的 R12。Rend 的膜定位使 THATCH 与 F- 肌动蛋白的结合呈启动状态，而 15 pN 下的力诱导的 Rend 展开终止了力的传递。我们表明，Rend 和 THATCH 的机械特性（机械稳定性、展开延伸、滞后）被调整为在肌动蛋白细胞骨架和膜之间形成力的起始、传递和终止的回路。Rend 和 THATCH 的机械回路可能在细胞黏附复合物中保守并被进化所采用。
