液泡在相分离的活性区凝聚物表面上的连接。
Vesicle Tethering on the Surface of Phase-Separated Active Zone Condensates.
机构信息
Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany.
出版信息
Mol Cell. 2021 Jan 7;81(1):13-24.e7. doi: 10.1016/j.molcel.2020.10.029. Epub 2020 Nov 16.
Tethering of synaptic vesicles (SVs) to the active zone determines synaptic strength, although the molecular basis governing SV tethering is elusive. Here, we discover that small unilamellar vesicles (SUVs) and SVs from rat brains coat on the surface of condensed liquid droplets formed by active zone proteins RIM, RIM-BP, and ELKS via phase separation. Remarkably, SUV-coated RIM/RIM-BP condensates are encapsulated by synapsin/SUV condensates, forming two distinct SUV pools reminiscent of the reserve and tethered SV pools that exist in presynaptic boutons. The SUV-coated RIM/RIM-BP condensates can further cluster Ca channels anchored on membranes. Thus, we reconstitute a presynaptic bouton-like structure mimicking the SV-tethered active zone with its one side attached to the presynaptic membrane and the other side connected to the synapsin-clustered SV condensates. The distinct interaction modes between membraneless protein condensates and membrane-based organelles revealed here have general implications in cellular processes, including vesicular formation and trafficking, organelle biogenesis, and autophagy.
突触小泡 (SVs) 与活性区的连接决定了突触强度,尽管控制 SV 连接的分子基础仍难以捉摸。在这里,我们发现小单层囊泡 (SUVs) 和来自大鼠大脑的 SV 通过相分离在由活性区蛋白 RIM、RIM-BP 和 ELKS 形成的浓缩液滴表面上包被。值得注意的是,SUV 包被的 RIM/RIM-BP 凝聚物被 synapsin/SUV 凝聚物包裹,形成两个不同的 SUV 池,让人联想到存在于突触前末梢的储备和连接的 SV 池。SUV 包被的 RIM/RIM-BP 凝聚物可以进一步聚集锚定在膜上的 Ca 通道。因此,我们重建了一个类似于突触前末梢的结构,其一侧附着在突触前膜上,另一侧与聚集了 synapsin 的 SV 凝聚物相连,模拟了 SV 连接的活性区。这里揭示的无膜蛋白凝聚物和基于膜的细胞器之间的独特相互作用模式在包括囊泡形成和运输、细胞器发生和自噬在内的细胞过程中具有普遍意义。