Cell Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands.
Cell Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands; International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
Cell Rep. 2015 Nov 3;13(5):933-43. doi: 10.1016/j.celrep.2015.09.062. Epub 2015 Oct 22.
Lateral diffusion in the membrane and endosomal trafficking both contribute to the addition and removal of AMPA receptors (AMPARs) at postsynaptic sites. However, the spatial coordination between these mechanisms has remained unclear, because little is known about the dynamics of AMPAR-containing endosomes. In addition, how the positioning of AMPAR-containing endosomes affects synapse organization and functioning has never been directly explored. Here, we used live-cell imaging in hippocampal neuron cultures to show that intracellular AMPARs are transported in Rab11-positive recycling endosomes, which frequently enter dendritic spines and depend on the microtubule and actin cytoskeleton. By using chemically induced dimerization systems to recruit kinesin (KIF1C) or myosin (MyosinV/VI) motors to Rab11-positive recycling endosomes, we controlled their trafficking and found that induced removal of recycling endosomes from spines decreases surface AMPAR expression and PSD-95 clusters at synapses. Our data suggest a mechanistic link between endosome positioning and postsynaptic structure and composition.
在膜中的侧向扩散和内体运输都有助于在突触后位点添加和去除 AMPA 受体 (AMPAR)。然而，这些机制之间的空间协调仍然不清楚，因为关于包含 AMPAR 的内体的动力学知之甚少。此外，包含 AMPAR 的内体的定位如何影响突触的组织和功能从未被直接探索过。在这里，我们使用海马神经元培养物中的活细胞成像来显示细胞内 AMPAR 是在 Rab11 阳性的再循环内体中运输的，这些内体经常进入树突棘，并依赖于微管和肌动蛋白细胞骨架。通过使用化学诱导二聚化系统将驱动蛋白 (KIF1C) 或肌球蛋白 (MyosinV/VI) 马达募集到 Rab11 阳性的再循环内体，我们控制它们的运输，发现诱导再循环内体从棘突中去除会减少突触处的表面 AMPAR 表达和 PSD-95 簇。我们的数据表明，内体定位与突触后结构和组成之间存在机制联系。
