Institute of Molecular Medicine, Department of Life Science, National Tsing Hua University, Hsinchu, 30013, Taiwan.
Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan.
Biochem Biophys Res Commun. 2018 Nov 2;505(3):664-670. doi: 10.1016/j.bbrc.2018.09.129. Epub 2018 Oct 2.
Intercellular endosomes (IEs) are endocytosed vesicles shuttled through the adherens junctions (AJs) between two neighboring epidermal cells during Drosophila dorsal closure. The cell-to-cell transport of IEs requires DE-cadherin (DE-cad), microtubules (MTs) and kinesin. However, the mechanisms by which IEs can be transported through the AJs are unknown. Here, we demonstrate the presence of AJ-associated pores with MTs traversing through the pores. Live imaging allows direct visualization of IEs being transported through the AJ-associated pores. By using an optogenetic dimerization system, we observe that the dimerized IE-kinesin complexes move across AJs into the neighboring cell. The AJ-associated pores also allow intercellular movement of soluble proteins. Importantly, most epidermal cells form dorsoventral-oriented two-cell syncytia. Together, we present a model in which an AJ-associated pore mediates the intercellular transport of IEs and proteins between two cells in direct contact.
细胞间内体（IEs）是在果蝇背腹闭合过程中通过两个相邻表皮细胞之间的黏着连接（AJs）穿梭的内吞小泡。IEs 的细胞间运输需要 DE-钙黏蛋白（DE-cad）、微管（MTs）和驱动蛋白。然而，IEs 如何通过 AJs 进行运输的机制尚不清楚。在这里，我们证明了存在与 MT 穿过的 AJ 相关的孔，并且可以通过活细胞成像直接观察到 IEs 通过 AJ 相关的孔进行运输。通过使用光遗传学二聚化系统，我们观察到二聚化的 IE-驱动蛋白复合物穿过 AJ 进入相邻细胞。AJ 相关的孔还允许可溶性蛋白在细胞间运动。重要的是，大多数表皮细胞形成背腹向的双细胞合胞体。综上所述，我们提出了一个模型，其中 AJ 相关的孔介导两个直接接触的细胞之间 IEs 和蛋白质的细胞间运输。
