Yang, W.T., Li, Y.C., Lin, C.M., Tang, W.C., Chen, B.C., Suzuki, E., Hsu, J.C. (2018). Adherens junction-associated pores mediate the intercellular transport of endosomes and cytoplasmic proteins.  Biochem. Biophys. Res. Commun. 505(3): 664--670.

FBrf0240416

Research paper

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.