Myosin V facilitates polarised E‐cadherin secretion

Abstract

E‐cadherin has a fundamental role in epithelial tissues by providing cell–cell adhesion. Polarised E‐cadherin exocytosis to the lateral plasma membrane is central for cell polarity and epithelial homeostasis. Loss of E‐cadherin secretion compromises tissue integrity and is a prerequisite for metastasis. Despite this pivotal role of E‐cadherin secretion, the transport mechanism is still unknown. Here we identify Myosin V as the motor for E‐cadherin secretion. Our data reveal that Myosin V and F‐actin are required for the formation of a continuous apicolateral E‐cadherin belt, the zonula adherens. We show by live imaging how Myosin V transports E‐cadherin vesicles to the plasma membrane, and distinguish two distinct transport tracks: an apical actin network leading to the zonula adherens and parallel actin bundles leading to the basal‐most region of the lateral membrane. E‐cadherin secretion starts in endosomes, where Rab11 and Sec15 recruit Myosin V for transport to the zonula adherens. We also shed light on the endosomal sorting of E‐cadherin by showing how Rab7 and Snx16 cooperate in moving E‐cadherin into the Rab11 compartment. Thus, our data help to understand how polarised E‐cadherin secretion maintains epithelial architecture and prevents metastasis.