α- Epithelial catenin (E-catenin) is an important cell - cell adhesion protein. In this study, we show that α- E-catenin also regulates intracellular traffi c by binding to the dynactin complex component dynamitin. Dynactin-mediated organelle traffi cking is increased in α- E-catenin -/- keratinocytes, an effect that is reversed by expression of exogenous α- E-catenin. Disruption of adherens junctions in low-calcium media does not affect dynactinmediated traffi c, indicating that α- E-catenin regulates traffi c independently from its function in cell - cell adhesion. Although neither the integrity of dynactin - dynein complexes nor their association with vesicles is affected by α- E-catenin, α- E-catenin is necessary for the attenuation of microtubule-dependent traffi cking by the actin cytoskele ton. Because the actin-binding domain of α- E-catenin is necessary for this regulation, we hypothesize that α- E-catenin functions as a dynamic link between the dynactin complex and actin and, thus, integrates the microtubule and actin cytoskeleton during intracellular traffi cking.
ASJC Scopus subject areas
- Cell Biology