Alpha-E-catenin binds to dynamitin and regulates dynactin-mediated intracellular traffic.

Publication Type:

Journal Article

Source:

The Journal of cell biology, Volume 183, Issue 6, p.989-97 (2008)

Keywords:

2008, Actins, ADHERENS JUNCTIONS, alpha Catenin, Animals, Cell Adhesion, Cell Line, Cell Membrane, Cytoskeleton, Human Biology Division, Humans, Intracellular Space, MICE, Microtubule-Associated Proteins, Microtubules, Organelles, Protein Binding, Protein Transport

Abstract:

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