Disease mutations in desmoplakin inhibit Cx43 membrane targeting mediated by desmoplakin–EB1 interactions

Abstract

Mechanisms by which microtubule plus ends interact with regions of cell–cell contact during tissue development and morphogenesis are not fully understood. We characterize a previously unreported interaction between the microtubule binding protein end-binding 1 (EB1) and the desmosomal protein desmoplakin (DP), and demonstrate that DP–EB1 interactions enable DP to modify microtubule organization and dynamics near sites of cell–cell contact. EB1 interacts with a region of the DP N terminus containing a hotspot for pathogenic mutations associated with arrhythmogenic cardiomyopathy (AC). We show that a subset of AC mutations, in addition to a mutation associated with skin fragility/woolly hair syndrome, impair gap junction localization and function by misregulating DP–EB1 interactions and altering microtubule dynamics. This work identifies a novel function for a desmosomal protein in regulating microtubules that affect membrane targeting of gap junction components, and elucidates a mechanism by which DP mutations may contribute to the development of cardiac and cutaneous diseases.