14-3-3γ-mediated transport of plakoglobin to the cell border is required for the initiation of desmosome assembly in vitro and in vivo

The regulation of cell-cell adhesion is important for the processes of tissue formation and morphogenesis. Here, we report that loss of 14-3-3 gamma leads to a decrease in cell-cell adhesion and a defect in the transport of plakoglobin and other desmosomal proteins to the cell border in HCT116 cells and cells of the mouse testis. 14-3-3 gamma binds to plakoglobin in a PKC mu-dependent fashion, resulting in microtubule-dependent transport of plakoglobin to cell borders. Transport of plakoglobin to the border is dependent on the KIF5B-KLC1 complex. Knockdown of KIF5B in HCT116 cells, or in the mouse testis, results in a phenotype similar to that observed upon 14-3-3 gamma knockdown. Our results suggest that loss of 14-3-3 gamma leads to decreased desmosome formation and a decrease in cell-cell adhesion in vitro, and in the mouse testis in vivo, leading to defects in testis organization and spermatogenesis.