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

Abstract

The regulation of cell-cell adhesion is important for the processes of tissue formation and morphogenesis. Here we report that loss of 14-3-3γ leads to a decrease in cell-cell adhesion and a defect in the transport of plakoglobin (PG) and other desmosomal proteins to the cell border in HCT116 cells and in the mouse testis. 14-3-3γ binds to PG in a PKCμ dependent fashion resulting in microtubule dependent transport of PG to the border. Transport of PG 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 with 14-3-3γ knockdown. Our results suggest that loss of 14-3-3γ leads to decreased desmosome formation and a decrease in cell-cell adhesion in vitro and in vivo in the mouse testis leading to defects in testis organization and spermatogenesis.

14-3-3σ Gene Loss Leads to Activation of the Epithelial to Mesenchymal Transition Due to the Stabilization of c-Jun Protein

“…Therefore, these are two distinct molecular mechanisms, and they reflect the diversity of mechanisms by which the 14-3-3 protein family regulates cellular pathways. These results are also consistent with data from our laboratory and from other laboratories suggesting that different 14-3-3 isoforms form complexes with and alter the function of different ligands, leading to differences in phenotype both in cells in culture and in mouse models (70,(82)(83)(84)(85).…”

“…Immunofluorescence and Confocal Microscopy-Immunofluorescence with antibodies against plakoglobin, desmocollin2/3, desmoglein2, HA, plakophilin3, desmoplakin, ZO1, E-cadherin, ␤-catenin, ␣-tubulin, and keratin8 were performed as described (66,69,70). Vimentin (Sigma; dilution, 1:500) or N-cadherin (BD Transduction Laboratories; dilution, 1:10) were immunostained using methanol fixation as described (66).…”

“…Reverse Transcription-PCR and Quantitative Real Time PCR-Reverse transcription assays and quantitative real time PCR were performed as described (70,72). Primers used for both RT-PCR and quantitative real time PCR for PKP3, CK8, CK18, vimentin, c-Jun, and different 14-3-3 isoforms were described previously (65,72,73).…”

14-3-3 recruits keratin intermediate filaments to mechanically sensitive cell-cell contacts

“…This suggests that there is a scaffold intermediate that may facilitate interaction between 14-3-3/keratin protein complexes and other molecules of the cell-cell junction, and which may play a role in the reorganization event. 14-3-3 has been demonstrated to associate with a number of molecules important for the linkage of cytokeratins to the cell-cell adhesion (Acehan et al, 2008) including plakoglobin (Sehgal et al, 2014;Vishal et al, 2018) and plakophilin (Jin et al, 2004;Roberts et al, 2013).…”

“…14-3-3 homo-and heterodimers have been shown to exert control over target substrates by alternatively limiting or enhancing affinity of these molecules for other binding partners (Tzivion et al, 2000;Margolis et al, 2006;Zhou et al, 2010;Obsil and Obsilova, 2011). In this fashion, 14-3-3 proteins are recognized to modulate the activity of a variety of IFs (Li et al, 2006;Miao et al, 2013), as well as other cytoskeleton associated proteins such as motors and scaffold molecules (Jin et al, 2004;Roberts et al, 2013;Sehgal et al, 2014;Vishal et al, 2018).…”