Nonmuscle myosin IIA is involved in recruitment of apical junction components through activation of ?-catenin.

ABSTRACT: MDCK dog kidney epithelial cells express two isoforms of nonmuscle myosin heavy chain II, IIA and IIB. Using the CRISPR/Cas9 system, we established cells in which the IIA gene was ablated. These cells were then transfected with a vector that expresses GFP-IIA chimeric molecule under the control of a tetracycline-responsible element. In the absence of Dox (doxycyclin), when GFP-IIA is expressed (GFP-IIA+), the cells exhibit epithelial cell morphology, but in the presence of Dox, when expression of GFP-IIA is repressed (GFP-IIA-), the cells lose epithelial morphology and strong cell-cell adhesion. Consistent with these observations, GFP-IIA- cells failed to assemble junction components such as E-cadherin, desmoplakin, and occludin at cell-cell contact sites. Therefore, IIA is required for assembly of junction complexes. MDCK cells with an ablation of the ?-catenin gene also exhibited the same phenotype. However, when in GFP-IIA- cells expressed ?-catenin lacking the inhibitory region or E-cadherin/?-catenin chimeras, the cells acquired the ability to establish the junction complex. These experiments reveal that IIA acts as an activator of ?-catenin in junction assembly.

SUBMITTER: Ozawa M 

PROVIDER: S-EPMC5992523 | biostudies-other | 2018 Apr

REPOSITORIES: biostudies-other