Description:
<jats:sec><jats:label /><jats:p>Protocadherin LKC (PLKC) shows characteristics of a potential tumor‐suppressor by inducing contact inhibition of cell proliferation after downregulation of beta‐catenin signaling. Here, we expressed an YFP‐tagged version of PLKC in Chinese Hamster Ovary (CHO) cells to directly assess its potential function in non‐polarized cells and implication in changing cell morphology. The results indicate that PLKC exhibits a significant calcium‐dependent adhesion activity which is not mediated by the actin cytoskeleton. Interestingly, this activity is nearly as strong as that of E‐cadherin and stronger than that of N‐cadherin. PLKC is localized at sites of cell‐cell interaction concomitant with morphological alteration of the transfected CHO cells. Nevertheless, no significant change could be assessed in the trans‐epithelial resistance in the PLKC‐expressing cells versus mock transfected controls indicating that PLKC per se is not directly implicated in triggering cell polarity. The mode of interaction of PLKC molecules in the cell and at the sites of cell‐cell interaction revealed a calcium‐dependent dimerisation of PLKC in the Golgi membranes and at the cell surface, while calcium is not required for dimerisation in the ER. The results shed light on a dual role for calcium in the structure and function of PLKC.</jats:p></jats:sec>