Ca(2+) lightning conveys cell–cell contact information inside the cells

Cells communicate with each other to form organized structures by cell–cell adhesion and cell–cell repulsion, but it remains to be clarified how cell–cell contact information is converted into intracellular signals. Here, we show that cells in contact with neighbouring cells generate local transient intracellular Ca(2+) signals (Ca(2+) lightning). Ca(2+) lightning was observed near cell–cell contact regions and was not observed in the central regions of cells or in solitary cells that were not in contact with other cells. We also show that Ca(2+) lightning is able to regulate cell–cell repulsion by means of PYK2, a Ca(2+)-activated protein tyrosine kinase, which induces focal adhesion disassembly in a Ca(2+)-dependent manner. These results show that cell–cell contact information might be transmitted by Ca(2+) lightning to regulate intracellular events