Cell to cell adhesion depends upon

Cell-to-cell adhesion depends upon Ca²⁺ and Mg²⁺ of the middle lamella.
Cell adhesion is the process by which cells interact and attach to neighboring cells through specialized molecules of the cell surface.
This family of CAMs is membrane proteins that mediate cell-cell adhesion through its extracellular domains and require extracellular Ca²⁺ ions to function correctly.
Cadherins form a homophilic attachment between themselves, which results in cells of a similar type sticking together and can lead to selective cell adhesion, allowing vertebrate cells to assemble into organized tissues.