Calcium-dependent cell-adhesion protein involved in cells self-recognition and non-self discrimination. Thereby, it is involved in the establishment and maintenance of specific neuronal connections in the brain. Forms homodimers in trans (molecules expressed by two different cells). Forms promiscuous heterodimers in cis (at the plasma membrane of the same cell) with other protocadherins. Cadherin 1 to cadherin 4 domains mediate homophilic trans-interaction, the interaction with an identical protocadherin expressed by a neighboring cell. This is a head-to-tail interaction, the cadherin 1 domain interacting with the cadherin 4 domain and the cadherin 2 domain interacting the cadherin 3 domain of the other protocadherin. The cadherin 6 domain mediates promiscuous interactions with protocadherins on the same cell membrane. Each cadherin domain binds three calcium ions.