Protocadherin-1
Protocadherin-1 (PCDH1), once named Arcadlin, belongs to the delta-group protocadherins and is expressed mainly in the brain, retina, and olfactory epithelium. Its ectodomain holds six cadherin repeats that support homophilic and heterophilic adhesion, but unlike classical cadherins its cytoplasmic tail does not bind beta-catenin and instead associates with the actin cytoskeleton through other adaptors. PCDH1 localizes to dendritic spines and postsynaptic densities, where it has been linked to NMDA receptor trafficking, spine maturation, and activity-dependent adhesion during memory formation. Altered PCDH1 expression has been reported in epilepsy models and in certain carcinomas.
