Synaptic adhesion protein. Regulates the formation of excitatory synapses. The trans-synaptic adhesion between LRRC4B and PTPRF regulates the formation of excitatory synapses in a bidirectional manner. Interacts with PTPRF. Interacts with DLG4 (By similarity). Mainly expressed in the brain. Widespread distribution in various brain regions (at protein level). Detected both embryonically and postnatally with stronger expression in postnatal stages. The extreme C-terminus binds to the first 2 PDZ domains of DLG4. N-glycosylated. O-glycosylated; contains sialic acid.