Essential for the proper localization of brevican (BCAN), mainly as a perineuronal nets (PNNs)-type deposition in the brainstem and cerebellum thereby playing a key role in the formation and structural organization of PNNs (By similarity). Contributes to the formation and transmission of inhibitory GABAergic synapses between Purkinje cells and deep cerebellar nuclei neurons (By similarity). Expressed predominantly in brain. Belongs to the HAPLN family. Extended N-terminus.