Regulates voltage-gated potassium channels assembled from KCNA1, KCNA4 and KCNAB1. It slows down channel inactivation by precluding channel closure mediated by the KCNAB1 subunit. Ligand for ADAM22 that positively regulates synaptic transmission mediated by AMPA-type glutamate receptors. Plays a role in suppressing the production of MMP1/3 through the phosphatidylinositol 3-kinase/ERK pathway (By similarity). Oligomer (By similarity). Interacts with KCNA1 within a complex containing KCNA1, KCNA4 and KCNAB1 (By similarity). Part of a complex containing ADAM22, DLG4/PSD95 and CACNG2 (stargazin) (By similarity). Can bind to ADAM11 and ADAM23. Isoform 1 and isoform 2 are detected in the cytosolic and microsomal fractions respectively. Brain. Highly expressed in the dentate gyrus and CA3 field of the hippocampus. Glycosylated.