Regulatory subunit of Kv4/D (Shal)-type voltage-gated rapidly inactivating A-type potassium channels (PubMed:10676964, PubMed:11423117, PubMed:17187064, PubMed:34552243, PubMed:34997220). Regulates channel density, inactivation kinetics and rate of recovery from inactivation in a calcium-dependent and isoform-specific manner (PubMed:10676964, PubMed:11423117, PubMed:17187064, PubMed:34552243, PubMed:34997220). In vitro, modulates KCND1/Kv4.1 and KCND2/Kv4.2 currents (PubMed:34552243). Increases the presence of KCND2 at the cell surface (PubMed:12829703). {ECO:0000269|PubMed:10676964, ECO:0000269|PubMed:11423117, ECO:0000269|PubMed:12829703, ECO:0000269|PubMed:17187064, ECO:0000269|PubMed:34552243, ECO:0000269|PubMed:34997220}. This is the function of Ensembl gene identifier ENSG00000182132 (KCNIP1, potassium voltage-gated channel interacting protein 1).