Promotes cell surface expression of the potassium channel KCND2 (PubMed:15454437, PubMed:19441798). Modulates the activity and gating characteristics of the potassium channel KCND2 (PubMed:18364354). Has no dipeptidyl aminopeptidase activity (PubMed:15476821, PubMed:8103397). {ECO:0000269|PubMed:15454437, ECO:0000269|PubMed:18364354, ECO:0000269|PubMed:8103397, ECO:0000305|PubMed:15476821}. This is the function of Ensembl gene identifier ENSG00000130226 (DPP6, dipeptidyl peptidase like 6).