Keratinocytes and fibroblasts endogenously express DPP9 transcript and protein. DPP9 is localized mostly in cytoplasm;its sub-localization in Golgi is very scarce. DPP8/9 enzyme activity was shown in cytosolic fraction of both skin cells types. DPP8/9 enzyme activity participates in regulation of the skin cells’ proliferation. DPP9 participates in regulation of adhesion and/or migration of the skin cells.