The DMKN gene encodes several different isoforms of the DMKN protein. Of these, the DMKN delta-5 isoform is ubiquitously expressed in cells and is believed to play a role in early endosomal vesicle formation and trafficking. It carries out this function by interacting with endogenous HeLa cell RAB5 and promoting GTP loading onto RAB5. DMKN-beta, a secreted isoform specific to keratinocytes, is believed to play a role in the terminal differentiation of the epidermis and cornified envelope assembly. Recent studies in human keratinocytes have identified DMKN-beta to inhibit the phosphorylation of extracellular-signal-regulated kinase (ERK) and increase caspase activity.