Updated project metadata. TGM1 is an enzyme that cross-links structural proteins in the uppermost granular layer of the epidermis to form cornified envelopes. Cornified envelopes ensure functional stratum corneum and epidermal barrier formation. It has been suggested that the activity of TGM1 is regulated on a posttranslational level. To identify endogenous TGM1 interactors, Virotrap has been performed.