Transglutaminases: Effector molecules in physiologic cell death

TRANSGLUTAMINASES are protein cross-linking enzymes that catalyze the formation of large protein aggregates. The intracellular members of the family, keratinocyte transglutaminase (type I) and tissue transglutaminase (type II), appear to be involved in the apoptotic program. The keratinocyte- specific enzyme is restricted to the epidermis and responsible for the cornification of keratinocytes by forming the cornified envelopes. The tissue enzyme can be found in other organs and participates in the formation of apoptotic bodies by cross-linking substrate proteins.