Enables protein-glutamine gamma-glutamyltransferase activity. Involved in cellular calcium ion homeostasis; positive regulation of cell adhesion; and regulation of apoptotic cell clearance. Acts upstream of or within branching involved in salivary gland morphogenesis and salivary gland cavitation. Located in collagen-containing extracellular matrix. Is expressed in several structures, including alimentary system; central nervous system; cranium; genitourinary system; and sensory organ. Used to study maturity-onset diabetes of the young. Orthologous to human TGM2 (transglutaminase 2). [provided by Alliance of Genome Resources, Apr 2022]