Clarification of the molecular details of forms of natural cell death,
including apoptosis, has become one of the most challenging issues of
contemporary biomedical sciences. One of the effector elements of var
ious cell death pathways is the covalent cross-linking of cellular pro
teins by transglutaminases. This review will discuss the accumulating
data related to the induction and regulation of these enzymes, particu
larly of tissue type transglutaminase, in the molecular program of cel
l death. A wide range of signalling pathways can lead to the parallel
induction of apoptosis and transglutaminase, providing a handle for be
tter understanding the exact molecular interactions responsible for th
e mechanism of regulated cell death.