Overexpressed transglutaminase 5 triggers cell death.
Transglutaminases are a class of nine different proteins involved in many biological phenomena such as differentiation, tissue repair, endocytosis. Transglutaminase 5 was originally cloned from skin keratinocytes, and a partial biochemical characterization showed its involvement in skin differentiation. Here we demonstrate that transglutaminase 5 is able to induce cell death when intracellularly overexpressed. Transfected cells show enzymatic activity, as demonstrated by fluoresceincadaverine staining. Transfected cells died due to the formation of hypodiploid DNA content, indicating the induction of cell death under these pharmacological conditions. We also show that the primary sequence of transglutaminase 5 contains GTP binding domains which are similar to those in transglutaminase 2. This raises the possibility that transglutaminase 5 is regulated by GTP in a similar fashion to transglutaminase 2.
Biochemistry Laboratory, IDI-IRCCS, University of Rome Tor Vergata, Rome, Italy.
B
B
Cadot
A
A
Rufini
V
V
Pietroni
S
S
Ramadan
P
P
Guerrieri
G
G
Melino
E
E
Candi
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D016923:Cell Death / Q000502:physiology*; D002460:Cell Line; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D011503:Transglutaminases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D006160:Guanosine Triphosphate; C418703:transglutaminase 5; D011503:Transglutaminases