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Tissue transglutaminase (TG2, tTG) is an enzyme () of the transglutaminase family. Like other transglutaminases, it crosslinks proteins between an ε-N and a glutamine residue in two protein chains, creating a bond that is highly resistant to proteolysis (protein degradation). It is particularly notable for being the autoantigen in coeliac disease, but is also known to play a role in apoptosis, cellular differentiation and matrix stabilisationGriffin M, Casadio R, Bergamini CM. Transglutaminases: nature's biological glues. Biochem J 2002;368:377-96. PMID 12366374.
Genetics
The human tTG gene is located on the 20th chromosome (20q11.2-q12).
Physiology
tTG is expressed ubiquitously. It requires calcium as a cofactor. Transcription is increased by retinoic acid. Amongst its many supposed functions, it appears to play a role wound healing, apoptosis and extracellular matrix development
Role in disease
tTG is best known for its link with coeliac disease, an allergy to gluten (wheat protein) in which an autoimmune process leads to malabsorption.Dieterich W, Ehnis T, Bauer M, Donner P, Volta U, Riecken EO, Schuppan D. Identification of tissue transglutaminase as the autoantigen of celiac disease. Nature Med 1997;3:797-801. PMID 9212111.
Recent developments are the possible role of tTG in inflammation, degenerative diseases and tumour biology.
Diagnostic use
Serology for anti-tTG antibodies has superseded older serological tests (anti-endomysium, anti-gliadin and anti-reticulin) and has a strong sensitivity (99%) and specificity (>90%) for identifying coeliac disease. Modern anti-tTG assays rely on a human recombinant protein as an antigenSblattero D, Berti I, Trevisiol C, Marzari R, Tommasini A, Bradbury A, Fasano A, Ventura A, Not T. Human recombinant tissue transglutaminase ELISA: an innovative diagnostic assay for celiac disease. Am J Gastroenterol 2000;95:1253-7. PMID 10811336.
Therapeutic use
Use of tTG as a form of surgical glue is still experimental. It is also being studied as an attenuator of metastasis in certain tumours.
References
External links
"Tissue transglutaminase"