TISSUE TRANSGLUTAMINASE

'Tissue transglutaminase' (abbreviated as 'TG2' or 'tTG') is an enzyme () of the transglutaminase family. Like other transglutaminases, it crosslinks proteins between an ε-nitrogen of a lysine residue 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.

Contents

Genetics

Physiology

Role in disease

Diagnostic use

Therapeutic use

External links

References

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 in wound healing, apoptosis and extracellular matrix development

Role in disease

Tissue transglutaminase is best known for its link with coeliac disease. Anti-transglutaminase antibodies (ATA) result in a form of gluten sensitivity in which a cellular response to ''Triticeae'' glutens that are crosslinked to tTG are able to stimulate transglutaminase specific B-cell responses that eventually result in the production of ATA IgA and IgG.^[1]
Recent studies suggest that tTG plays a role 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Serology for anti-tTG antibodies has superseded older serological tests (anti-endomysium, anti-gliadin and anti-reticulin) and has a strong sensitivity (99%) and specificity (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 antigen^[2]

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.

External links

★ Endomysial antibodies

References

1. 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
2. Sblattero 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.