Transglutaminase 4, Prostate (TGM4)

Transglutaminases (EC 2.3.2.13) catalyze the posttranslational modification of proteins by the formation of epsilon-(gamma-glutamyl) lysine isopeptide bonds. The transglutaminases (TGMs) described in eukaryotic cells include both intracellular and extracellular forms. The intracellular forms are tissue TGM (TGM2), keratinocyte TGM, and hair follicle transglutaminase; extracellular TGMs include factor XIIIa and prostate transglutaminase (TGM4, or TGP).

In rodents, TGP is involved in the formation of copulatory plugs in the female genital tract after coitus, and may play a role in masking the antigenicity of the male gamete, thereby suppressing an immune response in the female genital tract against the sperm cells.