Transglutaminase II: A new class of GTP-binding protein with new biological functions

Tissue type transglutaminase (TGase II) is historically a member of the transglutaminase family, which covalently cross-links cellular proteins and polyamines. A recent new finding in the TGase II field is that the enzyme functions as a signal mediator from receptors so an effector in transmembrane signaling. This review will discuss the recent development of TGase II. This new signal transducer was termed G(h) when initially discovered and was recently found to be TGase II. To help the reader understand the role of G(h) as a signal mediator, the role of heterotrimeric G-proteins in hormone-mediated transmembrane signaling is briefly discussed. We have highlighted how G(h) transmits the alpha(1)-adrenoceptor signal to the phospholipase C-delta 1 and how G(h) is activated and deactivated compared to the prototype oi heterotrimeric G-proteins. Recent developments regarding the structure-function of G(h) and other biological functions of G(h) are discussed to facilitate understanding the impact of G(h) in cells. (C) 1997 Elsevier Science Inc.