[Frontiers in Bioscience 11, 221-231, January 1, 2006]

Role of protein modifications mediated by transglutaminase 2 in human viral diseases

Ju-Hong Jeon and In-Gyu Kim

Department of Biochemistry and Molecular Biology, Aging and Apoptosis Research Center (AARC), Seoul National University College of Medicine, 28 Yongon Dong, Chongno Gu, Seoul 110-799, Korea


1. Abstract
2. Introduction
3. Enzyme characteristics of transglutaminase 2
3.1. Nature of modification depends on acyl acceptor substrates
3.2. Intracellular transglutaminase 2 activity does not correlate with the protein level
3.3. Intracellular transglutaminase 2 is activated by oxidative stress
3.4. Protein-specific functional alterations of modified protein
4. Transglutaminase 2 and viral infection
4.1. Mechanism of transglutaminase 2 activation in virus-infected cells
4.2. Viral proteins modified by transglutaminase 2
4.3. Cellular proteins modified by transglutaminase 2 during viral infection
5. Implications for human viral diseases; is transglutaminase 2 activation a double-edged sword?
6. Acknowledgements
7. References


Transglutaminase 2 (TG2) belongs to a family of calcium-dependant enzymes that catalyze transamidation reaction, producing polymerized, polyaminated or deamidated proteins. Recently, a growing number of viral proteins as well as cellular proteins with which they interact have been found to be modified by TG2, suggesting a novel function for TG2 in viral pathogenesis. This review summarizes the results of relevant research, examines the mechanisms underlying TG2 function in host-virus interactions and proposes a model for viral pathogenesis involving TG2.