Biopolymers and cell. 1999; 15 (2): 168 - 172

Cytokine activity of the non-catalytic EMAP-2-like domain of mammalian tyrosyl-tRNA synthetase

Alexander Kornelyuk, Maarten P. R. Tas, Alexei Dubrovsky, J. Clifford Murray

Cytokine activity of the isolated recombinant C-terminal domain of mammalian lyrosyl-tRNA synthetasg (TyrRS), which is homologous to a tumor-derived cytokine, endothelial and monocyte activating polypeptide (EMAP-2) has been studied. It was shown that C-domain induced a ~ 2-fold increase of monocyte chemotaxis. This effect is comparable with the values of chemotaxis induction by EMAP-2 cytokine and proEMAP-2. The truncated catalytic form of bovine TyrRS (2 x 39 kDa) lias no effect on monocyte chemotaxis. C-domain of TyrRS also induced a «• 3-fold increase in tissue factor activity in cultured human endothelial cells. A hypothesis is forwarded that the isolated C-domain of mammalian TyrRS may be released at proteoiytic cleavage of TyrRS by some protease, activated ui stress conditions, and functions as a mediator via signal transduction through interaction with a ^uiative EMAP-2 receptor.