Controllable endogenic proteolysis as a major factor of switching tryptophanyl-tRNA synthetase from canonical aminoacylation activity to non-canonical regulatory functions

Tryptophanyl-tRNA synthetase has a unique set of additional non-canonical activities in addition main aminoacylation activity, in particular for the control of angiogenesis [7]. It is important to study the role of endogenous limited controlled proteolysis as a possible molecular mechanism of switching from the canonical source aminoacylation activity of the native enzyme to non-canonical anti-angiogenic activity. We consider important data on the possible role of the significant for the activity zinc ion discovered earlier in the tryptophanyl-tRNA synthetase [8], and endogenous tryptophan in the activation of the regulatory functions of the enzyme. We have developed a novel approach to the identification of the role of endogenous proteolysis induced by intracellular proteases in the modification of the enzyme, as well as the role of the endogenous enzyme bound tryptophan and varying content of zinc ion essential for tryptophanyl-tRNA synthetase activity, as important factors in the complex process of activation of the non-canonical cytokine functions of the enzyme. Proteolytic transition of native tryptophanyl-tRNA synthetase as a result of above modifications of the enzyme and resulting cleavage of N-terminal fragment of 20 kDa have been shown with chromatographic, immunochemical methods, and confirmed by electrophoresis and immunoblotting.

cascades of proteolytic reactions, autophagy, apoptosome, inflammasome, important for the activity zinc ion, Trp-tRNA synthetase, canonical and non-canonical functions, DEAE chromatography, gel filtration chromatography, immunoassay, immunoblotting