Table 1.

Schematic structure of ARSs containing WHEP domain. EPRS and MRS are components of the multi-tRNA synthetase complex (MSC) and the cell regulatory activities are controlled by specific phosphorylation [5,35,36,37,38,39]. WRS, HRS, and GRS exist in a free form and are induced under various pathological conditions [12,40,41,42,43,44]. The regulatory activities of WRS are controlled by proteolytic cleavage. The secreted WRS are cleaved and produce WRS variants such mini-, T1- and T2-WRS. GST, Glutathione S-transferase; CD, catalytic domain; ERS, glutamyl-tRNA synthetase; PRS, prolyl-tRNA synthetase; EPRS, glutamyl-prolyl-tRNA synthetase; MRS, methionyl-tRNS synthetase; HRS, histidyl-tRNA synthetase; GRS, glycyl-tRNA synthetase.

	ARSs	Schematic Structure	Alternative Variants	Proteolytic Cleavage	References
MCS form	EPRS	1 1512	EPRSN1		[17,18,35,36]
	MRS	1 900			[37,38,39]
Free form	WRS	1 471	mini-WRS	T1-WRS T2-WRS	[6,13,20,22,27,28,30,31,32]
	HRS	1 509	HRSΔC		[40,41,42]
	GRS	1 739			[43,44]