Editors' ChoiceEVOLUTION

Evolving from an Enzyme and into a Regulator

Sci. Signal.  22 Jul 2014:
Vol. 7, Issue 335, pp. ec198
DOI: 10.1126/scisignal.2005705

Proteins, the workhorses of the cell, are made on a messenger RNA (mRNA) template. An enzyme called aminoacyl tRNA synthetases (AARSs) attaches the correct amino acid to a transfer RNA so that mRNA is accurately translated. Over evolution, additional sequences have been added to AARSs. Lo et al. found a large number of AARS variants in which the domain responsible for enzyme function was deleted. Ninety-four such variants had diverse signaling activities. Thus, AARSs are used both as enzymes and alternately as regulators of signaling pathways.

W.-S. Lo, E. Gardiner, Z. Xu, C.-F. Lau, F. Wang, J. J. Zhou, J. D. Mendlein, L. A. Nangle, K. P. Chiang, X.-L. Yang, K.-F. Au, W. H. Wong, M. Guo, M. Zhang, P. Schimmel, Human tRNA synthetase catalytic nulls with diverse functions. Science 345, 328–332 (2014). [Abstract] [Full Text]