Mathew Sajish & Paul Schimmel
autumn by Alexey Klimchuk-
Resveratrol is reported to extend lifespan1, 2 and provide cardio-neuro-protective3, anti-diabetic4, and anti-cancer effects3, 5 by initiating a stress response2 that induces survival genes. Because human tyrosyl transfer-RNA (tRNA) synthetase (TyrRS) translocates to the nucleus under stress conditions6, we considered the possibility that the tyrosine-like phenolic ring of resveratrol might fit into the active site pocket to effect a nuclear role. Here we present a 2.1 Å co-crystal structure of resveratrol bound to the active site of TyrRS. Resveratrol nullifies the catalytic activity and redirects TyrRS to a nuclear function, stimulating NAD+-dependent auto-poly-ADP-ribosylation of poly(ADP-ribose) polymerase 1 (PARP1). Downstream activation of key stress signalling pathways are causally connected to TyrRS–PARP1–NAD+ collaboration. This collaboration is also demonstrated in the mouse, and is specifically blocked in vivo by a resveratrol-displacing tyrosyl adenylate analogue. In contrast to functionally diverse tRNA synthetase catalytic nulls created by alternative splicing events that ablate active sites7, here a non-spliced TyrRS catalytic null reveals a new PARP1- and NAD+-dependent dimension to the physiological mechanism of resveratrol.