Arabidopsis O-fucosyltransferase SPINDLY activates growth repressor DELLA ($)

The SPINDLY (SPY) gene was identified through a genetic screen; spy mutants are abnormally tall and thin, suggesting that they are overly sensitive to gibberellins. Later, the SPY gene was shown to act downstream of GIBBEERLLIN INSENSITIVE (GAI), which is a DELLA-domain containing protein. SPY was previously identified as showing homology to O-GlcNac transferases, but this activity has not been demonstrated. In this new work, Zentelli, Sui et al. show that in fact SPY is an O-fucosyltransferase, and that O-fucosylation activates DELLA-containing proteins. This paper not only solves a 20-year old mystery the function of SPY, but also opens a new line of inquiry into O-fucosylation as a post-translational regulator. Nature Chem. Biol. 10.1038/nchembio.2320