RT Journal Article
SR Electronic
T1 The Arabidopsis Mutant sleepy1<sup>gar2-1</sup> Protein Promotes Plant Growth by Increasing the Affinity of the SCF<sup>SLY1</sup> E3 Ubiquitin Ligase for DELLA Protein Substrates
JF The Plant Cell
JO Plant Cell
FD American Society of Plant Biologists
SP 1406
OP 1418
DO 10.1105/tpc.021386
VO 16
IS 6
A1 Fu, Xiangdong
A1 Richards, Donald E.
A1 Fleck, Barbara
A1 Xie, Daoxin
A1 Burton, Nicolas
A1 Harberd, Nicholas P.
YR 2004
UL http://www.plantcell.org/content/16/6/1406.abstract
AB DELLA proteins restrain the cell proliferation and enlargement that characterizes the growth of plant organs. Gibberellin stimulates growth via 26S proteasome–dependent destruction of DELLAs, thus relieving DELLA-mediated growth restraint. Here, we show that the Arabidopsis thaliana sleepy1gar2-1 (sly1gar2-1) mutant allele encodes a mutant subunit (sly1gar2-1) of an SCFSLY1 E3 ubiquitin ligase complex. SLY1 (the wild-type form) and sly1gar2-1 both confer substrate specificity on this complex via specific binding to the DELLA proteins. However, sly1gar2-1 interacts more strongly with the DELLA target than does SLY1. In addition, the strength of the SCFSLY1–DELLA interaction is increased by target phosphorylation. Growth-promoting DELLA destruction is dependent on SLY1 availability, on the strength of the interaction between SLY1 and the DELLA target, and on promotion of the SCFSLY1–DELLA interaction by DELLA phosphorylation.