Dissection of the phosphorylation of rice [Oryza sativa] DELLA protein, SLENDER RICE1
DELLA proteins are repressors of gibberellin signaling in plants. Our previous studies have indicated that gibberellin signaling is derepressed by SCF(GID2)-mediated proteolysis of the DELLA protein, SLENDER RICE1 (SLR1), in rice. In addition, the gibberellin-dependent increase of phosphorylated SLR...
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Published in | Plant and cell physiology Vol. 46; no. 8; pp. 1392 - 1399 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Japan
Oxford University Press
01.08.2005
Oxford Publishing Limited (England) |
Subjects | |
Online Access | Get full text |
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Summary: | DELLA proteins are repressors of gibberellin signaling in plants. Our previous studies have indicated that gibberellin signaling is derepressed by SCF(GID2)-mediated proteolysis of the DELLA protein, SLENDER RICE1 (SLR1), in rice. In addition, the gibberellin-dependent increase of phosphorylated SLR1 in the loss-of-function gid2 mutant suggests that the SCF(GID2)-mediated degradation of SLR1 might be initiated by gibberellin-dependent phosphorylation. To confirm the role of phosphorylation of SLR1 in its gibberellin-dependent degradation, we revealed that SLR1 is phosphorylated on an N-terminal serine residue(s) within the DELLA/TVHYNP and polyS/T/V domain. However, gibberellin-induced phosphorylation in these regions was not observed in the gid2 mutant following the constitutive expression of SLR1 under the control of the rice actin1 promoter. Treatment with gibberellin induced both the phosphorylated and non-phosphorylated forms of SLR1 with similar induction kinetics in gid2 mutant cells. Both the phosphorylated and non-phosphorylated SLR1 proteins were degraded by gibberellin treatment with a similar half-life in the rice callus cells, and both proteins interacted with recombinant glutathione S-transferase (GST)-GID2. These results demonstrate that the phosphorylation of SLR1 is independent of its degradation and is dispensable for the interaction of SLR1 with the GID2/F-box protein. |
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Bibliography: | F60 2006004155 Corresponding author: E-mail, makoto@nuagr1.agr.nagoya-u.ac.jp, Fax, +81-52-789-5226. local:pci152 istex:2DB90405AAC1B0BA5B91BA8A42414069E9651FCE ark:/67375/HXZ-4SHSGSZ3-N ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0032-0781 1471-9053 |
DOI: | 10.1093/pcp/pci152 |