Mechanism of auxin perception by the TIR1 ubiquitin ligase.
Auxin is a pivotal plant hormone that controls many aspects of plant growth and development. Perceived by a small family of F-box proteins including transport inhibitor response 1 (TIR1), auxin regulates gene expression by promoting SCF ubiquitin-ligase-catalysed degradation of the Aux/IAA transcrip...
| Main Authors: | , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2007
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| _version_ | 1797089068552552448 |
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| author | Tan, X Calderon-Villalobos, L Sharon, M Zheng, C Robinson, C Estelle, M Zheng, N |
| author_facet | Tan, X Calderon-Villalobos, L Sharon, M Zheng, C Robinson, C Estelle, M Zheng, N |
| author_sort | Tan, X |
| collection | OXFORD |
| description | Auxin is a pivotal plant hormone that controls many aspects of plant growth and development. Perceived by a small family of F-box proteins including transport inhibitor response 1 (TIR1), auxin regulates gene expression by promoting SCF ubiquitin-ligase-catalysed degradation of the Aux/IAA transcription repressors, but how the TIR1 F-box protein senses and becomes activated by auxin remains unclear. Here we present the crystal structures of the Arabidopsis TIR1-ASK1 complex, free and in complexes with three different auxin compounds and an Aux/IAA substrate peptide. These structures show that the leucine-rich repeat domain of TIR1 contains an unexpected inositol hexakisphosphate co-factor and recognizes auxin and the Aux/IAA polypeptide substrate through a single surface pocket. Anchored to the base of the TIR1 pocket, auxin binds to a partially promiscuous site, which can also accommodate various auxin analogues. Docked on top of auxin, the Aux/IAA substrate peptide occupies the rest of the TIR1 pocket and completely encloses the hormone-binding site. By filling in a hydrophobic cavity at the protein interface, auxin enhances the TIR1-substrate interactions by acting as a 'molecular glue'. Our results establish the first structural model of a plant hormone receptor. |
| first_indexed | 2024-03-07T02:59:10Z |
| format | Journal article |
| id | oxford-uuid:b05a8e5e-aad4-4f57-b187-7d5648787139 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:59:10Z |
| publishDate | 2007 |
| record_format | dspace |
| spelling | oxford-uuid:b05a8e5e-aad4-4f57-b187-7d56487871392022-03-27T03:55:49ZMechanism of auxin perception by the TIR1 ubiquitin ligase.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:b05a8e5e-aad4-4f57-b187-7d5648787139EnglishSymplectic Elements at Oxford2007Tan, XCalderon-Villalobos, LSharon, MZheng, CRobinson, CEstelle, MZheng, NAuxin is a pivotal plant hormone that controls many aspects of plant growth and development. Perceived by a small family of F-box proteins including transport inhibitor response 1 (TIR1), auxin regulates gene expression by promoting SCF ubiquitin-ligase-catalysed degradation of the Aux/IAA transcription repressors, but how the TIR1 F-box protein senses and becomes activated by auxin remains unclear. Here we present the crystal structures of the Arabidopsis TIR1-ASK1 complex, free and in complexes with three different auxin compounds and an Aux/IAA substrate peptide. These structures show that the leucine-rich repeat domain of TIR1 contains an unexpected inositol hexakisphosphate co-factor and recognizes auxin and the Aux/IAA polypeptide substrate through a single surface pocket. Anchored to the base of the TIR1 pocket, auxin binds to a partially promiscuous site, which can also accommodate various auxin analogues. Docked on top of auxin, the Aux/IAA substrate peptide occupies the rest of the TIR1 pocket and completely encloses the hormone-binding site. By filling in a hydrophobic cavity at the protein interface, auxin enhances the TIR1-substrate interactions by acting as a 'molecular glue'. Our results establish the first structural model of a plant hormone receptor. |
| spellingShingle | Tan, X Calderon-Villalobos, L Sharon, M Zheng, C Robinson, C Estelle, M Zheng, N Mechanism of auxin perception by the TIR1 ubiquitin ligase. |
| title | Mechanism of auxin perception by the TIR1 ubiquitin ligase. |
| title_full | Mechanism of auxin perception by the TIR1 ubiquitin ligase. |
| title_fullStr | Mechanism of auxin perception by the TIR1 ubiquitin ligase. |
| title_full_unstemmed | Mechanism of auxin perception by the TIR1 ubiquitin ligase. |
| title_short | Mechanism of auxin perception by the TIR1 ubiquitin ligase. |
| title_sort | mechanism of auxin perception by the tir1 ubiquitin ligase |
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