Abstract
Previously, a dysfunction of the SMALL ACIDIC PROTEIN1 (SMAP1) gene was identified as the cause of the anti-auxin resistant1 (aar1) mutant of Arabidopsis (Arabidopsis thaliana). SMAP1 is involved in the response pathway of synthetic auxin, 2,4-dichlorophenoxyacetic acid, and functions upstream of the auxin/indole-3-acetic acid protein degradation step in auxin signaling. However, the exact mechanism by which SMAP1 functions in auxin signaling remains unknown. Here, we demonstrate that SMAP1 is required for normal plant growth and development and the root response to indole-3-acetic acid or methyl jasmonate in the auxin resistant1 (axr1) mutation background. Deletion analysis and green fluorescent protein/glutathione S-transferase pull-down assays showed that SMAP1 physically interacts with the CONSTITUTIVE PHOTOMORPHOGENIC9 SIGNALOSOME (CSN) via the SMAP1 F/D region. The extremely dwarf phenotype of the aar1-1 csn5a-1 double mutant confirms the functional role of SMAP1 in plant growth and development under limiting CSN functionality. Our findings suggest that SMAP1 is involved in the auxin response and possibly in other cullin-RING ubiquitin ligase-regulated signaling processes via its interaction with components associated with RELATED TO UBIQUITIN modification.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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2,4-Dichlorophenoxyacetic Acid / pharmacology
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Acetates / pharmacology
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Arabidopsis / drug effects
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Arabidopsis / genetics
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Arabidopsis / growth & development*
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Arabidopsis / metabolism
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism*
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Caulimovirus / genetics
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Caulimovirus / metabolism
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Cyclopentanes / pharmacology
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Gene Expression Regulation, Plant
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Genetic Complementation Test
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Glutathione Transferase / genetics
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Glutathione Transferase / metabolism
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Green Fluorescent Proteins / metabolism
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Indoleacetic Acids / pharmacology
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Mutation
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Oxylipins / pharmacology
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Phenotype
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Plant Epidermis / genetics
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Plant Epidermis / metabolism
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Plant Roots / drug effects
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Plant Roots / genetics
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Plant Roots / metabolism
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Plants, Genetically Modified / genetics
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Plants, Genetically Modified / growth & development
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Plants, Genetically Modified / metabolism
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Promoter Regions, Genetic
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Protein Interaction Mapping
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RNA Interference
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Seeds / genetics
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Seeds / growth & development
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Seeds / metabolism
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Signal Transduction
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Ubiquitins / genetics
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Ubiquitins / metabolism*
Substances
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AXR1 protein, Arabidopsis
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Acetates
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Arabidopsis Proteins
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CONSTITUTIVE PHOTOMORPHOGENIC 9 protein, Arabidopsis
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Cyclopentanes
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Indoleacetic Acids
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Oxylipins
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SMAP1 protein, Arabidopsis
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Ubiquitins
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Green Fluorescent Proteins
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2,4-Dichlorophenoxyacetic Acid
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indoleacetic acid
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methyl jasmonate
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Glutathione Transferase