A missense allele of KARRIKIN-INSENSITIVE2 impairs ligand-binding and downstream signaling in Arabidopsis thaliana
| Autor: | Inhye Lee, Kuglae Kim, Sumin Lee, Seungjun Lee, Eunjin Hwang, Kihye Shin, Dayoung Kim, Jungki Choi, Hyunmo Choi, Jeong Seok Cha, Hoyoung Kim, Rin-A Lee, Suyeong Jeong, Jeongsik Kim, Yumi Kim, Hong Gil Nam, Soon-Ki Park, Hyun-Soo Cho, Moon-Soo Soh |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0106 biological sciences
0301 basic medicine Light Signal Transduction Light Positional cloning Hydrolases Physiology Mutant Arabidopsis Mutation Missense Plant Science Ligands medicine.disease_cause 01 natural sciences 03 medical and health sciences medicine Missense mutation Arabidopsis thaliana KAI2 Alleles phytochrome Mutation biology Arabidopsis Proteins Chemistry Ligand (biochemistry) biology.organism_classification Research Papers karrikin photomorphogenesis Karrikin Cell biology Phenotype 030104 developmental biology germination Growth and Development 010606 plant biology & botany |
| Zdroj: | Journal of Experimental Botany |
| ISSN: | 1460-2431 0022-0957 |
| DOI: | 10.1093/jxb/ery164 |
| Popis: | A missense mutation of KARRIKIN-INSENSITIVE2, KAI2ply2, compromises its ligand-binding activity, which subsequently impairs KAI2-signaling and multiple aspects of light-dependent responses. A smoke-derived compound, karrikin (KAR), and an endogenous but as yet unidentified KARRIKIN INSENSITIVE2 (KAI2) ligand (KL) have been identified as chemical cues in higher plants that impact on multiple aspects of growth and development. Genetic screening of light-signaling mutants in Arabidopsis thaliana has identified a mutant designated as ply2 (pleiotropic long hypocotyl2) that has pleiotropic light-response defects. In this study, we used positional cloning to identify the molecular lesion of ply2 as a missense mutation of KAI2/HYPOSENSITIVE TO LIGHT, which causes a single amino acid substitution, Ala219Val. Physiological analysis and genetic epistasis analysis with the KL-signaling components MORE AXILLARY GROWTH2 (MAX2) and SUPPRESSOR OF MAX2 1 suggested that the pleiotropic phenotypes of the ply2 mutant can be ascribed to a defect in KL-signaling. Molecular and biochemical analyses revealed that the mutant KAI2ply2 protein is impaired in its ligand-binding activity. In support of this conclusion, X-ray crystallography studies suggested that the KAI2ply2 mutation not only results in a narrowed entrance gate for the ligand but also alters the structural flexibility of the helical lid domains. We discuss the structural implications of the Ala219 residue with regard to ligand-specific binding and signaling of KAI2, together with potential functions of KL-signaling in the context of the light-regulatory network in Arabidopsis thaliana. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|