title: A C-terminal membrane association domain of phototropin 2 is necessary for chloroplast movement.
abstract: Phototropins (phot1 and phot2), plant-specific blue light receptor kinases, mediate a range of physiological responses in Arabidopsis, including phototropism, chloroplast photorelocation movement, stomatal opening and leaf flattening. Phototropins consist of two photoreceptive domains at their N-terminus, LOV1 (light, oxygen or voltage 1) and LOV2, and a serine/threonine kinase domain at their C-terminus. Here, we determined the molecular moiety for the membrane association of phototropins using the yeast CytoTrap and Arabidopsis protoplast systems. We then examined the physiological significance of the membrane association of phototropins. This detailed study with serial deletions narrowed down the association domain to a relatively small part of the C-terminal domain of phototropin. The functional analysis of phot2 deletion mutants in the phot2-deficient Adiantum and Arabidopsis mutants revealed that the ability to mediate the chloroplast avoidance response correlated well with phot2's membrane association, especially with the Golgi apparatus. Taken together, our data suggest that a small part of the C-terminal domain of phototropins is necessary not only for membrane association but also for the physiological activities that elicit phototropin-specific responses.
authors.affiliation: Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan. kong.samgeun@gmail.com
authors.forename: Sam-Geun
authors.initials: SG
authors.lastname: Kong
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Kagawa
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Wada
authors.forename: Akira
authors.initials: A
authors.lastname: Nagatani
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D006056:Golgi Apparatus / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D058503:Mesophyll Cells / Q000166:cytology / Q000378:metabolism; D009154:Mutation; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary; D011523:Protoplasts / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; C423903:PHOT2 protein, Arabidopsis; D010750:Phosphoproteins; D049452:Green Fluorescent Proteins; C103646:NPH1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases