A5091568680- Plant Reproductive Biology
- Photosynthetic Processes and Mechanisms
- Plant Molecular Biology Research
- Cellular transport and secretion
- Glycosylation and Glycoproteins Research
- Carbohydrate Chemistry and Synthesis
- Endoplasmic Reticulum Stress and Disease
- Galectins and Cancer Biology
- Microtubule and mitosis dynamics
- Plant Stress Responses and Tolerance
- Plant Gene Expression Analysis
- Plant nutrient uptake and metabolism
- Plant tissue culture and regeneration
- Lipid metabolism and biosynthesis
- Plant biochemistry and biosynthesis
- Natural product bioactivities and synthesis
- Autophagy in Disease and Therapy
- Plant responses to water stress
- Toxin Mechanisms and Immunotoxins
- Tree Root and Stability Studies
- Plant and Biological Electrophysiology Studies
- Biochemical and Structural Characterization
- Genomics, phytochemicals, and oxidative stress
- Magnetic and Electromagnetic Effects
- Nuclear Structure and Function
Kyoto University
2005-2025
Konan University
2018-2025
University of Hyogo
2011
Ochanomizu University
1999-2005
Otsuka (Japan)
1999-2003
Plants exhibit an ultimate case of the intracellular motility involving rapid organelle trafficking and continuous streaming endoplasmic reticulum (ER). Although it was long assumed that ER dynamics is actomyosin-driven, responsible myosins were not identified, characterized quantitatively. Here we developed software to generate a detailed velocity-distribution map for GFP-labeled ER. This revealed in most peripheral plane relatively static, whereas inner rapidly with velocities up ∼3.5...
Summary Flavonoids are the most important pigments for coloration of flowers and seeds. In plant cells, flavonoids synthesized by a multi‐enzyme complex located on cytosolic surface endoplasmic reticulum, they accumulate in vacuoles. Two non‐exclusive pathways have been proposed to mediate flavonoid transport vacuoles: membrane transporter‐mediated pathway vesicle trafficking‐mediated pathway. No molecules involved identified, however. Here, we show that trafficking factor, GFS 9, has role...
Abstract Brassicales plants, including Arabidopsis thaliana, have an ingenious two-compartment defense system, which sequesters myrosinase from the substrate glucosinolate and produces a toxic compound when cells are damaged by herbivores. Myrosinase is stored in vacuoles of idioblast myrosin cells. The molecular mechanism that regulates cell development remains elusive. Here, we identify basic helix-loop-helix transcription factor FAMA as essential component for along leaf veins. known...
Abstract Although light is essential for photosynthesis, it has the potential to elevate intracellular levels of reactive oxygen species (ROS). Since high ROS are cytotoxic, plants must alleviate such damage. However, cellular mechanism underlying ROS-induced leaf damage alleviation in peroxisomes was not fully explored. Here, we show that autophagy plays a pivotal role selective removal ROS-generating peroxisomes, which protects from oxidative during photosynthesis. We present evidence...
Myrosin cells in Capparales plants are idioblasts that accumulate thioglucoside glucohydrolase (TGG, also called myrosinase), which hydrolyzes glucosinolates to produce toxic compounds for repelling pests. Here, we show AtVAM3 is involved development of myrosin cells. It has been shown yeast VAM3 a Q(a)-SNARE vesicle transport vacuolar proteins and assembly. We found two Arabidopsis atvam3 alleles, atvam3-3 atvam3-4/ssm, large amounts TGG1 TGG2 enzymatically active. An immunogold analysis...
Abstract The endoplasmic reticulum (ER) is composed of tubules, sheets, and three-way junctions, resulting in a highly conserved polygonal network all eukaryotes. molecular mechanisms responsible for the organization these structures are obscure. To identify novel factors ER morphology, we employed forward genetic approach using transgenic Arabidopsis thaliana plant (GFP-h) with fluorescently labeled ER. We isolated two mutants defects morphology designated them morphology1 (ermo1) ermo2....
Abstract Seed storage proteins are synthesized on the endoplasmic reticulum (ER) as precursors and then transported to protein vacuoles, where they processed into mature forms. Here, we isolated an Arabidopsis thaliana mutant, maigo2 (mag2), that accumulated of two major proteins, 2S albumin 12S globulin, in dry seeds. mag2 seed cells contained many novel structures, with electron-dense core was composed precursor forms albumin. globulins were segregated from localized matrix region...
Abstract The endoplasmic reticulum (ER) is a network of tubules and sheet-like structures in eukaryotic cells. Some ER dynamically change their morphology, others form stable structures. In plants, it has been thought that the tubule extension driven by actin-myosin machinery. Here, we show microtubules also contribute to with an almost 20-fold slower rate than actin filament-based extension. Treatment actin-depolymerizing drug Latrunculin B made possible visualize slow transgenic...
In normal leaf development, a two-dimensional pattern of veins is known to form by differentiation vascular cells from ground meristem in manner that regulated the polar flow auxin. However, mechanisms regulating distribution auxin primordium are largely unknown. Here we show vacuolar SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors), VAM3 and VTI11, required for formation network dosage-dependent manner. This first report pre-vacuolar compartment (PVC)–vacuole...
Abstract The reticular network of the endoplasmic reticulum (ER) consists tubular and lamellar elements is arranged in cortical region plant cells. This constantly shows shape change remodeling motion. Tubular ER structures were formed when GTP was added to vesicles isolated from tobacco (Nicotiana tabacum) cultured BY-2 cells expressing ER-localized green fluorescent protein. hydrolysis during tubule formation higher than that under conditions which not induced. Furthermore, a shearing...
Plants accumulate starch and triacylglycerols (TAGs) as carbon sources. Leaves primarily store in chloroplasts, with some TAGs stored lipid droplets, but how resource allocation is regulated leaves during cellular metabolism largely unknown. Using a forward genetics approach, we isolated an Arabidopsis thaliana mutant more droplets its than the wild type, named rich 1 (liri1). The overaccumulation of was caused by loss function causal gene, encoding uncharacterized protein. TAG levels were...
Endoplasmic reticulum exit sites (ERESs) are ER subdomains where coat protein complex II carriers assembled for ER-to-Golgi transport. We previously proposed a dynamic capture-and-release model of ERESs by Golgi stacks in plants. However, how and maintain stable interaction plant cells with vigorous cytoplasmic streaming is unknown. Here, we show that plant-specific transmembrane protein, which designate as MAG3, plays crucial role mediating the Arabidopsis. isolated mutant (mag3) defective...
SYP2 proteins are a sub-family of Qa-SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) that may be responsible for trafficking between pre-vacuolar compartments (PVC) and vacuoles. Arabidopsis thaliana SYP22/VAM3/SGR3 SYP21/PEP12 function independently, but both reported to essential male gametophytic viability. Here, we systematically examined the redundancy three paralogs (i.e. SYP21, 22 23) using Col-0 ecotype harboring paralog (SYP23/PLP) lacked...
The trans-Golgi network (TGN) is a tubular-vesicular organelle that matures from the trans cisternae of Golgi apparatus. In plants, TGN functions as central hub for three trafficking pathways: secretory pathway, vacuolar pathway and endocytic pathway. Here, we describe novel TGN-localized membrane protein, CONTINUOUS VASCULAR RING (COV1), crucial function in Arabidopsis. COV1 gene was originally identified stem vascular patterning mutant Arabidopsis thaliana. However, molecular not...
The endoplasmic reticulum (ER) consists of dynamically changing tubules and cisternae. In animals yeast, homotypic ER membrane fusion is mediated by fusogens (atlastin Sey1p, respectively) that are membrane-associated dynamin-like GTPases. Arabidopsis (Arabidopsis thaliana), another GTPase, ROOT HAIR DEFECTIVE3 (RHD3), has been proposed as an fusogen, but direct evidence lacking. Here, we show RHD3 activity enhanced phosphorylation its C terminus. network was RHD3-dependently reconstituted...
The plant endoplasmic reticulum (ER), which is morphologically divided into tubules and sheets, seems to flow continuously as a whole, but locally, mobile immobile regions exist. In eukaryotes, the ER physically functionally interacts with plasma membrane (PM) at domains called ER-PM contact sites (EPCSs). Extended synaptotagmin family proteins are concentrated in cortical form one type of EPCS; however, it unclear whether localization extended corresponds EPCS where EPCSs formed. Here, we...
Autophagy is an essential system for degrading and recycling cellular components survival during starvation conditions. Under sucrose starvation, application of a papain protease inhibitor E-64d to the Arabidopsis root tobacco BY-2 cells induced accumulation vesicles, labeled with fluorescent membrane marker FM4-64. The E-64d-induced vesicle was reduced in mutant defective autophagy-related genes ATG2, ATG5, ATG7, suggesting autophagy involved formation these vesicles. To clarify vesicles...
The short stem and midrib (ssm) mutants of Arabidopsis thaliana show both semi-dwarf wavy leaf phenotypes due to defects in the elongation internodes leaves. Moreover, these abnormalities cannot be recovered by exogenous phytohormones. ssm was originally identified as a single recessive mutant ecotype Columbia (Col-0), but genetic crossing experiments have revealed that this phenotype is restored another gene functional Landsberg erecta (Ler) not Col-0. Map-based cloning defective has...
The adaptor protein (AP) complexes play crucial roles in vesicle formation post-Golgi trafficking. Land plants have five types of AP (AP-1 to AP-5), each which consists two large subunits, one medium subunit and small subunit. Here, we show that the Arabidopsis AP-1 complex mediates polarized secretion accumulation a pectic polysaccharide called mucilage seed coat cells. Previously, loss-of-function mutant AP1M2, AP-1, has been shown display deleterious growth defects because defective...
A lectin from the fruiting body of the<i>Psathyrella velutina</i> mushroom (PVL) was found to bind specifically <i>N</i>-acetylneuraminic acid, as well GlcNAc (Ueda, H., Kojima, K., Saitoh, T., and Ogawa, H. (1999)<i>FEBS Lett.</i> 448, 75–80). In this study, glycan sequences that PVL recognizes with high affinity on sialoglycoproteins were revealed. Among sialic acid-specific lectins only could reveal sialylated <i>N</i>-acetyllactosamine structure glycoproteins in blotting studies, based...