Yoji Kawano

Okayama University · Institute of Plant Sciences and Resources

The nucleotide-binding domain and leucine-rich repeat-containing (NLR) family proteins recognize pathogen-derived molecules and trigger immune responses in both plants and animals. In plants, the direct or indirect recognition of specific pathogen effectors by NLRs culminates in a hypersensitive response (HR) and the production of reactive oxygen s...

Significance The plant genome encodes resistance ( R ) genes that are one of the major genomic resources to enhance disease resistance in various crops. R gene products, R proteins, serve as intracellular receptors for pathogen effectors, leading to activation of effector-triggered immunity. Due to the importance of R proteins, elucidation of their...

Small signaling peptides, generated from larger protein precursors, are important components to orchestrate various plant processes such as development and immune responses. However, small signaling peptides involved in plant immunity remain largely unknown. Here, we developed a pipeline using transcriptomicsand proteomics‐based screening to identi...

Plants employ two different types of immune receptors, cell surface pattern recognition receptors (PRRs) and intracellular nucleotide-binding and leucine-rich repeat-containing proteins (NLRs), to cope with pathogen invasion. Both immune receptors often share similar downstream components and responses but it remains unknown whether a PRR and an NL...

Nucleotide‐binding leucine‐rich repeat (NLR) proteins work as crucial intracellular immune receptors. N‐terminal domains of NLRs fall into two groups, coiled‐coil (CC) and Toll‐interleukin 1 receptor domains, which play critical roles in signal transduction and disease resistance. However, the activation mechanisms of NLRs, and how their N‐termini...

Small signaling peptides play important roles in various plant processes, but information regarding their involvement in plant immunity is limited. We previously identified a novel small secreted protein in rice, named immune response peptide 1 (IRP1). Here, we studied IRP1 functions in rice immunity. Rice plants overexpressing IRP1 enhanced resist...

Organophosphate is the commonly used pesticide to control pest outbreak, such as those by aphids in many crops. Despite its wide use, however, necrotic lesion and/or cell death following the application of organophosphate pesticides has been reported to occur in several species. To understand this phenomenon, called organophosphate pesticide sensit...

Small signaling peptides play important roles in various plant processes, but information regarding their involvement in plant immunity is limited. We previously identified a novel small secreted protein in rice, named immune response peptide (IRP) by the integrated multi-omics analyses. Here, we studied IRP functions in rice immunity. Rice plants...

Background Small GTPases act as molecular switches that regulate various plant responses such as disease resistance, pollen tube growth, root hair development, cell wall patterning and hormone responses. Thus, to monitor their activation status within plant cells is believed to be the key step in understanding their roles. Results We have establis...

Plant height has a major effect on grain yield in crops such as rice (Oryza sativa), and the hormone gibberellic acid (GA) regulates many developmental processes that feed into plant height. Rice ELONGATED UPPERMOST INTERNODE 1 (Eui1) encodes a GA-deactivating enzyme governing elongation of uppermost internode. The expression of Eui1 is finely tune...

Small GTPases act as molecular switches that regulate various plant responses such as disease resistance, pollen tube growth, root hair development, cell wall patterning and hormone responses. Thus, to monitor their activation status within plant cells is believed to be the key step in understanding their roles. We have established a plant version...

Numerous plant defense-related proteins are thought to congregate in plasma membrane microdomains, which consist mainly of sphingolipids and sterols. However, the extent to which microdomains contribute to defense responses in plants is unclear. To elucidate the relationship between microdomains and innate immunity in rice (Oryza sativa), we establ...

Rice is one of the most important food crops, feeding about half population in the world. Rice pathogens cause enormous damage to rice production worldwide. In plant immunity research, considerable progress has recently been made in our understanding of the molecular mechanisms underlying microbe-associated molecular pattern (MAMP)-triggered immuni...

Molecular links between receptor-kinases and Rac/ROP family small GTPases mediated by activator guanine nucleotide exchange factors (GEFs) govern diverse biological processes. However, it is unclear how the Rac/ROP GTPases orchestrate such a wide variety of activities. Here, we show that rice OsRacGEF1 forms homodimers, and heterodimers with OsRacG...

The ubiquitin proteasome system in plants plays important roles in plant-microbe interactions and in immune responses to pathogens. We previously demonstrated that the rice U-box E3 ligase SPL11 and its Arabidopsis ortholog PUB13 negatively regulate programmed cell death (PCD) and defense response. However, the components involved in the SPL11/ PUB...

In plants, sophisticated forms of immune systems have developed to cope with a variety of pathogens. Accumulating evidence indicates that Rac (also known as Rop), a member of the Rho family of small GTPases, is a key regulator of immunity in plants and animals. Like other small GTPases, Rac/Rop GTPases function as a molecular switch downstream of i...

Rac/Rop proteins are Rho-type small GTPase that act as molecular switches in plants. Recent studies have identified these proteins as key components in many major plant signaling pathways such as innate immunity, pollen tube growth and root hair formation. In rice, the Rac/Rop protein OsRac1 plays an important role in regulating the production of r...

Plant resistance proteins of the class of nucleotide-binding and leucine-rich repeat domain proteins (NB-LRRs) are immune sensors which recognize pathogen-derived molecules termed avirulence (AVR) proteins. We show that RGA4 and RGA5, two NB-LRRs from rice, interact functionally and physically to mediate resistance to the fungal pathogen Magnaporth...

Nucleotide-binding domain and leucine-rich repeat (NLR)-containing family proteins function as intracellular immune sensors in both plants and animals. In plants, the downstream components activated by NLR family proteins and the immune response mechanisms induced by these downstream molecules are largely unknown. We have previously found that the...

Membrane traffic plays a crucial role in delivering proteins and lipids to their intracellular destinations. We previously identified α-taxilin as a binding partner of the syntaxin family, which is involved in intracellular vesicle traffic. α-Taxilin is overexpressed in tumor tissues and interacts with polymerized tubulin, but the precise function...

OsRac1 is a member of the plant small GTPase Rac/Rop family and plays a key role in rice immunity. The constitutively active (CA) G19V mutation of OsRac1 was previously shown to induce reactive oxygen species production, phytoalexin synthesis and defense gene activation, leading to resistance to rice blast infection. To study further the effect of...

OsCEBiP, a chitin-binding protein, and OsCERK1, a receptor-like kinase, are plasma membrane (PM) proteins that form a receptor complex essential for fungal chitin-driven immune responses in rice. The signaling events immediately following chitin perception are unclear. Investigating the spatiotemporal regulation of the rice small GTPase OsRac1, we...

Background The rice small GTPase OsRac1 is a molecular switch in rice innate immunity. The Receptor for Activated Kinase C-1 (RACK1) interacts with OsRac1 to suppress the growth of the rice blast fungus, Magnaporthe oryzae. RACK1 has two homologs in rice, RACK1A and RACK1B. Overexpressing RACK1A enhances resistance to the rice blast fungus. However...

Myosin light chain (MLC) phosphorylation plays important roles in various cellular functions such as cellular morphogenesis, motility, and smooth muscle contraction. MLC phosphorylation is determined by the balance between activities of Rho-associated kinase (Rho-kinase) and myosin phosphatase. An impaired balance between Rho-kinase and myosin phos...

Intracellular vesicle traffic plays an essential role in the establishment and maintenance of organelle identity and biosynthetic transport. We have identified α-taxilin as a binding partner of the syntaxin family, which is involved in intracellular vesicle traffic. Recently, we have found that α-taxilin is over-expressed in malignant tissues inclu...

The Rac/Rop GTPase OsRac1 plays an essential role in rice immunity. However, the regulatory genes acting downstream of OsRac1 are largely unknown. We focused on the RAI1 gene, which is up-regulated in suspension cells expressing a constitutively active form of OsRac1. RAI1 encodes a putative basic helix–loop–helix transcription factor. A microarray...

Two types of innate immune receptors, pattern recognition receptors, and resistance proteins, play crucial roles in plant innate immunity; however, the molecules activated by the receptors and how immune responses are transmitted are not well understood. Evidence has been accumulating for a decade that Rac, a small guanosine triphosphatase (GTPase;...

Small GTPase OsRac1 is a key regulator for induction of immune responses in rice. Activation of OsRac1 induces NADPH oxidase-mediated reactive oxygen species (ROS) production, PR gene expression, production of antimicrobial compounds, and lignification, which result in enhanced resistance to Magnaporthe oryzae and Xanthomonas oryzae. Inhibition of...

Rho belongs to the Rho family guanosine triphosphatases (GTPases) including Rho, Rac, Cdc42, TC10, and so on. Rho is categorized into RhoA, B, and C. The Rho family GTPases exhibit guanine nucleotide-binding activity and function as molecular switches by cycling between an inactive guanosine diphosphate (GDP)-bound form and an active GTP-bound form...

The establishment of a polarized morphology is an essential event in the differentiation of neurons into a single axon and dendrites. We previously showed that glycogen synthase kinase-3beta (GSK-3beta) is critical for specifying axon/dendrite fate by the regulation of the phosphorylation of collapsin response mediator protein-2 (CRMP-2). Here, we...

A neuron has two types of highly polarized cell processes, the single axon and multiple dendrites. One of the fundamental questions of neurobiology is how neurons acquire such specific and polarized morphologies. During neuronal development, various actin-binding proteins regulate dynamics of actin cytoskeleton in the growth cones of developing axo...

Collapsin response mediator protein 2 (CRMP-2) enhances the advance of growth cones by regulating microtubule assembly and Numb-mediated endocytosis. We previously showed that Rho kinase phosphorylates CRMP-2 during growth cone collapse; however, the roles of phosphorylated CRMP-2 in growth cone collapse remain to be clarified. Here, we report that...

After binding of epidermal growth factor (EGF), the EGF receptor is activated, internalized by endocytosis, and subsequently degraded in the lysosomal pathway. Endocytotic trafficking of the activated EGF receptor is essential for controlling EGF signaling. Upon ligand-induced activation of EGF receptors, Cbl (ubiquitin ligase) binds to the activat...

Neurons are one of the most highly polarized cells known and are comprised of two structurally and functionally distinct parts, an axon and dendrites. The specification of the axon is thought to depend on its length relative to the other minor processes, which are called immature neurites. Elongation of one of immature neurites is necessary for axo...

Neurons are highly polarized and comprised of two structurally and functionally distinct parts, an axon and dendrites. We previously showed that collapsin response mediator protein-2 (CRMP-2) is critical for specifying axon/dendrite fate, possibly by promoting neurite elongation via microtubule assembly. Here, we showed that glycogen synthase kinas...

An increment in a cytoplasmic Ca2+ concentration is the key event in smooth muscle contraction. However, smooth muscle contraction is modified upon the stimulation by agonists as well as in some pathophysiological situations through a Ca(2+)-independent mechanism. The molecular mechanism underlying this modulation has not been elucidated. Small GTP...

Abnormal contraction of vascular smooth muscle contributes to a variety of diseases such as hypertension and vasospasm in coronary and cerebral arteries. An increment in a cytoplasmic Ca2+ concentration is the key event in smooth muscle contraction. However, smooth muscle contraction is modified upon the stimulation by agonists as well as in some p...

In cultured hippocampal neurons, one axon and several dendrites differentiate from a common immature process. Here we found that CRMP-2/TOAD-64/Ulip2/DRP-2 (refs. 2-4) level was higher in growing axons of cultured hippocampal neurons, that overexpression of CRMP-2 in the cells led to the formation of supernumerary axons and that expression of trunc...

We recently demonstrated that the Rho-kinase-mediated pathway plays an important role for coronary artery spasm in our porcine model with interleukin-1beta (IL-1beta). In this study, we examined whether or not Rho-kinase is upregulated at the spastic site and if so, how it induces vascular smooth muscle hypercontraction. Segments of the left porcin...

Rho-associated kinase (Rho-kinase), which is activated by the small GTPase Rho, phosphorylates myosin-binding subunit (MBS) of myosin phosphatase and thereby inactivates the phosphatase activity in vitro. Rho-kinase is thought to regulate the phosphorylation state of the substrates including myosin light chain (MLC), ERM (ezrin/radixin/moesin) fami...

AF-6 contains two putative Ras-associating domains (RA domains) which are seen in several Ras effectors such as RalGDS and RIN1. We previously showed that an AF-6 fragment containing the amino-terminal (N-terminal) RA domain directly binds to activated Ras and ZO-1 in vitro. In this study, we showed that a single amino acid mutation in the N-termin...

Adducin is a membrane skeletal protein that binds to actin filaments (F-actin) and thereby promotes the association of spectrin with F-actin to form a spectrin-actin meshwork beneath plasma membranes such as ruffling membranes. Rho-associated kinase (Rho- kinase), which is activated by the small guanosine triphosphatase Rho, phosphorylates alpha-ad...

The Ras target AF-6 has been shown to serve as one of the peripheral components of cell-cell adhesions, and is thought to participate in cell-cell adhesion regulation downstream of Ras. We here purified an AF-6-interacting protein with a molecular mass of approximately 220 kD (p220) to investigate the function of AF-6 at cell-cell adhesions. The pe...

http://library.naist.jp/mylimedio/dllimedio/show.cgi?bookid=95305 博士 (Doctor) バイオサイエンス (Bioscience) 博第148号 甲第148号