Biology subjects

Fujita, S.

Publications and source records attributed to Fujita, S..

40 records · Page 3Linked to original sources

bioRxiv2019

ROS production by localized SCHENGEN receptor module drives lignification at subcellular precision

Production of reactive-oxygen species (ROS) by NADPH oxidases (NOXs) impacts many processes in animals and plants and many plant receptor pathways involve rapid, NOX-dependent increases of ROS. Yet, their general reactivity has made it challenging to pinpoint the precise role and direct cellular targets of ROS. A well-understood ROS target in plants are lignin peroxidases in the cell wall. Lignin can be deposited with exquisite spatial control, but the underlying mechanisms have remained elusive. Here we establish a full kinase signaling relay that exerts direct, spatial control over ROS production and lignification within the cell wall. We show that polar localization of a single kinase component is crucial for pathway function. Our data indicates that an intersection of more broadly localized components allows for micrometer-scale precision of lignification and that this system is triggered through initiation of ROS production as a critical peroxidase co-substrate.

plant biology↗

bioRxiv2019

A two-way molecular dialogue between embryo and endosperm required for seed development

The plant embryonic cuticle is a hydrophobic barrier deposited de novo by the embryo during seed development. At germination it protects the seedling from water loss and is thus critical for survival. Embryonic cuticle formation is controlled by a signaling pathway involving the protease ALE1 and the receptor-like kinases GSO1 and GSO2. We show that a sulfated peptide, TWISTED SEED1 (TWS1) acts as a GSO1/GSO2 ligand. Cuticle surveillance depends on the action of ALE1 which, unlike TWS1 and GSO1/2, is not produced in the embryo but in the neighboring endosperm. Cleavage of an embryo-derived TWS1 precursor by ALE1 releases the active peptide, triggering GSO1/2-dependent cuticle reinforcement in the embryo. A bidirectional molecular dialogue between embryo and endosperm thus safeguards cuticle integrity prior to germination.\n\nOne Sentence SummarySubtilase-mediated activation of the TWISTED SEED1 peptide provides spatial cues during embryo cuticle integrity monitoring.

plant biology↗

bioRxiv2019

Molecular mechanism for the recognition of sequence-divergent CIF peptides by the plant receptor kinases GSO1/SGN3 and GSO2.

Plants use leucine-rich repeat receptor kinases (LRR-RKs) to sense sequence diverse peptide hormones at the cell surface. A 3.0 [A] crystal structure of the LRR-RK GSO1/SGN3 regulating Casparian strip formation in the endodermis reveals a large spiral-shaped ectodomain. The domain provides a binding platform for 21 amino-acid CIF peptide ligands, which are tyrosine sulfated by the tyrosylprotein sulfotransferase TPST/SGN2. GSO1/SGN3 harbors a binding pocket for sulfotyrosine and makes extended backbone interactions with CIF2. Quantitative biochemical comparisons reveal that GSO1/SGN3 - CIF2 represents one of the strongest receptor-ligand pairs known in plants. Multiple missense mutations are required to block CIF2 binding in vitro, and GSO1/SGN3 function in vivo. Using structure-guided sequence analysis we uncover novel CIF peptides conserved among higher plants. Quantitative binding assays with known and novel CIFs suggest that the homologous LRR-RKs GSO1/SGN3 and GSO2 have evolved unique peptide binding properties to control different developmental processes. A quantitative biochemical interaction screen, a CIF peptide antagonist and genetic analyses together implicate SERK LRR-RKs as essential co-receptor kinases required for GSO1/SGN3 and GSO2 receptor activation. 0ur work provides a mechanistic framework for the recognition of sequence-divergent peptide hormones in plants.\n\nSignificance StatementTwo sequence-related plant membrane receptor kinases and their shape-complementary co-receptors are shown to selectively sense members of a small family of secreted peptide hormones to control formation of an important diffusion barrier in the plant root.

plant biology↗

bioRxiv2018

Logical design of oral glucose ingestion pattern minimizing blood glucose in humans

Excessive increase in blood glucose level after eating increases the risk of macroangiopathy, and a method for not increasing the postprandial blood glucose level is desired. However, a logical design method of the dietary ingestion pattern controlling the postprandial blood glucose 2 level has not yet been established. We constructed a mathematical model of blood glucose control by oral glucose ingestion in 3 healthy human subjects, used the model to predict an optimal glucose ingestion pattern, and showed that the optimal ingestion pattern minimized the peak value of blood glucose level. Subjects orally ingested 3 doses of glucose by bolus or over 2 hours, and blood glucose, insulin, C-peptide and incretins were measured for 4 hours. We constructed an ordinary differential equation model that reproduced the time course data of the blood glucose and blood hormone levels. Using the model, we predicted that intermittent ingestion 30 minutes apart was the optimal glucose ingestion patterns that minimized the peak value of blood glucose level. We confirmed with subjects that this intermittent pattern decreased the peak value of blood glucose level. This approach could be applied to design optimal dietary ingestion patterns.\n\nIn BriefAs a forward problem, we measured blood glucose and hormones in three human subjects after oral glucose ingestion and constructed a mathematical model of blood glucose control. As an inverse problem, we used the model to predict the optimal oral glucose ingestion pattern that minimized the peak value of blood glucose level, and validated the pattern with the subjects.\n\nHighlightsO_LIModeling blood glucose concentrations predicts an intermittent ingestion pattern is optimal\nC_LIO_LIHuman validation shows ingestion at 30-minute intervals limits peak blood glucose\nC_LIO_LIWe provide a strategy to design optimal dietary ingestion patterns\nC_LI

systems biology↗