The dynamic assembly of the actin cytoskeleton is vital for Magnaporthe oryzae development and host infection.The actin-related protein MoFim1 is a key factor for organizing the M.oryzae actin cytoskeleton.Currently,h...The dynamic assembly of the actin cytoskeleton is vital for Magnaporthe oryzae development and host infection.The actin-related protein MoFim1 is a key factor for organizing the M.oryzae actin cytoskeleton.Currently,how MoFim1 is regulated in M.oryzae to precisely rearrange the actin cytoskeleton is unclear.In this study,we found that MoFim1 associates with the M.oryzae mitogen-activated protein(MAP)kinase Pmk1 to regulate actin assembly.MoFim1 directly interacted with Pmk1,and the phosphorylation level of MoFim1 was decreased inΔpmk1,which led to a change in the subcellular distribution of MoFim1 in the hyphae ofΔpmk1.Moreover,the actin cytoskeleton was aberrantly organized at the hyphal tip in theΔpmk1,which was similar to what was observed in theΔmofim1 during hyphal growth.Furthermore,phosphorylation analysis revealed that Pmk1 could phosphorylate MoFim1 at serine 94.Loss of phosphorylation of MoFim1 at serine 94 decreased actin bundling activity.Additionally,the expression of the site mutant of MoFim1 S94D(in which serine 94 was replaced with aspartate to mimic phosphorylation)inΔpmk1 could reverse the defects in actin organization and hyphal growth inΔpmk1.It also partially rescues the formation of appressorium failure inΔpmk1.Taken together,these findings suggest a regulatory mechanism in which Pmk1 phosphorylates MoFim1 to regulate the assembly of the actin cytoskeleton during hyphal development and pathogenesis.展开更多
Plastins are a family of actin binding proteins （ABPs） known to cross-link actin microfilaments in mammalian cells, creating actin microfilament bundles necessary to confer cell polarity and cell shape. Plastins als...Plastins are a family of actin binding proteins （ABPs） known to cross-link actin microfilaments in mammalian cells, creating actin microfilament bundles necessary to confer cell polarity and cell shape. Plastins also support cell movement in response to changes in environment, involved in cell/tissue growth and development. They also confer plasticity to cells and tissues in response to infection or other pathological conditions （e.g., inflammation）. In the testis, the cell-cell anchoring junction unique to the testis that is found at the Sertoli cell-cell interface at the blood-testis barrier （BTB） and at the Sertoli-spermatid （e.g., 8-19 spermatids in the rat testis） is the basal and the apical ectoplasmic specialization （ES）, respectively. The ES is an F-actin-rich anchoring junction constituted most notably by actin microfilament bundles. A recent report using RNAi that specifically knocks down plastin 3 has yielded some insightful information regarding the mechanism by which plastin 3 regulates the status of actin microfilament bundles at the ES via its intrinsic actin filament bundling activity. Herein, we provide a brief review on the role of plastins in the testis in light of this report, which together with recent findings in the field, we propose a likely model by which plastins regulate ES function during the epithelial cycle of sDermatogenesis via their intrinsic activity on actin microfilament organization in the rat testis.展开更多
Fimbrin, a regulator of actin cytoskeletal dynamics that participates in numerous physiological and biochemical processes, controls multiple developmental processes in a variety of tissues and cell types. However, the...Fimbrin, a regulator of actin cytoskeletal dynamics that participates in numerous physiological and biochemical processes, controls multiple developmental processes in a variety of tissues and cell types. However, the role of fimbrin in pathogen defense of wheat and the mechanisms have not been well studied. Here, we investigated that the expression of TaFIM1 gene of wheat was significantly induced in response to avirulent race of Puccinia striiformis f. sp. tritici(Pst) and silencing of TaFIM1 by virus-induced gene silencing method. The results show that silencing of TaFIM1 resulted in a reduction of resistance against the stripe rust indicated by both phenotypes and a histological examination of Pst growth. Additionally, the expression level of Ta FIM1 gene was up-regulated under abiotic stresses. These findings suggest that Ta FIM1 functions as a positive regulator of pathogen resistance of wheat plants and response to abiotic stress. Our work may show new light on understanding the roles of fimbrin in wheat.展开更多
Organelles form essential compartments of all eukaryotic cells. Mechanisms that ensure the unbiased inheritance of organelles during cell division are therefore necessary to maintain the viability of future cell gener...Organelles form essential compartments of all eukaryotic cells. Mechanisms that ensure the unbiased inheritance of organelles during cell division are therefore necessary to maintain the viability of future cell generations. Although inheritance of organelles represents a fundamental component of the cell cycle, surprisingly little is known about the underlying mechanisms that facilitate unbiased organelle inheritance. Evidence from a select number of studies, however, indicates that ordered organelle inheritance strategies exist in dividing cells of higher plants. The basic requirement for unbiased organelle inheritance is the duplication of organelle volume and distribution of the resulting organelle populations in a manner that facilitates unbiased partitioning of the organelle population to each daughter cell. Often, partitioning strategies are specific to the organelle, being influenced by the functional requirements of the organelle and whether the cells are mitotically active or re-entering into the cell cycle. Organelle partitioning mechanisms frequently depend on interactions with either the actin or microtubule cytoskeleton. In this focused review, we attempt to summarize key findings regarding organelle partitioning strategies in dividing cells of higher plants. We particularly concentrate on the role of the cytoskeleton in mediating unbiased organelle partitioning.展开更多
基金funded by the Natural Science Foundation of Fujian Province,China(2022J01616 and 2023J01483)the Distinguished Young Scientists Fund of Fujian Agriculture and Forestry University of China(xjq202121)+1 种基金the National Natural Science Foundation of China(grant numbers.31970284,31900385)the Fujian Provincial Science and Technology Key Project(2022NZ030014).
文摘The dynamic assembly of the actin cytoskeleton is vital for Magnaporthe oryzae development and host infection.The actin-related protein MoFim1 is a key factor for organizing the M.oryzae actin cytoskeleton.Currently,how MoFim1 is regulated in M.oryzae to precisely rearrange the actin cytoskeleton is unclear.In this study,we found that MoFim1 associates with the M.oryzae mitogen-activated protein(MAP)kinase Pmk1 to regulate actin assembly.MoFim1 directly interacted with Pmk1,and the phosphorylation level of MoFim1 was decreased inΔpmk1,which led to a change in the subcellular distribution of MoFim1 in the hyphae ofΔpmk1.Moreover,the actin cytoskeleton was aberrantly organized at the hyphal tip in theΔpmk1,which was similar to what was observed in theΔmofim1 during hyphal growth.Furthermore,phosphorylation analysis revealed that Pmk1 could phosphorylate MoFim1 at serine 94.Loss of phosphorylation of MoFim1 at serine 94 decreased actin bundling activity.Additionally,the expression of the site mutant of MoFim1 S94D(in which serine 94 was replaced with aspartate to mimic phosphorylation)inΔpmk1 could reverse the defects in actin organization and hyphal growth inΔpmk1.It also partially rescues the formation of appressorium failure inΔpmk1.Taken together,these findings suggest a regulatory mechanism in which Pmk1 phosphorylates MoFim1 to regulate the assembly of the actin cytoskeleton during hyphal development and pathogenesis.
文摘Plastins are a family of actin binding proteins （ABPs） known to cross-link actin microfilaments in mammalian cells, creating actin microfilament bundles necessary to confer cell polarity and cell shape. Plastins also support cell movement in response to changes in environment, involved in cell/tissue growth and development. They also confer plasticity to cells and tissues in response to infection or other pathological conditions （e.g., inflammation）. In the testis, the cell-cell anchoring junction unique to the testis that is found at the Sertoli cell-cell interface at the blood-testis barrier （BTB） and at the Sertoli-spermatid （e.g., 8-19 spermatids in the rat testis） is the basal and the apical ectoplasmic specialization （ES）, respectively. The ES is an F-actin-rich anchoring junction constituted most notably by actin microfilament bundles. A recent report using RNAi that specifically knocks down plastin 3 has yielded some insightful information regarding the mechanism by which plastin 3 regulates the status of actin microfilament bundles at the ES via its intrinsic actin filament bundling activity. Herein, we provide a brief review on the role of plastins in the testis in light of this report, which together with recent findings in the field, we propose a likely model by which plastins regulate ES function during the epithelial cycle of sDermatogenesis via their intrinsic activity on actin microfilament organization in the rat testis.
基金supported by the National Natural Science Foundation of China (31571960)the NSFC-Xinjiang Joint Fund, China (U1903110)the 111 Project from the Ministry of Education of China (B07049)。
文摘Fimbrin, a regulator of actin cytoskeletal dynamics that participates in numerous physiological and biochemical processes, controls multiple developmental processes in a variety of tissues and cell types. However, the role of fimbrin in pathogen defense of wheat and the mechanisms have not been well studied. Here, we investigated that the expression of TaFIM1 gene of wheat was significantly induced in response to avirulent race of Puccinia striiformis f. sp. tritici(Pst) and silencing of TaFIM1 by virus-induced gene silencing method. The results show that silencing of TaFIM1 resulted in a reduction of resistance against the stripe rust indicated by both phenotypes and a histological examination of Pst growth. Additionally, the expression level of Ta FIM1 gene was up-regulated under abiotic stresses. These findings suggest that Ta FIM1 functions as a positive regulator of pathogen resistance of wheat plants and response to abiotic stress. Our work may show new light on understanding the roles of fimbrin in wheat.
基金Supported by an Australian Research Council Centre of Excellence Grant to The University of Newcastle Node of the Centre of Excellence for Integrative Legume Research (to R.J.R.)
文摘Organelles form essential compartments of all eukaryotic cells. Mechanisms that ensure the unbiased inheritance of organelles during cell division are therefore necessary to maintain the viability of future cell generations. Although inheritance of organelles represents a fundamental component of the cell cycle, surprisingly little is known about the underlying mechanisms that facilitate unbiased organelle inheritance. Evidence from a select number of studies, however, indicates that ordered organelle inheritance strategies exist in dividing cells of higher plants. The basic requirement for unbiased organelle inheritance is the duplication of organelle volume and distribution of the resulting organelle populations in a manner that facilitates unbiased partitioning of the organelle population to each daughter cell. Often, partitioning strategies are specific to the organelle, being influenced by the functional requirements of the organelle and whether the cells are mitotically active or re-entering into the cell cycle. Organelle partitioning mechanisms frequently depend on interactions with either the actin or microtubule cytoskeleton. In this focused review, we attempt to summarize key findings regarding organelle partitioning strategies in dividing cells of higher plants. We particularly concentrate on the role of the cytoskeleton in mediating unbiased organelle partitioning.
