Pollen fertility is a crucial factor for successful pollination and essential for seed formation. Recent studies have suggested that a diverse range of internal and external factors, signaling components and their rel...Pollen fertility is a crucial factor for successful pollination and essential for seed formation. Recent studies have suggested that a diverse range of internal and external factors, signaling components and their related pathways are likely involved in pollen fertility. Here, we report a single C2-domain containing protein, OsPBP1, initially identified through cDNA microarray analysis. OsPBP1 is a single copy gene and preferentially expressed in pistil and pollen but downregulated by pollination. OsPBP1 had a calcium concentration-dependent phospholipid-binding activity and was localized mainly in cytoplasm and nucleus, but translocated onto the plasma membrane in response to an intracellular Ca^2＋ increase. Pollen grains of antisense OsPBP1 transgenic lines were largely nonviable, germinated poorly in vitro and of low fertility. OsPBP1 protein was localized in a region peripheral to pollen wall and vesicles of elongating pollen tube, and its repressed expression reduced substantially this association and led to alteration of microfilament polymerization during pollen germination. Taken together, these results indicate that OsPBP1 is a novel functional C2-domain phospholipids-binding protein that is required for pollen fertility likely by regulating Ca^2＋ and phospholipid signaling pathways.展开更多
运用还原论和整体论,剖析战争复杂性处理的一般思维:分解和综合.基于宏观尺度上指挥与控制(Command and Control,C2)活动的一般过程PREA环,分析体系作战复杂问题分解后的典型特征:多域性、并发性、异步性和冲突性,建立宏观作战体系C2活...运用还原论和整体论,剖析战争复杂性处理的一般思维:分解和综合.基于宏观尺度上指挥与控制(Command and Control,C2)活动的一般过程PREA环,分析体系作战复杂问题分解后的典型特征:多域性、并发性、异步性和冲突性,建立宏观作战体系C2活动内核框架.以宏观体系的稳定有序运行为目的,分析多域多环并发异步运行的冲突类型及冲突协调方法,建立宏观作战体系指挥控制过程多域多PREA环异步运行及冲突协调管理模型.以美海军航母打击大队指挥体制与指挥方式为例,运用冲突协调管理模型解释其科学性.基于多域多PREA环异步并发运行及冲突协调模型分析,提出宏观作战体系C2活动的指导.展开更多
钙离子作为植物细胞的第二信使,广泛参与植物应对不同逆境胁迫的信号调控过程。水稻G蛋白促进蛋白1(Oryza sativa GTPase-activating protein 1,OsGAP1)包含1个C2结构域,而含C2结构域的蛋白质是一类钙离子结合蛋白质,受钙信号的调控。...钙离子作为植物细胞的第二信使,广泛参与植物应对不同逆境胁迫的信号调控过程。水稻G蛋白促进蛋白1(Oryza sativa GTPase-activating protein 1,OsGAP1)包含1个C2结构域,而含C2结构域的蛋白质是一类钙离子结合蛋白质,受钙信号的调控。本研究鉴定了水稻OsGAP1的由5个保守性天冬氨酸残基组成的阳离子结合区域。该区域可结合2个钙离子或者钾离子,且其结合钙离子的强度高于其结合钾离子的强度,但是不能结合镁离子。当将其中2个保守的天冬氨酸残基(Asp-23和Asp-28)突变为丙氨酸后,其对钙离子的结合能力减弱。对OsGAP1 C2结构域阳离子结合区域结合金属离子能力的研究,有助于加深对钙信号调控蛋白质的认识,为其在农业生产中的应用提供理论依据。展开更多
Arabidopsis synaptotagmin 2 （SYT2） has been reported to participate in an unconventional secretory pathway in somatic cells. Our results showed that SYT2 was expressed mainly in the pollen ofArabidopsis thaliana. Th...Arabidopsis synaptotagmin 2 （SYT2） has been reported to participate in an unconventional secretory pathway in somatic cells. Our results showed that SYT2 was expressed mainly in the pollen ofArabidopsis thaliana. The pollen of syt2 T-DNA and RNA interference mutant lines exhibited reduced total germination and impeded pollen tube growth. Analysis of the expression of SYT2-GFP fusion protein in the pollen tube indicates that SYT2 was localized to distinct, patchy compartments but could co-localize with the Golgi markers, BODIPY TR C5 ceramide and GmManl-mCherry. However, SYT2-DsRed-E5 was localized to the plasma membrane in Arabidopsis suspension cells, in addition to the Golgi apparatus. The localization of SYT2 at the plasma membrane was further supported by immunofluorescence staining in pollen tubes. Moreover, brefeldin A treatment inhibited the transport of SYT2 to the plasma membrane and caused SYT2 to aggregate and form enlarged compartments. Truncation of the SYT2-C2AB domains also resulted in retention of SYT2 in the Golgi apparatus. An in vitro phospholipid-binding assay showed that SYT2-C2AB domains bind to the phospholipid membrane in a calcium-dependent manner. Take together, our results indicated that SYT2 was required for pollen germination and pollen tube growth, and was involved in conventional exocytosis.展开更多
In this paper we report that the C2 domain of synaptotagmin I (syt I) could associate with lipid rafts of plasma membrane. We demonstrate that phosphatidylinositol 4,5-bisphosphate (PIP2) in the target membrane and Ca...In this paper we report that the C2 domain of synaptotagmin I (syt I) could associate with lipid rafts of plasma membrane. We demonstrate that phosphatidylinositol 4,5-bisphosphate (PIP2) in the target membrane and Ca2+ are the key factors to enhance the raft association of the C2 domain. We also found that the raft association of the C2 domain could be fulfilled by either C2A or C2B alone, suggesting that their raft association might be complementary. Finally, we indicate that destroying lipid rafts or blocking syt I-raft association could significantly reduce the Ca2+-driven release of glutamates. Our data indicate that the raft association of the C2 domain might play an important role in the regulated exocytosis.展开更多
文摘Pollen fertility is a crucial factor for successful pollination and essential for seed formation. Recent studies have suggested that a diverse range of internal and external factors, signaling components and their related pathways are likely involved in pollen fertility. Here, we report a single C2-domain containing protein, OsPBP1, initially identified through cDNA microarray analysis. OsPBP1 is a single copy gene and preferentially expressed in pistil and pollen but downregulated by pollination. OsPBP1 had a calcium concentration-dependent phospholipid-binding activity and was localized mainly in cytoplasm and nucleus, but translocated onto the plasma membrane in response to an intracellular Ca^2＋ increase. Pollen grains of antisense OsPBP1 transgenic lines were largely nonviable, germinated poorly in vitro and of low fertility. OsPBP1 protein was localized in a region peripheral to pollen wall and vesicles of elongating pollen tube, and its repressed expression reduced substantially this association and led to alteration of microfilament polymerization during pollen germination. Taken together, these results indicate that OsPBP1 is a novel functional C2-domain phospholipids-binding protein that is required for pollen fertility likely by regulating Ca^2＋ and phospholipid signaling pathways.
文摘运用还原论和整体论,剖析战争复杂性处理的一般思维:分解和综合.基于宏观尺度上指挥与控制(Command and Control,C2)活动的一般过程PREA环,分析体系作战复杂问题分解后的典型特征:多域性、并发性、异步性和冲突性,建立宏观作战体系C2活动内核框架.以宏观体系的稳定有序运行为目的,分析多域多环并发异步运行的冲突类型及冲突协调方法,建立宏观作战体系指挥控制过程多域多PREA环异步运行及冲突协调管理模型.以美海军航母打击大队指挥体制与指挥方式为例,运用冲突协调管理模型解释其科学性.基于多域多PREA环异步并发运行及冲突协调模型分析,提出宏观作战体系C2活动的指导.
文摘Arabidopsis synaptotagmin 2 （SYT2） has been reported to participate in an unconventional secretory pathway in somatic cells. Our results showed that SYT2 was expressed mainly in the pollen ofArabidopsis thaliana. The pollen of syt2 T-DNA and RNA interference mutant lines exhibited reduced total germination and impeded pollen tube growth. Analysis of the expression of SYT2-GFP fusion protein in the pollen tube indicates that SYT2 was localized to distinct, patchy compartments but could co-localize with the Golgi markers, BODIPY TR C5 ceramide and GmManl-mCherry. However, SYT2-DsRed-E5 was localized to the plasma membrane in Arabidopsis suspension cells, in addition to the Golgi apparatus. The localization of SYT2 at the plasma membrane was further supported by immunofluorescence staining in pollen tubes. Moreover, brefeldin A treatment inhibited the transport of SYT2 to the plasma membrane and caused SYT2 to aggregate and form enlarged compartments. Truncation of the SYT2-C2AB domains also resulted in retention of SYT2 in the Golgi apparatus. An in vitro phospholipid-binding assay showed that SYT2-C2AB domains bind to the phospholipid membrane in a calcium-dependent manner. Take together, our results indicated that SYT2 was required for pollen germination and pollen tube growth, and was involved in conventional exocytosis.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 30670501 and 30628007)the National Basic Research Program of China (Grant No. 2004 CB720005)
文摘In this paper we report that the C2 domain of synaptotagmin I (syt I) could associate with lipid rafts of plasma membrane. We demonstrate that phosphatidylinositol 4,5-bisphosphate (PIP2) in the target membrane and Ca2+ are the key factors to enhance the raft association of the C2 domain. We also found that the raft association of the C2 domain could be fulfilled by either C2A or C2B alone, suggesting that their raft association might be complementary. Finally, we indicate that destroying lipid rafts or blocking syt I-raft association could significantly reduce the Ca2+-driven release of glutamates. Our data indicate that the raft association of the C2 domain might play an important role in the regulated exocytosis.
