Nuclear envelope proteins have important roles in chromatin organization and signal-dependent transcriptional regulation. A previous study reported that the inner nuclear membrane protein, Otefin （Ote）, was essentia...Nuclear envelope proteins have important roles in chromatin organization and signal-dependent transcriptional regulation. A previous study reported that the inner nuclear membrane protein, Otefin （Ote）, was essential for germline stem cell （GSC） maintenance via interaction with Smad complex. The interaction of Ore with the Smad complex recruits the barn locus to the nuclear periphery and subsequently results in bam transcriptional silencing, revealing that nuclear peripheral localization is essential for barn gene regulation. However, it remains unknown whether the nuclear peripheral localization is sufficient for barn silencing. To address this issue, we have established a tethering system, in which the Gal4 DNA binding domain （DBD） of the Flag：Gal4 DBD：Ote△LEM fusion protein physically interacts with the Gal4 binding sites upstream of bamP-gfp to artificially recruit the reporter gene gfp to the nuclear membrane. Our data demonstrated that the nuclear peripheral localization seemed to affect the expression of the target naked gene in S2 ceils. By contrast, in Drosophila germ cells, the nuclear membrane localization was not sufficient for gene silencing.展开更多
The TRPV4 cation channel is expressed in a broad range of tissues and participates in the generation of a Ca<sup>2+</sup> signal and/or depolarization of membrane potential. Here, human phosphoglucomutase-...The TRPV4 cation channel is expressed in a broad range of tissues and participates in the generation of a Ca<sup>2+</sup> signal and/or depolarization of membrane potential. Here, human phosphoglucomutase- 1 (PGM1), an enzyme that converts glucose-6 phosphate to glucose-1 phosphate in the glycolysis pathway, as the first auxiliary protein of TRPV4 Ca<sup>2+</sup> channels, is identified with yeast two hybrid system, coimmunoprecipitation, confocal microscopy, and GST pull-down assays. TRPV4 forms a complex with PGM1 through its C-terminal cytoplasmic domain. Because it is demonstrated that TRPV4 serine residue 824 (S824) is phosphorylated by serum/glucocorticoid regulated kinase 1, we elucidate the effect of TRPV4 S824 phosphorylation on TRPV association with PGM1. Even an inactivated mutant version of TRPV4, S824A, exhibited a decreased ability to bind PGM1, an activated phosphomimetic mutant version of TRPV4, S824D, exhibited enhanced binding to PGM1. Thus, formation of the TRPV4/PGM1 complex and localization of this complex to the plasma membrane appear to be regulated by the phosphorylation status of residue S824 in TRPV4. The newly identified interactor of TRPV4 may help the molecular pathways modulating transport activity or glucose metabolism, respectively.展开更多
Nucleotide-binding site leucine-rich repeat receptors (NBS-LRR/NLRs) are crucial intracellular immune proteins in plants. Previous article reported a novel NLR protein SUT1 (SUPPRESSORS OF TOPP4-1, 1), which is involv...Nucleotide-binding site leucine-rich repeat receptors (NBS-LRR/NLRs) are crucial intracellular immune proteins in plants. Previous article reported a novel NLR protein SUT1 (SUPPRESSORS OF TOPP4-1, 1), which is involved in autoimmunity initiated by type one protein phosphatase 4 mutation (topp4-1) in Arabidopsis, however, its role in planta is still unclear. This study employed Nicotiana benthamiana, a model platform, to conduct an overall structural and functional analysis of SUT1 protein. The transient expression results revealed that SUT1 is a typical CNL (CC-NBS-LRR) receptor, both fluorescence data and biochemical results showed the protein is mainly anchored on the plasma membrane due to its N-terminal acylation site. Further truncation experiments announced that its CC (coiled-coil) domain possessed cell-death-inducing activity. The outcomes of point mutations analysis revealed that not only the CC domain, but also the full-length SUT1 protein, whose function and subcellular localization are influenced by highly conserved hydrophobic residues. These research outcomes provided favorable clues for elucidating the activation mechanism of SUT1.展开更多
基金supported by the Postdoctoral Science Foundation of China(No.20090460517)
文摘Nuclear envelope proteins have important roles in chromatin organization and signal-dependent transcriptional regulation. A previous study reported that the inner nuclear membrane protein, Otefin （Ote）, was essential for germline stem cell （GSC） maintenance via interaction with Smad complex. The interaction of Ore with the Smad complex recruits the barn locus to the nuclear periphery and subsequently results in bam transcriptional silencing, revealing that nuclear peripheral localization is essential for barn gene regulation. However, it remains unknown whether the nuclear peripheral localization is sufficient for barn silencing. To address this issue, we have established a tethering system, in which the Gal4 DNA binding domain （DBD） of the Flag：Gal4 DBD：Ote△LEM fusion protein physically interacts with the Gal4 binding sites upstream of bamP-gfp to artificially recruit the reporter gene gfp to the nuclear membrane. Our data demonstrated that the nuclear peripheral localization seemed to affect the expression of the target naked gene in S2 ceils. By contrast, in Drosophila germ cells, the nuclear membrane localization was not sufficient for gene silencing.
文摘The TRPV4 cation channel is expressed in a broad range of tissues and participates in the generation of a Ca<sup>2+</sup> signal and/or depolarization of membrane potential. Here, human phosphoglucomutase- 1 (PGM1), an enzyme that converts glucose-6 phosphate to glucose-1 phosphate in the glycolysis pathway, as the first auxiliary protein of TRPV4 Ca<sup>2+</sup> channels, is identified with yeast two hybrid system, coimmunoprecipitation, confocal microscopy, and GST pull-down assays. TRPV4 forms a complex with PGM1 through its C-terminal cytoplasmic domain. Because it is demonstrated that TRPV4 serine residue 824 (S824) is phosphorylated by serum/glucocorticoid regulated kinase 1, we elucidate the effect of TRPV4 S824 phosphorylation on TRPV association with PGM1. Even an inactivated mutant version of TRPV4, S824A, exhibited a decreased ability to bind PGM1, an activated phosphomimetic mutant version of TRPV4, S824D, exhibited enhanced binding to PGM1. Thus, formation of the TRPV4/PGM1 complex and localization of this complex to the plasma membrane appear to be regulated by the phosphorylation status of residue S824 in TRPV4. The newly identified interactor of TRPV4 may help the molecular pathways modulating transport activity or glucose metabolism, respectively.
文摘Nucleotide-binding site leucine-rich repeat receptors (NBS-LRR/NLRs) are crucial intracellular immune proteins in plants. Previous article reported a novel NLR protein SUT1 (SUPPRESSORS OF TOPP4-1, 1), which is involved in autoimmunity initiated by type one protein phosphatase 4 mutation (topp4-1) in Arabidopsis, however, its role in planta is still unclear. This study employed Nicotiana benthamiana, a model platform, to conduct an overall structural and functional analysis of SUT1 protein. The transient expression results revealed that SUT1 is a typical CNL (CC-NBS-LRR) receptor, both fluorescence data and biochemical results showed the protein is mainly anchored on the plasma membrane due to its N-terminal acylation site. Further truncation experiments announced that its CC (coiled-coil) domain possessed cell-death-inducing activity. The outcomes of point mutations analysis revealed that not only the CC domain, but also the full-length SUT1 protein, whose function and subcellular localization are influenced by highly conserved hydrophobic residues. These research outcomes provided favorable clues for elucidating the activation mechanism of SUT1.
