The Experts below are selected from a list of 1500 Experts worldwide ranked by ideXlab platform
Xing Wang Deng - One of the best experts on this subject based on the ideXlab platform.
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The RING Finger Motif of Photomorphogenic Repressor COP1 Specifically Interacts with the RING-H2 Motif of a Novel
2014Co-Authors: Arabidopsis Protein, Minami Matsui, Xing Wang DengAbstract:The constitutive photomorphogenic 1 (COP1) protein of Arabidopsis functions as a molecular switch for the seedling developmental fates: photomorphogenesis under light conditions and skotomorphogenesis in darkness. The COP1 protein contains a cysteine-rich zincbinding RING Finger Motif found in diverse groups of regulatory proteins. To understand the role of the COP1 RING Finger in mediating protein-protein interaction, we have performed a yeast two-hybrid screen and isolated a novel protein with a RING-H2 Motif, a variant type of the RING Finger. This protein, designated COP1 Interacting Protein 8 (CIP8), is encoded by a single copy gene and localized to cytosol in a transient assay. In addition to the RING-H2 Motif, the predicted protein has a C4 zinc Finger, an acidic region, a glycine-ric
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the RING Finger Motif of photomorphogenic repressor cop1 specifically interacts with the RING h2 Motif of a novel arabidopsis protein
Journal of Biological Chemistry, 1999Co-Authors: Keiko U Torii, Chatanika Stoopmyer, Haruko Okamoto, Joseph E Coleman, Minami Matsui, Xing Wang DengAbstract:The constitutive photomorphogenic 1 (COP1) protein of Arabidopsis functions as a molecular switch for the seedling developmental fates: photomorphogenesis under light conditions and skotomorphogenesis in darkness. The COP1 protein contains a cysteine-rich zinc-binding RING Finger Motif found in diverse groups of regulatory proteins. To understand the role of the COP1 RING Finger in mediating protein-protein interaction, we have performed a yeast two-hybrid screen and isolated a novel protein with a RING-H2 Motif, a variant type of the RING Finger. This protein, designated COP1 Interacting Protein 8 (CIP8), is encoded by a single copy gene and localized to cytosol in a transient assay. In addition to the RING-H2 Motif, the predicted protein has a C4 zinc Finger, an acidic region, a glycine-rich cluster, and a serine-rich cluster. The COP1 RING Finger and the CIP8 RING-H2 domains are sufficient for their interaction with each other both in vitro and in yeast, whereas neither Motif displayed significant self-association. Moreover, site-directed mutagenesis studies demonstrated that the expected zinc-binding ligands of the RING Finger and RING-H2 Fingers are essential for their interaction. Our findings indicate that the RING Finger Motif, in this case, serves as autonomous protein-protein interaction domain. The allele specific effect of cop1 mutations on the CIP8 protein accumulation in seedlings indicates that its stability in vivo is dependent on the COP1 protein.
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RING Finger Motif of arabidopsis thaliana cop1 defines a new class of zinc binding domain
Journal of Biological Chemistry, 1993Co-Authors: A G Von Arnim, Xing Wang DengAbstract:The COP1 gene of Arabidopsis thaliana encodes a protein mediating the switch between the two developmental pathways utilized in light and darkness. A cysteine-rich Motif identified the COP1 protein as a member of a group of regulatory proteins which share the amino acid Motif Cys-X-X-Cys-loop I-Cys-X-His-X-X-Cys-X-X-Cys-loop II-Cys-X-X-Cys (RING Finger). Although this new class of cysteine-rich Motifs has been proposed to bind metal ions, no direct evidence supporting this has been presented. By analyzing the COP1 protein expressed in Escherichia coli, we demonstrate here that each COP1 molecule can bind up to two zinc atoms. The two zinc ions are bound with different affinities. One is tightly bound and resistant to urea and EDTA, whereas the other one is labile under those conditions. It is further shown that deletion of the RING Finger Motif abolishes the metal-binding capacity of COP1. We conclude that the RING Finger Motif constitutes a zinc-coordinating element distinct from previously characterized zinc-binding domains.
Roger D Everett - One of the best experts on this subject based on the ideXlab platform.
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herpes simplex virus type 1 immediate early protein icp0 and its isolated RING Finger domain act as ubiquitin e3 ligases in vitro
Journal of Virology, 2002Co-Authors: Chris Boutell, Seth Sadis, Roger D EverettAbstract:Proteasome-dependent degradation of ubiquitinated proteins plays a key role in many important cellular processes. Ubiquitination requires the E1 ubiquitin activating enzyme, an E2 ubiquitin conjugating enzyme, and frequently a substrate-specific ubiquitin protein ligase (E3). One class of E3 ubiquitin ligases has been shown to contain a common zinc-binding RING Finger Motif. We have previously shown that herpes simplex virus type 1 ICP0, itself a RING Finger protein, induces the proteasome-dependent degradation of several cellular proteins and induces the accumulation of colocalizing conjugated ubiquitin in vivo. We now report that both full-length ICP0 and its isolated RING Finger domain induce the accumulation of polyubiquitin chains in vitro in the presence of E1 and the E2 enzymes UbcH5a and UbcH6. Mutations within the RING Finger region that abolish the in vitro ubiquitination activity also cause severe reductions in ICP0 activity in other assays. We conclude that ICP0 has the potential to act as an E3 ubiquitin ligase duRING viral infection and to target specific cellular proteins for destruction by the 26S proteasome.
Noriyuki Matsuda - One of the best experts on this subject based on the ideXlab platform.
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diverse effects of pathogenic mutations of parkin that catalyze multiple monoubiquitylation in vitro
Journal of Biological Chemistry, 2006Co-Authors: Noriyuki Matsuda, Nobutaka Hattori, Yoshikuni Mizuno, Toshiaki Kitami, Toshiaki Suzuki, Keiji TanakaAbstract:Mutational dysfunction of PARKIN gene, which encodes a double RING Finger protein and has ubiquitin ligase E3 activity, is the major cause of autosomal recessive juvenile Parkinsonism. Although many studies explored the functions of Parkin, its biochemical character is poorly understood. To address this issue, we established an E3 assay system using maltose-binding protein-fused Parkin purified from Escherichia coli. Using this recombinant Parkin, we found that not the front but the rear RING Finger Motif is responsible for the E3 activity of Parkin, and it catalyzes multiple monoubiquitylation. Intriguingly, for autosomal recessive juvenile Parkinsonism-causing mutations of Parkin, whereas there was loss of E3 activity in the rear RING domain, other pathogenic mutants still exhibited E3 activity equivalent to that of the wild-type Parkin. The evidence presented allows us to reconsider the function of Parkin-catalyzed ubiquitylation and to conclude that autosomal recessive juvenile Parkinsonism is not solely attributable to catalytic impairment of the E3 activity of Parkin.
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Ubiquitin Ligase Activities of Bombyx mori Nucleopolyhedrovirus RING Finger Proteins
Journal of Virology, 2003Co-Authors: Noriko Imai, Keiji Tanaka, Noriyuki Matsuda, Akihiko Nakano, Shogo Matsumoto, Wonkyung KangAbstract:The genome of Bombyx mori nucleopolyhedrovirus (BmNPV) is predicted to contain six RING Finger proteins: IAP1, ORF35, IAP2, CG30, IE2, and PE38. Several other members of the RING Finger family have recently been shown to have the ubiquitin-ligase (E3) activity. We thus examined whether BmNPV RING Finger proteins have the E3 activity. In vitro ubiquitination assay with the rabbit reticulocyte lysates and BmNPV RING Finger proteins fused with maltose-binding protein (MBP) showed that four of them (IAP2, IE2, PE38, and CG30) were polyubiquitinated in the presence of zinc ion. Furthermore, MBP-IAP2, MBP-IE2, and MBP-PE38 were able to reconstitute ubiquitination activity in cooperation with the Ubc4/5 subfamily of ubiquitin-conjugating enzymes. Mutational analysis also showed that ubiquitination activity of MBP-IAP2, MBP-IE2, and MBP-PE38 were dependent on their RING Finger Motif. Therefore, these results suggest that IAP2, IE2, and PE38 may function as E3 enzymes duRING BmNPV infection.
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rma1 a novel type of RING Finger protein conserved from arabidopsis to human is a membrane bound ubiquitin ligase
Journal of Cell Science, 2001Co-Authors: Noriyuki Matsuda, Keiji Tanaka, Toshiaki Suzuki, Akihiko NakanoAbstract:Rma1 is a protein with a RING Finger Motif and a C-terminal membrane-anchoRING domain and is well conserved among higher eukaryotes. We show that fusion proteins between maltose binding protein (MBP) and human or Arabidopsis Rma1 are polyubiquitinated, when incubated with the rabbit reticulocyte or the wheat germ lysate, respectively. The polyubiquitination of MBP-Rma1 has been reconstituted by incubation with purified ubiquitin, the ubiquitin-activating enzyme E1, and one of the two ubiquitin-conjugating E2 enzymes (Ubc4 or UbcH5a). Other E2 enzymes tested, E2-20k, E2-25k, Ubc3 and Ubc8, are not able to confer this modification. Mutational analysis shows that the RING Finger Motif of Rma1 is necessary for the auto-ubiquitination of MBP-Rma1. Thus, Rma1 represents a novel, membrane-bound type of ubiquitin ligase E3, which probably functions with the Ubc4/5 subfamily of E2. The MBP moiety but not Rma1 itself is ubiquitinated in the auto-ubiquitination reaction of MBP-Rma1. Free MBP in solution is not a substrate of Rma1. These observations indicate that bRINGing the substrate into its physical vicinity is very important for the action of ubiquitin ligase.
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rma1 an arabidopsis thaliana gene whose cdna suppresses the yeast sec15 mutation encodes a novel protein with a RING Finger Motif and a membrane anchor
Plant and Cell Physiology, 1998Co-Authors: Noriyuki Matsuda, Akihiko NakanoAbstract:To identify molecules that function in the plant secretory pathway, we screened for Arabidopsis thaliana cDNA clones that complement the temperature-sensitive (ts), secretion-deficient sec15 mutation of yeast Saccharomyces cerevisiae. RMA1, one of the genes obtained in this screening, suppressed not only the ts growth of sec15 but also its secretory defect. RMA1 is not a structural homologue of SEC15 but encodes a novel 28 kDa protein with a RING Finger Motif and a C-terminal membrane-anchoRING domain. Mutational analysis indicates that the RING Finger Motif of RMA1 is important for its suppression activity. In Arabidopsis plant, RMA1 is ubiquitously expressed. A search for homologous proteins in the database revealed that Arabidopsis, nematode, mouse and human possess close homologues of RMA1.
Saori Miyazaki - One of the best experts on this subject based on the ideXlab platform.
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a novel rna recognition Motif protein is required for premeiotic g1 s phase transition in rice oryza sativa l
PLOS Genetics, 2011Co-Authors: Ken-ichi Nonomura, Saori Miyazaki, Mitsugu Eiguchi, Mutsuko Nakano, Kazuya Takashima, Norio Komeda, Satoshi FukuchiAbstract:The molecular mechanism for meiotic entry remains largely elusive in floweRING plants. Only Arabidopsis SWI1/DYAD and maize AM1, both of which are the coiled-coil protein, are known to be required for the initiation of plant meiosis. The mechanism underlying the synchrony of male meiosis, characteristic to floweRING plants, has also been unclear in the plant kingdom. In other eukaryotes, RNA-recognition-Motif (RRM) proteins are known to play essential roles in germ-cell development and meiosis progression. Rice MEL2 protein discovered in this study shows partial similarity with human proline-rich RRM protein, deleted in Azoospermia-Associated Protein1 (DAZAP1), though MEL2 also possesses ankyrin repeats and a RING Finger Motif. Expression analyses of several cell-cycle markers revealed that, in mel2 mutant anthers, most germ cells failed to enter premeiotic S-phase and meiosis, and a part escaped from the defect and underwent meiosis with a significant delay or continued mitotic cycles. Immunofluorescent detection revealed that T7 peptide-tagged MEL2 localized at cytoplasmic perinuclear region of germ cells duRING premeiotic interphase in transgenic rice plants. This study is the first report of the plant RRM protein, which is required for regulating the premeiotic G1/S-phase transition of male and female germ cells and also establishing synchrony of male meiosis. This study will contribute to elucidation of similarities and diversities in reproduction system between plants and other species.
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A novel RNA-recognition-Motif protein is required for premeiotic G1/S-phase transition in rice (Oryza sativa L.).
PLoS genetics, 2011Co-Authors: Ken-ichi Nonomura, Saori Miyazaki, Mitsugu Eiguchi, Mutsuko Nakano, Kazuya Takashima, Norio Komeda, Satoshi Fukuchi, Akio Miyao, Hirohiko Hirochika, Nori KurataAbstract:The molecular mechanism for meiotic entry remains largely elusive in floweRING plants. Only Arabidopsis SWI1/DYAD and maize AM1, both of which are the coiled-coil protein, are known to be required for the initiation of plant meiosis. The mechanism underlying the synchrony of male meiosis, characteristic to floweRING plants, has also been unclear in the plant kingdom. In other eukaryotes, RNA-recognition-Motif (RRM) proteins are known to play essential roles in germ-cell development and meiosis progression. Rice MEL2 protein discovered in this study shows partial similarity with human proline-rich RRM protein, deleted in Azoospermia-Associated Protein1 (DAZAP1), though MEL2 also possesses ankyrin repeats and a RING Finger Motif. Expression analyses of several cell-cycle markers revealed that, in mel2 mutant anthers, most germ cells failed to enter premeiotic S-phase and meiosis, and a part escaped from the defect and underwent meiosis with a significant delay or continued mitotic cycles. Immunofluorescent detection revealed that T7 peptide-tagged MEL2 localized at cytoplasmic perinuclear region of germ cells duRING premeiotic interphase in transgenic rice plants. This study is the first report of the plant RRM protein, which is required for regulating the premeiotic G1/S-phase transition of male and female germ cells and also establishing synchrony of male meiosis. This study will contribute to elucidation of similarities and diversities in reproduction system between plants and other species.
Akihiko Nakano - One of the best experts on this subject based on the ideXlab platform.
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Ubiquitin Ligase Activities of Bombyx mori Nucleopolyhedrovirus RING Finger Proteins
Journal of Virology, 2003Co-Authors: Noriko Imai, Keiji Tanaka, Noriyuki Matsuda, Akihiko Nakano, Shogo Matsumoto, Wonkyung KangAbstract:The genome of Bombyx mori nucleopolyhedrovirus (BmNPV) is predicted to contain six RING Finger proteins: IAP1, ORF35, IAP2, CG30, IE2, and PE38. Several other members of the RING Finger family have recently been shown to have the ubiquitin-ligase (E3) activity. We thus examined whether BmNPV RING Finger proteins have the E3 activity. In vitro ubiquitination assay with the rabbit reticulocyte lysates and BmNPV RING Finger proteins fused with maltose-binding protein (MBP) showed that four of them (IAP2, IE2, PE38, and CG30) were polyubiquitinated in the presence of zinc ion. Furthermore, MBP-IAP2, MBP-IE2, and MBP-PE38 were able to reconstitute ubiquitination activity in cooperation with the Ubc4/5 subfamily of ubiquitin-conjugating enzymes. Mutational analysis also showed that ubiquitination activity of MBP-IAP2, MBP-IE2, and MBP-PE38 were dependent on their RING Finger Motif. Therefore, these results suggest that IAP2, IE2, and PE38 may function as E3 enzymes duRING BmNPV infection.
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rma1 a novel type of RING Finger protein conserved from arabidopsis to human is a membrane bound ubiquitin ligase
Journal of Cell Science, 2001Co-Authors: Noriyuki Matsuda, Keiji Tanaka, Toshiaki Suzuki, Akihiko NakanoAbstract:Rma1 is a protein with a RING Finger Motif and a C-terminal membrane-anchoRING domain and is well conserved among higher eukaryotes. We show that fusion proteins between maltose binding protein (MBP) and human or Arabidopsis Rma1 are polyubiquitinated, when incubated with the rabbit reticulocyte or the wheat germ lysate, respectively. The polyubiquitination of MBP-Rma1 has been reconstituted by incubation with purified ubiquitin, the ubiquitin-activating enzyme E1, and one of the two ubiquitin-conjugating E2 enzymes (Ubc4 or UbcH5a). Other E2 enzymes tested, E2-20k, E2-25k, Ubc3 and Ubc8, are not able to confer this modification. Mutational analysis shows that the RING Finger Motif of Rma1 is necessary for the auto-ubiquitination of MBP-Rma1. Thus, Rma1 represents a novel, membrane-bound type of ubiquitin ligase E3, which probably functions with the Ubc4/5 subfamily of E2. The MBP moiety but not Rma1 itself is ubiquitinated in the auto-ubiquitination reaction of MBP-Rma1. Free MBP in solution is not a substrate of Rma1. These observations indicate that bRINGing the substrate into its physical vicinity is very important for the action of ubiquitin ligase.
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rma1 an arabidopsis thaliana gene whose cdna suppresses the yeast sec15 mutation encodes a novel protein with a RING Finger Motif and a membrane anchor
Plant and Cell Physiology, 1998Co-Authors: Noriyuki Matsuda, Akihiko NakanoAbstract:To identify molecules that function in the plant secretory pathway, we screened for Arabidopsis thaliana cDNA clones that complement the temperature-sensitive (ts), secretion-deficient sec15 mutation of yeast Saccharomyces cerevisiae. RMA1, one of the genes obtained in this screening, suppressed not only the ts growth of sec15 but also its secretory defect. RMA1 is not a structural homologue of SEC15 but encodes a novel 28 kDa protein with a RING Finger Motif and a C-terminal membrane-anchoRING domain. Mutational analysis indicates that the RING Finger Motif of RMA1 is important for its suppression activity. In Arabidopsis plant, RMA1 is ubiquitously expressed. A search for homologous proteins in the database revealed that Arabidopsis, nematode, mouse and human possess close homologues of RMA1.
