12 results on '"Chiang, Y."'
Search Results
2. Cbl Enforces an SLP76-dependent Signaling Pathway for T Cell Differentiation
- Author
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Chiang, Y. Jeffrey, primary, Jordan, Martha S., additional, Horai, Reiko, additional, Schwartzberg, Pamela L., additional, Koretzky, Gary A., additional, and Hodes, Richard J., additional
- Published
- 2009
- Full Text
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3. Arg15-Lys17-Arg18 turkey ovomucoid third domain inhibits human furin
- Author
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Lu, W., primary, Zhang, W., additional, Molloy, S.S., additional, Thomas, G., additional, Ryan, K., additional, Chiang, Y., additional, Anderson, S., additional, and Laskowski, M., additional
- Published
- 1993
- Full Text
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4. Loss of Dact1 Disrupts Planar Cell Polarity Signaling by Altering Dishevelled Activity and Leads to Posterior Malformation in Mice.
- Author
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Jun Wen, Chiang, Y. Jeffrey, Chan Gao, Hua Xue, Jingyue Xu, Yuanheng Ning, Hodes, Richard J., Xiang Gao, and Ye-Guang Chen
- Subjects
- *
CELL polarity , *EMBRYOLOGY , *LYSOSOMES , *MICE , *WNT proteins , *GLYCOPROTEINS - Abstract
Wnt signaling plays a key role in embryogenesis and cancer development. Dvl (Dishevelled) is a central mediator for both the canonical and noncanonical Wnt pathways. Dact1 (Dapper1, Dpr1), a Dvl interactor, has been shown to negatively modulate Wnt signaling by promoting lysosomal degradation of Dvl. Here we report that Dact1-deficient mice have multiple physiological defects that resemble the human neonate disease congenital caudal regression syndrome, including caudal vertebrae agenesis, anorectal malformation, renal agenesis/dysplasia, fused kidneys, and loss of bladder. These urogenital defects can be traced to impaired hindgut formation starting at embryonic day 8.25. Examination of morphological changes and Wnt target gene expression revealed that the planar cell polarity (PCP) signaling is deregulated, whereas the canonical Wnt//3-catenin pathway is largely unaffected in mutant embryos. Consistently, the activity of the PCP signal mediators Rho GTPase and c-Jun N-terminal kinase is altered in Dact1-/- mouse embryonic fibroblasts. We further observed alterations in the protein level and the cellular distribution of Dvl in the primitive streak of mutant embryos. An increased amount of Dvl2 tends to be accumulated in the cortical regions of the cells, especially at the primitive streak ectoderm close to the posterior endoderm that lately forms the hindgut diverticulum. Together, these data suggest that Dact1 may regulate vertebrate PCP by controlling the level and the cellular localization of Dvl protein. [ABSTRACT FROM AUTHOR]
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- 2010
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5. Reciprocal regulatory interaction between human herpesvirus 8 and human immunodeficiency virus type 1.
- Author
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Huang, L M, Chao, M F, Chen, M Y, Hm, Shih, Chiang, Y P, Chuang, C Y, and Lee, C Y
- Abstract
Human herpesvirus 8 (HHV8) is the primary viral etiologic agent in Kaposi's sarcoma (KS). However, individuals dually infected with both HHV8 and human immunodeficiency virus type 1 (HIV-1) show an enhanced prevalence of KS when compared with those singularly infected with HHV8. Host immune suppression conferred by HIV infection cannot wholly explain this increased presentation of KS. To better understand how HHV8 and HIV-1 might interact directly in the pathogenesis of KS, we queried for potential regulatory interactions between the two viruses. Here, we report that HHV8 and HIV-1 reciprocally up-regulate the gene expression of each other. We found that the KIE2 immediate-early gene product of HHV8 interacted synergistically with Tat in activating expression from the HIV-1 long terminal repeat. On the other hand, HIV-1 encoded Tat and Vpr proteins increased intracellular HHV8-specific expression. These results provide molecular insights correlating coinfection with HHV8 and HIV-1 with an unusually high incidence of KS.
- Published
- 2001
- Full Text
- View/download PDF
6. ADR1 activation domains contact the histone acetyltransferase GCN5 and the core transcriptional factor TFIIB.
- Author
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Chiang, Y C, Komarnitsky, P, Chase, D, and Denis, C L
- Abstract
The yeast transcriptional activator ADR1, which is required for ADH2 and peroxisomal gene expression, contains four separable and partially redundant activation domains (TADs). Mutations in ADA2 or GCN5, encoding components of the ADA coactivator complex involved in histone acetylation, severely reduced LexA-ADR1-TAD activation of a LexA-lacZ reporter gene. Similarly, the ability of the wild-type ADR1 gene to activate an ADH2-driven promoter was compromised in strains deleted for ADA2 or GCN5. In contrast, defects in other general transcription cofactors such as CCR4, CAF1/POP2, and SNF/SWI displayed much less or no effect on LexA-ADR1-TAD activation. Using an in vitro protein binding assay, ADA2 and GCN5 were found to specifically contact individual ADR1 TADs. ADA2 could bind TAD II, and GCN5 physically interacted with all four TADs. Both TADs I and IV were also shown to make specific contacts to the C-terminal segment of TFIIB. In contrast, no significant binding to TBP was observed. TAD IV deletion analysis indicated that its ability to bind GCN5 and TFIIB was directly correlated with its ability to activate transcription in vivo. ADR1 TADs appear to make several contacts, which may help explain both their partial redundancy and their varying requirements at different promoters. The contact to and dependence on GCN5, a histone acetyltransferase, suggests that rearrangement of nucleosomes may be one important means by which ADR1 activates transcription.
- Published
- 1996
7. A complex of cardiac cytochrome c1 and cytochrome c.
- Author
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Chiang, Y L, primary, Kaminsky, L S, additional, and King, T E, additional
- Published
- 1976
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8. Some properties of mammalian cardiac cytochrome c1.
- Author
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Kaminsky, L S, primary, Chiang, Y L, additional, and King, T E, additional
- Published
- 1975
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9. The 2.3-A crystal structure of the shikimate 5-dehydrogenase orthologue YdiB from Escherichia coli suggests a novel catalytic environment for an NAD-dependent dehydrogenase.
- Author
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Benach J, Lee I, Edstrom W, Kuzin AP, Chiang Y, Acton TB, Montelione GT, and Hunt JF
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- Alcohol Oxidoreductases metabolism, Amino Acid Sequence, Binding Sites, Catalysis, Crystallization, Crystallography, X-Ray, Models, Molecular, Molecular Sequence Data, Molecular Structure, NAD metabolism, Protein Structure, Quaternary, Protein Structure, Secondary, Protein Structure, Tertiary, Sequence Alignment, Shikimic Acid metabolism, Alcohol Oxidoreductases chemistry, Escherichia coli enzymology, NAD pharmacology, Shikimic Acid analogs & derivatives
- Abstract
We present here the 2.3-A crystal structure of the Escherichia coli YdiB protein, an orthologue of shikimate 5-dehydrogenase. This enzyme catalyzes the reduction of 3-dehydroshikimate to shikimate as part of the shikimate pathway, which is absent in mammals but required for the de novo synthesis of aromatic amino acids, quinones, and folate in many other organisms. In this context, the shikimate pathway has been promoted as a target for the development of antimicrobial agents. The crystal structure of YdiB shows that the protomer contains two alpha/beta domains connected by two alpha-helices, with the N-terminal domain being novel and the C-terminal domain being a Rossmann fold. The NAD+ cofactor, which co-purified with the enzyme, is bound to the Rossmann domain in an elongated fashion with the nicotinamide ring in the pro-R conformation. Its binding site contains several unusual features, including a cysteine residue in close apposition to the nicotinamide ring and a clamp over the ribose of the adenosine moiety formed by phenylalanine and lysine residues. The structure explains the specificity for NAD versus NADP in different members of the shikimate dehydrogenase family on the basis of variations in the amino acid identity of several other residues in the vicinity of this ribose group. A cavity lined by residues that are 100% conserved among all shikimate dehydrogenases is found between the two domains of YdiB, in close proximity to the hydride acceptor site on the nicotinamide ring. Shikimate was modeled into this site in a geometry such that all of its heteroatoms form high quality hydrogen bonds with these invariant residues. Their strong conservation in all orthologues supports the possibility of developing broad spectrum inhibitors of this enzyme. The nature and disposition of the active site residues suggest a novel reaction mechanism in which an aspartate acts as the general acid/base catalyst during the hydride transfer reaction.
- Published
- 2003
- Full Text
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10. Characterization of CAF4 and CAF16 reveals a functional connection between the CCR4-NOT complex and a subset of SRB proteins of the RNA polymerase II holoenzyme.
- Author
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Liu HY, Chiang YC, Pan J, Chen J, Salvadore C, Audino DC, Badarinarayana V, Palaniswamy V, Anderson B, and Denis CL
- Subjects
- Adenosine Triphosphatases genetics, Alleles, Carrier Proteins genetics, Cell Cycle Proteins metabolism, Chromatography, Gel, Cyclin-Dependent Kinase 8, Cyclin-Dependent Kinases metabolism, Cyclins metabolism, Fungal Proteins metabolism, Genotype, Mediator Complex, Mutation, Phenotype, Plasmids metabolism, Precipitin Tests, Protein Binding, Protein Kinases metabolism, Protein Serine-Threonine Kinases, RNA Polymerase II metabolism, Repressor Proteins metabolism, Sequence Analysis, DNA, Suppression, Genetic, Transcription Factors metabolism, Two-Hybrid System Techniques, Adenosine Triphosphatases chemistry, Adenosine Triphosphatases physiology, Carrier Proteins chemistry, Carrier Proteins physiology, Cell Cycle Proteins chemistry, Fungal Proteins chemistry, RNA Polymerase II chemistry, Ribonucleases, Saccharomyces cerevisiae Proteins, Transcription Factors chemistry
- Abstract
The CCR4-NOT transcriptional regulatory complex affects transcription both positively and negatively and consists of the following two complexes: a core 1 x 10(6) dalton (1 MDa) complex consisting of CCR4, CAF1, and the five NOT proteins and a larger, less defined 1.9-MDa complex. We report here the identification of two new factors that associate with the CCR4-NOT proteins as follows: CAF4, a WD40-containing protein, and CAF16, a putative ABC ATPase. Whereas neither CAF4 nor CAF16 was part of the core CCR4-NOT complex, both CAF16 and CAF4 appeared to be present in the 1.9-MDa complex. CAF4 also displayed physical interactions with multiple CCR4-NOT components and with DBF2, a likely component of the 1.9-MDa complex. In addition, both CAF4 and CAF16 were found to interact in a CCR4-dependent manner with SRB9, a component of the SRB complex that is part of the yeast RNA polymerase II holoenzyme. The three related SRB proteins, SRB9, SRB10, and SRB11, were found to interact with and to coimmunoprecipitate DBF2, CAF4, CCR4, NOT2, and NOT1. Defects in SRB9 and SRB10 also affected processes at the ADH2 locus known to be controlled by components of the CCR4-NOT complex; an srb9 mutation was shown to reduce ADH2 derepression and either an srb9 or srb10 allele suppressed spt10-enhanced expression of ADH2. In addition, srb9 and srb10 alleles increased ADR1(c)-dependent ADH2 expression; not4 and not5 deletions are the only other known defects that elicit this phenotype. These results suggest a close physical and functional association between components of the CCR4-NOT complexes and the SRB9, -10, and -11 components of the holoenzyme.
- Published
- 2001
- Full Text
- View/download PDF
11. Cytochrome c1 complexes.
- Author
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Chiang YL and King TE
- Subjects
- Animals, Cattle, Chemical Phenomena, Chemistry, Drug Stability, Hydrogen-Ion Concentration, Macromolecular Substances, Membranes, Artificial, Oxidation-Reduction, Phospholipids, Submitochondrial Particles, Cytochrome c Group analogs & derivatives, Cytochrome c Group metabolism, Cytochromes c1 metabolism, Electron Transport Complex IV metabolism
- Abstract
Cytochrome c1 forms an active complex with cytochrome c as previously reported (Chiang, Y. L., Kaminsky, L. S., and King, T. E. (1976) J. Biol. Chem. 251, 29-36). It also forms a complex with cytochrome oxidase with heme ratio of 1:1. This cytochrome c1.oxidase complex has been purified by ammonium sulfate fractionation and is stable in media of high ionic strength (greater than 0.1 M) but dissociates as the pH deviates from neutral. The purified cytochrome c1 aggregates to an oligomer, presumably a pentamer. No agent has been found to depolymerize isolated c1 without denaturation. However, in the cytochrome c1.oxidase complex, these two cytochromes apparently were depolymerized to form smaller aggregates, if not monomeric units, as judged by sedimentation behavior. Cytochrome c1 also forms a ternary complex with cytochrome c and oxidase in the heme ratio of 1:1:1. This complex can be prepared by any of the following four methods: (i) c1 + c + oxidase: (ii) c1.c complex + oxidase; (iii) c1 + c.oxidase complex: or (iv) c + c1.oxidase complex. The mode of formation of these complexes is all from pure protein-protein interactions. Cytochrome c1 is also incorporated into phospholipid vesicles and these vesicles show about 200 molecules of phospholipid/cytochrome c1 in terms of heme. The spectrophotometric, circular dichroic, sedimentation behavior and enzymic properties of these complexes have been investigated.
- Published
- 1979
12. Photoreduction of cytochrome c1.
- Author
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Yu CA, Chiang YL, Yu L, and King TE
- Subjects
- Animals, Antimycin A pharmacology, Cattle, Hydroxymercuribenzoates, Kinetics, Light, Myocardium enzymology, Oxidation-Reduction, Photochemistry, Protein Binding, Cytochrome c Group metabolism
- Abstract
1. Ferricytochrome c1 solution was reduced completely between pH 7 and 10 by illumination under anaerobic conditions. Photoreduction was not affected by the ionic strength of the medium. However, it did not take place at pH lower than 6 or higher than 10, or in the presence of p-hydroxymercuric benzoate. The ferricyanide-reoxidized photoreduced c1 was not further reduced upon illumination. The reductant was most probably a specific sulfhydryl group in the subunit containing the heme of the cytochrome since this subunit contained one less p-HMB-titratable group in the photoreduced sample than in the untreated preparation. 2. The photoreduced cytochrome c1 showed the same spectra as the native cytochrome, and was not reactive with carbon monoxide. The equilibrium constant of the reaction c12+ + c3+ equilibrium c13+ + c2+ for the photoreduced c1 was found to be slightly lower (Keq = 2.6) than that for the native c1 (Keq = 3.5). The antimycin A-sensitive electron acceptor activity of ferricyanide-reoxidized photoreduced c13+ catalyzed by succinate-cytochrome c reductase was about 80% of that of the native c1. 3. A somewhat simplified method for isolation of cytochrome c1 was developed. Anaerobic ammonium sulfate fractionation and calcium phosphate gel chromatography were still used in order to achieve the purity level of about 25 nmol of heme/mg of protein. The cytochrome c1 prepared by this procedure showed the same properties tested as that by the beta-mercaptoethanol method (Yu, C.A., Yu, L., and King, T.E. (1972) J. Biol. Chem. 247, 1012-1019).
- Published
- 1975
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