A 70 Amino Acid Region within the Semaphorin Domain Activates Specific Cellular Response of Semaphorin Family Members

wingless (wg) and its vertebrate homologues, the Wnt genes, play critical roles in the generation of embryonic pattern. In the developing Drosophila epidermis, wg is expressed in a single row of cells in each segment, but it influences cell identities in all rows of epidermal cells in the 10- to 12-cell-wide segment. Wg signaling promotes specification of two distinct aspects of the wild-type intrasegmental pattern: the diversity of denticle types present in the anterior denticle belt and the smooth or naked cuticle constituting the posterior surface of the segment. We have manipulated the expression of wild-type and mutant wg transgenes to explore the mechanism by which a single secreted signaling molecule can promote these distinctly different cell fates. We present evidence consistent with the idea that naked cuticle cell fate is specified by a cellular pathway distinct from the denticle diversity-generating pathway. Since these pathways are differentially activated by mutant Wg ligands, we propose that at least two discrete classes of receptor for Wg may exist, each transducing a different cellular response. We also find that broad Wg protein distribution across many cell diameters is required for the generation of denticle diversity, suggesting that intercellular transport of the Wg protein is an essential feature of pattern formation within the epidermal epithelium. Finally, we demonstrate that an 85 amino acid region not conserved in vertebrate Wnts is dispensable for Wg function and we discuss structural features of the Wingless protein required for its distinct biological activities.

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The N-terminal 20-Amino Acid Region of Guanine Nucleotide Exchange Factor Vav1 Plays a Distinguished Role in T Cell Receptor-mediated Calcium Signaling

Journal of Biological Chemistry ◽

10.1074/jbc.m112.426221 ◽

2012 ◽

Vol 288 (6) ◽

pp. 3777-3785 ◽

Cited By ~ 12

Author(s):

Shi-Yang Li ◽

Ming-Juan Du ◽

Ya-Juan Wan ◽

Bei Lan ◽

Yao-Hui Liu ◽

...

Keyword(s):

Amino Acid ◽

Calcium Signaling ◽

T Cell Receptor ◽

Cell Receptor ◽

Guanine Nucleotide ◽

Nucleotide Exchange ◽

Amino Acid Region ◽

Guanine Nucleotide Exchange ◽

Nucleotide Exchange Factor ◽

Acid Region

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A Carboxy-Terminal 16-Amino-Acid Region of ς38 ofEscherichia coli Is Important for Transcription under High-Salt Conditions and Sigma Activities In Vivo

Journal of Bacteriology ◽

10.1128/jb.182.16.4628-4631.2000 ◽

2000 ◽

Vol 182 (16) ◽

pp. 4628-4631 ◽

Cited By ~ 21

Author(s):

Mio Ohnuma ◽

Nobuyuki Fujita ◽

Akira Ishihama ◽

Kan Tanaka ◽

Hideo Takahashi

Keyword(s):

Amino Acid ◽

Bacterial Species ◽

High Potassium ◽

Transcription Analysis ◽

Amino Acid Region ◽

Sigma Subunit ◽

Carboxy Terminal ◽

Acid Region

ABSTRACT ς38 (or ςS, the rpoS gene product) is a sigma subunit of RNA polymerase in Escherichia coli and directs transcription from a number of stationary-phase promoters as well as osmotically inducible promoters. In this study, we analyzed the function of the carboxy-terminal 16-amino-acid region of ς38 (residues 315 to 330), which is well conserved among the rpoS gene products of enteric bacterial species. Truncation of this region was shown to result in the loss of sigma activity in vivo using promoter-lacZ fusion constructs, but the mutant ς38 retained the binding activity in vivo to the core enzyme. The in vitro transcription analysis revealed that the transcription activity of ς38 holoenzyme under high potassium glutamate concentrations was significantly decreased by the truncation of the carboxy-terminal tail element.

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An Amino Acid Region at the N-Terminus of Rat Hepatoma α1→2 Fucosyltransferase Modulates Enzyme Activity and Interaction with Lipids: Strong Preference for Glycosphingolipids Containing Terminal Galβ1→3GalNAc- Structures†

Biochemistry ◽

10.1021/bi0102104 ◽

2001 ◽

Vol 40 (19) ◽

pp. 5708-5719 ◽

Cited By ~ 2

Author(s):

Anne L. Sherwood ◽

Mark R. Stroud ◽

Steven B. Levery ◽

Eric H. Holmes

Keyword(s):

Enzyme Activity ◽

Amino Acid ◽

Strong Preference ◽

Amino Acid Region ◽

N Terminus ◽

Rat Hepatoma ◽

Acid Region

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The DNA-binding specificity of the hepatocyte nuclear factor 3/forkhead domain is influenced by amino-acid residues adjacent to the recognition helix.

Molecular and Cellular Biology ◽

10.1128/mcb.14.4.2755 ◽

1994 ◽

Vol 14 (4) ◽

pp. 2755-2766 ◽

Cited By ~ 253

Author(s):

D G Overdier ◽

A Porcella ◽

R H Costa

Keyword(s):

Amino Acid ◽

Dna Binding ◽

Hepatocyte Nuclear Factor ◽

Binding Properties ◽

Winged Helix ◽

Amino Acid Region ◽

Dna Binding Specificity ◽

Recognition Helix ◽

Dna Binding Properties ◽

Acid Region

Three distinct hepatocyte nuclear factor 3 (HNF-3) proteins (HNF-3 alpha, -3 beta, and -3 gamma) are known to regulate the transcription of liver-specific genes. The HNF-3 proteins bind to DNA as a monomer through a modified helix-turn-helix, known as the winged helix motif, which is also utilized by a number of developmental regulators, including the Drosophila homeotic forkhead (fkh) protein. We have previously described the isolation, from rodent tissue, of an extensive family of tissue-specific HNF-3/fkh homolog (HFH) genes sharing homology in their winged helix motifs. In this report, we have determined the preferred DNA-binding consensus sequence for the HNF-3 beta protein as well as for two divergent family members, HFH-1 and HFH-2. We show that these HNF-3/fkh proteins bind to distinct DNA sites and that the specificity of protein recognition is dependent on subtle nucleotide alterations in the site. The HNF-3, HFH-1, and HFH-2 consensus binding sequences were also used to search DNA regulatory regions to identify potential target genes. Furthermore, an analysis of the DNA-binding properties of a series of HFH-1/HNF-3 beta protein chimeras has allowed us to identify a 20-amino-acid region, located adjacent to the DNA recognition helix, which contributes to DNA-binding specificity. These sequences are not involved in base-specific contacts and include residues which diverge within the HNF-3/fkh family. Replacement of this 20-amino-acid region in HNF-3 beta with corresponding residues from HFH-1 enabled the HNF-3 beta recognition helix to bind only HFH-1-specific DNA-binding sites. We propose a model in which this 20-amino-acid flanking region influences the DNA-binding properties of the recognition helix.

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Rho1p-Bni1p-Spa2p Interactions: Implication in Localization of Bni1p at the Bud Site and Regulation of the Actin Cytoskeleton inSaccharomyces cerevisiae

Molecular Biology of the Cell ◽

10.1091/mbc.9.5.1221 ◽

1998 ◽

Vol 9 (5) ◽

pp. 1221-1233 ◽

Cited By ~ 140

Author(s):

Takeshi Fujiwara ◽

Kazuma Tanaka ◽

Akihisa Mino ◽

Mitsuhiro Kikyo ◽

Kazuo Takahashi ◽

...

Keyword(s):

Amino Acid ◽

Actin Cytoskeleton ◽

Binding Protein ◽

Microscopic Analysis ◽

Mitogen Activated Protein Kinase ◽

Gene Encoding ◽

Amino Acid Region ◽

Genes Encoding ◽

Mitogen Activated Protein ◽

Acid Region

Rho1p is a yeast homolog of mammalian RhoA small GTP-binding protein. Rho1p is localized at the growth sites and required for bud formation. We have recently shown that Bni1p is a potential target of Rho1p and that Bni1p regulates reorganization of the actin cytoskeleton through interactions with profilin, an actin monomer-binding protein. Using the yeast two-hybrid screening system, we cloned a gene encoding a protein that interacted with Bni1p. This protein, Spa2p, was known to be localized at the bud tip and to be implicated in the establishment of cell polarity. The C-terminal 254 amino acid region of Spa2p, Spa2p(1213–1466), directly bound to a 162-amino acid region of Bni1p, Bni1p(826–987). Genetic analyses revealed that both thebni1 and spa2 mutations showed synthetic lethal interactions with mutations in the genes encoding components of the Pkc1p-mitogen-activated protein kinase pathway, in which Pkc1p is another target of Rho1p. Immunofluorescence microscopic analysis showed that Bni1p was localized at the bud tip in wild-type cells. However, in the spa2 mutant, Bni1p was not localized at the bud tip and instead localized diffusely in the cytoplasm. A mutant Bni1p, which lacked the Rho1p-binding region, also failed to be localized at the bud tip. These results indicate that both Rho1p and Spa2p are involved in the localization of Bni1p at the growth sites where Rho1p regulates reorganization of the actin cytoskeleton through Bni1p.

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The F12-Vif derivative Chim3 inhibits HIV-1 replication in CD4+ T lymphocytes and CD34+-derived macrophages by blocking HIV-1 DNA integration

Blood ◽

10.1182/blood-2008-06-158790 ◽

2009 ◽

Vol 113 (15) ◽

pp. 3443-3452 ◽

Cited By ~ 13

Author(s):

Simona Porcellini ◽

Luca Alberici ◽

Francesco Gubinelli ◽

Rossella Lupo ◽

Clelia Olgiati ◽

...

Keyword(s):

Gene Therapy ◽

Amino Acid ◽

T Lymphocytes ◽

Genetic Manipulation ◽

Natural Resistance ◽

Dna Integration ◽

Amino Acid Region ◽

Antiviral Function ◽

Hiv 1 ◽

Acid Region

Abstract The viral infectivity factor (Vif) is essential for HIV-1 infectivity and hence is an ideal target for promising anti–HIV-1/AIDS gene therapy. We previously demonstrated that F12-Vif mutant inhibits HIV-1 replication in CD4+ T lymphocytes. Despite macrophage relevance to HIV-1 pathogenesis, most gene therapy studies do not investigate macrophages because of their natural resistance to genetic manipulation. Here, we confirm the F12-Vif antiviral activity also in macrophages differentiated in vitro from transduced CD34+ human stem cells (HSCs). Moreover, we identified the 126- to 170-amino-acid region in the C-terminal half of F12-Vif as responsible for its antiviral function. Indeed, Chim3 protein, containing this 45-amino-acid region embedded in a WT-Vif backbone, is as lethal as F12-Vif against HIV-1. Of major relevance, we demonstrated a dual mechanism of action for Chim3. First, Chim3 functions as a transdominant factor that preserves the antiviral function of the natural restriction factor APOBEC3G (hA3G). Second, Chim3 blocks the early HIV-1 retrotranscript accumulation and thereby HIV-1 DNA integration regardless of the presence of WT-Vif and hA3G. In conclusion, by impairing the early steps of HIV-1 life cycle, Chim3 conceivably endows engineered cells with survival advantage, which is required for the efficient immune reconstitution of patients living with HIV/AIDS.

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