scholarly journals Dominant-Negative Modification Reveals the Regulatory Function of the Multimeric Cysteine Synthase Protein Complex in Transgenic Tobacco

2007 ◽  
Vol 19 (2) ◽  
pp. 625-639 ◽  
Author(s):  
Markus Wirtz ◽  
Rüdiger Hell
Keyword(s):  
Transgenic Tobacco ◽  
Protein Complex ◽  
Dominant Negative ◽  
Regulatory Function ◽  
Cysteine Synthase

scholarly journals Atypical Protein Kinase C Is Involved in the Evolutionarily Conserved Par Protein Complex and Plays a Critical Role in Establishing Epithelia-Specific Junctional Structures

2001 ◽  
Vol 152 (6) ◽  
pp. 1183-1196 ◽  
Author(s):  
Atsushi Suzuki ◽  
Tomoyuki Yamanaka ◽  
Tomonori Hirose ◽  
Naoyuki Manabe ◽  
Keiko Mizuno ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cell Polarity ◽  
Protein Complex ◽  
Mdck Cells ◽  
Critical Role ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Surface Polarity ◽  
C Elegans ◽  
Evolutionarily Conserved

We have previously shown that during early Caenorhabditis elegans embryogenesis PKC-3, a C. elegans atypical PKC (aPKC), plays critical roles in the establishment of cell polarity required for subsequent asymmetric cleavage by interacting with PAR-3 [Tabuse, Y., Y. Izumi, F. Piano, K.J. Kemphues, J. Miwa, and S. Ohno. 1998. Development (Camb.). 125:3607–3614]. Together with the fact that aPKC and a mammalian PAR-3 homologue, aPKC-specific interacting protein (ASIP), colocalize at the tight junctions of polarized epithelial cells (Izumi, Y., H. Hirose, Y. Tamai, S.-I. Hirai, Y. Nagashima, T. Fujimoto, Y. Tabuse, K.J. Kemphues, and S. Ohno. 1998. J. Cell Biol. 143:95–106), this suggests a ubiquitous role for aPKC in establishing cell polarity in multicellular organisms. Here, we show that the overexpression of a dominant-negative mutant of aPKC (aPKCkn) in MDCK II cells causes mislocalization of ASIP/PAR-3. Immunocytochemical analyses, as well as measurements of paracellular diffusion of ions or nonionic solutes, demonstrate that the biogenesis of the tight junction structure itself is severely affected in aPKCkn-expressing cells. Furthermore, these cells show increased interdomain diffusion of fluorescent lipid and disruption of the polarized distribution of Na+,K+-ATPase, suggesting that epithelial cell surface polarity is severely impaired in these cells. On the other hand, we also found that aPKC associates not only with ASIP/PAR-3, but also with a mammalian homologue of C. elegans PAR-6 (mPAR-6), and thereby mediates the formation of an aPKC-ASIP/PAR-3–PAR-6 ternary complex that localizes to the apical junctional region of MDCK cells. These results indicate that aPKC is involved in the evolutionarily conserved PAR protein complex, and plays critical roles in the development of the junctional structures and apico-basal polarization of mammalian epithelial cells.

Transgenic tobacco plants expressing a rice cysteine synthase gene are tolerant to toxic levels of cadmium

2001 ◽  
Vol 158 (5) ◽  
pp. 655-661 ◽  
Author(s):  
Emiko Harada ◽  
Yong-Eui Choi ◽  
Atsunari Tsuchisaka ◽  
Hitoshi Obata ◽  
Hiroshi Sano
Keyword(s):  
Transgenic Tobacco ◽  
Transgenic Tobacco Plants ◽  
Cysteine Synthase ◽  
Tobacco Plants

scholarly journals Helminth secretions induce de novo T cell Foxp3 expression and regulatory function through the TGF-β pathway

2010 ◽  
Vol 207 (11) ◽  
pp. 2331-2341 ◽  
Author(s):  
John R. Grainger ◽  
Katie A. Smith ◽  
James P. Hewitson ◽  
Henry J. McSorley ◽  
Yvonne Harcus ◽  
...  
Keyword(s):  
Transforming Growth Factor ◽  
Fluorescent Protein ◽  
De Novo ◽  
Foxp3 Expression ◽  
Dominant Negative ◽  
Regulatory Function ◽  
Intestinal Helminth ◽  
Helminth Parasites

Foxp3-expressing regulatory T (T reg) cells have been implicated in parasite-driven inhibition of host immunity during chronic infection. We addressed whether parasites can directly induce T reg cells. Foxp3 expression was stimulated in naive Foxp3− T cells in mice infected with the intestinal helminth Heligmosomoides polygyrus. In vitro, parasite-secreted proteins (termed H. polygyrus excretory-secretory antigen [HES]) induced de novo Foxp3 expression in fluorescence-sorted Foxp3− splenocytes from Foxp3–green fluorescent protein reporter mice. HES-induced T reg cells suppressed both in vitro effector cell proliferation and in vivo allergic airway inflammation. HES ligated the transforming growth factor (TGF) β receptor and promoted Smad2/3 phosphorylation. Foxp3 induction by HES was lost in dominant-negative TGF-βRII cells and was abolished by the TGF-β signaling inhibitor SB431542. This inhibitor also reduced worm burdens in H. polygyrus–infected mice. HES induced IL-17 in the presence of IL-6 but did not promote Th1 or Th2 development under any conditions. Importantly, antibody to mammalian TGF-β did not recognize HES, whereas antisera that inhibited HES did not affect TGF-β. Foxp3 was also induced by secreted products of Teladorsagia circumcincta, a related nematode which is widespread in ruminant animals. We have therefore identified a novel pathway through which helminth parasites may stimulate T reg cells, which is likely to be a key part of the parasite’s immunological relationship with the host.

FRET ‐based analysis and molecular modeling of the human GPN ‐loop GTP ases 1 and 3 heterodimer unveils a dominant‐negative protein complex

FEBS Journal ◽  
2019 ◽  
Vol 286 (23) ◽  
pp. 4797-4818 ◽  
Author(s):  
Gema R. Cristóbal‐Mondragón ◽  
Bárbara Lara‐Chacón ◽  
Ángel Santiago ◽  
Víctor De‐la‐Rosa ◽  
Rogelio González‐González ◽  
...  
Keyword(s):  
Molecular Modeling ◽  
Protein Complex ◽  
Dominant Negative

scholarly journals Mutations in Residues Involved in Zinc Binding in the Catalytic Site of Escherichia coli Threonyl-tRNA Synthetase Confer a Dominant Lethal Phenotype

2007 ◽  
Vol 189 (19) ◽  
pp. 6839-6848 ◽  
Author(s):  
Joël Caillet ◽  
Monique Graffe ◽  
Flore Eyermann ◽  
Pascale Romby ◽  
Mathias Springer
Keyword(s):  
Escherichia Coli ◽  
Trna Synthetase ◽  
Dominant Negative ◽  
Zinc Binding ◽  
Regulatory Function ◽  
Dominant Negative Effect ◽  
Multicopy Plasmid ◽  
Wild Type ◽  
Zinc Binding Site ◽  
Negative Effect

ABSTRACT Escherichia coli threonyl-tRNA synthetase is a homodimeric protein that acts as both an enzyme and a regulator of gene expression: the protein aminoacylates tRNAThr isoacceptors and binds to its own mRNA, inhibiting its translation. The enzyme contains a zinc atom in its active site, which is essential for the recognition of threonine. Mutations in any of the three amino acids forming the zinc-binding site inactivate the enzyme and have a dominant negative effect on growth if the corresponding genes are placed on a multicopy plasmid. We show here that this particular property is not due to the formation of inactive heterodimers, the titration of tRNAThr by an inactive enzyme, or its misaminoacylation but is, rather, due to the regulatory function of threonyl-tRNA synthetase. Overproduction of the inactive enzyme represses the expression of the wild-type chromosomal copy of the gene to an extent incompatible with bacterial growth.

Heavy metal tolerance of transgenic tobacco plants over-expressing cysteine synthase

2004 ◽  
Vol 26 (2) ◽  
pp. 153-157 ◽  
Author(s):  
Cintia Goulart Kawashima ◽  
Masaaki Noji ◽  
Michimi Nakamura ◽  
Yasumitsu Ogra ◽  
Kazuo T. Suzuki ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Transgenic Tobacco ◽  
Metal Tolerance ◽  
Heavy Metal Tolerance ◽  
Transgenic Tobacco Plants ◽  
Cysteine Synthase ◽  
Tobacco Plants
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