wingless signal and Zeste-white 3 kinase trigger opposing changes in the intracellular distribution of Armadillo

Development ◽  
1994 ◽  
Vol 120 (2) ◽  
pp. 369-380 ◽  
Author(s):  
M. Peifer ◽  
D. Sweeton ◽  
M. Casey ◽  
E. Wieschaus
Keyword(s):  
Signal Transduction ◽  
Genetic Analysis ◽  
Cell Fate ◽  
Intracellular Distribution ◽  
Beta Catenin ◽  
Signal Transduction System ◽  
Protein Levels ◽  
Wingless Signaling

wingless/wnt-1 signaling directs cell fate during development. Genetic analysis in Drosophila identified genes that may encode components of the wingless signal transduction system. Drosophila Armadillo, homolog of vertebrate beta-catenin, is required for wingless signaling. Unlike armadillo RNA, Armadillo protein accumulates non-uniformly in different cells of each embryonic segment. We found that cells alter their intracellular distribution of Armadillo in response to Wingless signal, accumulating increased levels of cytoplasmic Armadillo relative to those of membrane-associated protein. Levels of cytoplasmic Armadillo are also regulated by Zeste-White 3 kinase. Analysis of double mutants demonstrates that Armadillo's role in wingless signaling is direct, and that Armadillo functions downstream of both wingless and zeste-white 3. We present a model for the role of Armadillo stripes in transduction of wingless signal.

scholarly journals The β-Arrestin-Like Protein Rim8 Is Hyperphosphorylated and Complexes with Rim21 and Rim101 To Promote Adaptation to Neutral-Alkaline pH

2012 ◽  
Vol 11 (5) ◽  
pp. 683-693 ◽  
Author(s):  
Jonathan Gomez-Raja ◽  
Dana A. Davis
Keyword(s):  
Signal Transduction ◽  
Transcription Factor ◽  
G Protein ◽  
Signal Transduction Pathway ◽  
Multivesicular Bodies ◽  
Ph Sensing ◽  
Content Type ◽  
Protein Levels ◽  
G Protein Coupled

ABSTRACTβ-Arrestin proteins are critical for G-protein-coupled receptor desensitization and turnover. However, β-arrestins have recently been shown to play direct roles in nonheterotrimeric G-protein signal transduction. TheCandida albicansβ-arrestin-like protein Rim8 is required for activation of the Rim101 pH-sensing pathway and for pathogenesis. We have found thatC. albicansRim8 is posttranslationally modified by phosphorylation and specific phosphorylation states are associated with activation of the pH-sensing pathway. Rim8 associated with both the receptor Rim21 and the transcription factor Rim101, suggesting that Rim8 bridges the signaling and activation steps of the pathway. Finally, upon activation of the Rim101 transcription factor,C. albicansRim8 was transcriptionally repressed and Rim8 protein levels were rapidly reduced. Our studies suggest that Rim8 is taken up into multivesicular bodies and degraded within the vacuole. In total, our results reveal a novel mechanism for tightly regulating the activity of a signal transduction pathway. Although the role of β-arrestin proteins in mammalian signal transduction pathways has been demonstrated, relatively little is known about how β-arrestins contribute to signal transduction. Our analyses provide some insights into potential roles.

Possible role of inositol phospholipid signal transduction system inDunaliella salina under hypoosmotic shock

1997 ◽  
Vol 42 (2) ◽  
pp. 151-155
Author(s):  
Sixue Chen ◽  
Lin Li ◽  
Jiqiong Yan ◽  
Zhengkai Xu ◽  
Xinzhi Jiao
Keyword(s):  
Signal Transduction ◽  
Signal Transduction System ◽  
Hypoosmotic Shock ◽  
Inositol Phospholipid

scholarly journals The LisRK Signal Transduction System Determines the Sensitivity of Listeria monocytogenes to Nisin and Cephalosporins

2002 ◽  
Vol 46 (9) ◽  
pp. 2784-2790 ◽  
Author(s):  
Paul D. Cotter ◽  
Caitriona M. Guinane ◽  
Colin Hill
Keyword(s):  
Signal Transduction ◽  
Listeria Monocytogenes ◽  
Histidine Kinase ◽  
Antimicrobial Agents ◽  
Response Regulator ◽  
Signal Transduction System ◽  
Enhanced Sensitivity ◽  
Virulence Potential ◽  
Two Component Signal Transduction

ABSTRACT The Listeria monocytogenes two-component signal transduction system, LisRK, initially identified in strain LO28, plays a significant role in the virulence potential of this important food-borne pathogen. Here, it is shown that, in addition to its major contribution in responding to ethanol, pH, and hydrogen peroxide stresses, LisRK is involved in the ability of the cell to tolerate important antimicrobials used in food and in medicine, e.g., the lantibiotic nisin and the cephalosporin family of antibiotics. A ΔlisK mutant (lacking the LisK histidine kinase sensor component) displays significantly enhanced resistance to the lantibiotic nisin, a greatly enhanced sensitivity to the cephalosporins, and a large reduction in the expression of three genes thought to encode a penicillin-binding protein, another histidine kinase (other than LisK), and a protein of unknown function. Confirmation of the role of LisRK was obtained when the response regulator, LisR, was overexpressed using both constitutive and inducible (nisin-controlled expression) systems. Under these conditions we observed a reversion of the ΔlisK mutant to wild-type growth kinetics in the presence of nisin. It was also found that overexpression of LisR complemented the reduced expression of two of the aforementioned genes. These results demonstrate the important role of LisRK in the response of L. monocytogenes to a number of antimicrobial agents.

scholarly journals Negative regulation of Armadillo, a Wingless effector in Drosophila

Development ◽  
1997 ◽  
Vol 124 (11) ◽  
pp. 2255-2266 ◽  
Author(s):  
L.M. Pai ◽  
S. Orsulic ◽  
A. Bejsovec ◽  
M. Peifer
Keyword(s):  
Signal Transduction ◽  
Amino Acid ◽  
Cell Fate ◽  
Normal Development ◽  
Negative Regulation ◽  
Beta Catenin ◽  
Wild Type ◽  
Amino Acid Deletion ◽  
Numerous Cell ◽  
Cell Cell

Drosophila Armadillo and its vertebrate homolog beta-catenin play essential roles both in the transduction of Wingless/Wnt cell-cell signals and in the function of cell-cell adherens junctions. Wingless and Wnts direct numerous cell fate choices during development. We generated a mutant protein, Armadillo(S10), with a 54 amino acid deletion in its N-terminal domain. This mutant is constitutively active in Wingless signaling; its activity is independent of both Wingless signal and endogenous wild-type Armadillo. Armadillo's role in signal transduction is normally negatively regulated by Zeste-white 3 kinase, which modulates Armadillo protein stability. Armadillo(S10) is more stable than wild-type Armadillo, suggesting that it is less rapidly targeted for degradation. We show that Armadillo(S10) has escaped from negative regulation by Zeste white-3 kinase, and thus accumulates outside junctions even in the absence of Wingless signal. Finally, we present data implicating kinases in addition to Zeste white-3 in Armadillo phosphorylation. We discuss two models for the negative regulation of Armadillo in normal development and discuss how escape from this regulation contributes to tumorigenesis.

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