Membrane Perturbation by Bile Acids Causes Signal Transduction Through Caveolae

2004 ◽  
Author(s):  
Samira Jean-Louis ◽  
Jesse D. Martinez
Keyword(s):  
Signal Transduction ◽  
Bile Acids ◽  
Membrane Perturbation

scholarly journals Endogenous membrane stress induces T6SS activity inPseudomonas aeruginosa

2020 ◽  
Vol 118 (1) ◽  
pp. e2018365118
Author(s):  
Anne-Sophie Stolle ◽  
Bradley Thomas Meader ◽  
Jonida Toska ◽  
John J. Mekalanos
Keyword(s):  
Signal Transduction ◽  
Outer Membrane ◽  
Cell Envelope ◽  
Signal Transduction Pathway ◽  
Polymyxin B ◽  
Transduction Pathway ◽  
Dynamic Activity ◽  
Membrane Perturbation ◽  
Tit For Tat ◽  
Outer Membrane Biogenesis

The type 6 secretion system (T6SS) is a dynamic organelle encoded by many gram-negative bacteria that can be used to kill competing bacterial prey species in densely occupied niches. Some predatory species, such asVibrio cholerae, use their T6SS in an untargeted fashion while in contrast,Pseudomonas aeruginosaassembles and fires its T6SS apparatus only after detecting initial attacks by other bacterial prey cells; this targeted attack strategy has been termed the T6SS tit-for-tat response. Molecules that interact with theP. aeruginosaouter membrane such as polymyxin B can also trigger assembly of T6SS organelles via a signal transduction pathway that involves protein phosphorylation. Recent work suggests that a phospholipase T6SS effector (TseL) ofV. choleraecan induce T6SS dynamic activity inP. aeruginosawhen delivered to or expressed in the periplasmic space of this organism. Here, we report that inhibiting expression of essential genes involved in outer membrane biogenesis can also trigger T6SS activation inP. aeruginosa. Specifically, we developed a CRISPR interference (CRISPRi) system to knock down expression ofbamA,tolB, andlptDand found that these knockdowns activated T6SS activity. This increase in T6SS activity was dependent on the same signal transduction pathway that was previously shown to be required for the tit-for-tat response. We conclude that outer membrane perturbation can be sensed byP. aeruginosato activate the T6SS even when the disruption is generated by aberrant cell envelope biogenesis.

Bile acids and signal transduction: Role in glucose homeostasis

2008 ◽  
Vol 20 (12) ◽  
pp. 2180-2197 ◽  
Author(s):  
Amy Nguyen ◽  
Bernard Bouscarel
Keyword(s):  
Signal Transduction ◽  
Bile Acids ◽  
Glucose Homeostasis

Ultrastructural aspects of olfactory signal transduction and its development

1994 ◽  
Vol 52 ◽  
pp. 142-143
Author(s):  
Bert Ph. M. Menco
Keyword(s):  
Signal Transduction ◽  
Olfactory Receptor ◽  
Receptor Cell ◽  
Freeze Substitution ◽  
Luminal Surface ◽  
Tissue Sections ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Olfactory Signal ◽  
Odor Molecule

Vertebrate olfactory receptor cells are specialized neurons that have numerous long tapering cilia. The distal parts of these cilia line the interface between the external odorous environment and the luminal surface of the olfactory epithelium. The length and number of these cilia results in a large surface area that presumably increases the chance that an odor molecule will meet a receptor cell. Advanced methods of cryoprepration and immuno-gold labeling were particularly useful to preserve the delicate ultrastructural and immunocytochemical features of olfactory cilia required for localization of molecules involved in olfactory signal-transduction. We subjected olfactory tissues to freeze-substitution in acetone (unfixed tissues) or methanol (fixed tissues) followed by low temperature embedding in Lowicryl K11M for that purpose. Tissue sections were immunoreacted with several antibodies against proteins that are presumably important in olfactory signal-transduction.

Signal-regulated oxidation of proteins via MICAL

2020 ◽  
Vol 48 (2) ◽  
pp. 613-620
Author(s):  
Clara Ortegón Salas ◽  
Katharina Schneider ◽  
Christopher Horst Lillig ◽  
Manuela Gellert
Keyword(s):  
Signal Transduction ◽  
Hydrogen Peroxide ◽  
Cell Death ◽  
Redox Regulation ◽  
Signal Transduction Pathways ◽  
Cellular Functions ◽  
Intracellular Signals ◽  
Amino Acid Side Chains ◽  
Specific Receptors ◽  
Sulfur Containing

Processing of and responding to various signals is an essential cellular function that influences survival, homeostasis, development, and cell death. Extra- or intracellular signals are perceived via specific receptors and transduced in a particular signalling pathway that results in a precise response. Reversible post-translational redox modifications of cysteinyl and methionyl residues have been characterised in countless signal transduction pathways. Due to the low reactivity of most sulfur-containing amino acid side chains with hydrogen peroxide, for instance, and also to ensure specificity, redox signalling requires catalysis, just like phosphorylation signalling requires kinases and phosphatases. While reducing enzymes of both cysteinyl- and methionyl-derivates have been characterised in great detail before, the discovery and characterisation of MICAL proteins evinced the first examples of specific oxidases in signal transduction. This article provides an overview of the functions of MICAL proteins in the redox regulation of cellular functions.

Specificity of receptor-mediated signal transduction by E. coli type its heat-labile toxin

2001 ◽  
Vol 120 (5) ◽  
pp. A700-A700
Author(s):  
S WIMERMACKIN ◽  
R HOLMES ◽  
A WOLF ◽  
W LENCER ◽  
M JOBLING
Keyword(s):  
Signal Transduction ◽  
E Coli ◽  
Heat Labile
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