451 INVITED Molecular imaging strategies to assess signal transduction and protein-protein interactions non invasively: real time imaging of drug target responses

AbstractWe present two high-throughput compatible methods to detect the interaction of ectopically expressed (RT-Bind) or endogenously tagged (EndoBind) proteins of interest. Both approaches provide temporal evaluation of dimer formation over an extended duration. Using examples of the Nrf2-KEAP1 and the CRAF-KRAS-G12V interaction, we demonstrate that our method allows for the detection of signal for more than 2 days after substrate addition, allowing for continuous monitoring of endogenous protein-protein interactions in real time.

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Properties of the phage-shock-protein (Psp) regulatory complex that govern signal transduction and induction of the Psp response in Escherichia coli

Microbiology ◽

10.1099/mic.0.040055-0 ◽

2010 ◽

Vol 156 (10) ◽

pp. 2920-2932 ◽

Cited By ~ 29

Author(s):

Goran Jovanovic ◽

Christoph Engl ◽

Antony J. Mayhew ◽

Patricia C. Burrows ◽

Martin Buck

Keyword(s):

Escherichia Coli ◽

Signal Transduction ◽

Protein Interactions ◽

Leucine Zipper ◽

Negative Control ◽

Stress Conditions ◽

Bacterial Cells ◽

Protein Protein Interactions ◽

Regulatory Complex ◽

And Function

The phage-shock-protein (Psp) response maintains the proton-motive force (pmf) under extracytoplasmic stress conditions that impair the inner membrane (IM) in bacterial cells. In Escherichia coli transcription of the pspABCDE and pspG genes requires activation of σ 54-RNA polymerase by the enhancer-binding protein PspF. A regulatory network comprising PspF–A–C–B–ArcB controls psp expression. One key regulatory point is the negative control of PspF imposed by its binding to PspA. It has been proposed that under stress conditions, the IM-bound sensors PspB and PspC receive and transduce the signal(s) to PspA via protein–protein interactions, resulting in the release of the PspA–PspF inhibitory complex and the consequent induction of psp. In this work we demonstrate that PspB self-associates and interacts with PspC via putative IM regions. We present evidence suggesting that PspC has two topologies and that conserved residue G48 and the putative leucine zipper motif are determinants required for PspA interaction and signal transduction upon stress. We also establish that PspC directly interacts with the effector PspG, and show that PspG self-associates. These results are discussed in the context of formation and function of the Psp regulatory complex.

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Protein-Protein Interactions in the Tetraspanin Web

Physiology ◽

10.1152/physiol.00015.2005 ◽

2005 ◽

Vol 20 (4) ◽

pp. 218-224 ◽

Cited By ~ 132

Author(s):

Shoshana Levy ◽

Tsipi Shoham

Keyword(s):

Signal Transduction ◽

Cell Proliferation ◽

Protein Interactions ◽

Membrane Microdomains ◽

Protein Protein Interactions ◽

Host Parasite Interactions ◽

Evolutionarily Conserved ◽

And Migration ◽

Host Parasite ◽

Partner Proteins

Tetraspanins are evolutionarily conserved membrane proteins that tend to associate laterally with one another and to cluster dynamically with numerous partner proteins in membrane microdomains. Consequently, members of this family are involved in the coordination of intracellular and intercellular processes, including signal transduction; cell proliferation, adhesion, and migration; cell fusion; and host-parasite interactions.

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