Signal transduction ligands

The endothelin receptor subtypes show differences in their signal transduction, ligand binding and tissue distribution. The ETA receptor is isopeptide-selective and binds ET-1 and ET-2 with the same and ET-3 with 70-100-fold lower affinity. The ETB receptor binds all three isoforms with the same affinity. 

Natural or synthethic receptor ligands that induce a conformational change (active conformation) and a signal transduction process upon receptor binding. Agonists may act as typical hormones or neurotransmitters or they may confer paracrine functions, recognize bacterial, viral or other environmental constituents via activating their dedicated receptors. 

Ligand-induced signal transduction processes that are mediated by a ligand-operated ion channel, e.g., by the nicotinic receptor in muscle, result in an almost... 

Figure 1. Simplified schematic of receptor-mediated signal transduction in neutrophils. Binding of ligand to the receptor activates a guanine-nucleotide-binding protein (G protein), which then stimulates phospholipase C. Phosphatidylinositol 4,5-bis-phosphate is cleaved to produce diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3). DAG stimulates protein kinase C. IP3 causes the release of Ca from intracellular stores, which results in an increase in the cytosolic Ca concentration. This increase in Ca may stimulate protein kinase C, calmodulin-dependent protein kinases, and phospholipase A2. Protein phosphorylation events are thought to be important in stimulating degranulation and oxidant production. In addition, ionic fluxes occur across the plasma membrane. It is possible that phospholipase A2 and ionic channels may be governed by G protein interactions. ...

S., Beglinger, C., and Eberle, A.N. A combinatorial peptoid library for the identification of novel MSH and GRP/ Bombesin receptor ligands. J. Receptor Signal Transduct. Res. 1999, 19, 449-466. 

Figure 43-13. Several signal transduction pathways converge on CBP/p300. Ligands that associate with membrane or nuclear receptors eventually converge on CBP/p300. Several different signal transduction pathways are employed. EGF, epidermal growth factor GH, growth hormone PrI, prolactin TNF, tumor necrosis factor other abbreviations are expanded in the text.

Myers SJ, Wong LM, Charo IF (1995) Signal transduction and ligand specificity of the human monocyte chemoattractant protein-1 receptor in transfected embryonic kidney cells. J Biol Chem 270 5786-5792... 

Liu J., Chen P., Wang D. and Halpem M. (1999). Signal transduction in the vomeronasal organ of garter snakes ligand-receptor binding mediated protein phosphorylation. Biochem Biophys Acta 1450, 320-330. 

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