Receptor mediated signaling pathways

The series of molecular events responsible for the uptake process constitutes the endocytic pathway, which enables cells to internalize macromolecules from the cell exterior, forming an endosome. The endosome is an intermediate organelle that serves as an essential component for many receptor-mediated signaling pathways and as a transport vector for eventual delivery to a specialized organelle known as the lysosome. Once in the lysosomal lumen, digestive enzymes provide essential metabolites from these macromolecules (i.e. free amino acids and lipids) directly to the cytosol for their use. 

What do we know about receptor-mediated signalling pathways in parasitic platyhelminths Unfortunately, as a larger taxonomic group, we know very little. In-depth studies of the human blood fluke, 5. mansoni, have provided some of the most complete information on receptor-mediated signal transduction, and are summarized in the section on Transforming Growth Factor Receptor (TGFR) Pathway. ... 

R. A. Heller, and M. Konkre, Tumor Necrosis Factor Receptor-Mediated Signaling Pathways, Journal of Cell Biology, 126 (1994) 5-9. 

Hwang D, Rhee SH. Receptor-mediated signaling pathways potential targets of modulation by dietary fatty acids. Am J Clin Nutr 1999 70 545-556. 

Yanagisawa, H., Hammer, R.E., Richardson, J.A., Williams, S.C., Clouthier, D.E., Yanagisawa, M. 1998a. Role of Endothelin-1/Endothelin-A receptor-mediated signaling pathway in the aortic arch patterning in mice. J. Clin. Invest. 102, 22-33. 

Heller R A, Kronke M (1994). Tumor necrosis factor receptor-mediated signaling pathways. /. Cell Bio. 126 5-9. 

Hwang, D., and Rhee, S.H. (1999) Receptor-Mediated Signaling Pathways Potential Targets of Modulation by Dietary Fatty Acids, Am. J. Clin. Nutr. 70,545-556. 

Three phases of receptor-mediated signaling can be identified 178 Four distinct molecular mechanisms that link agonist occupancy of cell-surface receptors to functional responses have been identified 178 Cross-talk can occur between intracellular signaling pathways 179 Signaling molecules can activate gene transcription 181 Nitric oxide acts as an intercellular signaling molecule in the central nervous system 181... 

IL-4 mediates its effects via specific IL-4 receptors that are expressed on a number of tissues including hematopoietic cells, endothelium, hepatocytes, epithelial cells, fibroblasts, neurons and muscles. The receptor is composed of an a chain, which is the high-affinity receptor, but its signaling requires a second chain, a y chain (yC), which is also a component of IL-2 receptors. However, the presence of a y chain does not significantly increase the affinity of the receptor complex for IL-4. IL-4 causes the heterodimerization of the a chain with the y chain, resulting in IL-4 receptor-dependent signaling pathway. As is the case with other cytokines,... 

Figure 15.4 Mechanisms of apoptosis induction by resveratrol. Resveratrol selectively induces apoptosis in various cancer cells in culture by several mechanisms including activation of death receptor-mediated signaling, mitochondria-dependent cytochrome c release and caspase activation, induction of p53 and p53-regulated proapototic genes, activation of MAP kinase-mediated p53 phosphorylation, blockade of Akt-mediated cell survival pathways, and accumulation of intracellular ceramide level.

Th2 cytokine IL-10 is an antiinflammatory cytokine that suppresses the secretion of proinflammatory cytokines (Dll), allergen-induced airway inflammation, and nonspecific airway responsiveness (T9). IL-13 shares a receptor component, signaling pathways, and many biological activities with IL-4. In fact, IL-13 is also an antiinflammatory cytokine and plays a unique role in the optimal induction and maintenance of IgE production and IgE-mediated allergic responses when IL-4 production is low or absent (DIO, W12). Moreover, IL-13 or IL-4 shows a synergistic effect with TNF-a or IL-5 on eosinophil activation (L20). Recently, IL-11 was found to be involved in the chronic remodeling seen in asthmatic airways and is associated with increasing severity of the disease (Ml6). 

Figure 2 Schematic model of the intracellular signaling mechanisms including phosphatidylinositol-specific phospholipase C (PI-PLC) isoforms, inositol-1,4,5-triphosphate (IP3) receptor, and protein kinase C (PKC) in the expression of delta opioid receptor agonist-induced spinal antinociception. In addition, PKC is considered to play a substantial role in an intracellular negative feedback action on the spinal delta opioid receptor-mediated antinociceptive pathway.

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