Intracellular signal transduction pathway

The smooth muscle cell does not respond in an all-or-none manner, but instead its contractile state is a variable compromise between diverse regulatory influences. While a vertebrate skeletal muscle fiber is at complete rest unless activated by a motor nerve, regulation of the contractile activity of a smooth muscle cell is more complex. First, the smooth muscle cell typically receives input from many different kinds of nerve fibers. The various cell membrane receptors in turn activate different intracellular signal-transduction pathways which may affect (a) membrane channels, and hence, electrical activity (b) calcium storage or release or (c) the proteins of the contractile machinery. While each have their own biochemically specific ways, the actual mechanisms are for the most part known only in outline. 

Lo, H-M, C-F Hung, Y-L Tseng, B-H Chen, J-S Jian, and W-B Wu. 2007. Lycopene binds PDGF-Bb and inhibits PDGD-BB-induced intracellular signaling transduction pathway in rat smooth muscle cells. Biochem Pharmacol 74 54-63. 

Intracellular Signal Transduction Pathways in the Treatment of Anxiety. .. 321... 

Ahn, H.Y., Hadizadeh, K.R., Seul, C., Yun, Y.P., Vetter, H., and Sachinidis, A., Epigallocathe-chin-3-gallate selectively Inhibits the PDGF-BB-induced intracellular signaling transduction pathway in vascular smooth muscle cells and inhibits transformation of ai-transfected NIH 3T3 fibroblasts and human glioblastoma cells (A172), Mol. Biol. Cell, 10, 1093, 1999. 

Fig. 1. Major chemokine and IL-3/IL-5/GM-CSF-mediated intracellular signal transduction pathways in granulocytes.

Eriksson, K., Magnusson, P., Dixelius, J., Claesson-Welsh, L., and Cross, M. J. 2003. Angiostatin and endostatin inhibit endothelial cell migration in response to FGF and VEGF without interfering with specific intracellular signal transduction pathways. FEBS Lett. 536 19-24. 

The intracellular signal transduction pathway by which the yeast [16, 17] Saccharomyces cerevisiae responds to the presence of peptide mating pheromone in its surroundings is one of the best understood signalling pathways in eukaryotes, yet continues to generate new surprises and insights. The signal is transmitted from the cell-surface receptor-coupled G protein, via a MAP kinase cascade, to the nucleus. 

The activities of many transcription factors are indirectly regulated by binding of extracellular proteins and peptides to cell-surface receptors. These receptors activate intracellular signal transduction pathways that regulate specific transcription factors through a variety of mechanisms discussed in Chapters 13 and 14. 

Second, some classes of receptors can initiate signaling via more than one intracellular signal-transduction pathway, leading to different cellular responses. This complication is typical of G protein-coupled receptors, receptor tyrosine kinases, and cytokine receptors. 

Binding of extracellular signaling molecules to cell-surface receptors triggers Intracellular signal-transduction pathways that ultimately modulate cellular metabolism, function, or gene expression (Figure 13-1). 

We turn now to a second important class of cell-surface receptors, the cytokine receptors, whose cytosolic domains are closely associated with a member of a family of cytosolic protein tyrosine kinases, the JAK kinases. A third class of receptors, the receptor tyrosine kinases (RTKs), contain intrinsic protein tyrosine kinase activity in their cytosolic domains. The mechanisms by which cytokine receptors and receptor tyrosine kinases become activated by ligands are very similar, and there is considerable overlap in the intracellular signal-transduction pathways triggered by activation of receptors in both classes. In this section, we first describe some similarities in signaling from these two receptor classes. We then discuss the JAK-STAT pathway, which is initiated mainly by activation of cytokine receptors. 

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