Signal phosphorylation

Vanhoose AM, Winder DG. 2003. NMDA and betal-adrenergic receptors differentially signal phosphorylation of glutamate receptor type 1 in area CA1 of hippocampus. J Neurosci 23 5827-5834. 

Positive control by phosphorylation and negative control by dephosphorylation are equally important. Depending on the properties of the signalling proteins and the nature of signals, phosphorylation may be more important in some cases and dephosphorylation in others. Moreover, in some cases dephosphorylation may have positive and phosphorylation negative effects on the activity of regulators. 

Insulin Signaling Phosphorylation Cascades Are Central to Many Signal-Transduction Processes... 

Rgu re 14.23 Action of a lipid kinase in insulin signaling. Phosphorylated IRS-1 and IRS-2 activate the enzyme phosphatidylinositide 3-kinase, an enzyme that converts PIP into PIPj,... 

In unstimulated cells, NF-kB is localized to the cytosol, bound to an inhibitor protein, I-kB. In response to extracellular signals, phosphorylation-dependent ubiquitination and degradation of I-kB in proteasomes releases active NF-kB, which translocates to the nucleus (see Figure 14-28). 

Phosphorylation at Thr inhibits protein phosphatase-1 (PP-1). Inhibition of PP-1 enhances signaling. Phosphorylation of Thr has an inhibitory effect on Thr phosphorylation (conversely, decreased Thr phosphorylation disinhibits PKA to increase Thr phosphorylation), whereas phosphorylation of Ser prevents... 

Ohira T., Arita M., Omori K., Recchiuti A., Van Dyke T. E., Serhan C. N. 2010. Resolvin El receptor activation signals phosphorylation and phagocytosis. Journal of Bioloeical... 

The last part of this account will be devoted to protein kinases and protein phosphatases and some recent results we have obtained for them. Protein kinases and phosphatases are signaling biomolecules that control the level of phosphorylation and dephosphorylation of tyrosine, serine or threonine residues in other proteins, and by this means regulate a variety of fundamental cellular processes including cell growth and proliferation, cell cycle and cytoskeletal integrity. 

There are five known classes of enzyme-linked receptors (1) receptor tyrosine kinases, which phosphorylate specific tyrosine residues on intracellular signaling proteins (2) tyrosine kinase-associated receptors, such as the prolactin and growth hormone receptors we have already discussed, which... 

The abundance of many protein kinases in cells is an indication of the great importance of protein phosphorylation in cellular regulation. Exactly 113 protein kinase genes have been recognized in yeast, and it is estimated that the human genome encodes more than 1000 different protein kinases. Tyrosine kinases (protein kinases that phosphorylate Tyr residues) occur only in multicellular organisms (yeast has no tyrosine kinases). Tyrosine kinases are components of signaling pathways involved in cell-cell communication (see Chapter 34). 

The majority of functional assays involve primary signaling. In the case of GPCRs, this involves activation of G-proteins. However, receptors have other behaviors— some of which can be monitored to detect ligand activity. For example, upon stimulation many receptors are desensitized through phosphorylation and subsequently taken into the cell and either recycled back to the cell surface or digested. This process can be monitored by observing ligand-mediated receptor internalization. For... 

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