Phosphorylation, stimulated

Glycogen synthase kinase-3 is itself subject to control by reversible phosphorylation. Stimulation of the liver cell by insulin, the key hormone of the postprandial state,... 

Reversible phosphorylation is the main control mechanism of liver phosphorylase allosteric effects being much less pronounced. This is in contrast with muscle phosphorylase, which is also controlled by phosphorylation, stimulated by an adrenaline-... 

We have proposed a mechanism by which lL-1 exerts its deleterious effects on islet function and viability (Fig. 11 Corbett et al., 1992). In this proposed mechanism, lL-1 is released by macrophages during the initial stages of islet infiltration. IL-1 binds to a specific IL-1 receptors on the /3 cell activating a tyrosine kinase. Tyrosine kinase phosphorylation stimulates second messengers to induce the expression of c-/os, c-jun, the activation of NF-xB, and possibly other early transcriptional regulators. These early-immediate transcriptional response elements may activate or stimulate the expression of inducible nitric oxide... 

The physiological effects of the kaempferol and quercetin derivatives are uncertain they inhibited indole-3-acetic acid oxidase in vitro they may induce dormancy, uncouple oxidative phosphorylation, stimulate plant... 

Answer Uncouplers of oxidative phosphorylation stimulate the rate of electron flow but not... 

Caution should however be taken in determining the proteins that are specifically tyrosine phosphoiylated in response to various agonists. This can be illustrated with thrombin, where studies have shown that removal of the autocrine stimulation in platelets during activation strongly reduces the tyrosine phosphorylation stimulated by thrombin (Figure 9.4.9.2). 

The results of experiments to be described below appear to show that anoxia and cell poisons which inhibit respiratory chain phosphorylation stimulate uptake of glucose by muscle and that under suitable conditions respiration of fatty acids and ketone bodies can lead to inhibition of glucose uptake. Since fatty acids and ketone bodies are oxidized by mitochondria and since the effects of anoxia and of these cell poisons will be exerted principally on mitochondrial metabolism it seems reasonable to accept these findings as common evidence for a regulatory effect of mitochondrial metabolism on glucose uptake. It is recognized that this concept is provisional until such time as the mechanism of this regulation has been established. 

Lin, K H.,Ashizawa,K., and Cheng, S.Y (1992) Phosphorylation stimulates the transcriptional activity of the human betal thyroid hormone nuclear receptor. Proc. Natl. Acad. Sci. USA, 89,7731-7741. 

The importance of quinones with unsaturated side chains in respiratory, photosynthetic, blood-clotting, and oxidative phosphorylation processes has stimulated much research in synthetic methods. The important alkyl- or polyisoprenyltin reagents, eg, (71) or (72), illustrate significant conversions of 2,3-dimethoxy-5-methyl-l,4-ben2oquinone [605-94-7] (73) to 75% (74) [727-81-1] and 94% (75) [4370-61-0] (71—73). 

FIGURE 23.22 The metabolic effects of insulin. As described in Chapter 34, binding of insulin to membrane receptors stimulates the protein kinase activity of the receptor. Subsequent phosphorylation of target proteins modulates the effects indicated. 

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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