Cellular signaling processes

AKAPs are a diverse family of about 75 scaffolding proteins. They are defined by the presence of a structurally conserved protein kinase A (PKA)-binding domain. AKAPs tether PKA and other signalling proteins to cellular compartments and thereby limit and integrate cellular signalling processes at specific sites. This compartmentalization of signalling by AKAPs contributes to the specificity of a cellular response to a given external stimulus (e.g. a particular hormone or neurotransmitter). 

The free thiol group of cysteine readily undergoes reversible oxidation to form a disulphide via a thiyl radical, which can be repaired in the presence of a thiol donor such as glutathione. This is important during reversible cellular signalling processes. Further oxidation leads irreversibly to cysteic acid [96]. Oxidation of the single amino acid cysteine is also complicated by the observation that the product may be a composite mixed disulphide formed between other thiol-containing molecules. 

Modulation of Cellular Signaling Processes by Reactive Oxygen Species 205... 

Numerous flavonoids have been reported to affect cellular signaling processes, from kinases to transcription factors. In fact, oligomeric procyanidins from pine bark were found to prevent the activation of the proinflammatory transcription factor NF-k-B on ultraviolet (UV) exposure [3]. The same procyanidins are also potent modulators of nitric oxide metabolism [4,5]. 

SIP may be involved in cell survival, cell migration, and inflammation [48], The involvement of S IP in these cellular processes is largely through interactions with the G-protein-coupled receptors, known as SIP receptors [48], Inside the cell, SIP can induce calcium release, which is independent of the S1P receptors, the mechanism of which remains unknown. Other sphingolipids such as GluCer and gangliosides are also involved in cellular signaling processes [36,49],... 

Ras superfamily of small GTPases comprises more than 100 different proteins that are involved in many cellular signalling processes regulating among others cell growth and proliferation, cell motility, or vesicle transport. Ras members are expressed with a C-terminal sequence known as CAAX box (where C is a cysteine, A can be any aliphatic amino acid, and X is any amino acid and determines the isoprenyl group to be attached to the cysteine) [5]. This CAAX box is recognized by prenyl transferases (farnesyltransferase... 

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