Regulation of physiological processes

The functioning of G proteins may be influenced by phosphorylation. G proteins, as well as their associated receptors and RGS proteins, have been reported to undergo phosphorylation by a host of protein serine/ threonine kinases and protein tyrosine kinases. While the ramifications of receptor phosphorylation are becoming increasingly well understood (see Chs 23 and 24), the effect of phosphorylation of G proteins and RGS proteins, and its role in the regulation of physiological processes, have been more difficult to establish with certainty. This remains an important area of future investigation. 

Reversible protein phosphorylation occurs by means of protein kinases. Eukaryotic protein kinases comprise a 250-amino acid, conserved catalytic domain. They are widely exploited in the regulation of physiological processes according to estimates the mammalian genome contains over 2000 PK genes. 

Studies of IFN expression, structure, and function have provided a number of scientific advances. The study of transcription of IFN-stimulated genes (ISGs) and analysis of IFN-induced proteins have provided not only a tool to observe the complexities of inducible gene expression in eukaryotic cells but also led to identification of important regulators of physiological processes. 

Strand, F.L. . Neuropeptides Regulators of Physiological Processes, MIT Press, 1999. 

Implications of steroids in a variety of biological processes provide a continuous impetus for improved analytical techniques. In particular, the hormonal regulation of physiological processes that remains one of the most investigated areas of modern biomedical research requires measurement techniques of considerable sophistication. The sensitivity of such measurements is being continuously challenged by the requirements to determine ever smaller quantities of steroid hormones and their metabolites in various body fluids and tissues. 

F. L. Strand, Neuropeptides Regulators of physiological processes, The MIT Press, Cambridge, 1999. 

Prostaglandins play critical roles in a number of physiological processes. These molecules regulate blood flow to organs, stimulate secretion of protective mucosal linings in the gastrointestinal tract, participate in the initiation of platelet aggrega-... 

We can see from Figure 3 that the moderate deficit of I, Co, Zn, Cu, Mo, B, and Mn with optimal ratios of trace metals to I and Si, is characteristic for all links of a biogeochemical food web. These biogeochemical peculiarities favor the optimal physiological regulation of exchange processes in animal and human organisms. However, a moderate deficit of essential trace nutrients weakens the human immune... 

Nicotinic receptors are widely distributed in the brain and are involved in a number of physiological processes. The prefrontal cortex is a major site for the cognitive effects of nicotine (Vidal 1996). Some of the cognitive benefits of nicotine may occur after chronic treatment, resulting in part from nicotinic receptor up-regulation in frontal, entorhinal, and dorsal hippocampal regions (Abdulla et al. 1996). Chronic nicotine treatment also increases the sensitivity of muscarinic receptors (Wang et al. 1996). 

Yet another example of combinatorial histone codes come to fore in yeast, wherein H2B K123 monoubiquitination was shown to be a necessary prerequisite for H3K24 and H3K79 methylation resulting in opening of the chromatin (Sun and Allis, 2002). Combination of histone marks in the regulation of physiologically relevant processes such as embryonic development and lymphocyte maturation have also been described. 

Glucocorticoids (GC) are steroid hormones that regulate various physiological processes via stimulation of the nuclear glucocorticoid receptors (1). Chronically elevated levels of active GC hormones (e.g., cortisol) have been associated with many... 

Calcium ions are essential in a variety of physiological processes including blood clotting, release of neurotransmitter at the synapse, cell division, cell adhesion, secretion, bioluminescence, membrane permeability, muscle contraction, and bio-mineralization35,174 176. In most of these systems, the disposition and functions of membrane proteins are a key in transport and regulation of calcium. Thus in order to understand the functionality of calcium one should look at a membrane system where the biochemical interplay of calcium is known in detail. 

The endocrine glands regulate a variety of physiologic processes through the release of specific hormones. Hormones are the equivalent of endogenously produced drugs that usually travel through the blood-... 

There is no obvious correlation between MAA and scytonemin concentrations in free-living or symbiotic cyanobacteria. This lack of covariance suggests that although both compounds have UV-absorbing properties, they may respond to different stimuli. It has been suggested that scytonemin and MAAs have different UV photoreceptors.168 It is also possible that primary or secondary functions may differ. In addition to UV absorption, MAAs may have physiological functions related to antioxidant activity, regulation of reproductive processes, or maintenance of osmotic balance. Scytonemin is more likely to provide only radiation protection, and, therefore, there may be little reason to expect concentrations of these compounds to be correlated. 

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