Regulation of protein synthesis

Factors, such as o-, affect RNA polymerase activity. These factors bind to the core RNA polymerase and increase its ability to bind to specific promoters. 

Eukaryotes contain nuclei. Therefore, transcription is separated from translation. In prokaryotes, transcription and translation occur simultaneously. 

The mammalian genome contains about 1000 times more DNA than E. coli (109 versus 106 base pairs). 

The major part of the genome of mammalian cells does not code for proteins. 

Eukaryotic cells undergo differentiation, and the organisms go through various developmental stages. 

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Singh, N.K., La Rosa, P.C., Handa, A.K., Hasegawa, P.M. Bressan, R.A. (1987f>). Hormonal regulation of protein synthesis associated with salt tolerance in plant cells. Proceedings of the National Academy of Sciences, USA, 84,739-43. 

Lindquist, S. (1981). Regulation of protein synthesis during heat shock. Nature, 294, 311-14. 

Palfrey, H. C. and Nairn, A. C. Calcium-dependent regulation of protein synthesis. Adv. Second Messenger Phosphoprotein Res. 30 191-223,1995. 

Finally, this section has focused almost entirely on axonal transport, but dendritic transport also occurs [25]. Since dendrites usually include postsynaptic regions while most axons terminate in presynaptic elements, the dendritic and axonal transport each receive a number of unique proteins. An added level of complexity for intraneuronal transport phenomena is the intriguing observation that mRNA is routed into dendrites where it is implicated in local protein synthesis at postsynaptic sites, but ribosomal components and mRNA are largely excluded from axonal domains [26]. Regulation of protein synthesis in dendritic compartments is an important mechanism is synaptic plasticity [27,28]. The importance of dendritic mRNA transport and local protein synthesis is underscored by the demonstration that the mutation associated with Fragile X syndrome affects a protein important for transport and localization of mRNA in dendrites [27, 29], Similar processes of mRNA transport have been described in glial cells [30]. 

XVII. CARNOSINE, REGULATION OF PROTEIN SYNTHESIS, AND AGING... 

The intercalating drugs and nucleic acid synthesis inhibitors discussed in the preceding sections interfere indirectly with every phase of nucleic acid action because the DNA is rendered nonfunctional. Other drugs, discussed below, affect the regulation of protein synthesis even when the genome, the DNA structure, is intact. Such activity can be the result of interference either with transcription of messenger RNA or with translation of the mRNA to protein. 

The purine and pyrimidine bases play an important role in the metabolic processes of cells through their involvement in the regulation of protein synthesis. Thus, several synthetic analogues of these compounds are used to interrupt the cancer cell growth. One such example is an adenine mimic, 6-mercaptopurine, which is a well known anticancer drug. 

The DAG produced by the hydrolysis of PIP2 by PLC remains in the plasma membrane where it activates a family of membrane-associated protein kinases collectively termed protein kinase C (PKC). Activated PKC produces a variety of cellular responses, including the regulation of protein synthesis and key metabolic pathways. 

The behavior of the various mutations we have just discussed led Jacob and Monod to propose a model for the regulation of protein synthesis. The genetic elements of this model consist of a structural gene or genes, a regulator gene, and an operator locus (fig. 30.6). 

Regulation of protein synthesis in the rabbit reticulocyte. The vast majority of the protein synthesized in the rabbit reticulocyte is hemoglobin. The gross rate of protein synthesis in the reticulocyte is controlled indirectly by the concentration of heme. Heme inactivates a kinase that would otherwise inactivate the initiation complex involving eIF-2 and eIF-2B. The kinase phosphorylates the eIF-2 factor, making it impossible for the eIF-2-eIF-2B complex to exchange GDP for GTP. 

Bolster DR, Jefferson LS, Kimball SR. Regulation of protein synthesis associated with skeletal muscle hypertrophy by insulin-, amino acid- and exercise-induced signalling. Proc Nutr Soc. 2004 63 351-356. 

Siddiqui, A. A. Podesta, R. B. (1985a). Development regulation of protein synthesis in Hymenolepis diminuta 2-dimensional electrophoretic and fluorographic analysis of polypeptide synthesis in formation of brush border membranes. Cellular and Molecular Biology, 31 209-16. 

Developmental regulation of protein synthesis in Hymenolepis diminuta two-dimensional electrophoretic and fluorographic analysis of protein synthesis in oncospheres. Journal of... 

Werdan, K. (1992b). Application ofhigh resolution two-dimensional polyacrylamide gel electrophoresis of polypeptides from culmred neonatal rat cardiomyocytes regulation of protein synthesis by catecholamines. Electrophoresis 13, 748-754. 

The ribosomal elongation Factor 11 is the acceptor protein for the ADP-ribosyltransferase activity of diphtheria toxin and P. aeruginosa exotoxin A, as well as a mammalian cytosolic ADP-ribosyltransferase. ADP-ribosylation results in loss of activity. The uncontrolled action of the bacterial toxins causes the cessation ofprotein synthesis andhence cell death. The more regulated action of the endogenous ADP-ribosyltransferase is part of the normal regulation of protein synthesis. 

Chen JJ, London IM. Regulation of protein synthesis by heme-regulated eIF-2 alpha kinase. Trends Biochenu Sci. 1995 20 105-108. 

Regulation of protein synthesis in prokaryotes occurs mainly at the transcriptional level and involves genetic units known as operons. 

In eukaryotes, regulation of protein synthesis may occur by modification of DNA or at the level of transcription or translation. 

Each of the following statements about regulation of protein synthesis in eukaryotes is correct EXCEPT... 

Garry RF, Bishop JM, Parker S, Westbrook K, Lewis G, Waite MR (1979) Na-t and K-t concentrations and the regulation of protein synthesis in Sindbis virus-infected chick cells. Virology 96 108-120... 

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