Chapter 10 Protein synthesis and regulation in eukaryotes

Protein synthesis is one of the most complex processes in the cell. Its regulation during different stages of growth, division, differentiation, development, aging, and death is a crucial aspect of a living system. In order to translate one mRNA molecule transcribed from a gene, almost 200 small and large components are required to function effectively and accurately, while using large quantities of cellular energy. Ribosomes, initiation factors, elongation factors, amino acids, tRNAs, and aminoacyl-tRNA synthetases are the major components of the protein synthetic apparatus. Protein synthesis proceeds in three steps—initiation, elongation, and termination, followed by posttranslational modifications. The rate-limiting factors for the regulation of total protein synthesis can be any of the components of the protein synthetic machinery. The availability of mRNA and the amounts and activities of ribosomes, initiation factors, and elongation factors are the major regulators of protein synthesis. Posttranslational modifications such as phosphorylation of various protein synthetic components are involved in determining their activity and stability.