Biopolymers and cell. 1989. Volume 5. № 5. 5 - 18

B. S. Negrutskii

TRANSFER RNA AS A FACTOR OF THE PROTEIN HOMEOSTASIS REGULATION

Summary

    The problem on coordinate regulation of protein synthesis and degradation in eukaryotes is now among the most undeveloped and intriguing problems of protein homeostasis. Transfer RNA has been suggested to be one of the intracellular mediators in transfer of regulatory signals. The data concerning protein synthesis and degradation in cell extracts, cultures, perfused organs and intact animals during amino acid starvation are discussed. It is concluded that tRNA participates in the elongation control, while initiation of the protein synthesis is supposed to be affected by other factors. The control mechanism of tRNA participation is discussed with description of a new model concerning deacylated tRNA effect on the elongation of polypeptide chains. The possible role of tRNA conformational changes within extreme states of the eukaryotic organism is considered. The possibility of tRNA participation in the endogenous proteolysis regulation is analyzed. The attention is paid to the significance of tRNA functional state. Although the data reviewed do not provide much more insight into the mechanism of communication between protein synthesis and degradation in eukaryotes, they point directly to the possibility of tRNA involvement in such a cooperation.