Pathways of tRNA turnover in eukaryotic cells

Cell ability to control amount of a transfer RNA is one of the ways to regulate rate of protein synthesis. Because 80–90% dry mass of cells are proteins, the level of translation is determinant to the cell growth. Growth of cells is a key question in tumors therapy and biotechnology. tRNA turnover consist of a three pathways described in a last few years: exosome and TRAMP complex dependent pathway in nucleus, directed to hypomodified or affected tRNA; rapid tRNA decay pathway involving two 5’–3’ exonucleases Rat1 and Xrn1, proposed to occur in nucleus and cytoplasm; stress-activated endonucleolytic cleavage to tRNA halves pathway, founded in cytoplasm with a clear role to direct regulation of translation by tRNA half-molecules inhibition