Ribosomal protein S6 explained

Ribosomal protein S6 (rpS6 or eS6) is a component of the 40S ribosomal subunit and is therefore involved in translation. Mouse model studies have shown that phosphorylation of eS6 is involved in the regulation of cell size, cell proliferation, and glucose homeostasis.^{[1] [2] [3]}

Studies show that the p70 ribosomal protein S6 kinases (S6K1 and S6K2) and p90 ribosomal protein S6 kinases (RSK) both phosphorylate eS6 and that S6K1 and S6K2 predominate this function.

Pathways leading to the induction of human eS6 phosphorylation have been found to enhance IL-8 protein synthesis. This mechanism is dependent on A/U-rich proximal sequences (APS) found in the 3'UTR of IL-8 immediately after the stop codon.^[4]

Notes and References

1. Ruvinsky I, Sharon N, Lerer T, Cohen H, Stolovich-Rain M, Nir T, Dor Y, Zisman P, Meyuhas O . 6 . Ribosomal protein S6 phosphorylation is a determinant of cell size and glucose homeostasis . Genes & Development . 19 . 18 . 2199–211 . September 2005 . 16166381 . 1221890 . 10.1101/gad.351605 .
2. Ruvinsky I, Meyuhas O . Ribosomal protein S6 phosphorylation: from protein synthesis to cell size . Trends in Biochemical Sciences . 31 . 6 . 342–8 . June 2006 . 16679021 . 10.1016/j.tibs.2006.04.003 .
3. Ruvinsky I, Katz M, Dreazen A, Gielchinsky Y, Saada A, Freedman N, Mishani E, Zimmerman G, Kasir J, Meyuhas O . 6 . Mice deficient in ribosomal protein S6 phosphorylation suffer from muscle weakness that reflects a growth defect and energy deficit . PLOS ONE . 4 . 5 . e5618 . May 2009 . 19479038 . 2682700 . 10.1371/journal.pone.0005618 . 2009PLoSO...4.5618R . free .
4. Ang Z, Abdi Gunawan Koen R, Er JZ, Lee LT, Tam Kit Chung J, Guo H, Ding JL . Novel AU-rich proximal UTR sequences (APS) enhance CXCL8 synthesis upon the induction of rpS6 phosphorylation. . PLOS Genet. . 15 . 4 . e1008077 . 2019 . 30969964 . 6476525 . 10.1371/journal.pgen.1008077 . free .