Regulation of p70s6k/p85s6k and its role in the cell cycle

Prog Cell Cycle Res. 1995;1:21-32. doi: 10.1007/978-1-4615-1809-9_3.


Two to three-fold increases in the rate of protein synthesis are required both to enter the G1 phase of the cell cycle from G0 and to proceed to S phase in response to growth factors and mitogens. This increase is in part regulated via multiple phosphorylation of the 40S ribosomal protein S6 by the mitogen-stimulated p70s6k/p85s6k. At the protein synthesis level this event appears to be involved in specifically increasing the efficiency of translation of a family of essential mRNAs containing a polypyrimidine tract at their 5' transcriptional start site. The activation of p70s6k/p85s6k and maintenance of its activity throughout G1 is controlled via multiple phosphorylation events mediated by a complex signalling network acting on distinct sets of phosphorylation sites.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Cell Cycle / physiology*
  • Cell Cycle Proteins / physiology
  • Cyclic AMP / physiology
  • Enzyme Inhibitors / pharmacology
  • Mice
  • Models, Biological
  • Peptide Fragments / chemistry
  • Phosphorylation
  • Platelet-Derived Growth Factor / physiology
  • Polyenes / pharmacology
  • Protein Biosynthesis
  • Protein Processing, Post-Translational*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptors, Platelet-Derived Growth Factor / physiology
  • Ribosomal Protein S6
  • Ribosomal Protein S6 Kinases / antagonists & inhibitors
  • Ribosomal Protein S6 Kinases / chemistry
  • Ribosomal Protein S6 Kinases / physiology*
  • Ribosomal Proteins / metabolism
  • Signal Transduction / physiology
  • Sirolimus


  • Cell Cycle Proteins
  • Enzyme Inhibitors
  • Peptide Fragments
  • Platelet-Derived Growth Factor
  • Polyenes
  • RNA, Messenger
  • Ribosomal Protein S6
  • Ribosomal Proteins
  • Cyclic AMP
  • Receptors, Platelet-Derived Growth Factor
  • Ribosomal Protein S6 Kinases
  • Sirolimus