Cell Biology

Mutant ATM Withdraws Translation

Science's STKE  12 Dec 2000:
Vol. 2000, Issue 62, pp. tw8
DOI: 10.1126/stke.2000.62.tw8

Ataxia telangiectasia mutated (ATM) is a serine-threonine protein kinase involved in DNA damage repair. Some AT patients also exhibit severe insulin resistance, and cells from AT patients require greater amounts of growth factors for proliferation. Additionally, in vitro, ATM can phosphorylate 4E-BP1, a protein that, when unphosphorylated, binds to and represses the translation-facilitating activity of eIF-4E. These results hint at a role for ATM outside of DNA damage repair. Yang and Kastan have shown that ATM-dependent phosphorylation of 4E-BP1 is important in vivo. The authors demonstrated that, in response to insulin, wild-type ATM kinase activity increased and that ATM phosphorylated 4E-BP1 on Ser111. Phosphorylation of 4E-BP1 correlated with dissociation of 4E-BP1 from eIF-4E. Catalytically inactive ATM mutants did not phosphorylate 4E-BP1, which maintained the sequestration of eIF-4E. Thus, these data indicate that ATM can provide a link between insulin signaling and increased protein translation, and suggest that ATM's activity in the cell may be much wider than previously suspected. In an accompanying News & Views, Lavin provides excellent background and discusses other possible roles of ATM in the cell.

Yang, D.-Q., and Kastan, M.B. (2000) Participation of ATM in insulin signalling through phosphorylation of eIF-4E-binding protein 1. Nat. Cell Biol. 2: 893-898. [Online Journal]

Lavin, M.F. (2000) An unlikely player joins the ATM signaling network. Nat. Cell Biol. 2: E215-E217. [Online Journal]