The tRNA methylase METTL1 is phosphorylated and inactivated by PKB and RSK in vitro and in cells
Open Access
- 5 April 2005
- journal article
- research article
- Published by Springer Science and Business Media LLC in The EMBO Journal
- Vol. 24 (9), 1696-1705
- https://doi.org/10.1038/sj.emboj.7600648
Abstract
A substrate for protein kinase B (PKB)α in HeLa cell extracts was identified as methyltransferase‐like protein‐1 (METTL1), the orthologue of trm8, which catalyses the 7‐methylguanosine modification of tRNA in Saccharomyces cerevisiae . PKB and ribosomal S6 kinase (RSK) both phosphorylated METTL1 at Ser27 in vitro . Ser27 became phosphorylated when HEK293 cells were stimulated with insulin‐like growth factor‐1 (IGF‐1) and this was prevented by inhibition of phosphatidyinositol 3‐kinase. The IGF‐1‐induced Ser27 phosphorylation did not occur in 3‐phosphoinositide‐dependent protein kinase‐1 (PDK1)‐deficient embryonic stem cells, but occurred normally in PDK1[L155E] cells, indicating that the effect of IGF‐1 is mediated by PKB. METTL1 also became phosphorylated at Ser27 in response to phorbol‐12‐myristate 13‐acetate and this was prevented by PD 184352 or pharmacological inhibition of RSK. Phosphorylation of METTL1 by PKB or RSK inactivated METTL1 in vitro , as did mutation of Ser27 to Asp or Glu. Expression of METTL1[S27D] or METTL1[S27E] did not rescue the growth phenotype of yeast lacking trm8 . In contrast, expression of METTL1 or METTL1[S27A] partially rescued growth. These results demonstrate that METTL1 is inactivated by PKB and RSK in cells, and the potential implications of this finding are discussed.Keywords
This publication has 45 references indexed in Scilit:
- Identification of filamin C as a new physiological substrate of PKBα using KESTRELBiochemical Journal, 2004
- A novel UBA and UBX domain protein that binds polyubiquitin and VCP and is a substrate for SAPKsBiochemical Journal, 2004
- AlkB Restores the Biological Function of mRNA and tRNA Inactivated by Chemical MethylationMolecular Cell, 2004
- tRNAHis maturation: An essential yeast protein catalyzes addition of a guanine nucleotide to the 5′ end of tRNAHisGenes & Development, 2003
- Dual function of the tRNA(m5U54)methyltransferase in tRNA maturationRNA, 2002
- Specificity and mechanism of action of some commonly used protein kinase inhibitorsBiochemical Journal, 2000
- Isolation and Characterization of a Human Chromosome 21q22.3 Gene (WDR4) and Its Mouse Homologue That Code for a WD-Repeat ProteinGenomics, 2000
- Transfer RNA modification: influence on translational frameshifting and metabolismFEBS Letters, 1999
- Molecular basis for the substrate specificity of protein kinase B; comparison with MAPKAP kinase‐1 and p70 S6 kinaseFEBS Letters, 1996
- tRNA Ligase Is Required for Regulated mRNA Splicing in the Unfolded Protein ResponseCell, 1996