Take our Survey

Reference: Porras-Yakushi TR, et al. (2005) A novel SET domain methyltransferase modifies ribosomal protein Rpl23ab in yeast. J Biol Chem 280(41):34590-8

Reference Help

Abstract


In vivo studies have shown that the ribosomal large subunit protein L23a (Rpl23ab) in Saccharomyces cerevisiae is methylated at lysine residues. However, the gene encoding the methyltransferase responsible for the modification has not been identified. We show here that the yeast YPL208w gene product, a member of the SET domain family of methyltransferases, catalyzes the reaction, and we have now designated it Rkm1 (ribosomal lysine (K) methyltransferase 1). Yeast strains with deletion mutations in candidate SET domain-containing genes were in vivo labeled with S-adenosyl-l-[methyl-(3)H]methionine. [(3)H]Methyl radioactivity was determined after lysates were fractionated by SDS gel electrophoresis. When compared with the parent strain or other candidate deletion strains, a loss of a radiolabeled 15-kDa species was observed in the rkm1 (Deltaypl208w) knock-out strain. Treatment of wild-type cell extracts with RNase or proteinase K demonstrated that the methyl-accepting substrate is a protein. Cellular lysates from parent and knockout strains were fractionated using high salt sucrose gradients. Analysis of the gradient fractions by SDS gel electrophoresis demonstrated that the 15-kDa methyl-accepting substrate elutes with the large ribosomal subunit. In vitro methylation experiments using purified ribosomes confirmed that the methyl-accepting substrate is a ribosomal protein. Amino acid analysis of the in vivo labeled 15 kDa polypeptide showed that it contains epsilon-[(3)H]dimethyllysine residues. Mass spectrometry of tryptic peptides of the 15 kDa polypeptide identified it as Rpl23ab. Analysis of the intact masses of the large ribosomal subunit proteins by electrospray mass spectrometry confirmed that the substrate is Rpl23ab and that it is specifically dimethylated at two distinct sites by Rkm1. These results show that SET domain methyltransferases can be involved in translational roles as well as in the previously described transcriptional roles.

Reference Type
Journal Article | Research Support, N.I.H., Extramural | Research Support, U.S. Gov't, P.H.S.
Authors
Porras-Yakushi TR, Whitelegge JP, Miranda TB, Clarke S
Primary Lit For
Additional Lit For
Review For

Interaction Annotations


Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.

Interactor Interactor Type Assay Annotation Action Modification Phenotype Source Reference

Gene Ontology Annotations


Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.

Gene Gene Ontology Term Qualifier Aspect Method Evidence Source Assigned On Annotation Extension Reference

Phenotype Annotations


Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details.

Gene Phenotype Experiment Type Mutant Information Strain Background Chemical Details Reference

Regulation Annotations


Increase the total number of rows displayed on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; to filter the table by a specific experiment type, type a keyword into the Filter box (for example, “microarray”); download this table as a .txt file using the Download button or click Analyze to further view and analyze the list of target genes using GO Term Finder, GO Slim Mapper, SPELL, or YeastMine.

Regulator Target Experiment Assay Construct Conditions Strain Background Reference