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Yeast proteins Gar1p, Nop1p, Npl3p, Nsr1p, and Rps2p are natively methylated and are substrates of the arginine methyltransferase Hmt1p
Author(s) -
Yagoub Daniel,
HartSmith Gene,
Moecking Jonas,
Erce Melissa A.,
Wilkins Marc R.
Publication year - 2015
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.201500075
Subject(s) - fibrillarin , methylation , methyltransferase , biochemistry , protein methylation , biology , protein arginine methyltransferase 5 , microbiology and biotechnology , ribosomal protein , arginine , ribosomal rna , ribosome , amino acid , rna , gene
The Hmt1 methyltransferase is the predominant arginine methyltransferase in Saccharomyces cerevisiae . There are 18 substrate proteins described for this methyltransferase, however native sites of methylation have only been identified on two of these proteins. Here we used peptide immunoaffinity enrichment, followed by LC‐ETD‐MS/MS, to discover 21 native sites of arginine methylation on five putative Hmt1 substrate proteins, namely Gar1p (H/ACA ribonucleoprotein complex subunit 1), Nop1p (rRNA 2’‐O‐methyltransferase fibrillarin), Npl3p (nucleolar protein 3), Nsr1p (nuclear localization sequence‐binding protein), and Rps2p (40S ribosomal protein S2). The sites, many of which were found to be mono‐ or di‐methylated, were predominantly found in RGG (Arg‐Gly‐Gly) motifs. Heavy methyl‐SILAC validated the majority of these peptides. The above proteins, and relevant sites of methylation, were subsequently validated by in vitro methylation with recombinant Hmt1. This brings the total of Hmt1 substrate proteins for which native methylation sites have been identified to five.