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Formation of ω‐NG–monomethylarginine as the sole product of human protein arginine methyltransferase 7 (PRMT7): a true type III methyltransferase?
Author(s) -
Lopez Cecilia I,
Sandberg Troy,
Clarke Steven G.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.904.5
Subject(s) - protein arginine methyltransferase 5 , methyltransferase , enzyme , chemistry , o methyltransferase , biochemistry , arginine , methylation , protein methylation , amino acid , gene
Methylaton of arginine residues is an important posttranslational modification involved in transcriptional regulation, mRNA splicing, and signal transduction. Mammalian protein arginine methyltransferases (PRMTs) have been found to generate three different products. Type I PRMTs form both ω‐NG–monomethylarginine (ω‐MMA) and asymmetric ω‐NG,NG ‐dimethylarginine (ADMA), type II enzymes form ω‐MMA and symmetric ω‐NG,N'G–dimethylarginine (SDMA), and type III enzymes form solely ω‐MMA. Although the first six PRMTs discovered were clearly either type I or type II enzymes, the seventh has proven difficult to characterize. Initially, full‐length human PRMT7 expressed in E. coli was found to generate only ω‐MMA residues in small peptides, suggesting this is a type III enzyme. Other researchers, however, later reported that PRMT7 is also capable of forming SDMA in both peptides and protein substrates, characterizing it as a type II enzyme. We have now analyzed a more active PRMT7 preparation with both peptides and proteins and see only type III activity, forming ω‐MMA. It is possible that the substrate specificity of PRMT7 may depend upon additional co‐factors or binding to additional polypeptides. This work was supported by an NRSA award to CZL (GM078761) and an NIGMS grant to SGC (GM026020).