Protein-arginine methyltransferase I, the predominant protein-arginine methyltransferase in cells, interacts with and is regulated by interleukin enhancer-binding factor 3.
Arginine methylation is a common post-translation modification found in many proteins. Protein-arginine methyltransferase I (PRMT1) contributes >90% of type I protein-arginine methyltransferase activity in cells and tissues. To expand our knowledge on the regulation and role of PRMT1 in cells, we used the yeast two-hybrid system to identify proteins that interact with PRMT1. One of the interacting proteins we cloned is interleukin enhancer-binding factor 3 (ILF3), also known as M phase phosphoprotein 4. ILF3 is closely related to nuclear factor 90 (NF90). Using an immunofluorescence analysis, we determined that ILF3 and PRMT1 co-localize in the nucleus. Moreover, PRMT1 and ILF3 co-precipitate in immunoprecipitation assays and can be isolated together in "pull-down" experiments using recombinant fusion proteins. ILF3 is a robust substrate for methylation by PRMT1 and can modulate PRMT1 activity in in vitro methylation assays. Deletion studies demonstrated that the COOH-terminal region of ILF3, which is rich in arginine, glycine, and serine, is responsible for the strong interaction between PRMT1 and ILF3 and is the site of ILF3 methylation by PRMT1. Although ILF3 and NF90 are highly similar, they differ in their carboxyl-terminal regions. Because of this difference, NF90 does not interact with PRMT1, is a much poorer substrate than ILF3 for PRMT1-dependent methylation, and does not modulate PRMT1 enzyme activity.
Tang
J
J
Molecular Biology Institute and the Department of Biological Chemistry, UCLA School of Medicine, Los Angeles, California 90095, USA.
Kao
P N
PN
Herschman
H R
HR
D000595:Amino Acid Sequence; D000818:Animals; D019921:Biotinylation; D015152:Blotting, Northern; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D015723:Gene Library; D005982:Glutathione Transferase / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism; D051379:Mice; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D016296:Mutagenesis; D050778:NFATC Transcription Factors; D050779:Nuclear Factor 90 Proteins; D009687:Nuclear Proteins; D010957:Plasmids; D011233:Precipitin Tests; D011485:Protein Binding; D011484:Protein-Arginine N-Methyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D004268:DNA-Binding Proteins; C494015:Ilf3 protein, mouse; C494016:Ilf3 protein, rat; D050778:NFATC Transcription Factors; D050779:Nuclear Factor 90 Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D008780:Methyltransferases; D011484:Protein-Arginine N-Methyltransferases; D005982:Glutathione Transferase