title: PRMT1 is required for RAP55 to localize to processing bodies.
abstract: In eukaryotic cells, components of messenger ribonucleoproteins (mRNPs) are often detected in cytoplasmic granules, such as processing bodies (P-bodies) and stress granules (SGs) where translationally repressed mRNAs accumulate. RAP55A, which is an RNA binding component of mRNPs, acts as a translational repressor and localizes to P-bodies and SGs. We found here that a homologous protein RAP55B also localized to P-bodies when expressed in human cultured cells. When RAP55A or RAP55B was highly expressed in the cells, they induced the formation of SG-like large cytoplasmic mRNP granules that contained both P-body and SG components, indicating that RAP55 is important for the assembly of cytoplasmic mRNP granules. In addition, we found that RAP55A associated with protein arginine methyltransferases PRMT1 and PRMT5. Multiple arginine residues of RAP55A were indeed asymmetrically dimethylated in the cell and PRMT1 was shown to be a component of large mRNP granules induced by RAP55A overexpression. Although PRMT1 did not accumulate in P-bodies, siRNA-mediated knockdown of PRMT1 impaired the localization of RAP55A to P-bodies, while other components were still retained in these structures. Thus, our data indicate that RAP55 is important for the assembly of cytoplasmic mRNP granules and that PRMT1 is required for RAP55A to localize to P-bodies.
authors.affiliation: Molecular Entomology Laboratory, RIKEN Advanced Science Institute, Wako, Saitama, Japan. matsumok@riken.jp
authors.forename: Ken
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakayama
authors.forename: Mami
authors.initials: M
authors.lastname: Yoshimura
authors.forename: Akiko
authors.initials: A
authors.lastname: Masuda
authors.forename: Naoshi
authors.initials: N
authors.lastname: Dohmae
authors.forename: Shogo
authors.initials: S
authors.lastname: Matsumoto
authors.forename: Masafumi
authors.initials: M
authors.lastname: Tsujimoto
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001120:Arginine / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D008745:Methylation; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011484:Protein-Arginine N-Methyltransferases / Q000378:metabolism / Q000502:physiology*; D034741:RNA, Small Interfering / Q000235:genetics; D012097:Repressor Proteins / Q000378:metabolism / Q000502:physiology*; D012261:Ribonucleoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA
chemical_list: D010446:Peptide Fragments; D020033:Protein Isoforms; D034741:RNA, Small Interfering; C510649:RNA-associated protein 55, human; D012097:Repressor Proteins; D012261:Ribonucleoproteins; C026452:messenger ribonucleoprotein; D001120:Arginine; C099988:PRMT1 protein, human; C400529:PRMT5 protein, human; D011484:Protein-Arginine N-Methyltransferases