title: Identification and Functional Characterizations of N-Terminal α-N-Methylation and Phosphorylation of Serine 461 in Human Poly(ADP-ribose) Polymerase 3.
abstract: Poly(ADP-ribose) polymerase 3 (PARP3) is a member of the PARP family enzymes which catalyze the ADP-ribosylation of proteins. PARP3 plays an important role in DNA damage repair and mitotic progression. In this study, we identified, using mass spectrometric techniques, two novel post-translational modification sites in PARP3, α-N-methylation and phosphorylation of serine 461 (S461). We found that the N-terminal α-amino group of PARP3 is heavily methylated in human cells, and N-terminal RCC1 methyltransferase (NRMT) is a key enzyme required for this methylation. We also observed that the phosphorylation level of S461 in PARP3 could be reduced in human cells upon treatment with flavopiridol, a cyclin-dependent kinase inhibitor. Moreover, we demonstrated that S461 phosphorylation, but not α-N-methylation of PARP3, may be involved in the cellular response toward DNA double-strand breaks. These findings provide novel insights into the post-translational regulation of PARP3.
authors.affiliation: †Department of Chemistry, University of California, Riverside, California 92521-0403, United States.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Dai
authors.affiliation: ‡Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, U.K.
authors.forename: Stuart L
authors.initials: SL
authors.lastname: Rulten
authors.affiliation: †Department of Chemistry, University of California, Riverside, California 92521-0403, United States.
authors.forename: Changjun
authors.initials: C
authors.lastname: You
authors.affiliation: ‡Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, U.K.
authors.forename: Keith W
authors.initials: KW
authors.lastname: Caldecott
authors.affiliation: †Department of Chemistry, University of California, Riverside, California 92521-0403, United States.
authors.forename: Yinsheng
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D008745:Methylation; D010766:Phosphorylation; D011065:Poly(ADP-ribose) Polymerases / Q000737:chemistry / Q000378:metabolism*; D012694:Serine / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: D018797:Cell Cycle Proteins; D012694:Serine; C480979:PARP3 protein, human; D011065:Poly(ADP-ribose) Polymerases
keywords: DNA double-strand break; LC−MS/MS; N-terminal methylation; NRMT; PARP3; phosphorylation; post-translational modification