title: Ribosomal protein S3 is phosphorylated by Cdk1/cdc2 during G2/M phase.
abstract: Ribosomal protein S3 (rpS3) is a multifunctional protein involved in translation, DNA repair, and apoptosis. The relationship between rpS3 and cyclin-dependent kinases (Cdks) involved in cell cycle regulation is not yet known. Here, we show that rpS3 is phosphorylated by Cdk1 in G2/M phase. Co-immunoprecipitation and GST pull-down assays revealed that Cdk1 interacted with rpS3. An in vitro kinase assay showed that Cdk1 phosphorylated rpS3 protein. Phosphorylation of rpS3 increased in nocodazole-arrested mitotic cells; however, treatment with Cdk1 inhibitor or Cdk1 siRNA significantly attenuated this phosphorylation event. The phosphorylation of a mutant form of rpS3, T221A, was significantly reduced compared with wild-type rpS3. Decreased phosphorylation and nuclear accumulation of T221A was much more pronounced in G2/M phase. These results suggest that the phosphorylation of rpS3 by Cdk1 occurs at Thr221 during G2/M phase and, moreover, that this event is important for nuclear accumulation of rpS3.
authors.affiliation: Department of Advanced Technology Fusion, Konkuk University, Seoul, Korea.
authors.forename: In-Soo
authors.initials: IS
authors.lastname: Yoon
authors.forename: Ji Hyung
authors.initials: JH
authors.lastname: Chung
authors.forename: Soo-Hyun
authors.initials: SH
authors.lastname: Hahm
authors.forename: Min Ju
authors.initials: MJ
authors.lastname: Park
authors.forename: You Ri
authors.initials: YR
authors.lastname: Lee
authors.forename: Sung Il
authors.initials: SI
authors.lastname: Ko
authors.forename: Lin-Woo
authors.initials: LW
authors.lastname: Kang
authors.forename: Tae-Sung
authors.initials: TS
authors.lastname: Kim
authors.forename: Joon
authors.initials: J
authors.lastname: Kim
authors.forename: Ye Sun
authors.initials: YS
authors.lastname: Han
mesh_terms: D016203:CDC2 Protein Kinase; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D019926:Cyclin B / Q000378:metabolism*; D018844:Cyclin-Dependent Kinases; D016195:G2 Phase; D057809:HEK293 Cells; D006801:Humans; D010766:Phosphorylation; D010769:Phosphothreonine / Q000378:metabolism; D011485:Protein Binding; D012269:Ribosomal Proteins / Q000378:metabolism*
chemical_list: D019926:Cyclin B; D012269:Ribosomal Proteins; C044152:ribosomal protein S3; D010769:Phosphothreonine; D016203:CDC2 Protein Kinase; C528899:CDK1 protein, human; D018844:Cyclin-Dependent Kinases