Downregulation of PEA-15 reverses G1 arrest, and nuclear and chromatin changes of senescence phenotype via pErk1/2 translocation to nuclei.
We previously showed that senescent cells respond to TPA with translocation of senescence associated-pErk1/2 (SA-pErk1/2) into nuclei along with reversal of senescence morphology. Here, we describe that the reversal of senescence phenotype was manifested by knockdown of cytoplasmic PEA-15 expression, a sequestrator of cytoplasmic pErk1/2. Transfection of short-interfering RNA to PEA-15 (siPEA-15) significantly induced nuclear translocation of SA-pErk1/2, and siPEA-15 with TPA co-treatment further increased the translocation. Moreover, the reversal of senescence phenotype, such as expressions of SA-β-galactosidase, p53, p21(WAF1), PML body, 53BP1 and H3K9me2, was modified by either knockdown of PEA-15 or TPA treatment, indicating that nuclear translocation of SA-pErk1/2 might inhibit senescence progression. Indeed, knockdown of PEA-15 or TPA treatment significantly induced progression of G1 arrested cells to S-phase in human diploid fibroblast (HDF) senescent cells, examined by immunocytochemistry, FACS and immunoblot analyses. In conclusion, downregulation of PEA-15 expression reverses senescence phenotypes via nuclear translocation of SA-pErk1/2, which suggests in vivo maintenance of senescence phenotype by sequestration of pErk1/2 in cytoplasm.
Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, World cup-ro 164, Suwon 443-380, Republic of Korea; Department of Biomedical Sciences, The Graduate School, Ajou University, World cup-ro 164, Suwon 443-380, Republic of Korea.
Yun Yeong
YY
Lee
Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, World cup-ro 164, Suwon 443-380, Republic of Korea.
Hong Seok
HS
Kim
Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, World cup-ro 164, Suwon 443-380, Republic of Korea; Department of Biomedical Sciences, The Graduate School, Ajou University, World cup-ro 164, Suwon 443-380, Republic of Korea. Electronic address: iklim@ajou.ac.kr.
In Kyoung
IK
Lim
D051017:Apoptosis Regulatory Proteins; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D016922:Cellular Senescence / Q000187:drug effects; D002843:Chromatin / Q000378:metabolism*; D015536:Down-Regulation; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D010641:Phenotype; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection
D051017:Apoptosis Regulatory Proteins; D002843:Chromatin; D047908:Intracellular Signaling Peptides and Proteins; C092039:PEA15 protein, human; D010750:Phosphoproteins; D016760:Proto-Oncogene Proteins c-fos; D034741:RNA, Small Interfering; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D013755:Tetradecanoylphorbol Acetate
PEA-15; Reversal of senescence phenotype; Senescence associated-pErk1/2; TPA (12-O-tetradecanoylphorbol-13-acetate)