title: Nek1 silencing slows down DNA repair and blocks DNA damage-induced cell cycle arrest.
abstract: Never in mitosis A (NIMA)-related kinases (Nek) are evolutionarily conserved proteins structurally related to the Aspergillus nidulans mitotic regulator NIMA. Nek1 is one of the 11 isoforms of the Neks identified in mammals. Different lines of evidence suggest the participation of Nek1 in response to DNA damage, which is also supported by the interaction of this kinase with proteins involved in DNA repair pathways and cell cycle regulation. In this report, we show that cells with Nek1 knockdown (KD) through stable RNA interference present a delay in DNA repair when treated with methyl-methanesulfonate (MMS), hydrogen peroxide (H(2)O(2)) and cisplatin (CPT). In particular, interstrand cross links induced by CPT take much longer to be resolved in Nek1 KD cells when compared to wild-type (WT) cells. In KD cells, phosphorylation of Chk1 in response to CPT was strongly reduced. While WT cells accumulate in G(2)/M after DNA damage with MMS and H(2)O(2), Nek1 KD cells do not arrest, suggesting that G(2)/M arrest induced by the DNA damage requires Nek1. Surprisingly, CPT-treated Nek1 KD cells arrest with a 4N DNA content similar to WT cells. This deregulation in cell cycle control in Nek1 KD cells leads to an increased sensitivity to genotoxic agents when compared to WT cells. These results suggest that Nek1 is involved in the beginning of the cellular response to genotoxic stress and plays an important role in preventing cell death induced by DNA damage.
authors.affiliation: Department of Biophysics, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, Porto Alegre, RS, Brazil.
authors.forename: Alessandra Luíza
authors.initials: AL
authors.lastname: Pelegrini
authors.forename: Dinara Jaqueline
authors.initials: DJ
authors.lastname: Moura
authors.forename: Bethânia Luise
authors.initials: BL
authors.lastname: Brenner
authors.forename: Pitia Flores
authors.initials: PF
authors.lastname: Ledur
authors.forename: Gabriela Porto
authors.initials: GP
authors.lastname: Maques
authors.forename: João Antônio Pegas
authors.initials: JA
authors.lastname: Henriques
authors.forename: Jenifer
authors.initials: J
authors.lastname: Saffi
authors.forename: Guido
authors.initials: G
authors.lastname: Lenz
mesh_terms: D002166:Camptothecin / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D000071877:Checkpoint Kinase 1; D003432:Cross-Linking Reagents / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects; D016195:G2 Phase / Q000187:drug effects; D055785:Gene Knockdown Techniques; D020868:Gene Silencing / Q000187:drug effects; D006657:Histones / Q000378:metabolism; D006801:Humans; D009153:Mutagens / Q000633:toxicity; D000072380:NIMA-Related Kinase 1; D010766:Phosphorylation / Q000187:drug effects; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency* / Q000235:genetics* / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D003432:Cross-Linking Reagents; C468783:H2AX protein, human; D006657:Histones; D009153:Mutagens; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; C000606914:NEK1 protein, human; D000072380:NIMA-Related Kinase 1; D017346:Protein Serine-Threonine Kinases; D002166:Camptothecin