title: Enhanced phosphorylation of transcription factor sp1 in response to herpes simplex virus type 1 infection is dependent on the ataxia telangiectasia-mutated protein.
abstract: The ataxia telangiectasia-mutated (ATM) protein, a member of the related phosphatidylinositol 3-like kinase family encoded by a gene responsible for the human genetic disorder ataxia telangiectasia, regulates cellular responses to DNA damage and viral infection. It has been previously reported that herpes simplex virus type 1 (HSV-1) infection induces activation of protein kinase activity of ATM and hyperphosphorylation of transcription factor, Sp1. We show that ATM is intimately involved in Sp1 hyperphosphorylation during HSV-1 infection rather than individual HSV-1-encoded protein kinases. In ATM-deficient cells or cells silenced for ATM expression by short hairpin RNA targeting, hyperphosphorylation of Sp1 was prevented even as HSV-1 infection progressed. Mutational analysis of putative ATM phosphorylation sites on Sp1 and immunoblot analysis with phosphopeptide-specific Sp1 antibodies clarified that at least Ser-56 and Ser-101 residues on Sp1 became phosphorylated upon HSV-1 infection. Serine-to-alanine mutations at both sites on Sp1 considerably abolished hyperphosphorylation of Sp1 upon infection. Although ATM phosphorylated Ser-101 but not Ser-56 on Sp1 in vitro, phosphorylation of Sp1 at both sites was not detected at all upon infection in ATM-deficient cells, suggesting that cellular kinase(s) activated by ATM could be involved in phosphorylation at Ser-56. Upon viral infection, Sp1-dependent transcription in ATM expression-silenced cells was almost the same as that in ATM-intact cells, suggesting that ATM-dependent phosphorylation of Sp1 might hardly affect its transcriptional activity during the HSV-1 infection. ATM-dependent Sp1 phosphorylation appears to be a global response to various DNA damage stress including viral DNA replication.
authors.affiliation: Division of Virology, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya 464-8681, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Iwahori
authors.forename: Noriko
authors.initials: N
authors.lastname: Shirata
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: Sandra K
authors.initials: SK
authors.lastname: Weller
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Sato
authors.forename: Ayumi
authors.initials: A
authors.lastname: Kudoh
authors.forename: Sanae
authors.initials: S
authors.lastname: Nakayama
authors.forename: Hiroki
authors.initials: H
authors.lastname: Isomura
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Tsurumi
mesh_terms: D019943:Amino Acid Substitution; D001260:Ataxia Telangiectasia / Q000235:genetics / Q000378:metabolism / Q000821:virology; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage / Q000235:genetics; D004261:DNA Replication / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020868:Gene Silencing; D006367:HeLa Cells; D006561:Herpes Simplex / Q000235:genetics / Q000378:metabolism*; D018259:Herpesvirus 1, Human / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism; D014779:Virus Replication / Q000502:physiology*
chemical_list: D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D016329:Sp1 Transcription Factor; D025521:Tumor Suppressor Proteins; D014764:Viral Proteins; C576324:ATM protein, human