title: Molecular chaperone Hsp90 regulates REV1-mediated mutagenesis.
abstract: REV1 is a Y-family polymerase that plays a central role in mutagenic translesion DNA synthesis (TLS), contributing to tumor initiation and progression. In a current model, a monoubiquitinated form of the replication accessory protein, proliferating cell nuclear antigen (PCNA), serves as a platform to recruit REV1 to damaged sites on the DNA template. Emerging evidence indicates that posttranslational mechanisms regulate REV1 in yeast; however, the regulation of REV1 in higher eukaryotes is poorly understood. Here we show that the molecular chaperone Hsp90 is a critical regulator of REV1 in human cells. Hsp90 specifically binds REV1 in vivo and in vitro. Treatment with a specific inhibitor of Hsp90 reduces REV1 protein levels in several cell types through proteasomal degradation. This is associated with suppression of UV-induced mutagenesis. Furthermore, Hsp90 inhibition disrupts the interaction between REV1 and monoubiquitinated PCNA and suppresses UV-induced focus formation. These results indicate that Hsp90 promotes folding of REV1 into a stable and/or functional form(s) to bind to monoubiquitinated PCNA. The present findings reveal a novel role of Hsp90 in the regulation of TLS-mediated mutagenesis.
authors.affiliation: Laboratory of Molecular Genetics, The Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma 371-8512, Japan.
authors.forename: Franklin Mayca
authors.initials: FM
authors.lastname: Pozo
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Oda
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sekimoto
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Murakumo
authors.forename: Chikahide
authors.initials: C
authors.lastname: Masutani
authors.forename: Fumio
authors.initials: F
authors.lastname: Hanaoka
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yamashita
mesh_terms: D002460:Cell Line; D004249:DNA Damage; D004260:DNA Repair; D018841:HSP90 Heat-Shock Proteins / Q000502:physiology*; D006801:Humans; D018832:Molecular Chaperones; D016296:Mutagenesis / Q000528:radiation effects; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D009713:Nucleotidyltransferases / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011485:Protein Binding; D017510:Protein Folding; D054875:Ubiquitination; D014466:Ultraviolet Rays / Q000009:adverse effects; D000099270:Y-Family DNA Polymerases
chemical_list: D018841:HSP90 Heat-Shock Proteins; D018832:Molecular Chaperones; D009687:Nuclear Proteins; D009713:Nucleotidyltransferases; D018809:Proliferating Cell Nuclear Antigen; C429004:REV1 protein, human; D000099270:Y-Family DNA Polymerases