title: Acetylation by p300 regulates nuclear localization and function of the transcriptional corepressor CtBP2.
abstract: CtBP family members, CtBP1 and CtBP2, are unique transcriptional regulators that adapt a metabolic enzyme fold, and their activities are regulated by NAD(H)-binding. CtBP1 is both cytoplasmic and nuclear, and its subcellular localization is regulated by sumoylation, phosphorylation, and binding to a PDZ protein. In contrast, we showed that CtBP2 is exclusively nuclear. CtBP1 and CtBP2 are highly similar, but differ at the N-terminal 20 amino acid region. Substitution of the N-terminal domain of CtBP1 with the corresponding CtBP2 domain confers a dominant nuclear localization pattern to CtBP1. The N-terminal domain of CtBP2 contains three Lys residues. Our results show that these Lys residues are acetylated by the nuclear acetylase p300. Although all three Lys residues of CtBP2 (Lys-6, Lys-8, and Lys-10) appear to be acetylated, acetylation of Lys-10 is critical for nuclear localization. CtBP2 with a single amino acid substitution at Lys-10 (K10R) is predominantly localized in the cytoplasm. The cytoplasmic localization of the K10R mutant is correlated with enhanced nuclear export that is inhibited by leptomycin B. Furthermore, lack of acetylation at Lys-10 renders CtBP2 to be more efficient in repression of the E-cadherin promoter. Our studies have revealed the important roles of acetylation in regulating subcellular localization and transcriptional activity of CtBP2.
authors.affiliation: Institute for Molecular Virology, Saint Louis University Health Sciences Center, Missouri 63110, USA.
authors.forename: Ling-Jun
authors.initials: LJ
authors.lastname: Zhao
authors.forename: T
authors.initials: T
authors.lastname: Subramanian
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhou
authors.forename: G
authors.initials: G
authors.lastname: Chinnadurai
mesh_terms: D000107:Acetylation; D000429:Alcohol Oxidoreductases; D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000502:physiology*; D002467:Cell Nucleus / Q000737:chemistry*; D056970:Co-Repressor Proteins; D004268:DNA-Binding Proteins / Q000032:analysis; D005136:Eye Proteins / Q000032:analysis / Q000737:chemistry / Q000502:physiology*; D006367:HeLa Cells; D051548:Histone Acetyltransferases / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins / Q000032:analysis; D012097:Repressor Proteins / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor
chemical_list: D000429:Alcohol Oxidoreductases; D018797:Cell Cycle Proteins; D056970:Co-Repressor Proteins; D004268:DNA-Binding Proteins; D005136:Eye Proteins; D051548:Histone Acetyltransferases; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D012097:Repressor Proteins; D014157:Transcription Factors; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; C421248:CTBP2 protein, human; C096794:C-terminal binding protein