title: Nuclear Receptor-Like Structure and Interaction of Congenital Heart Disease-Associated Factors GATA4 and NKX2-5.
abstract: OBJECTIVE
  Transcription factor GATA4 is a dosage sensitive regulator of heart development and alterations in its level or activity lead to congenital heart disease (CHD). GATA4 has also been implicated in cardiac regeneration and repair. GATA4 action involves combinatorial interaction with other cofactors such as NKX2-5, another critical cardiac regulator whose mutations also cause CHD. Despite its critical importance to the heart and its evolutionary conservation across species, the structural basis of the GATA4-NKX2-5 interaction remains incompletely understood.
  
  
  RESULTS
  A homology model was constructed and used to identify surface amino acids important for the interaction of GATA4 and NKX2-5. These residues were subjected to site-directed mutagenesis, and the mutant proteins were characterized for their ability to bind DNA and to physically and functionally interact with NKX2-5. The studies identify 5 highly conserved amino acids in the second zinc finger (N272, R283, Q274, K299) and its C-terminal extension (R319) that are critical for physical and functional interaction with the third alpha helix of NKX2-5 homeodomain. Integration of the experimental data with computational modeling suggests that the structural arrangement of the zinc finger-homeodomain resembles the architecture of the conserved DNA binding domain of nuclear receptors.
  
  
  CONCLUSIONS
  The results provide novel insight into the structural basis for protein-protein interactions between two important classes of transcription factors. The model proposed will help to elucidate the molecular basis for disease causing mutations in GATA4 and NKX2-5 and may be relevant to other members of the GATA and NK classes of transcription factors.
authors.affiliation: Division of Pharmacology and Pharmacotherapy, University of Helsinki, Helsinki, Finland.|Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland.
authors.forename: Sini
authors.initials: S
authors.lastname: Kinnunen
authors.affiliation: Division of Pharmacology and Pharmacotherapy, University of Helsinki, Helsinki, Finland.|Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland.
authors.forename: Mika
authors.initials: M
authors.lastname: Välimäki
authors.affiliation: Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland.
authors.forename: Marja
authors.initials: M
authors.lastname: Tölli
authors.affiliation: Orion Pharma, Computer-Aided Drug Design, Espoo, Finland.
authors.forename: Gerd
authors.initials: G
authors.lastname: Wohlfahrt
authors.affiliation: Laboratory of Cardiac Development and Differentiation, Department of Biochemistry, Immunology and Microbiology, University of Ottawa, Ottawa, Canada.
authors.forename: Rami
authors.initials: R
authors.lastname: Darwich
authors.affiliation: Laboratory of Cardiac Development and Differentiation, Department of Biochemistry, Immunology and Microbiology, University of Ottawa, Ottawa, Canada.
authors.forename: Hiba
authors.initials: H
authors.lastname: Komati
authors.affiliation: Laboratory of Cardiac Development and Differentiation, Department of Biochemistry, Immunology and Microbiology, University of Ottawa, Ottawa, Canada.
authors.forename: Mona
authors.initials: M
authors.lastname: Nemer
authors.affiliation: Division of Pharmacology and Pharmacotherapy, University of Helsinki, Helsinki, Finland.|Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland.
authors.forename: Heikki
authors.initials: H
authors.lastname: Ruskoaho
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D050991:GATA4 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D006330:Heart Defects, Congenital / Q000235:genetics / Q000378:metabolism*; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D016335:Zinc Fingers
chemical_list: D050991:GATA4 Transcription Factor; C484171:Gata4 protein, mouse; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; C484469:Nkx2-5 protein, mouse; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D004247:DNA