Nuclear Receptor-Like Structure and Interaction of Congenital Heart Disease-Associated Factors GATA4 and NKX2-5

• Published in: PloS one 2015-12, Vol.10 (12), p.e0144145
• Main Authors: Kinnunen, Sini, Välimäki, Mika, Tölli, Marja, Wohlfahrt, Gerd, Darwich, Rami, Komati, Hiba, Nemer, Mona, Ruskoaho, Heikki
• Format: Article
• Language: English
• Subjects: Amino acids; Analysis; Animals; Binding sites; Biological evolution; Care and treatment; Cercopithecus aethiops; Cofactors; Combinatorial analysis; Computer applications; Congenital diseases; Congenital heart defects; Conservation; Coronary artery disease; COS Cells; Deoxyribonucleic acid; Developmental biology; DNA; DNA - genetics; DNA - metabolism; Evolutionary conservation; GATA4 Transcription Factor - genetics; GATA4 Transcription Factor - metabolism; Heart; Heart Defects, Congenital - genetics; Heart Defects, Congenital - metabolism; Heart diseases; Homeobox; Homeobox Protein Nkx-2.5; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; Homology; Identification methods; Kinases; Mammals; Mice; Models, Biological; Mutagenesis; Mutation; Natriuretic peptides; Nkx2.5 protein; Nuclear receptors; Protein Binding; Protein interaction; Protein Structure, Tertiary; Proteins; Receptors; Receptors, Cytoplasmic and Nuclear - genetics; Receptors, Cytoplasmic and Nuclear - metabolism; Regeneration; Risk factors; Site-directed mutagenesis; Transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; Wildlife conservation; Zinc; Zinc finger proteins; Zinc Fingers
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0144145

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. 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. 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.