title: The Cardiac Stress Response Factor Ms1 Can Bind to DNA and Has a Function in the Nucleus.
abstract: Ms1 (also known as STARS and ABRA) has been shown to act as an early stress response gene in processes as different as hypertrophy in skeletal and cardiac muscle and growth of collateral blood vessels. It is important for cardiac development in zebrafish and is upregulated in mouse models for cardiac hypertrophy as well as in human failing hearts. Ms1 possesses actin binding sites at its C-terminus and is usually found in the cell bound to actin filaments in the cytosol or in sarcomeres. We determined the NMR structure of the only folded domain of Ms1 comprising the second actin binding site called actin binding domain 2 (ABD2, residues 294-375), and found that it is similar to the winged helix-turn-helix fold adopted mainly by DNA binding domains of transcriptional factors. In vitro experiments show specific binding of this domain, in combination with a newly discovered AT-hook motif located N-terminally, to the sequence (A/C/G)AAA(C/A). NMR and fluorescence titration experiments confirm that this motif is indeed bound specifically by the recognition helix. In neonatal rat cardiomyocytes endogenous Ms1 is found in the nucleus in a spotted pattern, reminiscent of PML bodies. In adult rat cardiomyocytes Ms1 is exclusively found in the sarcomere. A nuclear localisation site in the N-terminus of the protein is required for nuclear localisation. This suggests that Ms1 has the potential to act directly in the nucleus through specific interaction with DNA in development and potentially as a response to stress in adult tissues.
authors.affiliation: Cardiovascular and Randall Division, King's College London, London, United Kingdom.
authors.forename: Mariola
authors.initials: M
authors.lastname: Zaleska
authors.affiliation: Department of Biochemistry, University of Leicester, Lancaster Road, Leicester, United Kingdom.
authors.forename: Claudia
authors.initials: C
authors.lastname: Fogl
authors.affiliation: Cardiovascular and Randall Division, King's College London, London, United Kingdom.
authors.forename: Ay Lin
authors.initials: AL
authors.lastname: Kho
authors.affiliation: Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, United Kingdom.
authors.forename: Abdessamad
authors.initials: A
authors.lastname: Ababou
authors.affiliation: Cardiovascular and Randall Division, King's College London, London, United Kingdom.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Ehler
authors.affiliation: Cardiovascular and Randall Division, King's College London, London, United Kingdom.
authors.forename: Mark
authors.initials: M
authors.lastname: Pfuhl
mesh_terms: D024761:AT-Hook Motifs; D000818:Animals; D001665:Binding Sites; D002467:Cell Nucleus / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D051381:Rats; D012518:Sarcomeres / Q000378:metabolism
chemical_list: C461039:Abra protein, rat; D008840:Microfilament Proteins