title: ZASP interacts with the mechanosensing protein Ankrd2 and p53 in the signalling network of striated muscle.
abstract: ZASP is a cytoskeletal PDZ-LIM protein predominantly expressed in striated muscle. It forms multiprotein complexes and plays a pivotal role in the structural integrity of sarcomeres. Mutations in the ZASP protein are associated with myofibrillar myopathy, left ventricular non-compaction and dilated cardiomyopathy. The ablation of its murine homologue Cypher results in neonatal lethality. ZASP has several alternatively spliced isoforms, in this paper we clarify the nomenclature of its human isoforms as well as their dynamics and expression pattern in striated muscle. Interaction is demonstrated between ZASP and two new binding partners both of which have roles in signalling, regulation of gene expression and muscle differentiation; the mechanosensing protein Ankrd2 and the tumour suppressor protein p53. These proteins and ZASP form a triple complex that appears to facilitate poly-SUMOylation of p53. We also show the importance of two of its functional domains, the ZM-motif and the PDZ domain. The PDZ domain can bind directly to both Ankrd2 and p53 indicating that there is no competition between it and p53 for the same binding site on Ankrd2. However there is competition for this binding site between p53 and a region of the ZASP protein lacking the PDZ domain, but containing the ZM-motif. ZASP is negative regulator of p53 in transactivation experiments with the p53-responsive promoters, MDM2 and BAX. Mutations in the ZASP ZM-motif induce modification in protein turnover. In fact, two mutants, A165V and A171T, were not able to bind Ankrd2 and bound only poorly to alpha-actinin2. This is important since the A165V mutation is responsible for zaspopathy, a well characterized autosomal dominant distal myopathy. Although the mechanism by which this mutant causes disease is still unknown, this is the first indication of how a ZASP disease associated mutant protein differs from that of the wild type ZASP protein.
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
authors.forename: Valentina C
authors.initials: VC
authors.lastname: Martinelli
authors.affiliation: Department of Paediatrics (Cardiology), Baylor College of Medicine, Houston, Texas, United States of America.
authors.forename: W Buck
authors.initials: WB
authors.lastname: Kyle
authors.affiliation: Laboratory of Molecular Biology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia.
authors.forename: Snezana
authors.initials: S
authors.lastname: Kojic
authors.affiliation: Centro di Ricerca Interdipartimentale per le Biotecnologie Innovative, University of Padua, Padova, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Vitulo
authors.affiliation: Department of Paediatrics (Cardiology), Baylor College of Medicine, Houston, Texas, United States of America.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Li
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Belgrano
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Trieste, Italy; Systems Cell Biology of Cell Polarity and Cell Division, Institut Curie, Paris, France.
authors.forename: Paolo
authors.initials: P
authors.lastname: Maiuri
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Banks
authors.affiliation: Department of Paediatrics (Cardiology), Baylor College of Medicine, Houston, Texas, United States of America; Department of Medical and Molecular Genetics, University of Indiana, Indianapolis, Indiana, United States of America.
authors.forename: Matteo
authors.initials: M
authors.lastname: Vatta
authors.affiliation: Centro di Ricerca Interdipartimentale per le Biotecnologie Innovative, University of Padua, Padova, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Valle
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Trieste, Italy; Centro di Ricerca Interdipartimentale per le Biotecnologie Innovative, University of Padua, Padova, Italy.
authors.forename: Georgine
authors.initials: G
authors.lastname: Faulkner
mesh_terms: D000185:Actinin / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D017089:Ankyrin Repeat; D001665:Binding Sites; D002460:Cell Line; D036681:Fluorescence Recovery After Photobleaching; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D060588:LIM Domain Proteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D009124:Muscle Proteins / Q000737:chemistry / Q000378:metabolism*; D054792:Muscle, Striated / Q000378:metabolism*; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D021381:Protein Transport; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism*; D015398:Signal Transduction; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: C401401:ACTN2 protein, human; C432364:ANKRD2 protein, human; D048868:Adaptor Proteins, Signal Transducing; C120696:LDB3 protein, human; D060588:LIM Domain Proteins; D009124:Muscle Proteins; D050505:Mutant Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; D012097:Repressor Proteins; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D000185:Actinin; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2