title: A novel role for cardiac ankyrin repeat protein Ankrd1/CARP as a co-activator of the p53 tumor suppressor protein.
abstract: The muscle ankyrin repeat protein (MARP) family member Ankrd1/CARP is a part of the titin-mechanosensory signaling complex in the sarcomere and in response to stretch it translocates to the nucleus where it participates in the regulation of cardiac genes as a transcriptional co-repressor. Several studies have focused on its structural role in muscle, but its regulatory role is still poorly understood. To gain more insight into the regulatory function of Ankrd1/CARP we searched for transcription factors that could interact and modulate its activity. Using protein array methodology we identified the tumor suppressor protein p53 as an Ankrd1/CARP interacting partner and confirmed their interaction both in vivo and in vitro. We demonstrate a novel role for Ankrd1/CARP as a transcriptional co-activator, moderately up regulating p53 activity. Furthermore, we show that p53 operates as an upstream effector of Ankrd1/CARP, by up regulating the proximal ANKRD1 promoter. Our findings suggest that, besides acting as a transcriptional co-repressor, Ankrd1/CARP could have a stimulatory effect on gene expression in cultured skeletal muscle cells. It is probable that Ankrd1/CARP has a role in the propagation of signals initiated by myogenic regulatory factors (MRFs) during myogenesis.
authors.affiliation: Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11010 Belgrade, Serbia. snezanakojic@eunet.rs
authors.forename: Snezana
authors.initials: S
authors.lastname: Kojic
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Nestorovic
authors.forename: Ljiljana
authors.initials: L
authors.lastname: Rakicevic
authors.forename: Anna
authors.initials: A
authors.lastname: Belgrano
authors.forename: Marija
authors.initials: M
authors.lastname: Stankovic
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Divac
authors.forename: Georgine
authors.initials: G
authors.lastname: Faulkner
mesh_terms: D000818:Animals; D017089:Ankyrin Repeat; D001483:Base Sequence; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D017931:DNA Primers / Q000235:genetics; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D024510:Muscle Development / Q000235:genetics / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D017570:MyoD Protein / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D040081:Protein Array Analysis; D025941:Protein Interaction Mapping; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: C491304:ANKRD1 protein, human; D017931:DNA Primers; D009124:Muscle Proteins; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D012097:Repressor Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53