title: Ankrd2/ARPP is a novel Akt2 specific substrate and regulates myogenic differentiation upon cellular exposure to H(2)O(2).
abstract: Activation of Akt-mediated signaling pathways is crucial for survival, differentiation, and regeneration of muscle cells. A proteomic-based search for novel substrates of Akt was therefore undertaken in C(2)C(12) murine muscle cells exploiting protein characterization databases in combination with an anti-phospho-Akt substrate antibody. A Scansite database search predicted Ankrd2 (Ankyrin repeat domain protein 2, also known as ARPP) as a novel substrate of Akt. In vitro and in vivo studies confirmed that Akt phosphorylates Ankrd2 at Ser-99. Moreover, by kinase assay with recombinant Akt1 and Akt2, as well as by single-isoform silencing, we demonstrated that Ankrd2 is a specific substrate of Akt2. Ankrd2 is typically found in skeletal muscle cells, where it mediates the transcriptional response to stress conditions. In an attempt to investigate the physiological implications of Ankrd2 phosphorylation by Akt2, we found that oxidative stress induced by H(2)O(2) triggers this phosphorylation. Moreover, the forced expression of a phosphorylation-defective mutant form of Ankrd2 in C(2)C(12) myoblasts promoted a faster differentiation program, implicating Akt-dependent phosphorylation at Ser-99 in the negative regulation of myogenesis in response to stress conditions.
authors: IGM-CNR, Unit of Bologna c/o IOR, 40136 Bologna, Italy. vittoria.cenni@cnr.it
authors: Vittoria
authors: V
authors: Cenni
authors: Alberto
authors: A
authors: Bavelloni
authors: Francesca
authors: F
authors: Beretti
authors: Francesca
authors: F
authors: Tagliavini
authors: Lucia
authors: L
authors: Manzoli
authors: Giovanna
authors: G
authors: Lattanzi
authors: Nadir M
authors: NM
authors: Maraldi
authors: Lucio
authors: L
authors: Cocco
authors: Sandra
authors: S
authors: Marmiroli
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D024510:Muscle Development; D009124:Muscle Proteins / Q000378:metabolism*; D032448:Myoblasts, Skeletal / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D009687:Nuclear Proteins / Q000378:metabolism*; D016877:Oxidants / Q000378:metabolism* / Q000494:pharmacology; D018384:Oxidative Stress; D010766:Phosphorylation; D011485:Protein Binding; D021381:Protein Transport; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D012694:Serine / Q000378:metabolism
chemical_list: C432364:ANKRD2 protein, human; D009124:Muscle Proteins; D009687:Nuclear Proteins; D016877:Oxidants; D012097:Repressor Proteins; D012694:Serine; D006861:Hydrogen Peroxide; C494921:AKT2 protein, human; D051057:Proto-Oncogene Proteins c-akt