Ataxin-3 plays a role in mouse myogenic differentiation through regulation of integrin subunit levels

• Published in: PloS one 2010-07, Vol.5 (7), p.e11728-e11728
• Main Authors: do Carmo Costa, Maria, Bajanca, Fernanda, Rodrigues, Ana-João, Tomé, Ricardo J, Corthals, Garry, Macedo-Ribeiro, Sandra, Paulson, Henry L, Logarinho, Elsa, Maciel, Patrícia
• Format: Article
• Language: English
• Subjects: Analysis; Animals; Antigens, CD - genetics; Antigens, CD - metabolism; Ataxia; Ataxin; Ataxin-3; Caenorhabditis elegans; Cell adhesion & migration; Cell Biology; Cell Differentiation - genetics; Cell Differentiation - physiology; Cell Line; Cytology; Delivery services; Developmental Biology/Cell Differentiation; Differentiation; DNA binding proteins; Embryo, Mammalian - cytology; Embryo, Mammalian - metabolism; Embryogenesis; Embryonic development; Embryonic growth stage; Embryos; Enzymes; Female; Fluorescent Antibody Technique; Genes; Health sciences; Homology; Immunoblotting; Immunofluorescence; Immunoprecipitation; In Vitro Techniques; Integrin alpha Chains - genetics; Integrin alpha Chains - metabolism; Integrin alpha5 - genetics; Integrin alpha5 - metabolism; Integrins; Isoelectric Focusing; Mice; Mice, Inbred C57BL; Misalignment; Molecular Biology; Muscle Development - genetics; Muscle Development - physiology; Mutation; Myoblasts; Myoblasts - cytology; Myoblasts - metabolism; Myogenesis; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Pregnancy; Proteasomes; Protein Binding; Protein biosynthesis; Protein synthesis; Proteins; Proteomics; Regulators; Reverse Transcriptase Polymerase Chain Reaction; Ribonucleic acid; RNA; RNA Interference; RNA-mediated interference; Signaling; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; Transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; Ubiquitin
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0011728

During myogenesis several transcription factors and regulators of protein synthesis and assembly are rapidly degraded by the ubiquitin-proteasome system (UPS). Given the potential role of the deubiquitinating enzyme (DUB) ataxin-3 in the UPS, and the high expression of the murine ataxin-3 homolog in muscle during embryogenesis, we sought to define its role in muscle differentiation. Using immunofluorescence analysis, we found murine ataxin-3 (mATX3) to be highly expressed in the differentiated myotome of E9.5 mouse embryos. C2C12 myoblasts depleted of mATX3 by RNA interference exhibited a round morphology, cell misalignment, and a delay in differentiation following myogenesis induction. Interestingly, these cells showed a down-regulation of alpha5 and alpha7 integrin subunit levels both by immunoblotting and immunofluorescence. Mouse ATX3 was found to interact with alpha5 integrin subunit and to stabilize this protein by repressing its degradation through the UPS. Proteomic analysis of mATX3-depleted C2C12 cells revealed alteration of the levels of several proteins related to integrin signaling. Ataxin-3 is important for myogenesis through regulation of integrin subunit levels.