title: Ubc9 expression is essential for myotube formation in C2C12.
abstract: Myogenic differentiation is a fundamental biological process that involves a hierarchical series of events that ultimately leads to muscle-specific gene expression and myofiber formation. Posttranslational modifications of the myogenic regulatory factors have been implicated as important regulatory mechanisms in this process. Here we investigate whether covalent protein modification by a small ubiquitin-like modifier (SUMO) that is known to affect transcription factor activity can impact muscle differentiation. We show that the overall load of sumoylated proteins present in myoblasts diminishes progressively throughout myogenesis. Interestingly, knockdown of the SUMO-conjugating enzyme, Ubc9, severely compromises C2C12 muscle cell terminal differentiation. However, it does not affect the expression, the localization and the activation of MyoD and myogenin. These novel results suggest that protein sumoylation plays a pivotal role in myoblast differentiation and is required to regulate the activity of key targets downstream of MyoD and myogenin.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado-Boulder, Boulder, CO 80309, USA.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Riquelme
authors.forename: Kristen K B
authors.initials: KK
authors.lastname: Barthel
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Qin
authors.forename: Xuedong
authors.initials: X
authors.lastname: Liu
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D015536:Down-Regulation / Q000187:drug effects; D008561:Membrane Fusion / Q000235:genetics; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000187:drug effects* / Q000378:metabolism*; D017570:MyoD Protein / Q000378:metabolism; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism*; D018006:Myogenic Regulatory Factors / Q000378:metabolism; D018008:Myogenin / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics / Q000502:physiology*; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; C503801:Myog protein, mouse; D018006:Myogenic Regulatory Factors; D018008:Myogenin; D034741:RNA, Small Interfering; D044763:Ubiquitin-Conjugating Enzymes; D000098843:Ubiquitin-Conjugating Enzyme UBC9