title: Creatine kinase B is necessary to limit myoblast fusion during myogenesis.
abstract: Myoblast fusion is critical for proper muscle growth and regeneration. During myoblast fusion, the localization of some molecules is spatially restricted; however, the exact reason for such localization is unknown. Creatine kinase B (CKB), which replenishes local ATP pools, localizes near the ends of cultured primary mouse myotubes. To gain insights into the function of CKB, we performed a yeast two-hybrid screen to identify CKB-interacting proteins. We identified molecules with a broad diversity of roles, including actin polymerization, intracellular protein trafficking, and alternative splicing, as well as sarcomeric components. In-depth studies of α-skeletal actin and α-cardiac actin, two predominant muscle actin isoforms, demonstrated their biochemical interaction and partial colocalization with CKB near the ends of myotubes in vitro. In contrast to other cell types, specific knockdown of CKB did not grossly affect actin polymerization in myotubes, suggesting other muscle-specific roles for CKB. Interestingly, knockdown of CKB resulted in significantly increased myoblast fusion and myotube size in vitro, whereas knockdown of creatine kinase M had no effect on these myogenic parameters. Our results suggest that localized CKB plays a key role in myotube formation by limiting myoblast fusion during myogenesis.
authors: Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University School of Medicine, Atlanta, Georgia; Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia; and.
authors: Adriana
authors: A
authors: Simionescu-Bankston
authors: Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia; and.
authors: Christophe
authors: C
authors: Pichavant
authors: Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia; and.
authors: James P
authors: JP
authors: Canner
authors: Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia; and.
authors: Luciano H
authors: LH
authors: Apponi
authors: Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia; and.
authors: Yanru
authors: Y
authors: Wang
authors: Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia; and.
authors: Craig
authors: C
authors: Steeds
authors: Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota.
authors: John T
authors: JT
authors: Olthoff
authors: Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota.
authors: Joseph J
authors: JJ
authors: Belanto
authors: Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota.
authors: James M
authors: JM
authors: Ervasti
authors: Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia; and gpavlat@emory.edu.
authors: Grace K
authors: GK
authors: Pavlath
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D017398:Alternative Splicing; D000818:Animals; D002459:Cell Fusion; D052276:Creatine Kinase, BB Form / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D052283:Creatine Kinase, MM Form / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D024510:Muscle Development / Q000235:genetics*; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000201:enzymology*; D032446:Myoblasts / Q000166:cytology / Q000201:enzymology*; D058105:Polymerization; D061251:Primary Cell Culture; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D020798:Two-Hybrid System Techniques
chemical_list: D000199:Actins; D020033:Protein Isoforms; D034741:RNA, Small Interfering; D052276:Creatine Kinase, BB Form; D052283:Creatine Kinase, MM Form
keywords: actin; adenosine triphosphate; muscle growth; myocyte; myotube