title: The mouse C2C12 myoblast cell surface N-linked glycoproteome: identification, glycosite occupancy, and membrane orientation.
abstract: Endogenous regeneration and repair mechanisms are responsible for replacing dead and damaged cells to maintain or enhance tissue and organ function, and one of the best examples of endogenous repair mechanisms involves skeletal muscle. Although the molecular mechanisms that regulate the differentiation of satellite cells and myoblasts toward myofibers are not fully understood, cell surface proteins that sense and respond to their environment play an important role. The cell surface capturing technology was used here to uncover the cell surface N-linked glycoprotein subproteome of myoblasts and to identify potential markers of myoblast differentiation. 128 bona fide cell surface-exposed N-linked glycoproteins, including 117 transmembrane, four glycosylphosphatidylinositol-anchored, five extracellular matrix, and two membrane-associated proteins were identified from mouse C2C12 myoblasts. The data set revealed 36 cluster of differentiation-annotated proteins and confirmed the occupancy for 235 N-linked glycosylation sites. The identification of the N-glycosylation sites on the extracellular domain of the proteins allowed for the determination of the orientation of the identified proteins within the plasma membrane. One glycoprotein transmembrane orientation was found to be inconsistent with Swiss-Prot annotations, whereas ambiguous annotations for 14 other proteins were resolved. Several of the identified N-linked glycoproteins, including aquaporin-1 and beta-sarcoglycan, were found in validation experiments to change in overall abundance as the myoblasts differentiate toward myotubes. Therefore, the strategy and data presented shed new light on the complexity of the myoblast cell surface subproteome and reveal new targets for the clinically important characterization of cell intermediates during myoblast differentiation into myotubes.
authors: Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA.
authors: Rebekah L
authors: RL
authors: Gundry
authors: Kimberly
authors: K
authors: Raginski
authors: Yelena
authors: Y
authors: Tarasova
authors: Irina
authors: I
authors: Tchernyshyov
authors: Damaris
authors: D
authors: Bausch-Fluck
authors: Steven T
authors: ST
authors: Elliott
authors: Kenneth R
authors: KR
authors: Boheler
authors: Jennifer E
authors: JE
authors: Van Eyk
authors: Bernd
authors: B
authors: Wollscheid
mesh_terms: D000818:Animals; D051398:Aquaporin 1 / Q000737:chemistry; D001665:Binding Sites; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry; D006031:Glycosylation; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D032446:Myoblasts / Q000378:metabolism*; D020543:Proteome / Q000737:chemistry*; D040901:Proteomics / Q000379:methods*; D049031:Sarcoglycans / Q000737:chemistry
chemical_list: D006023:Glycoproteins; D008565:Membrane Proteins; D020543:Proteome; D049031:Sarcoglycans; D051398:Aquaporin 1