TY - JOUR
T1 - Oligosaccharyltransferase activity is markedly increased during differentiation of a nonfusing myoblast cell line
AU - Grant, Stephen R.
AU - Welply, Joseph K.
AU - Olson, Eric N.
AU - Lennarz, William J.
N1 - Funding Information:
The developmentally regulated process of muscle formation involves withdrawal of proliferating myoblasts from the cell cycle and their subsequent fusion r This work was supported by grants from the National Science Foundation (DMB 8599876) and the Robert A. Welch Foundation to E.N.O., and a grant from the National Institutes of Health (GM 33185) to W.J.L. Dr. William J. Lennarz, who is a Robert A. Welch Professor of Chemistry, gratefully acknowledges the Robert A. Welch Foundation. a Present address: Monsanto Company, Chesterfield Village Parkway, St. Louis, Missouri 63198. ‘To whom correspondence should be addressed.
PY - 1986/7
Y1 - 1986/7
N2 - We have studied several aspects of glycoprotein synthesis in myoblast differentiation by using a nonfusing myoblast cell line, BC3H1. Previous studies showed that transfer of proliferating undifferentiated BC3H1 cells to mitogen-depleted medium results in the cells' withdrawal from the cell cycle and induction of a variety of muscle-specific gene products [E. N. Olson, L. Glaser, J. P. Merlie, R. Sebane, and J. Lindstrom (1983) J. Biol. Chem. 258, 13946-13953]. Because cell surface glycoproteins have been implicated in myoblast differentiation, in the present study we measured the amount of oligosaccharyltransferase in microsomes isolated from BC3H1 cells at various stages of differentiation. By using an acceptor peptide containing the sequence AsnLeuThr, enzyme activity was measured by formation of [3H]glycopeptide. In addition, active enzyme protein was measured with a 125I-labeled photoreactive derivative of the acceptor tripeptide. Both of these independent assay methods revealed a marked increase in oligosaccharyltransferase when differentiation was induced by serum depletion. Moreover, mitogenic stimulation of differentiated cells resulted in a return of oligosaccharyltransferase to near basal levels. This reversible increase in this key enzyme in protein glycosylation occurred despite the fact that both total protein and glycoprotein synthesis were depressed during differentiation. These data indicate that during myogenesis the level of oligosaccharyltransferase is regulated in parallel with a number of muscle-specific gene products. These results are discussed in the context of regulation of the pathway of glycoprotein synthesis.
AB - We have studied several aspects of glycoprotein synthesis in myoblast differentiation by using a nonfusing myoblast cell line, BC3H1. Previous studies showed that transfer of proliferating undifferentiated BC3H1 cells to mitogen-depleted medium results in the cells' withdrawal from the cell cycle and induction of a variety of muscle-specific gene products [E. N. Olson, L. Glaser, J. P. Merlie, R. Sebane, and J. Lindstrom (1983) J. Biol. Chem. 258, 13946-13953]. Because cell surface glycoproteins have been implicated in myoblast differentiation, in the present study we measured the amount of oligosaccharyltransferase in microsomes isolated from BC3H1 cells at various stages of differentiation. By using an acceptor peptide containing the sequence AsnLeuThr, enzyme activity was measured by formation of [3H]glycopeptide. In addition, active enzyme protein was measured with a 125I-labeled photoreactive derivative of the acceptor tripeptide. Both of these independent assay methods revealed a marked increase in oligosaccharyltransferase when differentiation was induced by serum depletion. Moreover, mitogenic stimulation of differentiated cells resulted in a return of oligosaccharyltransferase to near basal levels. This reversible increase in this key enzyme in protein glycosylation occurred despite the fact that both total protein and glycoprotein synthesis were depressed during differentiation. These data indicate that during myogenesis the level of oligosaccharyltransferase is regulated in parallel with a number of muscle-specific gene products. These results are discussed in the context of regulation of the pathway of glycoprotein synthesis.
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U2 - 10.1016/0003-9861(86)90439-X
DO - 10.1016/0003-9861(86)90439-X
M3 - Article
C2 - 3729427
AN - SCOPUS:0022505121
SN - 0003-9861
VL - 248
SP - 424
EP - 428
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 1
ER -