Correlation between fusion and the developmental regulation of membrane glycoproteins in L6 myoblasts.

Rosenberg, Jay M.; Szabo, Alex; Rheuark, Daryl; Kayalar, Celik

doi:10.1073/pnas.82.24.8409

Cited by 10 publications

(7 citation statements)

References 18 publications

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“…These changes were blocked by the MEPr inhibitors that block fusion (7). We now report that these same MEPr inhibitors also prevent the increased synthesis of muscle-specific proteins during myogenesis.…”

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confidence: 71%

Metalloendoprotease inhibitors that block fusion also prevent biochemical differentiation in L6 myoblasts.

Baldwin¹,

Kayalar²

1986

Proc. Natl. Acad. Sci. U.S.A.

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The effect of metalloendoprotease inhibitors on the biochemical differentiation of the rat skeletal muscle line, L6, was investigated. Confluent unfused L6 cells exposed briefly to 1,10-phenanthroline, a chelator of divalent metal cations, or continuously to dipeptide amide metalloendoprotease substrates that are blocked at the NH2-terminals, Ncarbobenzyloxyserylleucyl amide and N-carbobenzyloxyglycylleucyl amide, did not fuse or express creatine kinase, myosin heavy chain, or a-actin. These effects were reversible and dose-dependent. Exposure to N-carbobenzyloxylglycylglycyl amide, which is not a metalloendoprotease inhibitor, had no effect. As the differentiation in a culture progressed, 1,10-phenanthroline became less effective in blocking the accumulation of creatine kinase and myosin heavy chain. Exposure of partially fused cultures to N-carbobenzyloxyseryfleucyl amide prevented any further accumulation of muscle-specific proteins. In confluent cultures where cell division was blocked before the onset of differentiation, N-carbobenzyloxyserylleucyl amide still prevented fusion and the induction of creatine kinase. This indicates that these inhibitors do not act by interfering with the cell cycle. Experiments that measured DNA synthesis rates, plating efficiencies, and the effects ofsequential dipeptide and dimethyl sulfoxide treatments indicate that L6 myoblasts do not irreversibly withdraw from the cell cycle when exposed to N-carbobenzyloxyserylleucyl amide. These results are consistent with the role of a metalloendoprotease in initiating the terminal differentiation of cultured muscle cells.The rat skeletal muscle cell line, L6 (1), undergoes a developmental program in culture similar to muscle cells in vivo. Sparse myoblasts proliferate until confluency, after which they begin withdrawing from the cell cycle (Go state) and subsequently lose their proliferative capacity (commitment) (2, 3). These committed myoblasts then fuse their plasma membranes to form myotubes and biochemically differentiate by synthesizing large amounts of muscle-specific proteins, such as proteins for the contractile apparatus, creatine kinase, and the acetylcholine receptor. These processes result in a terminally differentiated muscle fiber and are collectively referred to as myogenesis. Couch and Strittmatter (4) showed that the metalloendoprotease (MEPr) inhibitors, 1,10-phenanthroline and certain N-carbobenzyloxy dipeptide amides, prevent the Ca2l-dependent fusion of primary rat myoblasts. They identified a MEPr activity in the cytosol of L6 myoblasts that is inhibited by the same compounds that block myoblast fusion (5). These inhibitors also prevent Ca2+-dependent fusion in vesicle secretory systems (6), suggesting that MEPrs may have a general role in catalyzing biological membrane fusion.Our laboratory has recently identified dramatic changes in major plasma membrane glycoproteins during myogenesis of L6 myoblasts. These changes were blocked by the MEPr inhibitors that block fusion (7). We now report that these sa...

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confidence: 71%

Metalloendoprotease inhibitors that block fusion also prevent biochemical differentiation in L6 myoblasts.

Baldwin¹,

Kayalar²

1986

Proc. Natl. Acad. Sci. U.S.A.

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“…In viral infections such as influenza virus (Anders et al 1990) or HIV (Lifson et al 1986, Matthews et al 1987 infection, the involvement of terminal highmannose type oligosaccharide has been reported. Cell-cell fusion reactions such as sperm-egg fusion (Primakoff et al 1987, Blobel et al 1990, myoblast fusion (Kaufman et al 1985, Rosenberg et al 1985, Menko & Boettiger 1987, Rosen et al 1992, monocyte fusion (Most et al 1990), or preosteoclast fusion (Kurachi et al 1993) are also protein mediated. From these observations (Kurachi et al 1994), we have already reported that mannose residues are expressed on the outer membranes of monocytes during osteoclast differentiation using pradimicin derivatives, which are antiviral and antifungal both in vitro and in vivo, and recognize and bind specific sugars such as mannose residues (Oki et al 1988(Oki et al , 1990.…”

Section: Discussionmentioning

confidence: 99%

“…Terminal high-mannose type oligosaccharide on the cell surface mediates cell-cell fusion reactions such as sperm-egg fusion (Primakoff et al 1987, Blobel et al 1990 and myoblast fusion (Kaufman et al 1985, Rosenberg et al 1985, Menko & Boettiger 1987, Rosen et al 1992. The involvement of terminal high-mannose type oligosaccharide has also been reported in the events of viral infections such as the influenza virus (Anders et al 1990) or human immunodeficiency virus (HIV) (Lifson et al 1986, Matthews et al 1987.…”

Section: Introductionmentioning

confidence: 99%

Expression and role of mannose receptor/terminal high-mannose type oligosaccharide on osteoclast precursors during osteoclast formation

Morishima

Morita

Tokushima³

et al. 2003

Journal of Endocrinology

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Osteoclasts are formed from hematopoietic precursors via cell-cell fusion. We have previously reported that mannose residues are expressed on the outer membranes of monocytes during osteoclast differentiation. In the present study, we have attempted to demonstrate the pattern of expression levels of terminal high-mannose type oligosaccharide and to show that the mannose receptor is expressed on osteoclast precursor cells. Osteoclasts were formed using three different systems, namely mouse bone marrow cell culture, co-culture of mouse spleen cells with stromal cells, and RAW264·7 cell cultures. During osteoclast differentiation, the expression of terminal highmannose type oligosaccharide gradually increased and then peaked at the stage of fusion in all three systems. Expression of the mannose receptor gradually increased during osteoclast differentiation in bone marrow cells and the co-culture system. In contrast, that in RAW264·7 cells had already been detected in the absence of the soluble receptor activator of NF-B ligand and did not change during osteoclast differentiation. To ascertain whether expression of high-mannose type oligosaccharide is involved in tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cell (MNC) formation, glycosidase inhibitors were used on RAW264·7 cell culture. Castanospermine, an inhibitor of glucosidase I, inhibited the TRAP-positive MNCs, and deoxymannojirimycin, an inhibitor of -mannosidase I, increased the TRAPpositive MNC formation. These results indicate that the binding of terminal high-mannose and mannose receptor is important for the process of cellular fusion in osteoclast formation.

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“…Compton and Konigsberg, however, found that arrest of myoblasts at Gl was not alone sufficient to activate their differentiative program (4). Changes of some proteins in the cell surface have been implicated in events before myoblast fusion (2, 3, 15,20,22). Moreover, there are reports of changes in the distributions of various antigens during fusion (9, ll, 21).…”

Section: Discussionmentioning

confidence: 99%

Differentiation of Quail Myoblasts Transformed with a Temperature Sensitive Mutant of Rous Sarcoma Virus. II. Relationship of Myoblast Fusion with Calcium and Temperature

Kim

Adachi

Saiuchi

et al. 1992

Cell Struct. Funct.

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ABSTRACT. The effects of calcium and temperature on fusion of quail embryonicmyoblasts were examined using cells transformed with a temperature-sensitive mutant of Rous sarcoma virus (ts-RSV). The transformed quail myoblasts (QM-RSV)fused to form myotubes at 41°C, the non-permissive temperature, but not at 35.5°C, the permissive temperature. On incubation at 41°C, a period of more than 10 hr was needed for the myoblasts to become fusion-competent, but calcium was not needed for development of fusion-competence.Once the cells had become competent, fusion proceeded even at 35.5°C. These results suggest that the src gene product expressed at 35.5°C may control the fusion of cells in the competent stage by inactivating a components) that is associated with fusion-competence. However, fusion of even myoblasts in the competent stage was blocked in calcium-deficient medium, suggesting that calcium is essential for the fusion, probably at a step immediately before membrane union. Unlike fusion, other biochemical processes of differentiation proceeded even in calcium-deficient medium, indicating a distinction of fusion from these other processes during myoblast differentiation.

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Correlation between fusion and the developmental regulation of membrane glycoproteins in L6 myoblasts.

Cited by 10 publications

References 18 publications

Metalloendoprotease inhibitors that block fusion also prevent biochemical differentiation in L6 myoblasts.

Metalloendoprotease inhibitors that block fusion also prevent biochemical differentiation in L6 myoblasts.

Expression and role of mannose receptor/terminal high-mannose type oligosaccharide on osteoclast precursors during osteoclast formation

Differentiation of Quail Myoblasts Transformed with a Temperature Sensitive Mutant of Rous Sarcoma Virus. II. Relationship of Myoblast Fusion with Calcium and Temperature

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