Involvement of cell surface phosphatidylinositol-anchored glycoproteins in cell-cell adhesion of chick embryo myoblasts.
During myogenesis myoblasts fuse to form multinucleate cells that express muscle-specific proteins. A specific cell-cell adhesion process precedes lipid bilayer union during myoblast fusion (Knudsen, K. A., and A. F. Horwitz. 1977. Dev. Biol. 58:328-338) and is mediated by cell surface glycoproteins (Knudsen, K. A., 1985. J. Cell Biol. 101:891-897). In this paper we show that myoblast adhesion and myotube formation are inhibited by treating fusion-competent myoblasts with phosphatidylinositol-specific phospholipase C (PI-PLC). The effect of PI-PLC on myoblast adhesion is dose dependent and inhibited by D-myo-inositol 1-monophosphate and the effect on myotube formation is reversible, suggesting a specific, nontoxic effect on myogenesis by the enzyme. A soluble form of adhesion-related glycoproteins is released from fusion-competent myoblasts by treatment with PI-PLC as evidenced by (a) the ability of phospholipase C (PLC)-released material to block the adhesion-perturbing activity of a polyclonal antiserum to intact myoblasts; and (b) the ability of PLC-released glycoprotein to stimulate adhesion-perturbing antisera when injected into mice. PI-PLC treatment of fusion-competent myoblasts releases an isoform of N-CAM into the supernate, suggesting that N-CAM may participate in mediating myoblast interaction during myogenesis.
Knudsen
K A
KA
Lankenau Medical Research Center, Philadelphia, Pennsylvania 19151.
Smith
L
L
McElwee
S
S
D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002449:Cell Aggregation / Q000187:drug effects; D002459:Cell Fusion; D002642:Chick Embryo; D004591:Electrophoresis, Polyacrylamide Gel; D007106:Immune Sera; D015151:Immunoblotting; D008562:Membrane Glycoproteins / Q000302:isolation & purification / Q000502:physiology*; D008563:Membrane Lipids / Q000502:physiology*; D009132:Muscles / Q000166:cytology / Q000502:physiology*; D010716:Phosphatidylinositols / Q000502:physiology*; D010738:Type C Phospholipases / Q000494:pharmacology
D007106:Immune Sera; D008562:Membrane Glycoproteins; D008563:Membrane Lipids; D010716:Phosphatidylinositols; D010738:Type C Phospholipases