IDENTIFICATION OF A CELL-SURFACE COMPONENT OF SWISS 3T3 CELLS ASSOCIATED WITH AN INHIBITION OF CELL-DIVISION

Polyclonal IgG, prepared to a purified bovine cell surface sialoglycopeptide (SGP) inhibitor of cell division, was used to identify an antigenically related molecule on the surface of Swiss 3T3 cells. SDS-PAGE and Western analyses showed that the anti-SGP antibody was monospecific and primarily recognized a 66-kDa protein of 3T3 cell membranes. Treatment of intact 3T3 cells or 3T3 cell membranes with either broad and phosphatidylinositol-specific phospholipase C enzymes suggested that the antigenic material most likely existed as an integral membrane molecule, or associated as a multimeric complex, and was not anchored at the cell surface by a phospholipid. The addition of anti-SGP IgG to 3T3 cell monolayer cultures was shown to promote cell division, suggesting a regulatory function for the membrane-associated molecule. © 1991.