Extensive disulfide bonding at the mammalian cell surface.

Abstract

Cell surface proteins of cultured cells [normal hamster NIL8 cells, hamster sarcoma virus transformed NIL8-HSV cells] were disulfide bonded to a greater degree than were total cellular proteins. In particular, the large external transformation-sensitive (LETS) protein, a major surface protein, was present almost exclusively in disulfide-bonded complexes including homodimers and also higher aggregates held together by disulfide bonds or noncovalent interactions. Other cell surface proteins appear to be involved in disulfide bonding, both intramolecular and intermolecular. In virally transformed cells, LETS protein and its disulfide complexes were absent and certain other disulfide-bonded proteins were also not observed.